Dissertations / Theses: 'Vegetation indece'

1

Roderick, Michael L. "Satellite derived vegetation indices for monitoring seasonal vegetation conditions in Western Australia." Thesis, Curtin University, 1994. http://hdl.handle.net/20.500.11937/518.

Full text

Abstract:

The monitoring of continental and global scale net primary production remains a major focus of satellite-based remote sensing. Potential benefits which follow are diverse and include contributions to, and improved scientific understanding of, ecological systems, rangeland management, famine warning, agricultural commodity trading, and the study of global climate change.A NOAA-AVHRR data set containing monthly observations of green vegetation cover over a ten year period was acquired and analysed, to extract information on seasonal conditions. The data were supplied as a vegetation index, commonly known as the Normalised Difference Vegetation Index (NDVI), with a spatial resolution of approximately five km. The data set was acquired from three different satellites, and calibration problems were known to exist. A new technique was developed to estimate, and subsequently remove, the calibration bias present in the data.Monthly rainfall measurements were used as surrogate ground truth to validate the NDVI data. For regions of native vegetation, linear models relating NDVI to previous rainfall were derived, using transfer function techniques in common use in systems engineering. The models demonstrate that, in mid-latitude regions, the NDVI is a linear function of rainfall recorded over the preceding seven or eight months.Annual summaries of the image data were developed to highlight the amount and timing of plant growth. Three fundamental questions were posed as an aid to the development of the summary technique: where, when and how much? These summaries highlight the extraordinary spatial and temporal variations in plant growth, and hence rainfall, over much of Western Australia each year.Standard analysis techniques used in time series analysis, such as classical decomposition, were successfully applied to the analysis of NDVI time series. These techniques highlighted structural differences in the image data, due to land use, climatic factors and vegetation type.Overall, the results of the research undertaken in this study, using NOAA-AVHRR data in Western Australia, demonstrate that vegetation indices acquired from satellite platforms can be used to monitor continental scale seasonal conditions in an effective manner. As a consequence of these results, further research using this type of data is proposed in rangeland management and climate change modelling.

APA, Harvard, Vancouver, ISO, and other styles

2

Magalhães, Leonardo Pinto de. "Análise de imagens no desenvolvimento e status de fósforo do minitomateiro grape cultivado em sistema semi-hidropônico." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-13032019-152808/.

Full text

Abstract:

A análise de imagens é uma das formas de avaliar o desenvolvimento das plantas, tanto para correlacionar aspectos biofísicos dos mesmos, como para a detecção de doenças. Através das imagens podem ser calculados índices vegetativos que se correlacionem com os teores de nutrientes nas folhas. Com essa perspectiva, o presente trabalho objetivou avaliar quais indices vegetativos melhor se correlacionariam com a taxa de fósforo nas folhas de tomateiros. Foi realizado o cultivo de uma cultivar de minitomate, com cinco doses de fósforo (0, 25, 50, 75 e 100%) do P recomendado (na formulação da solução nutritiva). Em diferentes etapas do desenvolvimento da planta foram coletadas amostras das folhas para obtenção das imagens, através de escâner e máquina fotográfica, e diagnose foliar. Foram determinadas as biorrespostas das plantas ao longo do tempo. Uma rede neural artificial foi desenvolvida para estimar os teores de fósforo foliares no minitomate grape. A análise do desenvolvimento da planta permitiu concluir que a dose 100% de P2O5 utilizada no experimento foi suficiente para suprir a demanda nutricional do minitomateiro. Aos 64 dias após o transplantio (DAT) foi observada a maior queda nos teores de fósforo nas folhas, coincidindo com o amadurecimento dos frutos. Propõe-se, para a cultivar estudada, que a dignose foliar seja feita aos 50 DAT. Os índices vegetativos obtidos pela análise de imagem e selecionados pela análise de componentes principais (ICVE e Bn, tanto da parte abaxial quanto adaxial) podem ser utilizados para estimar a diagnose foliar de P na cultivar de minitomate grape. A avaliação dos índices vegetativos indicou que a obtenção de imagens com o escâner é mais adequado do que com a câmera fotográfica. Para a cultivar estudada, verificou-se que na dosagem de 100% de P2O5 teor de P nas folhas fica abaixo de 4,0 g kg-1. Em relação à rede neural desenvolvida, ao categorizar os valores de P de acordo com a literatura, a mesma obteve uma taxa de acerto de 90%.
The analysis of images is one of the ways to evaluate the development of plants, both to correlate biophysical aspects of the same, as for the detection of diseases. Through the images can be calculated vegetative indexes that correlate with the contents of nutrients in the leaves. With this perspective, the present studied aimed to evaluate which vegetative indexes would best correlate with the phosphorus rate in tomato leaves. A minitomato grape cultivar with five phosphorus doses (0, 25, 50, 75 and 100%) of the recommended P (in the formulation of the nutrient solution) was carried out. At different stages of plant development, leaf samples were collected to obtain the images, with scanner and camera, and foliar diagnosis. The bio-responses of plants were determined over time. An artificial neural network was developed to estimate leaf phosphorus levels in the grape minitomate. The analysis of the development of the plant allowed to conclude that the dose 100% of P2O5 used in the experiment was enough to supply the nutritional demand of the minitomateiro. At 64 days after transplanting (DAT), the highest drop in phosphorus content in the leaves was observed, coinciding with the ripening of the fruits. It is proposed, for the studied cultivar, that the leaf dignity should be made at 50 DAT. The vegetative indexes obtained by the image analysis and selected by the principal components analysis (ICVE and Bn, both abaxial and adaxial) can be used to estimate the leaf diagnosis of P in the minitomate grape cultivar. The evaluation of vegetative indexes indicated that obtaining images with the scanner is more appropriate than with the photographic camera. For the cultivar studied, it was verified that in the dosage of 100% of P2O5 content of P in the leaves is below 4.0 g kg-1. In relation to the developed neural network, when categorizing the P values according to the literature, it obtained a 90% correctness rate.

APA, Harvard, Vancouver, ISO, and other styles

3

Roderick, Michael L. "Satellite derived vegetation indices for monitoring seasonal vegetation conditions in Western Australia." Curtin University of Technology, School of Surveying and Land Information, 1994. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14815.

Full text

Abstract:

The monitoring of continental and global scale net primary production remains a major focus of satellite-based remote sensing. Potential benefits which follow are diverse and include contributions to, and improved scientific understanding of, ecological systems, rangeland management, famine warning, agricultural commodity trading, and the study of global climate change.A NOAA-AVHRR data set containing monthly observations of green vegetation cover over a ten year period was acquired and analysed, to extract information on seasonal conditions. The data were supplied as a vegetation index, commonly known as the Normalised Difference Vegetation Index (NDVI), with a spatial resolution of approximately five km. The data set was acquired from three different satellites, and calibration problems were known to exist. A new technique was developed to estimate, and subsequently remove, the calibration bias present in the data.Monthly rainfall measurements were used as surrogate ground truth to validate the NDVI data. For regions of native vegetation, linear models relating NDVI to previous rainfall were derived, using transfer function techniques in common use in systems engineering. The models demonstrate that, in mid-latitude regions, the NDVI is a linear function of rainfall recorded over the preceding seven or eight months.Annual summaries of the image data were developed to highlight the amount and timing of plant growth. Three fundamental questions were posed as an aid to the development of the summary technique: where, when and how much? These summaries highlight the extraordinary spatial and temporal variations in plant growth, and hence rainfall, over much of Western Australia each year.Standard analysis techniques used in time series analysis, such as classical decomposition, were successfully applied to the analysis of NDVI time series. These techniques highlighted ++
structural differences in the image data, due to land use, climatic factors and vegetation type.Overall, the results of the research undertaken in this study, using NOAA-AVHRR data in Western Australia, demonstrate that vegetation indices acquired from satellite platforms can be used to monitor continental scale seasonal conditions in an effective manner. As a consequence of these results, further research using this type of data is proposed in rangeland management and climate change modelling.

APA, Harvard, Vancouver, ISO, and other styles

4

González, Garcia Isabel. "Influência do clima nas variações estacionais e interanuais do indice de vegetação de diferença normalizada (NDVI) no montado português." Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5467.

Full text

Abstract:

Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia
Nowadays the climate change makes more necessary the study of ecosystem dynamics. The Portuguese montado is an ecosystem with very particular characteristics, because is a combined system with pastures and forest, managed by men, and depends on this manage to continue. More than economic value, montado is very important system with a big biodiversity and landscape quality. For this study was propose to study about the seasonal variation of montado, since 2000 to 2012, using remote sensing and vegetation index as tools to analyze the response of montado to different environmental factors, as the precipitation, temperature and relative humidity. The chosen vegetation index was the NDVI (Normalized Difference Vegetation Index), because of all the advantages, and was calculated using MODIS sensor data. To find the relation between our vegetation index vegetation data, and the meteorological variables, was make a time series analysis, and a correlation study of each variable with the vegetation index. The results was satisfactory and was agree with the initial hypotheses. We find that the precipitation is the variable that influences NDVI the most, and this correlation is bigger when we use the accumulative inter-annual and seasonal data instead the original data. The results show the effects of the big drought of 2004 and 2005 too. The remote sensing appears as a very important and critical tool for this study area future and show that this study could be extend with new directions and new research hypotheses

APA, Harvard, Vancouver, ISO, and other styles

5

Jorge, Catarina Tonelo. "Phenology analysis in a cork oak woodland through digital photography and spectral vegetation indexes." Master's thesis, ISA, 2019. http://hdl.handle.net/10400.5/19543.

Full text

Abstract:

Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia
Digital repeat photography is a method to monitor the phenology of vegetation that has gained momentum this past decade. As a result, the need for further case-studies is required. This work aims to prove that it is possible to use digital cameras instead of spectral information to track phenology in a Mediterranean cork oak woodland. The photos will originate the green chromatic coordinates (GCC) index while the normalized difference vegetation index (NDVI) derives from the spectral data collected with a field spectroradiometer. The results were found by employing a regular commercial camera to take monthly pictures along with the spectral measurements. They showed good agreement among methods especially for the herbaceous layer whose GCC had a very good fit with NDVI. The coefficient of determination for the herbaceous layer, the shrub cistus and shrub ulex was 0.89, 0.62 and 0.30, respectively. However, these regressions may be improved upon by grouping the shrub species. The shrubs had a lower correlation between the two indices and all three groups showed a response to water availability. For these reasons, a linear regression between GCC and the normalized water difference index (NDWI) was pursued. This second regression showed better results for shrubs, with coefficients of determination of 0.78 e 0.55, respectively, and a similar value for the herbaceous layer (0.84). The herbaceous layer was found to react quickly to water. Because it only has access to superficial water, its phenology is dependent on precipitation. This group had a good outcome with more long-term observations than shrubs (eight years of data vs. three years). So, it would be the most suitable plant functional type to be tracked using the digital repeat photography method coupled with GCC. Nonetheless, using photos and GCC proves to have the potential to monitor a wide spectrum of vegetation types
N/A

APA, Harvard, Vancouver, ISO, and other styles

6

JULITTA, TOMMASO. "Optical proximal sensing for vegetation monitoring." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/70505.

Full text

Abstract:

Monitoring vegetation dynamics represents a fundamental practice to evaluate the response of the vegetation to environmental changes. Optical proximal sensed data allow the monitoring of the temporal and spatial variability of vegetation properties under natural conditions. Vegetation optical properties can be used to indirectly derive information about the phenological and/or physiological status of the plants. Optical sensors commonly used in the field can be divided into broadband sensors (usually multispectral, e.g. RGB cameras) and narrowband sensors (both multispectral and hyperspectral devices, e.g. spectroradiometers). The potential applications of these two categories of sensors differ. While broadband sensors have been applied in the last years to track the phenological development of the vegetation, spectroradiometers have been shown to be suitable also for the characterization of plant physiological status. In fact hyperspectral systems provide a more detailed optical characterization of the analysed targets, nevertheless the systems have to be accurately characterized in terms of spectral and radiometric performances in order to obtain repeatable and comparable. The first part of the research has been addressed to the determination of the sources of uncertainty of the optical measurement systems. Several of the most common optical devices available on the market have been characterized and compared. A particular attention has been paid to instrumental differences in the optical components which could affect the radiance measurements. Moreover the performances of spectroradiometers have been evaluated both indoors and outdoors in order to evaluate the impact of sensor characteristics on the estimation of parameters commonly used in vegetation studies. The analysis has been initially focused on the effect of different cosine receptors on the estimation of biochemical and biophysical properties of the vegetation, such as leaf area index and chlorophyll content. In a second step the analysis referred to the impact of instrumental characteristics (mainly spectral resolution and signal to noise ratio) on the estimation of the absolute value of sun-induced chlorophyll fluorescence. The results obtained suggest that instrument components affect the measurements and according to the required parameter estimations accuracy some instruments are more suitable rather than others. The second part of the study has been focused on the use of proximal sensors to monitor the dynamics of terrestrial vegetation. For this purpose both broadband and narrowband sensors have been separately considered. The first analysis referred to the possibility of using broadband imaging systems to investigate the temporal and spatial phenological dynamics of an alpine ecosystem. The phenological analysis has been conducted using a 3-year time series of digital RGB images collected in a grassland site. This spatiotemporal analysis provided interesting insights into the role of plant species composition on phenology in complex ecosystems, such as alpine grasslands. This study case indicates the potential of using RGB digital cameras as a tool for long term phenological monitoring, allowing the spatial characterization of the investigated ecosystem. The possibility of using hyperspectral narrowband sensors to detect vegetation physiological changes was also evaluated. In particular, this analysis focused on the use of sun-induced chlorophyll fluorescence for the early detection of vegetation stress. The study was conducted during a controlled experiment designed to modify the functional status of actual photosynthesis. The results indicate that fluorescence is immediately affected by physiological changes as a demonstration that such estimates can be used to track physiological traits better than traditional remote sensing techniques based on optical broadband vegetation indices.

APA, Harvard, Vancouver, ISO, and other styles

7

Eklund, Carl. "Ståndortsfaktorer och vegetation : En problematiserande litteraturstudie." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-144161.

Full text

Abstract:

Ståndort är ett område där ett bestånd av en viss växt finns, ofta avses träd inom skogsproduktion. Förutsättningarna för detta, ståndortsfaktorer, återfinns i markens egenskaper (edafiska faktorer) och klimatet. Dessa påverkar därigenom växtens produktion, något som särskilt är av intresse inom skogsbruket och de skogliga vetenskaperna. Till detta kommer att växter samspelar med andra växter och organismer såsom svampar, bakterier och djur, och även den antropogena påverkan med faktorer såsom husdjursbete, atmosfäriskt nedfall och skogsproduktion har en stark inverkan på vegetationen. Utifrån att studera några av de mer kända teorierna om växtsamhällen och -strategier samt olika vinklar av ståndortsfaktorer var hypotesen att det går att få fram en problematiserande bild och hitta störfaktorer (confoundingvariabler), som kan ge felaktiga tolkningar av resultat. Ett antal kända verk inom vegetationsklassificering gicks igenom, kompletterat med stödjande litteratur. En artikelsökning genomfördes också, med kombinationer av specifika sökord med anknytning till ståndort. För att begränsa urvalet och ge en mer regional prägel på arbetet ställdes sökfiltren i artikelsökningen in på att enbart visa resultat från Skandinavien och Finland. Artiklarna delades in efter teman och behandlades efter dessa. Även om få huvudsakliga faktorer styr vegetationen finns flera variabler som lokalt har en stor betydelse, såsom snö, genetiska egenskaper och symbios med andra organismer. Dessa variabler kan vara svåra att mäta och det finns mycket på detaljnivå som är dåligt undersökt. Markanvändningar påverkar de edafiska faktorerna långt efter att brukandet ändrats eller upphört, men detta har olika stor lokal påverkan. Kvävets och kolets halter och cykler är återkommande osäkerhetsfaktorer i artiklarna, där det atmosfäriska kvävenedfallet spelar en viktig men ojämn roll, och jämförbara mätningar försvåras av skillnader i väder och klimat. Till detta kommer påverkan av markorganismer, vilka har en mycket viktig del i växternas näringsupptag, men är svår att mäta. Även om alla aspekter av en växtplats inte kan tas med bör fler felkällor tas i beaktande och modeller ha möjlighet att kalibreras mot olika teorier om växtsamhällen och -strategier. Flera faktorer som traditionellt inte räknas som ståndortsfaktorer, såsom snödjup, symbios med markorganismer och markanvändning, kan vara betydelsefulla att ta med i exempelvis modellering.
A site is an area where a population of a specific plant species has its habitat, often the connotation is forestry. The prerequisites for this, the site indices (also site variables or stand variables), can be found in the characteristics of the ground (edaphic factors) as well as the climatic impact. These elements affect the growth and production, which is of interest in forestry and forest sciences. Upon this the plants interact with each other as well as with other organisms, i.e. fungi, bacteria and animals, and there is also an anthropogenic impact where factors such as livestock grazing, atmospheric deposition and forest production strongly affects the vegetation. By studying some of the more prominent theories on vegetation societies/sociologies and plant strategies, as well as different aspects of the site concept, the hypothesis was that a problematizing picture of site indices can be found and some confounding variables that can give erroneous interpretation of results. A number of major works in vegetation classification was gone through, supplemented by supporting literature. An article search was conducted to find journal articles, using combinations of specific search terms related to site indices. To narrow down the results and give a more regional touch to the thesis, the filter was set only to show results from Scandinavia and Finland. The articles were grouped into themes and handled theme-wise. Even though there are few principal factors controlling the vegetation there are a number of variables which locally can have a large impact, such as snow, genetic traits and symbiosis. These variables can be hard to measure, and a lot of things at a detailed level are poorly investigated. Land use modifies the edaphic properties long after the usage have changed or been discontinued. The amounts and cycles of nitrogen and carbon are recurrent uncertainties in the articles, where deposits of nitrogen from the atmosphere plays an important but uneven role and measurements can be hard to compare due to differences in weather and climate. Added to this, organisms in the ground have a major role in the plants’ nutrient uptake, but the effects can be hard to study. A concluding remark is that even though all aspects of a site cannot always be included more confounding variables could be taken in account and models should be able to be calibrated to different theories on vegetation societies/sociologies and plant strategies. Many factors normally not counted as site indices, i.e. snow depth, soil biota symbiosis, and land use, could be valuable to include in e.g. modelling.

APA, Harvard, Vancouver, ISO, and other styles

8

Hammer, Rachel Lynn. "Soil Respiration and Related Abiotic and Remotely Sensed Variables in Different Overstories and Understories in a High Elevation Southern Appalachian Forest." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/93272.

Full text

Abstract:

Forests have the ability to sequester carbon from our atmosphere. Soil respiration (Rs) plays a role in a forest's ability to do so as it is a significant source of carbon dioxide back to the atmosphere. Therefore, understanding the process of Rs under varying conditions is gaining more attention. As of now we have a relatively good understanding of Rs under managed forest ecosystems such as pine plantations. This particular study examined Rs under different overstories and understories in a high elevation Southern Appalachian forest in order to get a better understanding of Rs under a natural hardwood system. The four vegetation types under consideration were an eastern hemlock (Tsuga canadensis L. Carriere) dominated overstory, a hardwood overstory with little to no understory, a mountain laurel (Kalmia latifolia L.) dominated understory, and a cinnamon fern (Osmundastrum cinnamomeum (L.) C.Presl) dominated understory. Differing temporal variations of Rs were observed under the vegetation types. We found monthly differences in rates among vegetation type however, an overall annual difference in Rs rates between vegetation types was not observed. This simply indicates the importance of observing Rs under different time scales to get a better understanding of its variation. We also calculated vegetation indices from remotely-sensed data to explore any relationships to Rs as well as if the indices themselves could improve out model. A vegetation index is a number that is calculated for every pixel in a remotely sensed image and represents plant vigor or abundance. Few significant relationships were found between the indices and Rs. Future work may want to better understand vegetation indices' spatial extent and accuracy in order to find whether they may be beneficial in Rs estimation. Understanding the influence of varying vegetation type and soil temperature and moisture on Rs will ultimately improve our ability to predict what drives changes in carbon fluxes.
Master of Science
Forests have the ability to sequester carbon from our atmosphere. Soil respiration (Rs) plays a role in a forest’s ability to do so as it is a significant source of carbon dioxide back to the atmosphere. Therefore, understanding the process of Rs under varying conditions is gaining more attention. As of now we have a relatively good understanding of Rs under managed forest ecosystems such as pine plantations. This particular study examined Rs under different overstories and understories in a high elevation Southern Appalachian forest in order to get a better understanding of Rs under a natural hardwood system. The four vegetation types under consideration were an eastern hemlock (Tsuga canadensis L. Carriere) dominated overstory, a hardwood overstory with little to no understory, a mountain laurel (Kalmia latifolia L.) dominated understory, and a cinnamon fern (Osmundastrum cinnamomeum (L.) C.Presl) dominated understory. Differing temporal variations of Rs were observed under the vegetation types. We found monthly differences in rates among vegetation type however, an overall annual difference in Rs rates between vegetation types was not observed. This simply indicates the importance of observing Rs under different time scales to get a better understanding of its variation. We also calculated vegetation indices from remotely-sensed data to explore any relationships to Rs as well as if the indices themselves could improve out model. A vegetation index is a number that is calculated for every pixel in a remotely sensed image and represents plant vigor or abundance. Few significant relationships were found between the indices and Rs. Future work may want to better understand vegetation indices’ spatial extent and accuracy in order to find whether they may be beneficial in Rs estimation. Understanding the influence of varying vegetation type and soil temperature and moisture on Rs will ultimately improve our ability to predict what drives changes in carbon fluxes.

APA, Harvard, Vancouver, ISO, and other styles

9

Noumonvi, Koffi Dodji. "Estimation of carbon fluxes from eddy covariance data and satellite-derived vegetation indices in a karst grassland (Podgorski Kras, Slovenia)." Master's thesis, ISA/UL, 2018. http://hdl.handle.net/10400.5/17944.

Full text

Abstract:

Mestrado MEDfOR - Mediterranean Forestry and Natural Resources Management - Instituto Superior de Agronomia
The Eddy covariance method is a widespread method used for measuring carbon fluxes between the atmosphere and the ecosystem. It provides a high temporal resolution of measurements, but it is restricted to an area around the tower called footprint, and other methods are usually used in combination with eddy covariance data in order to estimate carbon fluxes for larger areas. Spectral vegetation indices derived from increasingly available satellite data can be combined with eddy covariance data to estimate carbon fluxes outside of the tower footprint. Following that approach, the present study attempted to model carbon fluxes for a karst grassland in Slovenia. Three types of model were considered: (1) a linear relationship between NEE or GPP and each vegetation index, (2) a linear relationship between GPP and the product of a vegetation index with PAR, and (3) a simplified LUE model assuming a constant LUE. We compared the performance of several vegetation indices from two sources (Landsat and SPOT-Vegetation) as predictors of NEE and GPP, based on three accuracy metrics (R², RMSE and AIC). Two types of aggregation of flux data were explored, midday average fluxes and daily average fluxes. The Vapor Pressure Deficit was used to separate the growing season in two phases, a greening phase and a dry phase, which were considered separately in the modelling process, in addition to the growing season as a whole. The results showed that NDVI was the best predictor of GPP and NEE during the greening phase, whereas water related vegetation indices, namely LSWI and MNDWI were the best predictors during the dry phase, both for midday and daily aggregates. Model type 1 (linear relationship) was found to be the best in many cases. The best regression equations obtained were used to illustrate the mapping of GPP and NEE for the study area
N/A

APA, Harvard, Vancouver, ISO, and other styles

10

Weiss, Marie. "DEVELOPPEMENT D'UN ALGORITHME DE SUIVI DE LA VEGETATION A LARGE ECHELLE." Phd thesis, Université de Nice Sophia-Antipolis, 1998. http://tel.archives-ouvertes.fr/tel-00707683.

Full text

Abstract:

L'objectif de ce travail est de développer un algorithme utilisant des réseaux neuronaux pour estimer des variables biophysiques des couverts végétaux à partir des données du capteur VEGETATION : la fraction de trou dans différentes directions de visée, l'indice foliaire, la fraction de rayonnement photosynthétiquement actif absorbé par le couvert, l'angle moyen d'inclinaison des feuilles, et la teneur en chlorophylle intégrée au niveau du couvert. Une base de données a été élaborée à partir de simulations de modèles de transfert radiatif dans la végétation. Ceci nous a permis de développer des réseaux de neurones pour estimer les différentes variables biophysiques considérées. L'estimation se fait à partir des réflectances bidirectionnelles mesurées par VEGETATION durant un cycle orbital, associées à l'angle zénithal solaire lors de l'acquisition de ces données. L'analyse de sensibilité à l'hétérogénéité intrapixellaire montre que les variables de type fraction de trou et fAPAR sont beaucoup moins sensibles que les variables de type LAI. La validation de l'algorithme sur des données expérimentales montre la robustesse de la méthode lorsque le nombre de données bidirectionnelles acquises durant le cycle orbital est faible. Par ailleurs, elle confirme que les performances d'estimation des variables biophysiques sont affectées non seulement par la représentativité du couvert et des conditions d'observation qui lui sont associées dans la base d'apprentissage, mais aussi par les hypothèses inhérentes aux modèles de transfert radiatif utilisés pour générer cette base. Nous mettons également en évidence la sensibilité de l'algorithme à des bruits de natures diverses (mesure, correction atmosphérique, ...). Les résultats obtenus sur les données expérimentales sont satisfaisants et aboutissent à un écart quadratique moyen inférieur à 0,1. L'intérêt des réseaux de neurones apparaît donc clairement, en particulier vis à vis des approches basées sur les indices de végétation.

APA, Harvard, Vancouver, ISO, and other styles

11

Penteado, Manuel Francisco Figueiredo Espírito Santo. "Utilização de imagens de alta resolução de detecção remota na gestão do montado de sobro." Master's thesis, ISA, 2014. http://hdl.handle.net/10400.5/7092.

Full text

Abstract:

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia
This work consists in a study of a useful technology applied in precision agriculture: remote sensing. Remote sensing in forest management has nowadays, an important role, enabling to prevent and fight forest fires, to study the plant sanitary state, to inventory, and, more importantly, to estimate forest production. Forest production is the topic of this study, applying this technology to cork forest management. In this thesis we collected data in the field, essential to the forest inventory. We analyzed the data and correlated with remote sensing data (through the calculation of several vegetation and geometric indices) captured by a ultra-high resolution camera attached to an airplane. The images constituted a efficient and cheap way to get information able to be compared with the field data through adjusted models, in order to explain the spatial variability of the productivity and quality of cork. Using the visible and infrared bands, it was possible to calculate the vegetation indices like NDVI, PCD and IPVI that were able to find strong relations with the field data. The adjusted models were able to explain 58% of the spatial variability of the cork productivity from the cork oak forest we studied and they even able to explain 50% of the spatial variability of cork's quality. With the results obtained of this study, in the future we will be able to predict and get accurate and reliable conclusions related to the productivity and quality of cork, just through the use of remote sensing

APA, Harvard, Vancouver, ISO, and other styles

12

Jesus, António Maria Grave Teixeira de. "Olivicultura de precisão. Avaliação da variabilidade espacial da produtividade e qualidade da azeitona e azeite num olival semi-intensivo." Master's thesis, ISA/UTL, 2013. http://hdl.handle.net/10400.5/5740.

Full text

Abstract:

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia
In the last twenty years precision agriculture has been increasingly adopted, with particular focus in some countries and crops. In this context, one of the tools that has aroused most interest has been remote sensing, and vegetation indices that are obtained from it. In oliviculture, aerial photography for remote sensing of plots is not yet a common practice, despite the possible interest for identifying different management zones, zones of higher or lower incidence of pests and diseases, or areas of better or worse olive quality and, finally, oil quality. In this study we tested the use of remote sensing tool to describe the spatial variability of several important variables from the viewpoint of grove management: yield, oil yield, oil quality, among others. The magnitude of the spatial variability of the variables was also assessed. To this end, a spatial sampling scheme of a semi-intensive olive grove was carried out in Elvas at each point were determined values of the variables to be described. Simultaneously, an aerial photograph was taken in visible and infrared, which allowed the calculation of various vegetation indices such as NDVI, the SAVI, and IPVI. Adjusted models were found to explain the spatial variability through indices obtained by using aerial photography, explaining between 26 and 51% of the variability, being the olive maturation index the variable best explained

APA, Harvard, Vancouver, ISO, and other styles

13

McCall, David S. "Expanding the Application of Spectral Reflectance Measurement in Turfgrass Systems." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/77971.

Full text

Abstract:

Light reflectance from plants can be used as a non-invasive predictor of health and yield for many cropping systems, and has been investigated to a lesser extent with managed turfgrass systems. The frequent agronomic inputs associated with maintaining golf course grasses allow for exceptional stand quality under harsh growing conditions, but often expend resources inefficiently, leading to either stand loss or unnecessary inputs in localized areas. Turfgrass researchers have adopted some basic principles of light reflectance formerly developed for cropping systems, but field radiometric-derived narrow-band algorithms for turfgrass-specific protocols are lacking. Research was conducted to expand the feasibility of using radiometry to detect various turfgrass stressors and improve speed and geographic specificity of turfgrass management. Methods were developed to detect applied turfgrass stress from herbicide five days before visible symptoms developed under normal field growing conditions. Soil volumetric water content was successfully estimated using a water band index of creeping bentgrass canopy reflectance. The spectral reflectance of turfgrass treated with conventional synthetic pigments was characterized and found to erroneously influence plant health interpretation of common vegetation indices because of near infrared interference by such pigments. Finally, reflectance data were used to estimate root zone temperatures and root depth of creeping bentgrass systems using a gradient of wind velocities created with turf fans. Collectively, these studies provide a fundamental understanding of several turfgrass-specific reflectance algorithms and support unique opportunities to detect stresses and more efficiently allocate resources to golf course turf.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

14

Santos, Tiago Rafael dos. "Caracterização fenológica da vegetação por análise harmônica em séries temporais EVI/MODIS no Parque Nacional das Araucárias." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/173721.

Full text

Abstract:

A floresta ombrófila mista, representada principalmente pela presença de Araucaria angustifolia possui elevada importância para a região sul do Brasil e o interesse econômico nessa espécie ocasionou uma forte exploração principalmente durante a primeira metade do século XX. O Parque Nacional das Araucárias possui a finalidade de preservar remanescentes de florestas com a presença de Araucaria angustifolia; sendo assim, a compreensão do comportamento da dinâmica fenológica das coberturas florestais é uma forma de auxiliar na gestão e manejo destas áreas. Dessa forma, foi executado a aplicação de uma metodologia baseada em análises harmônicas de séries temporais EVI/MODIS para realizar a caracterização e mapeamento fenológico das diferentes coberturas vegetais presentes no Parque Nacional das Araucárias, por meio desta metodologia foi possível identificar os valores médios de EVI durante toda a série temporal para as diferentes coberturas de uso e ocupação do solo, analisando a relação entre as variações fenológicas com dados de precipitação e temperatura máxima, representando essas variações de amplitude, fase e termo aditivo para a série completa e individualmente para cada ano. Baseado no algoritmo HANTS, aplicou-se a análise harmônica para uma série temporal de dez anos, compreendidas entre os anos de 2006 a 2015. A partir desse processamento foram analisadas as imagens de fase, amplitude e termo aditivo por meio de quatro conjunto de amostras previamente selecionadas, representando as quatro principais coberturas de vegetação presentes no parque. Com o intuito de auxiliar na interpretação visual dos dados, as imagens foram convertidas de RGB para HLS. Uma vez gerados todos os dados, foi possível caracterizar como ocorre a variação dos valores de índices de vegetação ao longo do ano, bem como o período do ano onde acontecem as maiores variações; além de ser possível indicar as áreas onde houve indicativos de mudanças significativas de uso do solo, mudanças ocasionadas por algum evento climático ou pelo próprio desenvolvimento da vegetação. Através dos dados extraídos com a análise harmônica e a identificação das diferentes fenologias gerou-se também uma classificação sobre a série temporal, com o objetivo de identificar as áreas que ainda apresentam remanescentes de Araucaria angustifolia de forma predominante. Por fim, concluiu-se que a aplicação de uma metodologia baseada em séries harmônicas possibilita uma maior compreensão das coberturas florestais presentes nesta unidade de conservação gerando informações úteis para a gestão e possível revisão do plano de manejo. Para alguma aplicação futura, espera-se utilizar esta metodologia em uma série temporal com maior resolução espacial.
The Mixed Coniferous-Broadleaf forest, mainly represented by the presence of Araucaria angustifolia, is highly important to the southern region of Brazil, the economic interest in this species led to a heavy exploration during the first half of the 20th century. The purpose of the Araucárias National Park is to preserve remnants of the forests with great presence of Araucaria angustifolia; therefore, the comprehension of the behavior of the phenological dynamic of the forest covers is a way of assisting the management and handling of these areas. Thereby, the goal is to apply a methodology based on harmonic analysis of EVI / MODIS time series to perform characterization and phenological mapping of the different vegetation covers present in Araucarias National Park; for that, it is intended to identify the medial values of EVI during the whole time series for different types of coverage of soil use and occupation, analyzing the relation between the phenological variations with precipitation data and maximum temperature, representing these variations of amplitude, phase and additive term for a complete series and individually for each year. Based on the HANTS algorithm, the harmonic analysis was applied to a time series of ten years, comprised between 2006 and 2015. Starting from this processing, images of the phase, amplitude and additive term were analyzed by means of four previously selected samples, representing the four main vegetation covers present in the park. In order to assist the visual interpretation of data, the images were converted from RGB to HLS. When all data was generated, it was possible to characterize how the variation in the value of vegetation indices happen throughout the year, as well as the time of the year when the biggest variations occur. Besides, it is possible to indicate the areas with significant changes in the use of soil, or changes caused by climatic events or by the vegetation own development. Through the data extracted with the harmonic analysis and the identification of the different phenologies, a classification was also generated on the time series, in order to identify the areas that still present remnants of Araucaria angustifolia predominantly.Ultimately, it is concluded that the application of a methodology based on the harmonic series enables a better comprehension of the forest covers present in this unity of conservation, generating useful information for the management and possible review of the management plan. For future application, the use of this methodology in a time series with greater spatial resolution is expected.

APA, Harvard, Vancouver, ISO, and other styles

15

Lucena, Cicero Cartaxo de. "Crescimento vegetativo, absorção de nutrientes e trocas gasosas em mangueiras submetidas a estresse salino." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/4507.

Full text

Abstract:

Made available in DSpace on 2015-03-26T13:39:32Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4575411 bytes, checksum: 554a48fc489b10966317de0d19bfc072 (MD5) Previous issue date: 2009-02-17
Conselho Nacional de Desenvolvimento Científico e Tecnológico
The present work dealt with the evaluation of the tolerance to salt stress by the characterization of the influence of salinity on vegetative growth, nutrient content and distribution, gas exchanges and photochemical efficiency of the photosytem II of four commercial cultivars of mango trees grafted on the root stock Imbú . The experiment was carried out in a randomized block factorial (4 x 4) design , with 4 salt concentrations (0; 15; 30; and 45 mmol L-1 NaCl) and 4 mango cultivars ('Haden', 'Palmer', 'Tommy Atkins', and 'Ubá', all of them grafted on the root stock Imbú ), with 5 replications and 1 plant per experimental unit. The shootings were about 18 months old and were transferred from plastic bags containing substrate (3:1 earth-sand) to vases containing 7dm³ of modified Hoagland's nutrient solution. After 30 days of acclimatization to the hydroponic system, the salt concentrations were added to the nutrient solution. The shootings were submitted to salt stress for 100 days. The solution was changed every time the electrical conductivity of the control treatment reduced 20% of the initial value. 15, 25, 45, 60, 75 and 95 days after the exposure to salt stress (DAEES), the stem length, stem diameter, plant height and leaf emission were evaluated, all of them grown after the exposure to salt stress, difference in temperature (room leaf) ºC, internal concentration of CO2 (Ci), stomatal conductance (gs), transpiratory rate (E), liquid photosynthesis (A), leaf water potential (MPa) and parameters of the chlorophyll fluorescence a (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv /Fm , PSII = [(Fm -Fs)/(Fm )], D = (1- Fv /Fm ) and ETR = ( PSII x FFF x 0,42). At the end of the experiment, at 100 DAEES, the plants were collected and and roots, stem and leaves were separated. The stem was subdivided into two parts: stem of the root stock and stem of the cultivar. Next, the average leaf area (cm2), total leaf area of the plant (cm2), toxicity index in the leaves (%) and the index of leaf abscission (%) were determined. The dry mass of the root, stem of the root stock stem of the cultivar, leaf and total were determined after drying in a greenhouse Then, the contents of N-total, P, K, Ca, Mg, Na and Cl were determined for the root, stem of the root stock, stem of the cultivar and leaves. The results achieved were submitted to the variance and regression analyses at the level of 5% of probability. The mango cultivars analyzed presented decreases in stem length and diameter, plant height, leaf emission, average leaf area and total leaf area of the plant. In all the cultivars, there was a decrease, in different degrees, in the gas exchanges, leaf water potential and photochemical efficiency of the photosystem II, which were intensified in the concentrations above 15 mmol L-1 NaCl. The cultivars presented decreases for the dry mass of roots, stem, leaf and total when submitted to concentrations above 15 mmol L- 1 NaCl. Increments were observed in the indexes of leaf toxicity and leaf abscission, although symptoms of leaf toxicity were not observed in 15 mmol L-1 NaCl. The nutrient absorption was reduced, and decreases were observed in the contents of essential elements, mainly in the roots and leaves. The highest contents of ions Na+ and Cl- were observed in the part of the stem next to the canopy of the plants and mainly in the leaves, as the NaCl concentrations increased. However, the distribution of ions Na+ and Cl- was more balanced in the plant organs (root, stem and leaf) when submitted to 15 mmol L-1 NaCl. The Tommy Atkins cultivar presented more tolerance to salt stress than the other cultivars evaluated.
Este trabalho teve como objetivo avaliar a tolerância ao estresse salino por meio da caracterização da influência da salinidade sobre o crescimento vegetativo, o teor e distribuição de nutrientes, as trocas gasosas e a eficiência fotoquímica do fotossistema II de quatro cultivares comerciais de mangueira enxertados sobre o portaenxerto Imbú . O experimento foi conduzido em arranjo fatorial (4 x 4) no delineamento em blocos ao acaso, sendo 4 concentrações de sal (0; 15; 30; e 45 mmol L-1 NaCl) e 4 cultivares de mangueira ('Haden', 'Palmer', 'Tommy Atkins', e 'Ubá', todos enxertados sobre o portaenxerto Imbú ) com 5 repetições e 1 planta por unidade experimental. As mudas estavam com aproximadamente 18 meses de idade e foram transferidas de sacolas plásticas contendo substrato (3:1 terra-areia) para vasos com 7dm³ de solução nutritiva de Hoagland modificada. Após 30 dias de aclimatação ao sistema hidropônico, as concentrações salinas foram adicionadas a solução nutritiva. As mudas foram submetidas a estresse salino por um período de 100 dias. A solução foi trocada sempre que a condutividade elétrica do tratamento controle reduzia 20% do valor inicial. Aos 15, 25, 45, 60, 75 e 95 dias após exposição ao estresse salino (DAEES), foram avaliadas comprimento do caule, diâmetro do caule, altura da planta e emissão foliar, todos crescidos após a exposição ao estresse salino, a diferença de temperatura (ambiente foliar) ºC, concentração interna de CO2 (Ci), condutância estomática (gs), taxa transpiratória (E), fotossíntese líquida (A), potencial hídrico foliar (MPa) e parâmetros da fluorescência da clorofila a (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv /Fm , PSII = [(Fm -Fs)/(Fm )], D = (1- Fv /Fm ) e ETR = (PSII x FFF x 0,42). Ao final do experimento, aos 100 DAEES, as plantas foram coletadas e separadas em raízes, caule e folhas. O caule foi subdividido em duas partes: caule do portaenxerto e caule do cultivar copa. Em seguida foram determinados a área média da folha (cm2), área foliar total da planta (cm2), o índice de toxidez nas folhas (%) e o índice de abscisão foliar (%). A massa seca de raiz, caule do portaenxerto, caule do cultivar copa, folha e total foram determinadas após secagem em estufa. Em seguida foram determinados os teores de N-total, P, K, Ca, Mg, Na e Cl na raiz, caule do portaenxerto, caule cultivar copa e folhas. Os resultados obtidos foram submetidos à análise de variância e de regressão ao nível de 5% de probabilidade. Os cultivares de mangueira analisados apresentaram decréscimos do comprimento e diâmetro do caule, da altura de planta, da emissão foliar, da área foliar média e área foliar total da planta. Em todos os cultivares, em grau diferenciados, ocorreu decréscimo nas trocas gasosas, no potencial hídrico foliar e na eficiência fotoquímica do fotossistema II, que se intensificaram nas concentrações maiores que 15 mmol L-1 NaCl. Os cultivares apresentaram decréscimos de massa seca de raízes, caule, folha e total quando submetidos a concentrações maiores que 15 mmol L-1 NaCl. Foram observados incrementos nos índices de toxidez foliar e abscisão foliar, embora não sendo observados sintomas visíveis de toxidez foliar em 15 mmol L-1 NaCl. A absorção de nutrientes foi reduzida, sendo observadas reduções nos teores de elementos essenciais, principalmente nas raízes e nas folhas. Os maiores teores dos íons Na+ e Cl-, ocorreram na parte do caule próximo a copa das plantas e principalmente nas folhas à medida que as concentrações de NaCl foram aumentadas. No entanto, a distribuição dos íons Na+ e Cl-, foram mais equitativa nos órgãos da planta (raiz, caule e folha) quando submetidas a 15 mmol L-1 NaCl. Dentre os cultivares avaliados, Tommy Atkins apresentou-se mais tolerante ao estresse salino.

APA, Harvard, Vancouver, ISO, and other styles

16

Carvalho, Suzana Maria Inácio de. "Influência da variabilidade climática na dinâmica da vegetação na região da Mata Atlântica Paulista." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154753.

Full text

Abstract:

Submitted by Suzana Maria Inácio De Carvalho (suzana-carvalho@live.com) on 2018-07-28T15:12:36Z No. of bitstreams: 1 Dissertacao_SMIC_2307_novo_repositorio.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5)
Approved for entry into archive by Lucimara Kurokawa Shinoda null (lucimaraks@sorocaba.unesp.br) on 2018-07-30T18:15:59Z (GMT) No. of bitstreams: 1 carvalho_smi_me_soro.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5)
Made available in DSpace on 2018-07-30T18:15:59Z (GMT). No. of bitstreams: 1 carvalho_smi_me_soro.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5) Previous issue date: 2018-06-04
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Alterações no clima causam impactos significativos sobre a estrutura e distribuição dos ecossistemas afetando a biodiversidade terrestre. O objetivo da pesquisa foi descrever os padrões da dinâmica da vegetação natural da Mata Atlântica Paulista na região da bacia hidrográfica do rio Paraíba do Sul (UGRHI 2) e identificar a relação que se estabelece entre a variabilidade climática e a vegetação. Dados de imagens de séries temporais de índices de vegetação como o EVI (Índice de Vegetação Melhorado), LSWI (Índice de umidade da vegetação) e LAI (Índice de Área Foliar) derivados de produtos de Sensoriamento Remoto (SR), foram adquiridos do sensor MODIS, pois são poderosas ferramentas indicadoras do desenvolvimento da vegetação. Dados de precipitação pluvial adquiridas por estações pluviométricas disponibilizadas pela ANA foram aplicados para cálculo dos índices climáticos como o SPI (Índice de Precipitação Padronizado) e RAI (Índice de Anomalia de chuva). Os índices conseguiram detectar a variação entre anos extremamente úmidos e anos extremamente secos. Destacaram-se os anos 2009 e 2014, sendo que o ano de 2009 representou um ano de anomalia positiva, com precipitação acima da média climatológica. Já em 2014, foi possível detectar uma condição de anomalia negativa, com condições mais severas com precipitação pluvial abaixo da média climatológica. Com a finalidade de avaliar como essa dinâmica climática influencia na dinâmica da vegetação, os índices EVI, LSWI e LAI foram analisados e mostraram que o comportamento da dinâmica da vegetação natural das regiões da Mata Atlântica Paulista acompanha a variabilidade do clima, já que foram observados padrões de maior produtividade no período da estação chuvosa, época em que a condição hídrica é mais intensa e favorece o verdejamento das folhas, o oposto foi observado quando há o déficit hídrico, que ocorre principalmente na estação seca onde nota-se o declínio dos valores dos índices, ou seja, indicando a queda foliar. Os índices capturaram o padrão esperado, vale destacar que o índice LSWI apresentou maior sensibilidade à condição hídrica, o que era esperado devido às bandas que compõe este índice, sendo possível verificar o potencial das imagens do sensor MODIS em capturar a resposta da floresta e consequentemente contribuir de forma significativa para estudos de mudanças climáticas.
Climate change causes significant impacts on the structure and distribution of ecosystems affecting terrestrial biodiversity. The objective of the research was to describe the patterns of the dynamics of the natural vegetation of the Atlantic forest in the region of the watershed of Rio Paraíba do Sul (UGRHI 2) and to identify the relationship that is established between climatic variability and vegetation. Image data from temporal series of vegetation indices as the improved Vegetation Index (EVI), Vegetation Humidity Index (LSWI) and foliar area index (LAI) derived from remote sensing products (SR), were acquired from the MODIS sensor, as they are Powerful tools indicating the development of vegetation. Rainfall precipitation data acquired by precipitation stations provided by the National Water Agency (ANA) were applied for calculating climatic indexes such as the Standardized Precipitation Index (SPI) and Rain Anomaly Index (RAI). The indexes were able to detect the variation between extremely humid years and extremely dry years. The years 2009 and 2014 were highlighted, and the year 2009 represented a year of positive anomaly, with precipitation above the average climatological. In 2014, it was possible to detect a negative anomaly condition, with harsher conditions with rainfall precipitation below the climatological average. For the purpose of evaluating how this climate dynamics influences the dynamics of vegetation, the indices EVI, LSWI and LAI were analyzed and showed that the behavior of the dynamics of the natural vegetation of the Regions of Atlantic Forest Paulista accompanies the Climate variability, since there were observed higher productivity patterns during the rainy season, when the water condition is more intense and favors the greenishing of the leaves, the opposite was observed when there is the water deficit, which occurs Mainly in the dry season where it is noted the decline of the values of the indices, that is, indicating the foliage fall. The indexes captured the expected pattern, it is worth noting that the LSWI index presented greater sensitivity to the water condition, which was expected due to the bands that make up this index, it is possible to verify the potential of the images of the MODIS sensor in capturing the Forest response and consequently contribute significantly to climate change studies.

APA, Harvard, Vancouver, ISO, and other styles

17

Moreira, Andreise. "Caracterização fenológica de tipologias campestres do Rio Grande do Sul a partir de produtos MODIS (NDVI, EVI e GPP)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179926.

Full text

Abstract:

Considerando que estudos sobre fenologia vegetal são importantes para a compreensão do funcionamento e verificação da ocorrência de padrões no ciclo vegetativo das plantas, resultando em melhorias nas atividades de conservação e manejo, o objetivo desta pesquisa foi caracterizar a dinâmica fenológica de diferentes tipologias campestres no estado do Rio Grande do Sul (RS), a partir da relação entre a variabilidade de elementos climáticos intra e interanual e eventos em larga escala e a distribuição espaço-temporal das tipologias predominantes. A área de estudo abrangeu 10 tipologias predominantes de campo no estado do RS. A base de dados orbitais utilizada foi obtida de diferentes produtos relacionados ao estudo da vegetação do sensor MODIS (Moderate Resolution Imaging Spectroradiometer), constando os índices de vegetação NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index) e GPP (Gross Primary Productivity). Também, foram utilizados dados meteorológicos provenientes da base TRMM (Tropical Rainfall Measuring Mission) e ERA Interim, para o período de fevereiro de 2000 a dezembro de 2014. O uso de séries temporais de dados NDVI e EVI/MODIS permitiram obter informações sobre a fenologia da vegetação campestre e a definição de padrões diretamente relacionados a variações meteorológicas. A sazonalidade da vegetação campestre apresenta cliclo anual bem marcado, com início e fim da estação de crescimento determinada pelas condições térmicas (temperatura do ar), porém alterado pela disponibilidade hídrica. A relação entre temperatura do ar e vigor vegetal apresentou maior correlação e tem influência direta sobre o início e fim da estação de crescimento (primavera e verão) A precipitação pluvial, no entanto, influencia as condições de crescimento/desenvolvimento das tipologias campestres, especialmente no verão, associado aos períodos de estiagem que tendem a ocorrer com maior frequência. Ambos os índices (EVI e NDVI) apresentam maior variabilidade durante a primavera e o verão, com diminuição da variabilidade durante o outono e inverno. A aplicação da Transformada de Ondaleta mostrou onde e quando ocorreram alterações no padrão fenológico da vegetação campestre e a Transformada Coerência apontou a intensidade (correlação) entre os índices de vegetação e a variabilidade das condições meteorológicas. O agrupamento das tipologias, com uso da técnica de Cluster, revelou seus comportamentos sazonais, sendo que a partir do índice EVI há a possibilidade de identificar diferenças entre as tipologias durante o outono e inverno, enquanto o NDVI apresentou diferença somente no inverno. As métricas fenológicas obtidas do Timesat para as imagens EVI permitiram obter dados importantes sobre o ciclo fenológico da vegetação campestre do RS, com a caracterização do padrão fenológico das tipologias predominantes. O uso de modelos para a estimativa da produtividade da vegetação campestre a partir do EVI revelou dentre as tipologias testadas que a CSR (campos de solos rasos) apresentou maior capacidade de explicar a variabilidade da produtividade dos campos por ser mais suscetível às variações meteorológicas. Os resultados obtidos permitiram confirmar a diversidade entre as tipologias campestres predominantes no RS, expressas por índices de vegetação, tanto no aspecto temporal como espacial. O uso dos índices de vegetação demonstrou potencial no monitoramento do padrão fenológico da vegetação campestre frente a variabilidade climática do RS.
Considering that studies on vegetal phenology are important to understand the mechanisms and pattern recognition on the vegetative cycle of plants, resulting in improvements in conservation and management activities, the aim of this research was to characterize the phenological dynamics of different grassland typologies in Rio Grande do Sul State (RS), based on the relationship between the variability of intra-annual and inter-annual climatic elements, large-scale events and the spatio-temporal distribution of predominant typologies . The study area included 10 predominant grassland typologies in RS state. The orbital database used was obtained from different products related to vegetation studies of MODIS sensor (Moderate Resolution Imaging Spectroradiometer), presenting the vegetation indices NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index) and GPP (Gross Primary Productivity). Also, meteorological data from TRMM base (Tropical Rainfall Measuring Mission) and ERA Interim were used for the period of February 2000 to December 2014. The use of time series data from NDVI and EVI/MODIS led to information on grassland vegetal phenology and the definition of patterns directly related to meteorological variations. The seasonality of grassland vegetation presents a well marked annual cycle, with the beginning and the end of growing season determined by thermal conditions (air temperature) but altered by water availability. The relationship between air temperature and vegetal vigor presented a strong correlation and influences directly on the beginning and on the end of the growth season (spring and summer). The rainfall, however, influences growth/development conditions of grassland typologies, especially in summer, associated to drought periods that tend to occur more frequently Both indices (EVI and NDVI) presented a greater variability during spring and summer, with a lesser variability during fall and winter. The application of Ondaleta Transform showed where and when alterations occurred in the phenological pattern of grassland vegetation and the Coherence Transform pointed the intensity (correlation) between vegetation indices and the variability of meteorological conditions. The grouping of typologies, using the Cluster technique, revealed their seasonal behaviors, and from the EVI index there is the possibility of identifying differences between typologies during fall and winter, whereas NDVI showed differences only in winter. The phenological metrics obtained from Timesat to EVI images allowed to obtain important data on the phenological cycle of grassland vegetation of RS state, with a characterization of the phenological pattern. The use of models for estimation of productivity of grassland vegetation based on EVI revealed among the typologies tested that the CSR (shallow soils grasslands) presented greater ability to explain the variability of grasslands productivity because it is more susceptible to meteorological variations. The obtained results allowed for the confirmation of diversity among the grassland typologies predominant in RS state, expressed by vegetation indices, both in temporal and spatial aspects. The use of vegetation indices demonstrated potential on the monitoring of phenological pattern of grassland vegetation considering the climatic variability of RS state.

APA, Harvard, Vancouver, ISO, and other styles

18

Lassalle, Guillaume. "Exploitation of hyperspectral data for assessing vegetation health under exposure to petroleum hydrocarbons." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0030.

Full text

Abstract:

L’exploration pétrolière et le monitoring de la contamination demeurent très limités dans les régions coloniséespar la végétation. La présence de suintements naturels et de fuites d’installations pétrolières est bien souventmasquée par le feuillage, rendant inopérantes les technologies actuelles de détection du pétrole brut et des produitspétroliers. L’exposition de la végétation à ces composés affecte toutefois son état de santé et, par conséquent, sespropriétés optiques dans le domaine [400:2500] nm. Cela suggère de pouvoir détecter les suintements et les fuitesd’installations de manière indirecte, en analysant l’état de santé de la végétation au travers de sa réflectancespectrale. Basée sur cette hypothèse, la présente thèse évalue le potentiel de l’imagerie hyperspectrale aéroportéeà très haute résolution spatiale pour détecter et quantifier la contamination pétrolière en région tempéréevégétalisée. Pour cela, une approche multi-échelles en trois étapes a été adoptée. La première étape a eu pourobjet de développer une méthode de détection et de caractérisation de la contamination en conditions contrôlées,exploitant les propriétés optiques de Rubus fruticosus L. La méthode proposée combine 14 indices de végétationen classification et permet de détecter divers contaminants pétroliers avec précision, depuis l’échelle de la feuillejusqu’à celle du couvert. Son utilisation en conditions naturelles a été validée sur un bourbier de productioncontaminé, colonisé par la même espèce. Au cours de la seconde étape, une méthode de quantification deshydrocarbures pétroliers totaux, basée sur l’inversion d’un modèle de transfert radiatif, a été développée. Cetteméthode exploite le contenu en pigments des feuilles, estimé à partir de leur signature spectrale, afin de prédireprécisément le taux de contamination en hydrocarbures du sol. La dernière étape de l’approche a démontré larobustesse des deux méthodes en imagerie aéroportée. Celles-ci se sont montrées très performantes pour détecteret quantifier la contamination des bourbiers. Une autre méthode de quantification, basée sur la régressionmultiple, a également été proposée. Au terme de cette thèse, les trois méthodes proposées ont été validées pourune utilisation sur le terrain, à l’échelle de la feuille et du couvert, ainsi qu’en imagerie hyperspectrale aéroportéeà très haute résolution spatiale. Leurs performances dépendent toutefois de l’espèce, de la saison et du niveau decontamination du sol. Une approche similaire a été conduite en conditions tropicales, permettant de mettre aupoint une méthode de quantification de la contamination adaptée à ce contexte. En vue d’une utilisationopérationnelle, un effort important reste nécessaire pour étendre le champ d’application des méthodes à d’autrescontextes et envisager leur application sur les futurs capteurs hyperspectraux embarqués sur satellite et sur drone.Enfin, l’apport de la télédétection active (radar et LiDAR) est à considérer dans les recherches futures, afin delever certaines limites propres à l’utilisation de la télédétection optique passive
Oil exploration and contamination monitoring remain limited in regions covered by vegetation. Natural seepages and oil leakages due to facility failures are often masked by the foliage, making ineffective the current technologies used for detecting crude oil and petroleum products. However, the exposure of vegetation to oil affects its health and, consequently, its optical properties in the [400:2500] nm domain. This suggest being able to detect seepages and leakages indirectly, by analyzing vegetation health through its spectral reflectance. Based on this assumption, this thesis evaluates the potential of airborne hyperspectral imagery with high spatial resolution for detecting and quantifying oil contamination in vegetated regions. To achieve this, a three-step multiscale approach was adopted. The first step aimed at developing a method for detecting and characterizing the contamination under controlled conditions, by exploiting the optical properties of Rubus fruticosus L. The proposed method combines 14 vegetation indices in classification and allows detecting various oil contaminants accurately, from leaf to canopy scale. Its use under natural conditions was validated on a contaminated mud pit colonized by the same species. During the second step, a method for quantifying total petroleum hydrocarbons, based on inverting the PROSPECT model, was developed. The method exploits the pigment content of leaves, estimated from their spectral signature, for predicting the level of hydrocarbon contamination in soils accurately. The last step of the approach demonstrated the robustness of the two methods using airborne imagery. They proved performing for detecting and quantifying mud pit contamination. Another method of quantification, based on multiple regression, was proposed. At the end of this thesis, the three methods proposed were validated for use both on the field, at leaf and canopy scales, and on airborne hyperspectral images with high spatial resolution. Their performances depend however on the species, the season and the level of soil contamination. A similar approach was conducted under tropical conditions, allowing the development of a method for quantifying the contamination adapted to this context. In a perspective of operational use, an important effort is still required for extending the scope of the methods to other contexts and for anticipating their use on satellite- and drone-embedded hyperspectral sensors. Finally, the contribution of active remote sensing (radar and LiDAR) should be considered in further research, in order to overcome some of the limits specific to passive optical remote sensing

APA, Harvard, Vancouver, ISO, and other styles

19

Rodrigues, Afonso Dias Ana Sofia. "The effect of vegetation on slope stability of shallow pyroclastic soil covers." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG002/document.

Full text

Abstract:

L'effet de la végétation locale, composée de Castanea sativa cultivé, sur la stabilité des pentes a été étudié sur un site d'essai au Mont Faito (Campanie, Italie). En Campanie, les sols pyroclastiques peu profonds sont sensibles aux glissements de terrain provoqués par les précipitations. Des périodes de pluies prolongées suivies de précipitations extrêmes à court terme déclenchent des glissements de terrain rapides et destructeurs au niveau des coupes routières et des escarpements pyroclastiques sur les falaises rocheuses dans les régions autour du volcan Vésuve.Des échantillons de sol pyroclastiques non perturbés contenant des racines de C. sativa matures ont été utilisés pour la caractérisation hydraulique par le biais d'un ensemble d'expériences en laboratoire. La perméabilité saturée, la réponse à l’évaporation et l’imbibition, la teneur en eau pour les fortes valeurs de succion et la biomasse sèche des racines ont été déterminées.La présence de racines a augmenté la perméabilité d'un ordre de grandeur dans les sols les plus superficiels (10-7 à 10-6 m s-1) et diminué la valeur d'entrée d'air des courbes de rétention (6 à 4 kPa). La variabilité de la perméabilité entre les couches de sol a été identifiée comme conditionnant l'écoulement de l'eau souterraine par rapport à la vitesse du mouvement du front de mouillage et à la génération de pressions positives de l'eau interstitielle dans le profil. L'étalonnage du modèle hystérétique pour caractériser les sols pyroclastiques naturels a fourni une méthode plus approximative de modélisation des réponses hydrauliques. Une bonne concordance entre le modèle et les observations a été obtenue.L’étude sur le terrain a permis de montrer que la distribution des racines de C. sativa est associée au régime des eaux souterraines. Les distributions spatiales et verticales de la densité et des traits des racines ont été quantifiées pour les racines de C. sativa prélevées dans des forages réalisés au Mont Faito. La succion minimale, la teneur minimale en eau et la pente minimale (indiquant un débit d'eau descendant) ont été surveillées tout au long de l'année et confrontées avec la distribution des racines et à la distribution spatiale des arbres. Une densité racinaire croissante était associée à des valeurs de succion plus faibles et à des gradients d'infiltration plus élevés, ce qui peut avoir une influence négative sur la stabilité de la pente.La modélisation du renforcement mécanique du sol par les racines des arbres a permis de comprendre l'importance des composantes hydrauliques et mécaniques sur la stabilité d'une pente. Les racines augmentent la résistance au cisaillement (jusqu'à 25,8 kPa) grâce à un renforcement mécanique et donc le facteur de sécurité de la pente augmente. L'examen du renforcement dû aux racines dans l'estimation du facteur de sécurité des surfaces de rupture potentielles a montré que la surface de rupture la plus faible a été trouvée à 2,2 m, où le renforcement dû aux racines était de 1,3 kPa, au lieu de 0,9 m sans le renforcement de 13,8 kPa. La surface de rupture la plus faible correspond aux surfaces de rupture observées lors de glissements de terrain antérieurs. Le site d'essai ne présentait pas les caractéristiques d'une zone de déclenchement d'un glissement de terrain. L'angle de pente des zones de déclenchement des glissements de terrain (35° à 45°) peut dépasser l'angle de frottement du sol (36,5° à 38,5°) et l'effet hydraulique ne serait pas suffisant pour garantir la stabilité de la pente pendant la saison humide (0 à 10 kPa). On estime que le renforcement dû aux racines peut maintenir les pentes jusqu'à un angle de 42°.On a donc constaté que la présence de racines d'arbres affectait la stabilité hydraulique et mécanique des couvertures de sol pyroclastiques. Ces conclusions peuvent être étendues aux autres zones de plantations de C. sativa. L'effet hydraulique de la végétation a été largement compensé par le renforcement mécanique dû aux racines
The effect of the local vegetation, composed of cultivated Castanea sativa, on slope stability was investigated on a test site in Mount Faito (Campania, Southern Italy). In Campania, shallow pyroclastic soil covers are susceptible to landslides triggered by rainfall. Prolonged rainfall periods followed by extreme short-term rainfall events trigger fast moving and highly destructive landslides in road cuts and pyroclastic scarps on rocky cliffs in the areas surrounding the Vesuvius volcano.Undisturbed pyroclastic soil samples containing roots of mature C. sativa were used for hydraulic characterization through an extensive set of laboratory experiments. Saturated permeability, evaporation and imbibition response, water content for high suction ranges, and the root dry biomass were determined.The presence of roots increased the hydraulic permeability by one order of magnitude in the most surficial soil (10-7 to 10-6 m s-1) and decreased the air-entry value of the water retention curves (6 to 4 kPa). The variability of soil permeability among soil layers was identified as conditioning of the groundwater flow with regard to the speed of the wetting front movement and generation of positive pore-water pressures within the soil profile. The calibration of hysteretic model to characterize natural pyroclastic soil provided a more approximate manner of modelling in situ hydraulic responses. A good agreement between the model and the field observations was obtained.Field monitoring was performed with the intent of showing that the distribution of roots of C. sativa is associated to the groundwater regime. The spatial and vertical distribution of root density and traits were quantified for C. sativa roots collected from several boreholes performed in Mount Faito. Minimum suction, minimum water content and minimum gradient (indicative of downward water flow), were monitored throughout the year and related to root distribution and spatial distribution of trees. An increasing root density was found to be associated to lower values of suction and higher gradients of infiltration, which can potentially have a negative influence of the slope stability.A modelling investigation on the mechanical reinforcement of soil by tree roots allowed us to understand the importance of hydraulic and mechanic components on the stability of a slope. Roots increase greatly the shear strength of soil (up to 25.8 kPa) through mechanical reinforcement and consequently, the safety factor of the slope increased significantly. Considering the root reinforcement in the estimation of potential failure surfaces safety factor showed that the weakest failure surface was found at 2.2 m, where the root reinforcement was 1.3 kPa, instead of 0.9 m without the root reinforcement of 13.8 kPa. The weakest failure surface found was in agreement with the failure surfaces observed from previous landslides. The test site did not present the characteristics of a landslide triggering area. The slope angle of the landslide triggering areas (35° to 45°) can easily exceed the soil friction angle (36.5° to 38.5°) and the hydraulic effect would not be enough to guarantee the stability of the slope during the wet season (0 to 10 kPa). However, the root reinforcement was estimated to be able to sustain the slopes until an angle of 42°.Therefore, the presence of tree roots was found to affect hydraulically and mechanically stability of pyroclastic soil covers. Such conclusions may be extended to the areas of Campania where C. sativa plantations are present. The hydraulic effect of vegetation was greatly compensated by the mechanical reinforcement of roots

APA, Harvard, Vancouver, ISO, and other styles

20

Ilangakoon, Nayani Thanuja. "Relationship between leaf area index (LAI) estimated by terrestrial LiDAR and remotely sensed vegetation indices as a proxy to forest carbon sequestration." Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1402857524.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Nambuthiri, Susmitha Surendran. "Soil water and crop growth processes in a farmer's field." Lexington, Ky. : [University of Kentucky Libraries], 2010. http://hdl.handle.net/10225/1140.

Full text

Abstract:

Thesis (Ph. D.)--University of Kentucky, 2010.
Title from document title page (viewed on May 12, 2010). Document formatted into pages; contains: xii, 310 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 298-309).

APA, Harvard, Vancouver, ISO, and other styles

22

Monteiro, Priscylla Ferraz Camara. "Efeitos das lâminas de irrigação e da adubação nitrogenada no comportamento espectral da cultura do feijão." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-25022010-094500/.

Full text

Abstract:

Este trabalho teve como objetivo principal analisar, em condições de campo, o efeito de lâminas de irrigação e de doses de nitrogênio sobre o comportamento espectral da cultura do feijão, a partir de medidas de reflectância hiperespectral, na faixa de 350 a 1150 nm, e da correlação entre os parâmetros biofísicos e as variáveis agronômicas da cultura, nessas condições. O experimento foi conduzido na área experimental de Agricultura Irrigada da Fazenda Areão, sob a responsabilidade do Departamento de Engenharia Rural da Escola Superior de Agricultura Luiz de Queiroz DER/ESALQ/USP, localizada no município de Piracicaba, SP, de setembro a dezembro de 2007. O delineamento experimental foi em blocos casualizados com parcelas subdivididas, alocando-se, nas parcelas, os tratamentos relacionados aos níveis de irrigação ((179,5; 256,5; 357,5 e 406,2 mm) e nas subparcelas os tratamentos relativos às doses de nitrogênio (0; 80 e 160 kg ha-1), totalizando doze tratamentos em cada bloco. Como os tratamentos foram dispostos em quatro blocos (repetições), o total de parcelas experimentais foi de 48. As medidas radiométricas de campo foram adquiridas por meio do espectrorradiômetro SPECTRON SE-590, em sete datas, durante o ciclo da cultura. Foram coletados, ainda, a altura das plantas, o índice de área foliar, a produtividade de grãos, o número de grãos por vagem e o número de vagens por planta. Os índices espectrais calculados foram o NDVI e o NB_NDVI. Foi aplicada a remoção do contínuo nos espectros de reflectância para analisar a profundidade da banda e a área da banda de absorção, centrada em 665 nm. O fator água influenciou as variáveis biofísicas (IAF, altura da planta, produtividade, número de vagens por planta e número de grãos por vagem), sendo maiores os valores encontrados nas plantas que receberam maiores quantidades de água. O aumento da dose de nitrogênio não influenciou as variações das variáveis biofísicas, devido, possivelmente, ao processo de lixiviação desse nutriente para as camadas abaixo do sistema radicular da cultura. As análises dos índices de vegetação e dos parâmetros da remoção do contínuo (área e profundidade da banda de absorção) mostraram que as lâminas de irrigação afetaram o comportamento espectral do feijão no comprimento de onda de 665 nm, e que esses parâmetros não foram influenciados pelas doses de N. Os índices de vegetação (NDVI e NB_NDVI) e os parâmetros da remoção do contínuo (a profundidade da banda e a área da banda de absorção) foram eficientes na estimativa do IAF, da altura de plantas e da produtividade de grãos. Durante todo o desenvolvimento da cultura, as melhores correlações entre as variáveis biofísicas e as variáveis espectrais foram observadas nos estádios V4 e R6 de acordo com a variável analisada, sendo, portanto, estes os melhores estádios para monitorar espectralmente a cultura. Diante das metodologias utilizadas, as variáveis biofísicas foram mais bem estimadas pelo índice NB_NDVI, nos estádios V4 e R6, quando comparado ao índice NDVI e aos parâmetros da remoção do contínuo (profundidade e área da banda de absorção).
The objective of this research was to analyze the effect of irrigation levels and nitrogen fertilization on the spectral behavior, in the wavelength range of 350 to 1150 nm, of bean crop and the correlation between biophysical parameters and agronomical variables. The experiment was carried on at the Fazenda Areão, located at the University of São Paulo (ESALQ/USP) campus, Piracicaba, São Paulo, Brazil, from September to December, 2007. The experimental design was the randomized blocks, with split plots, with 12 treatments, 4 irrigation levels (179,5; 256,5; 357,5 e 406,2 mm) and 3 nitrogen rates (0; 80 e 160 kg ha-1), and four blocks. The field radiometric data were acquired with the SPECTRON-SE 590 spectroradiometer for seven dates during the crop growing season. Plant height, leaf area index (LAI), grain yield, the pod number per plant and the grain number per pod were also acquired. The spectral indices used were NDVI and NB_NDVI. The continuum removal was applied for the reflectance spectrum, on visible region centered on 665 nm, to analyze the band area and band depth. The irrigation also influenced the biophysical variables, so the largest medium values were observed in the treatments that used the largest irrigation levels. The nitrogen fertilization did not interfere on the biophysical variables, probably due to the leaching process. The vegetation indices and continuum removal analysis showed that irrigation levels affected the spectral behavior of bean crop on 665 nm and this parameters had not been influenced by nitrogen levels. The vegetation indices (NDVI and NB_NDVI) and the continuum removal parameters (band area and band depth) were efficient in the estimate of IAF, plant height and grain yield. During all the crop development, the best correlations between biophysical variables and spectral variables were observed on V4 and R6 stages, according to the variable analized. In face of the methodologies used, the biophysical variables were better estimated by NB_NDVI, on V4 and R6 stages, when compared with NDVI and the continuum removal parameters.

APA, Harvard, Vancouver, ISO, and other styles

23

Nordheim-Shelt, Barbara Ann. "Effects of Anthropogenic Activity on the Green Swamp Preserve Ecosystem." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6734.

Full text

Abstract:

The Green Swamp Preserve is a large geographic area that has sustained many changes since Europeans settled in Florida. There has been little published research on the impacts of anthropogenic activity on this system. This thesis research seeks to document more recent changes in the Green Swamp and to evaluate the effects of various human activities on the system. The study period is from 1985 to 2015. For this time period changes in land use and landcover were examined using neural network classifications. Changes in vegetation health were evaluated by examining Normalized Difference Vegetation Index (NDVI) and Green Vegetation Index differences. Field site visits were made to document current conditions at thirty sample locations within the study area. Changes in land use and landcover and vegetation health were evaluated in relation to anthropogenic activities such as proximity to pollution sources, conservation lands and restoration sites. Statistical analysis was conducted to determine if statistically significant clustering occurred in these changes and if present geographically weighted regressions were performed to determine if a significant spatial relationship existed between the clustering and the various human activities. WAP data showed an overall decline in wetland health at the assessment sites and showed a trend of lower wetland health at sites within 2 Km of pollution sources, specifically petroleum tank contamination sites and state roads. The statistically significant clustering identified in land use landcover changes from 1985 to 2015 were in relation to changes from field, forested and wetland landcover types to built environments. Spatial relationships were identified between the proximity of petroleum tank contamination sites, state roads and solid waste facilities and clustering of NDVI decreases from 1985 to 2015. NDVI increases in the study area from 1985 to 2015 also showed statistically significant clustering in relation to conservation lands and lands purchased by the Southwest Florida Water Management District for environmental protection. These preliminary findings suggest that human activities may have influenced changes in the health of the Green Swamp. Further, more extensive research is suggested to confirm these findings.

APA, Harvard, Vancouver, ISO, and other styles

24

Souza, José Carlos de [UNESP]. "Metodologia para avaliação ambiental em bacias hidrográficas, utilizando técnicas de geoprocessamento e sensoriamento remoto." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151549.

Full text

Abstract:

Submitted by JOSÉ CARLOS DE SOUZA null (jcsouza1974@gmail.com) on 2017-09-02T20:13:33Z No. of bitstreams: 1 Tese_final_PDF.pdf: 5571055 bytes, checksum: 5bf13179b0dee373575a49ac318f9a43 (MD5)
Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-09-06T14:02:59Z (GMT) No. of bitstreams: 1 souza_jc_dr_soro.pdf: 5571055 bytes, checksum: 5bf13179b0dee373575a49ac318f9a43 (MD5)
Made available in DSpace on 2017-09-06T14:02:59Z (GMT). No. of bitstreams: 1 souza_jc_dr_soro.pdf: 5571055 bytes, checksum: 5bf13179b0dee373575a49ac318f9a43 (MD5) Previous issue date: 2017-08-18
A espacialização de dados ambientais através de técnicas de geoprocessamento e o monitoramento do comportamento espectral da vegetação por meio de imagens orbitais são instrumentos importantes nos estudos ambientais de análise da paisagem, em especial os aplicados a bacias hidrográficas. O objetivo da presente pesquisa foi desenvolver uma metodologia de avaliação ambiental aplicada à bacia hidrográfica, através da estimativa de parâmetros biofísicos, gerados por imagens Landsat 8 e determinação de parâmetros físico-químicos dos solos. O estudo foi aplicado na Bacia Hidrográfica do Rio Una, localizada em Ibiúna, no Estado de São Paulo, Brasil. Foram estimados o índice de vegetação por diferença normalizada – NDVI; o índice de vegetação ajustado do solo – SAVI; o índice de água por diferença normalizada – NDWI e o índice de ressecamento da vegetação por temperatura – TVDI. O estudo foi desenvolvido utilizando imagens do satélite Landsat 8 datadas de janeiro (período úmido) e agosto (período seco) do ano de 2015. O processamento digital das imagens foi realizado no software ArcGis 10.3. Foram geradas matrizes de correlação com base na combinação pixel a pixel para os índices NDVI, SAVI e NDWI utilizando o software Matlab para a análise espacial e temporal da cobertura vegetal. Além disso, foram coletados amostras de solo para determinação dos teores de matéria orgânica e carbono orgânico total – COT e levantamento in situ, dos teores de umidade e pH da área de estudo. Os resultados levantados foram interpolados pelo método do inverso do quadrado da distância - IQD. Os índices estimados apresentaram padrão espacial com forte relação com a sazonalidade climática, com ênfase ao regime de chuvas. Os resultados obtidos mostraram uma redução dos índices NDVI e SAVI, em 87,5% e 92% respectivamente, do período úmido para o seco. No NDWI foi identificado perda em conteúdo de água na vegetação em 73,03% dos pixels. As reduções nos valores dos pixels, nos três índices analisados, evidenciam a influência direta das condições climáticas no vigor e no teor de umidade da vegetação. O TVDI também apresentou influencia da sazonalidade climática. No mês de janeiro predominaram valores entre 0.2 e 0.4, indicando umidade normal, e em agosto predominaram valores entre 0.4 e 0.8, indicando condições ligeiramente seca ou estresse hídrico moderado. O TVDI se mostrou adequado para avaliar o déficit hídrico em diferentes coberturas do solo, com potencial para monitorar as perdas de umidade do solo e da vegetação. A umidade do solo, com medição in loco, registrou valores maiores nos meses com maior total de chuva, em todas as amostras, com exceção de algumas áreas agrícolas que ocorriam irrigação por aspersão, no período seco. Os solos apresentaram fraca acidez em todas as amostras, registrando pequena variação do pH entre os períodos, indicando condições de menor acidez no período de estiagem. Os teores de COT e matéria orgânica dos solos, indicaram as áreas de pastagens com teores mais elevados e as culturas temporárias com teores mais reduzidos, em relação aos demais tipos de cobertura do solo da bacia. A prática de cultivo e o processo de intemperismo explicam a redução nos teores de TOC e MO nos solos de culturas temporárias. Já as pastagens com suas estruturas radiculares, explicam a potencialização no armazenamento do carbono. As imagens Landsat 8 se mostraram eficientes na estimativa de parâmetros biofísicos da vegetação e as técnicas de geoprocessamento contribuíram substancialmente nas análises espaciais, se apresentando como ferramentas indispensáveis em estudos ambientais aplicados a bacias hidrográficas.
The spatialization of environmental data through geoprocessing techniques and the monitoring of vegetation spectral behavior through orbital images are important tools in environmental studies of landscape analysis, in special those applied to watershad. The objective of the present research was to develop an environmental assessment methodology applied to the watershad, through the estimation of biophysical parameters, generated by Landsat 8 images and determination of chemical-physical parameters of the soils. The study was applied in the Una Watershad, located in Ibiúna, in the State of São Paulo, Brazil. Were estimated the Normalized Difference Vegetation Index - NDVI; The Soil Adjusted Vegetation Index - SAVI; Normalized Difference Water Index - NDWI and the Temperature Vegetation Dryness Index - TVDI. The study was developed using Landsat 8 satellite images dated January (wet period) and August (dry period) of the year 2015. The digital process of images was performed in ArcGis 10.3 software. Correlation matrices were generated based on the pixel by pixel combination for the NDVI, SAVI and NDWI indexes using the Matlab software for the spatial and temporal analysis of the vegetation cover. In addition, soil samples were collected to determine the organic matter and total organic carbon (TOC) and survey in loco of soil moisture content and pH of the study area. The results obtained were interpolated by the Inverse Distance Weighting - IDW. The estimated indices presented a spatial pattern with strong relation with climatic seasonality, with emphasis on the rainfall regime. The results showed a reduction of the NDVI and SAVI indices, in 87.5% and 92%, respectively, from the wet to the dry period. In the NDWI, loss of water content in the vegetation was detected in 73.03% of the pixels. The reductions in the values of the pixels, in the three indices analyzed, show the direct influence of the climatic conditions on the vigor and the moisture content of the vegetation. TVDI also had an influence of climatic seasonality. In January values between 0.2 and 0.4 predominated, indicating normal humidity, and in August, values between 0.4 and 0.8 were predominant, indicating conditions slightly dry or moderate water stress. The TVDI proved to be suitable to evaluate the water deficit in different soil coverages, with potential to monitor soil and vegetation moisture losses. Soil moisture, with in loco measurement, recorded higher values in the months with the highest total rainfall, in all samples, except for some agricultural areas that were irrigated by sprinkling in the dry period. Soils presented low acidity in all samples, registering a small pH variation between the periods, indicating conditions of lower acidity in the dry season. The TOC and organic matter contents of the soils indicated the pasture areas with higher contents and the temporary crops with lower levels, in relation to the other types of soil cover in the watershed. The cultivation practice and the weathering process explain the reduction in TOC and OM contents in soils of temporary crops. On the other hand, pastures with their root structures explain the potential of carbon storage. Landsat 8 images were efficient in estimating biophysical parameters of the vegetation and geoprocessing techniques contributed substantially to spatial analysis, presenting themselves as indispensable tools in environmental studies applied to watersheds.

APA, Harvard, Vancouver, ISO, and other styles

25

García-Romero, Antonio, Julio Muñoz, Nuria Andrés, and Estremera David Palacios. "Influencia del cambio climático en la evolución de la vegetación nival de las montañas mediterráneas. sierra de guadarrama, españa." Pontificia Universidad Católica del Perú. Centro de Investigación en Geografía Aplicada, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/119816.

Full text

Abstract:

It studies recent climate variation and its consequences on the nival vegetation distributionin two basins of the Sierra de Guadarrama, Spain. The climate change was documented from eighteen different variables related to temperature, pluvial and snow precipitation, snow du ration within the period 1951-2000. To evaluate vegetation response to climate variation we determined the nival correlation of the distinct vegetation classes. To do this, we considered their spatial and / or temporal relation with distinct variables of climate, snow variation, and nival geoforms. Nival vegetation maps were made of five dates (1956 to 1998) and to quan tify and explain tendencies it was necessary to calculate surfaces and percentages of change, annual mean transformation index (ITMA’s) and transition matrixes. The results show that in the area studied there are 14 vegetation classes belonging to four groups of high, medium, low and negative nival correlation. Evolution of the last fifty years is summarized in a notable spatial reduction of vegetation with high nival correlation, moderate vegetation reduction with medium nival correlation and significant vegetation expansion with negative nival correlation. Change processes leave a main succession that consists on the herbal formation substitution highly correlated with snow duration and the abundance of fusion water, by leguminous shrubsapart from the nival influence, which slowly densify.
Se estudia la variación reciente del clima y sus consecuencias sobre la distribución de la vegetación nival en dos cuencas de la Sierra de Guadarrama, España. El cambio climático se documentó a partir de dieciocho variables referentes a temperatura, precipitación pluvial y nival, y duración de la nieve, durante el período 1951-2000. Para evaluar la respuesta de la vegetación a la variación del clima se partió de determinar la correlación nival de las distintas clases de vegetación, para lo cual, se consideró su relación espacial y/o temporal con distintas variables del clima, la duración de la nieve y las geoformas nivales. Se generaron mapas de la vegetación nival en cinco fechas (1956 a 1998) y para cuantificar y explicar las tendencias se calcularon superficies y porcentajes de cambio, índices de transformación media anual (ITMA) y matrices de transición. Los resultados muestran que el área de estudio incluye catorce clases de vegetación pertenecientes a cuatro grupos de alta, media, baja y negativa correlación nival. La evolución de los últimos cincuenta años se resume en una notable reducción espacial de la vegetación con correlación nival alta, moderada reducción de la vegetación con correlación nival media y significativa expansión de la vegetación con correlación nival negativa. Los procesosde cambio dejan ver una línea principal de sucesión que consiste en la sustitución de las formaciones herbáceas altamente correlacionadas con alta duración de la nieve y abundancia de las aguas de fusión, por matorrales de leguminosas alejados de la influencia nival, que se densifican paulatinamente.

APA, Harvard, Vancouver, ISO, and other styles

26

Prudente, Victor Hugo Rohden. "Dinâmica espectro-temporal da soja e do feijão por meio de sensoriamento remoto terrestre." Universidade Estadual do Oeste do Paraná, 2017. http://tede.unioeste.br/handle/tede/3062.

Full text

Abstract:

Submitted by Neusa Fagundes (neusa.fagundes@unioeste.br) on 2017-09-18T12:59:07Z No. of bitstreams: 1 Victor_Prudente2017.pdf: 2943373 bytes, checksum: 9bc7b35805d7987e01d85665f9ba8802 (MD5)
Made available in DSpace on 2017-09-18T12:59:07Z (GMT). No. of bitstreams: 1 Victor_Prudente2017.pdf: 2943373 bytes, checksum: 9bc7b35805d7987e01d85665f9ba8802 (MD5) Previous issue date: 2017-02-09
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
The spatio-temporal dynamics of agricultural crops can be monitored through Vegetation Indices (VI) on multiple dates. The use of IV in a given period of crop development or throughout its cycle, has generated good relations with agronomic parameters. There are several IV, the NDVI (Normalized Difference Vegetation Index) being one of the most used. NDVI correlates with some agronomic variables such as plant height, leaf area index (LAI), dry matter, chlorophyll index (CI), soil cover degree, plant height and photosynthetically active intercepted radiation (PAIR). Hence, the objective of this work is to compare and intercalibrate NDVI spectral-temporal profiles obtained by different terrestrial remote Sensors, and to use these profiles to estimate biophysical parameters (LAI, CI, PAIR, and Plant Height) for soybean and bean, in addition to estimating and studying soybean yield through models with spectral-temporal data obtained by different terrestrial remote sensors. The ground sensors used are the GreenSeeker 505 Handheld active sensor and the passive hyperspectral FieldSpec4 Standard-Res model. The NDVI values of the passive (NDVI FS) and active (NDVI GS) sensors presented high correlation (soybean rs = 0.90 and bean rs = 0.93) and the linear models respond well to an intercalibration considering the entire phenological cycle of soybean (R² = 0.83, RMSE = 0.0161 e dr = 0.85) and beans (R² = 0.92, RMSE = 0.0038 e dr = 0.89). The saturation of the NDVI values at the survey dates that are located during the vegetative peak of the crops and the presence of adverse climatic events decreased the precision of the models in certain periods of the phenological cycle of the crops. The variables LAI and Height for both crops and CI for the soybean crop obtained better results when estimated by the values of NDVI GS. PAIR for both crops and CI for bean obtained better adjustments considering the models using NDVI FS values. For the variable productivity, there was no significant correlation with the NDVI GS and NDVI FS. However, it presented relations with the accumulation of reflectance observed in the RED and NIR bands for both sensors as a result of different collection dates. The best relations of productivity were with the accumulation of reflectance values of the spectroradiometer bands on DAS76 and DAS71 dates.
A dinâmica espaço-temporal das culturas agrícolas pode ser monitorada por meio de Índices de Vegetação (IV) em múltiplas datas. A utilização do IV, em um determinado período do desenvolvimento das culturas, ou, ainda, em todo o seu ciclo, possui boas relações com parâmetros agronômicos. Há diversos IVs, sendo o NDVI (Normalized Difference Vegetation Index) um dos mais utilizados. O NDVI possui relação com algumas variáveis agronômicas como altura de planta, Índice de Área Foliar (IAF), matéria seca, índice de clorofila (IC), grau de cobertura do solo, altura de planta e radiação fotossinteticamente ativa interceptada (RFAI). Neste sentido, o objetivo deste trabalho foi comparar perfis espectro-temporais NDVI obtidos por diferentes sensores remotos terrestres, e utilizar esses perfis para estimar parâmetros biofísicos (IAF, IC, RFAI e altura de planta) para a soja e o feijão, além de estimar/estudar a produtividade da soja por meio de modelos com dados espectro-temporais obtidos por diferentes sensores remotos terrestres. Utilizou-se o sensor ativo GreenSeeker 505 Handheld e o sensor passivo hiperespectral FieldSpec4 modelo Standard-Res. Os valores de NDVI dos sensores passivos (NDVI FS) e ativos (NDVI GS) apresentaram alta correlação (soja rs = 0,90 e feijão rs = 0,93), e os modelos lineares respondem bem a um ajuste, ao se considerar todo o ciclo fenológico da soja (R² = 0,83, RMSE = 0,0161 e dr = 0,85) e feijão (R² = 0,92, RMSE = 0,0038 e dr = 0,89). A saturação dos valores de NDVIs nas datas de levantamento que se situam durante o pico vegetativo das culturas e a presença de eventos climáticos adverso diminuíram a precisão dos modelos em determinados períodos do ciclo fenológico das culturas. As variáveis IAF e altura para a soja e o feijão e IC para a soja obtiveram melhores resultados ao ser estimadas por meio dos valores de NDVI GS. RFAI para ambas as culturas e IC para o feijão obtiveram melhores ajustes por meio dos modelos que se utilizavam de valores de NDVI FS. Para a produtividade, não houve correlação significativa com os NDVI GS e NDVI FS. Entretanto, apresentou relações com o acúmulo de refletância observados nas bandas RED e NIR para ambos os sensores em diferentes datas de coleta. As melhores relações da produtividade foram com o acúmulo de refletância das bandas do espectroradiômetro nas datas DAS76 e DAS71.

APA, Harvard, Vancouver, ISO, and other styles

27

Garófano, Gómez Virginia. "Riparian vegetation patterns according to hydrogeomorphological factors at different spatial and temporal scales in Mediterranean rivers." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/29395.

Full text

Abstract:

Los corredores riparios en ambientes semiáridos mediterráneos son ecosistemas de gran biodiversidad y complejidad. En ellos confluyen una gran variedad de perturbaciones naturales capaces de crear un mosaico espacial y temporal con pocos paralelos en otros ecosistemas. Sin embargo, a pesar de su valor, los ecosistemas riparios están amenazados debido a los altos niveles de intervención humana. La construcción de presas (y la consecuente manipulación del caudal) está considerada como la perturbación humana más importante que se cierne sobre ellos. Esta tesis ha tenido como objetivo analizar el ecosistema ripario, abarcando diferentes escalas espaciales y temporales, y centrándose en los factores que influyen en la distribución, estructura, composición, calidad y dinámica de su vegetación, tanto en tramos naturales como hidrológicamente alterados de ríos mediterráneos, concretamente de la Demarcación Hidrográfica del Júcar (Este de España). Para lograr este objetivo, se han hecho los siguientes aportes a la investigación: A) Determinar los patrones de distribución de especies leñosas riparias en el gradiente transversal de la ribera y definir grupos de especies con respuesta similar a las condiciones físicas del hábitat; B) Comparar la respuesta de dichas especies en tramos naturales y alterados hidrológicamente; C) Definir curvas de respuesta y gremios hidrológicos de especies en tramos con régimen natural; D) Establecer los principales factores que determinan la calidad del hábitat ripario y fluvial y los patrones longitudinales de la composición florística, así como de las características del hábitat fluvial en un segmento hidrológicamente alterado; E) Describir los cambios espacio-temporales en la estructura y complejidad de la vegetación, y los cambios temporales en el régimen de caudales del corredor ripario de un tramo hidrológicamente alterado. Los objetivos anteriores fueron abordados con diferentes metodologías que implicaron la combinación de diversas fuentes de información y un esfuerzo importante en la toma de datos en varios lugares de estudio de los ríos Cabriel, Mijares y Serpis. Para cumplir con los objetivos A y B, se llevaron a cabo un muestreo de suelos y un muestreo georreferenciado de vegetación a través de transectos transversales al cauce en dos tramos naturales y tres regulados. Los datos fueron analizados con estadística robusta y multivariante. Para cumplir el objetivo C, el muestreo georreferenciado anterior (junto con un muestreo dendrocronológico) fue acoplado con un modelo hidráulico en los dos tramos naturales, con el fin de obtener la serie temporal de cotas del agua a la que habían estado expuestas cada una de las plantas durante su vida. La respuesta de las especies y su posible agregación en gremios hidrológicos fue comparada mediante estadística robusta en relación a la duración de la inundación, duración de la inundación durante el período de crecimiento, duración continua de la inundación, frecuencia de inundación y elevación de la planta respecto al caudal base. Para lograr el objetivo D, toda la sección regulada del río Serpis (desde la presa Beniarrés - hasta la desembocadura; 40 km) se dividió en segmentos. En cada uno de ellos se llevó a cabo un inventario de flora y se aplicaron índices hidromorfológicos. Los segmentos fueron agrupados de acuerdo a su composición florística y características del hábitat fluvial utilizando diferentes técnicas de estadística multivariante. Finalmente se discutieron los factores principales que controlan los patrones espaciales de la composición florística, las características del hábitat fluvial, la calidad del hábitat ribereño y la heterogeneidad del hábitat fluvial. Para alcanzar el objetivo E, se combinaron series históricas de caudales y su manipulación humana con imágenes aéreas históricas (reveladoras de cambios en la cubierta vegetal) y observaciones de campo de la distribución de edades de la vegetación y morfología del corredor ripario del río Mijares en los últimos 60 años. De esta información, se extrajeron métricas del paisaje e índices hidrológicos para identificar y resumir los cambios espacio-temporales en la estructura de la ribera y en el régimen de caudales. El estudio a escala transversal nos ayudó a comprender en cada uno de los tramos la zonación de las especies leñosas riparias en función de la morfología y características del suelo, revelando que la alteración del caudal puede influir en la modificación de los patrones posicionales de las especies. Se definieron tres gremios hidrológicos: ¿altamente tolerante a la inundación¿, ¿tolerante intermedio¿ y ¿de transición entre ripario y terrestre¿. El estudio a escala longitudinal sugirió que la respuesta de la vegetación a un cambio hidrológico es altamente dependiente de la geomorfología local. Se constató que los factores principales que determinan los patrones hidromorfológicos y florísticos son un régimen de caudales artificial y altamente variable (identificado en los segmentos con peor calidad del hábitat ripario y fluvial), la presencia de estructuras laterales en el cauce y las características geomorfológicas. Como efectos importantes de la regulación del caudal a largo plazo, el estudio a escala espacio-temporal reveló un aumento en la cobertura y densidad de la vegetación leñosa, una deriva en la composición de especies y una disminución en las áreas de sedimento desnudo (esencial para el reclutamiento de las especies riparias pioneras), junto con una reducción sincrónica en la complejidad de la ribera. Estos cambios estarían relacionados con la disminución de la magnitud y variabilidad de los caudales en las últimas seis décadas. Solo una mejor comprensión de los procesos ecohidrológicos y de las implicaciones de la alteración hidrológica sobre los ecosistemas riparios mediterráneos podrá apoyar la integración eficaz de estos sistemas en las decisiones de gestión del agua.
Garófano Gómez, V. (2013). Riparian vegetation patterns according to hydrogeomorphological factors at different spatial and temporal scales in Mediterranean rivers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/29395
TESIS

APA, Harvard, Vancouver, ISO, and other styles

28

Gorenstein, Mauricio Romero. "Diversidade de espécies em comunidades arbóreas: aplicação de índices de distinção taxonômica em três formações florestais do Estado de São Paulo." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-10092009-082240/.

Full text

Abstract:

Este trabalho faz parte do projeto Biota/FAPESP, Métodos de Inventário da Biodiversidade de Espécies Arbóreas, e analisou a diferença na estrutura florística entre as áreas estudadas. Na Estação Ecológica de Assis, SP, área de Cerradão, foram amostradas 102 espécies, 72 gêneros e 43 famílias; 67% das espécies foram exclusivas desta fitofisionomia. Na Floresta Estacional Semidecidual da Estação Ecológica dos Caetetus, município de Gália-SP, foram amostradas 208 espécies, 138 gêneros e 49 famílias; sendo 65% das espécies exclusivas. Na Floresta Ombrófila Densa do Parque Estadual de Carlos Botelho, município de São Miguel Arcanjo-SP, foram encontradas 410 espécies, pertencentes a 152 gêneros e 64 famílias; 84% das espécies exclusivas desta fitofisionomia. A Floresta Estacional apresentou maior similaridade com a Floresta Ombrófila do que com o Cerradão. Apesar de apresentar maior número de espécies, a Floresta Ombrófila Densa apresenta concentração de espécies nas famílias Myrtaceae e Lauraceae. Em outra análise foram calculados os índices de distinção taxonômica nas 5 grades amostrais para os métodos de amostragem testados. O método de Bitterlich apresentou tendência nos índices de diversidade e distinção taxonômica, conforme a diversidade taxonômica do sub-bosque. Esses índices apresentaram média independente e variância decrescente com o aumento da amostra. Os índices de distinção taxonômica média e variância da distinção taxonômica média também apresentaram variância decrescente. Porém, a estabilização da média ocorreu com amostras de maior tamanho, principalmente para as parcelas de área fixa na Estação Ecológica dos Caetetus. Na Floresta Ombrófila Densa, a distinção taxonômica média foi menor e a variância da distinção taxonômica média foi maior, devido a alta concentração de espécies de Myrtales e Laurales nesta fitofisionomia.
This research is part of the project Biota / FAPESP, \"Tree Species Biodiversity Inventory Methods, and analised floristic structural differences among three areas. In Assis Ecological Station, Forest Savanna area were sampled 102 species, 72 genus and 43 families, 67% of this species were exclusive of this phytophisiognomy. Semideciduous seasonal forest in the Caetetus Ecological Station, 208 species were sampled, 138 genus and 49 families, with 65% of exclusive species. Rain Forest in the Carlos Botelho State Park, were found 410 species, belonging to 152 genus and 64 families, 84% of exclusive species. The seasonal forest showed greater similarity to the rain forest than the Savanna. In spite of the greater number of species, the Rain Forest presents concentration of species in the Myrtaceae and Lauraceae families. In another analysis were calculated the taxonomic indices in tree species data provided by sampling methods tested in five sampling grids. The Bitterlich sampling method was tendecious in estimates the taxonomic diversity and taxonomic distinctness indices because the taxonomic diversity in the understory. These indices showed average independent and variance decreasing with increasing sample. The average taxonomic distinctness and variation in taxonomic distinctness also showed decreased, but the stabilization of the average occurred with samples of greater size, mainly for fixed area plots at Caetetus Ecological Station. In the Rain Forest the average taxonomic distinctness was lower and the variation of taxonomic distinctness was higher due to high concentration of species of Myrtales and Laurales in this phytophisiognomy.

APA, Harvard, Vancouver, ISO, and other styles

29

Power, Mitchell J. "Recent and Holocene fire, climate, and vegetation linkages in the northern Rocky Mountains, USA /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?index=0&did=1232403871&SrchMode=1&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1180996482&clientId=11238.

Full text

Abstract:

Thesis (Ph. D.)--University of Oregon, 2006.
Typescript. Includes vita and abstract. Includes appendices with Foy Lake pollen and charcoal data and fire atlas metadata. Includes bibliographical references (leaves 233-244). Also available for download via the World Wide Web; free to University of Oregon users.

APA, Harvard, Vancouver, ISO, and other styles

30

Santana, Sidney Henrique Campelo de. "Análise da biomassa florestal de Pinus uncinata por meio de ferramentas de sensoriamento remoto passivo e ativo." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/16721.

Full text

Abstract:

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-19T14:14:56Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_SidneySantana_2015.pdf: 7597504 bytes, checksum: bf6a44dd30bc34dca577bb38b4fb038f (MD5)
Made available in DSpace on 2016-04-19T14:14:56Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_SidneySantana_2015.pdf: 7597504 bytes, checksum: bf6a44dd30bc34dca577bb38b4fb038f (MD5) Previous issue date: 2015-08-31
As florestas têm um papel fundamental no sequestro de carbono da atmosfera. Dessa forma, este trabalho tem como principal objetivo quantificar e analisar a biomassa de um fragmento florestal de Pinus uncinata pertencente ao Espaço Natural da Montanha de Alinyà, por meio de ferramentas de sensoriamento remoto. O espaço natural está localizado no município de Figòls y Alinyà, na província Lleida, situada na Catalunha – Espanha. Assim, para realizar este estudo foram selecionadas 7 imagens do sensor TM do Landsat 5 correspondentes aos 1984, 2003, 2006, 2008, 2009, 2010 e 2011 com rota 198 e ponto 31. Seguidamente foram trabalhadas as bandas espectrais de cada imagem e calculados a calibração radiométrica, a reflectância e os índices de vegetação NDVI e SAVI. Com os dados LiDAR foram gerados os Modelos Digitais de Terreno (MDT) e realizados os cálculos estatísticos pertinentes para calcular a biomassa florestal, a área basal e o teor de carbono. As informações obtidas foram projetadas em mapas. Como resultado, o NDVI mostrou-se importante por proporcionar a análise temporal do comportamento da massa florestal. No entanto, o NDVI e o SAVI tiveram seus resultados prejudicados pela influência dos efeitos topográficos. Os modelos de regressão linear para biomassa, área basal e teor de carbono tiveram uma correlação satisfatória com os dados de inventário para duas das cinco zonas consideradas. Dessa forma, foi possível estimar estas variáveis florestais para a zona de estudo. O cálculo de biomassa florestal pelos dados LiDAR resultaram em 9.138,6 t para uma área de 69,04 ha, enquanto que os cálculos de inventário resultaram em 11.638,4 tn. O Teor de carbono o cálculo com os dados LiDAR resultaram em 5.425,04 t diante de 6.520,18 t resultantes dos cálculos com os dados de inventário. Portanto se pode afirmar que a tecnologia LiDAR traz ao estudo florestal uma série de aplicações necessárias para uma efetiva gestão dos sistemas florestais. Além disso, o LiDAR apresenta vantagens diante dos outros métodos convencionais, em relação à sua precisão, temporalidade e varredura, ainda mais diante da urgência de se obter resultados confiáveis no cenário atual de mudanças climáticas e vulnerabilidade dos ecossistemas.
The forests have a vital role in carbon capture from the atmosphere. Thus, this work has as its main objective to quantify and analyze biomass of a forest fragment of a Pinus uncinata that belongs to Alinyà Mountain Natural Space, through remote sensing tools. The natural area is located in the County of Figòls y Alinyà, in the Lleida province, located in Catalonia-Spain. In this sense, to conduct this study, 7 images were selected from the Landsat 5 TM sensor corresponding to 1984, 2003, 2006, 2008, 2009, 2010 and 2011 with path 198 and row 31. Subsequently, the spectral bands of each image were manipulated, and then the radiometric calibration, reflectance, and the NDVI and SAVI vegetation indexes were calculated. Using the LiDAR data, the Digital Terrain Models (DTM) were generated, and relevant statistical calculations were made to subsequently calculate the forest biomass, basal area, and carbon content. The information obtained was projected on maps. As a result, the NDVI has supported the study by temporally analyzing the behavior of the forest. However, this index, and even more the SAVI, suffered with the influence of topographic effects. The linear regression models for biomass, basal area, and carbon content had a satisfactory correlation with the inventory data for 2 of the 5 areas considered. In this sense, it was possible to estimate these forest variables for the study area. The calculation of forest biomass by LiDAR data resulted in 9,138.6 ton to an area of 69.04 ha, while the inventory calculations resulted in 11,638.4 ton. For the carbon content, the calculation with the LiDAR data resulted in 5,425.04 ton in comparison with the 6,520 .18 ton resulting from the calculations with the inventory data. Hence, it is safe to say that LiDAR technology brings to the forest study a series of applications that are required for an effective management of forest systems. In addition, the LiDAR presents advantages before other conventional methods, regarding its accuracy, temporality, and range, especially on the urgency of obtaining reliable results in the current scenario of climate change and vulnerability of ecosystems.

APA, Harvard, Vancouver, ISO, and other styles

31

Camargo, Alexandre Pansini. "Estratificação de povoamentos de Eucalyptus spp. em classes de idade por escaneamento a laser aeroembarcado." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-05012018-182841/.

Full text

Abstract:

As condições climáticas do Brasil aliadas ao desenvolvimento tecnológico favorecem a obtenção de sucessivos incrementos em produção florestal e estimulam a expansão de área cultivada com povoamentos voltados para a produção madeireira. Com o objetivo de contribuir para o processo de quantificação das florestas plantadas em uma escala regional, este estudo propõe utilizar informações combinadas de imagens de satélites e dados obtidos do LiDAR (Light Detecting and Ranging) para a construção de modelos determinísticos capazes de distinguir em duas categorias de idade agrupamentos de florestas plantadas no Vale do Paraíba, estado de São Paulo. A primeira etapa constitui utilizar informações de parcelas de campo como resposta para modelos gerados com variáveis de escaneamento a laser aeroembarcado (ALS) e extrapolar os parâmetros para toda a região da plantação; em um segundo momento, utilizar as informações extrapoladas para gerar um modelo composto por variáveis de índice de vegetação (IV) calculados das imagens de satélite. As informações LiDAR (Light Detecting and Ranging) foram obtidas de sete fazendas da região do Vale do Paraíba, estado de São Paulo, em 2012, mesmo ano em que foram coletados os dados das parcelas de campo dos inventários florestais e que as imagens foram obtidas pela constelação de satélites RapidEye. Como variáveis de dados ALS foram utilizados o cálculo de todos os pontos por célula de 5 x 5 m avaliados, alturas máxima, mínima, média, desvio padrão e percentis de altura, calculados pelo programa de análise de dados LASTools®. Foram incluídas também métricas de diferença de alturas do percentil 90 e o percentil 10 (p9010) e a medida dessa diferença relativa à altura do percentil 90 (p9010r). Na modelagem dos dados LiDAR para imagens de satélite foram utilizadas como variáveis, de forma individual ou conjuntamente, os índices NDVI, NDVI705, EVI, GNDVI, SAVI, Red-Green ratio e SRI. Os modelos foram avaliados quanto ao seu desempenho no coeficiente de determinação (R2) e na raíz do erro quadrático médio (RMSE) e em uma análise final predizendo as fazendas em categorias de idade jovem e maduro. O modelo com melhores estimativas (R2 e RMSE) para idade na primeira etapa foi o que possuía variáveis Hp90 e Hp9010r, com R2=0,85 e RMSE=11,736 meses, e para a segunda etapa foi o modelo contendo como variáveis os índices de vegetação NDVI705, Red-Green índex e SAVI, com R2=0,49 e RMSE=0,378 meses. Apesar dos resultados melhores, o modelo contendo índices de vegetação GNDVI e Red-Green índex foi o que melhor representou a distribuição das florestas quanto a sua maturidade.
Brazil\'s climate conditions combined with the technological development promote the obtaining of successive increments in forest production and stimulate the expansion of cultivated area with stands for timber production. In order to contribute to the process of quantification of planted forests at regional scale, this study proposes to use combined information from satellite images and data obtained from the LiDAR (Light Detecting and Ranging) for the construction of deterministic models able to distinguish two categories of age groupings of planted forests in the Paraíba Valley, State of São Paulo in Brazil. The first step is to use field plots information in response to models generated with airborne laser scanning (ALS) variables and extrapolate the parameters for the whole region of the plantation; in a second moment, use the information extrapolated to generate a model composed of vegetation index variables (IV) calculated from satellite images. The information LiDAR (Light Detecting and Ranging) were obtained from seven farms in the region of the Paraíba Valley, State of São Paulo, in 2012, the same year in which the data were collected from plots of field forest inventories and that the images were obtained by the RapidEye satellite constellation. As data variables ALS were used the calculation of all points by cell size of 5 x 5 m evaluated, maximum height, minimum, mean, standard deviation and height percentiles, calculated by the data analysis program called LASTools®. Also included height difference metrics 90th percentile and percentile 10th (p9010) and the extent of this difference relative of the 90th percentile (p9010r). In the modeling of data LiDAR data for satellite images were used as variables, individually or jointly, the NDVI index, NDVI705, EVI, GNDVI, SAVI, Red-Green index and SRI. The models were evaluated regarding their performance on the coefficient of determination (R2) and root mean square error (RMSE) and a final analysis predicting the farms into categories of age, young and mature. The model with best estimates (R2 and RMSE) for age at first stage was what possessed variables Hp90 and Hp9010r, with R2 = 0.85 and RMSE = 11.736 months, and the second stage was the model containing as variables the NDVI705 vegetation, Red-Green index and SAVI, with R2 = 0.49 and RMSE = 0.378 months. Despite the better results, the model containing GNDVI and Red-Green vegetation indices was the best represented distribution of forests about your maturity.

APA, Harvard, Vancouver, ISO, and other styles

32

Formigoni, Mileide de Holanda. "Análise multi-temporal da vegetação na região nordeste do Brasil através do EVI do sensor MODIS." Universidade Federal do Espírito Santo, 2008. http://repositorio.ufes.br/handle/10/6589.

Full text

Abstract:

Made available in DSpace on 2016-12-23T14:37:35Z (GMT). No. of bitstreams: 1 mileide.pdf: 1266050 bytes, checksum: 2566f7a76319b066b6b3af42e3af0d23 (MD5) Previous issue date: 2008-03-04
The Brazilian Northeast (NEB) region presented different vegetation types that are essential component of its ecosystem. With remote sensing techniques it is possible, for example, to analyzed variations in vegetation community and alterations in vegetation phenological. Analysis the main objective of this work is to evaluate the temporal behavior of the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), of different vegetation types in the NEB over period between February/2000 and July/2006. The study area was the NEB, where it was used to characterize the vegetations types a vegetation map of Brazil, in the 1:5,000,000 scale from Brazilian Institute of Geography and Statistics (IBGE). A total of 140 cloud-free EVI images with spatial resolution 250 m were acquired from National Aeronautics and Space Administration (NASA). Four CBERS-2/CCD images spatian resolution 20 m were also acquired from National Institute for Espace Research (INPE) to assist EVI data sample collection for each vegetation type. Precipitation data of the cities Petrolina and Pesqueira (Pernambuco), São Luiz and Carolina (Maranhão) located in regions of Caatinga, Atlantic Forest, Amazon and Savannah biome vegetation, respectively, were used to analyze its relationship with EVI from these vegetation. Also, EVI from irrigated area at Petrolina were used in these analysis. Results obtained showed that: i) multi-temporal EVI data from different vegetation types were sensitive to the vegetation phenological cycles, with minor and greater values of EVI in the periods of less and greater precipitation, respectively; ii) amazon biome vegetation presented lesser variation in the multitemporal EVI, however with greater values, justified by vegetation species the are always with green leaf; iii) Caatinga biome vegetation presented greater EVI values variation because the vegetation species on the dry periods occur total defoliation and on wet period the vegetation became green; iv) all EVI data from the vegetations studied presented significant relationship with precipitation (p-value< 0.05).
O Nordeste Brasileiro (NEB) apresenta diferentes tipos de vegetação, sendo importantes para o seu ecossistema. Com a utilização de técnicas de sensoriamento remoto é possível, por exemplo, analisar variações de comunidades de vegetação e suas alterações fenológicas. O objetivo principal deste trabalho é avaliar o comportamento temporal do Índice de Vegetação Melhorado (EVI) do sensor Spectroradiômetro de Resolução Espacial Moderada (MODIS), de diferentes tipos de vegetação do NEB no período entre fevereiro de 2000 a julho de 2006. A área de estudo foi a região do NEB, sendo utilizado para caracterização dos tipos de vegetação um mapa de vegetação na escala de 1:5.000.000 do Instituto Brasileiro de Geografia e Estatística (IBGE). Um total de 140 imagens EVI livres de nuvens com resolução espacial de 250 m foram adquiridas da Agência Nacional Aeroespacial Norteamericana (NASA). Quatro imagens CBERS-2/CCD com resolução espacial de 20 m foram também adquiridas do Instituto Nacional de Pesquisas Espaciais (INPE) para auxiliar na coleta das amostras de dados de EVI dos diferentes tipos de vegetação. Dados de precipitação das cidades de Petrolina e Pesqueira (Pernambuco), Barra do Corda e Carolina (Maranhão) localizadas nas regiões de vegetação do tipo Caatinga, Floresta Atlântica, Amazônia e Cerrado, respectivamente, foram utilizados para avaliar sua relação com os dados de EVI sob estas vegetações. Dados de EVI sobre área irrigada também foram utilizados para esta análise. Os resultados obtidos mostraram que: i) os dados multitemporais EVI de diferentes tipos de vegetação foram sensíveis às respectivas variações fenológicas, com os menores e maiores valores de EVI ocorrendo nos períodos de seca e chuva respectivamente; ii) a vegetação Amazônia apresentou a menor variação multitemporal dos valores de EVI, todavia apresentando os valores mais elevados, podendo-se justificar pela maior quantidade de folhas e por estarem sempre verdes; iii) a vegetação de caatinga analisada apresentou a maior variação dos valores de EVI, pois na época de seca, perde todas as folhas e na época de chuva, se torna verde devido a menor variabilidade da precipitação; iv) todos os dados de EVI das vegetações apresentaram relação significativa (valor-p<0,05) com a precipitação.

APA, Harvard, Vancouver, ISO, and other styles

33

SANTOS, Taciana Oliveira dos. "Identificação de ilhas de calor em Recife-PE por meio de sensoriamento remoto e dados meteorológicos de superfície." Universidade Federal Rural de Pernambuco, 2011. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5740.

Full text

Abstract:

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-10-18T12:47:21Z No. of bitstreams: 1 Taciana Oliveira dos Santos.pdf: 6392936 bytes, checksum: c3276b7eadcc0a19441877f4f21521af (MD5)
Made available in DSpace on 2016-10-18T12:47:21Z (GMT). No. of bitstreams: 1 Taciana Oliveira dos Santos.pdf: 6392936 bytes, checksum: c3276b7eadcc0a19441877f4f21521af (MD5) Previous issue date: 2011-09-08
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The phenomenon of urban heat islands is directly related to human activities and the type of materials and equipment used in the expansion of the urban fabric (concrete, asphalt, roofing, etc..), Which absorb and retain heat from sunlight, mainly because it is not just used to process Evaporative which certainly feeds the increase in air temperature in cities. Thus, this study was to analyze and identify the phenomenon of urban heat island between urban areas of Recife-PE, from TM images Landsat 5. For the study was obtained images from orbit 214 points 65 and 66, the dates of 04/08/1998 and 06/09/2010. From the image processing were generated letters of the surface temperature, albedo and NDVI to the city of Recife and five selected districts (Pina Santo Amaro, Casa Amarela, Dois irmãos and Curado ), to analyze the dynamics of transformation occurring in area study. Through the profile developed for the study area was perceived to increase spatial and temporal surface temperature toward the center-suburbs, resulting in a difference of 6°C between these areas. Neighborhoods with urban concentrations, lots of buildings vertical and horizontal, stood out as those at higher temperatures, performing over 27°C, found in the districts of Casa Amarela and the Santo Amaro. In areas where there was a reduction of the vegetation index was an increase in surface temperatures around 3°C. The emergence heat islands can be attributed to following factors: concentration buildings which implies in increased temperature; energy production anthropogenic issuing heat coming industries, transits and dwellings; replacement vegetation by asphalt; radiation, caused by emissivity bodies.
O fenômeno ilhas de calor urbano está diretamente relacionado com as atividades humanas e com o tipo de materiais e equipamentos empregados na expansão da malha urbana (concreto, asfaltos, telhados, etc.), os quais absorvem e conservam o calor proveniente da radiação solar, principalmente por não ser praticamente utilizado no processo evaporativo o que certamente alimenta o aumento da temperatura do ar nas cidades. Assim, este trabalho foi conduzido com objetivo analisar e identificar o fenômeno ilha de calor entre áreas urbanas da cidade do Recife-PE, a partir de imagens TM do satélite Landsat 5. Para a realização do estudo foram obtidas imagens da órbita 214 dos pontos 65 e 66, nas datas de 04/08/1998 e 06/09/2010. A partir do processamento das imagens foram geradas cartas de temperatura da superfície, albedo e NDVI para a cidade do Recife e cinco bairros selecionados (Pina, Santo Amaro, Casa Amarela, Dois Irmão e Curado), para analisar a dinâmica de transformação ocorrida na região de estudo. Por meio do perfil desenvolvido para área de estudo foi perceptível o aumento espacial e temporal das temperaturas da superfície no sentido centro-subúrbio, resultando em uma diferença de 6°C entre essas áreas. Os bairros com adensamento urbano, grande quantidade de construções verticais e horizontais, destacaram-se como os que possuem temperaturas mais elevadas, apresentando-se acima de 27°C, constatado nos bairros de Casa Amarela e Santo Amaro. Nas áreas onde ocorreu redução do índice de vegetação houve um aumento da temperatura da superfície em torno de 3°C. O surgimento das ilhas de calor pode ser atribuído aos seguintes fatores: concentração de edificações, que implica no acréscimo da temperatura; produção de energia antropogênica pela emissão de calor provenientes das indústrias, trânsitos e habitações; substituição da cobertura vegetal pelo asfalto; a radiação, causada pela emissividade de corpos.

APA, Harvard, Vancouver, ISO, and other styles

34

Tucker, David Ian. "The assessment of ecological condition in south-east Queensland, Australia: An evaluation of reliability across variable environments and surrogate efficacy for biodiversity values." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/94285/1/David_Tucker_Thesis.pdf.

Full text

Abstract:

Multimetric ecological condition assessment has become an important biodiversity management tool. This study was the first to examine the reliability of these ecological surrogates across variable environments, and the implications for surrogate efficacy. It was demonstrated that through strategic application and design of the multimetric ecological condition index, the effects of environmental gradients and disturbance regimes can be mitigated, and that ecological condition assessment may serve as a scientifically rigorous approach for conservation planning.

APA, Harvard, Vancouver, ISO, and other styles

35

CASTELLANETA, MARIA. "Integrated approach for monitoring the vulnerability of Mediterranean forests affected by drought-induced dieback." Doctoral thesis, Università degli studi della Basilicata, 2022. http://hdl.handle.net/11563/156227.

Full text

Abstract:

Rising aridity, mostly driven by higher temperatures and reduced precipitation, will likely undermine the health status of forest ecosystems. Experiments and observations point to the likelihood that if climate changes proceed at its current rate, the resilience of many forests will be threated by altering their structure and functions and reducing their capability to provide ecosystem services. Such increasing drought conditions, coupled to other biotic and abiotic drivers, are synergistically leading to responses in tree morphology, physiology, growth, reproduction, and forest mortality in different areas of the Mediterranean Basin. However, our understanding of vegetation dynamics in response to climate changes is still lacking, as a robust comprehension relies on the need to obtain insights at multiple temporal and spatial scales. In this context, we sought to forecasting vegetation response to climate stressors, particularly during dieback episodes when tree vulnerability is exacerbated. The first section of this study focused on tree and shrub populations exhibiting recent dieback phenomena in Italy (Quercus pubescens, Quercus frainetto) and Spain (Pinus sylvestris, Juniperus phoenicea). The general aim was to investigate how remotely sensed measures of vegetation activity and radial growth (BAI, basal area increment) responded to climate extreme events. To this purpose, we compared trees and nearby stands showing different vigor, i.e., dieback vs non-dieback, assessed as growth decline, elevated canopy defoliation and rising tree mortality rate. To disentangle growth and NDVI responses to drought, we accounted for two components of drought, namely elevated vapor pressure deficit (VPD) and low soil moisture. As a whole, the response of the investigated species to VPD increase was characterized by growth reduction. In Scots pine, high VPD was linked to a loss of growth in declining individuals which did not respond to changes in soil moisture. Oaks responded mostly to soil moisture, whereas the juniper was the most negatively affected by higher VPD. Indeed, the different hydraulic strategies (anisohydric vs. isohydric species) could partially explain the contrasting growth responses to drought proxies. We also found that dieback stands exhibited lower NDVI values than non-dieback stands. In most cases, NDVI and BAI was positively correlated and such relation likely relied on specific time windows. In the second part of the thesis, the phenological behavior of Mediterranean oak forest stands (Quercus cerris, Quercus pubescens, and Quercus frainetto), showing evident decline symptoms, are investigated by using a satellite-based approach. We explored how a phenological (PPI, Plant Phenology Index) index would be capable to reflect the seasonal vegetative dynamics of forests affected by dieback phenomena. We found that dieback forest stands - characterized by a higher ratio of crown-defoliated trees - showed distinct phenological performance as compared to non-dieback stands. In detail, our results revealed that dieback stands lengthened the growing season by delaying autumn leaf senescence. Nevertheless, both seasonal amplitude and productivity were found to have higher values for non-dieback stands as compared to dieback stands. Furthermore, it was highlighted that non-dieback stands experienced either greening up or senescence periods more rapidly than dieback ones. Overall, our framework demonstrated that the effects of climate extremes on vegetation can be detected either in terms of canopy greenness or radial growth reductions, thus hinting at the opportunity to both employ remotely sensed data as a stand-level indicator of vegetation stress and to scaling up informations from tree to stand levels by using the maximum growing season NDVI and tree-ring width data taken at the individual scales. Our findings also highlighted how patterns of vegetation response to climate extremes may depend on both the water use strategies of trees and shrubs and site-specific climatic conditions. Hence, coupling proxies of forest productivity (NDVI, BAI) may be employed for retrospective modeling of the impact of drought stress on forest productivity and tree growth, enhancing our knowledge and forecast of drought-induced dieback phenomena in woody plant communities. Furthermore, the second part of the work revealed the phenological behaviour of Mediterranean forest populations showing clear symptoms of decline. We speculated that the lengthened growing season may be related to the dieback trees' effort to compensate for the reduction in whole-plant photosynthesis, associated to canopy decline. Increased photosynthesis during the season under higher temperatures and increased light availability, due to global warming, provided a possible explanation for the greater seasonal amplitude and productivity of healthier stands. Our findings may provide new insights on phenological response to climate change in semi-arid regions, highlighting how trees, showing clear symptoms of decline, may keep their vital activities by changing their phenological performance. What described above leads to a crucial question concerning the potential implications of observed phenological shifts on the global carbon and water balance of terrestrial ecosystems under future climate change. Hence, in the coming years, this study could provide a more comprehensive overview on climate-vegetation interactions, mainly in the Mediterranean Basin, where intensified global warming and aridification trends are expected. Nonetheless, more investigations on the interactive effects among different environmental factors, are needed to improve our understanding of the underlying mechanisms affecting vegetation response.

APA, Harvard, Vancouver, ISO, and other styles

36

Brock, Justin Alan. "Rooting stem cuttings of shantung maple (Acer truncatum), mound layering shantung and caddo sugar maples (Acer saccharum), and using Eastern redcedar (Juniperus virginiana) as a substrate component in stem cutting propagation." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/17575.

Full text

Abstract:

Master of Science
Department of Horticulture, Forestry, and Recreation Resources
Jason J. Griffin
Heat and drought tolerance make shantung maple (Acer truncatum) and caddo sugar maple (A. saccharum) good candidates for midwestern landscapes. Improving cutting propagation or mound layering techniques could increase the availability of these species. The influence of time of year, cutting position, and auxin concentration, formulation, and solvent on rooting of stem cuttings of shantung maple was investigated. Semi-hardwood cuttings rooted best (55%). Generally, rooting percentage decreased as indole-3-butyric acid (IBA) concentration increased. Cutting position, auxin formulation, and solvent did not affect rooting. Mean root number and mean root length were unaffected by treatments. Results suggest semi-hardwood cuttings and low IBA concentrations [< 2500 ppm (0.25%)] promote rooting. Auxin concentration influenced rooting of caddo and shantung maple mound layered shoots. Rooting peaked at 15,000 ppm (1.5%) IBA for both caddo (71%) and shantung maples (34%). Mean root number for caddo, but not shantung, increased as IBA concentration increased. Differences in mean root length were not significant. Growers may now propagate caddo maple by mound layering. For shantung maple propagation, stem cuttings are recommended. Propagation substrates can strongly influence rooting success of stem cuttings. Eastern redcedar (Juniperus virginiana) chips (ERC) have been suggested as a propagation substrate component. This report investigated ERC as a perlite substitute in a 3 perlite: 1 sphagnum peat moss (v/v) rooting substrate. Stem cuttings of spreading euonymus (Euonymus kiautschovicus), forsythia (Forsythia x intermedia), English ivy (Hedera helix), lantana (Lantana camara), and coleus (Solenostemon scutellarioides) were rooted in substrates containing increasing concentrations of ERC hammer milled to pass a 4.8 mm (0.19 in) screen. All species rooted well (≥95%) in all substrates except forsythia which rooted poorly in all substrates (8% to 36%). ERC did not affect mean root number or mean root length in any species except spreading euonymus where mean root number peaked at 0% and 100% ERC content and mean root length decreased with increasing ERC content. Bulk density, container capacity, and total porosity increased as ERC replaced perlite. Physical properties of all substrates were suitable for cutting propagation. ERC can effectively replace perlite in rooting substrates for many ornamental species.

APA, Harvard, Vancouver, ISO, and other styles

37

Nakai, Érica Silva. "Quantificação da biomassa e estoque de carbono em diferentes coberturas vegetais por meio de sensoriamento remoto." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-28112016-141806/.

Full text

Abstract:

O aquecimento global desencadeia algumas alterações ambientais, que são causadas pelo aumento da concentração dos gases do efeito estufa. As florestas têm grande importância na regulação climática, no ciclo do carbono e na conservação da biodiversidade. A vegetação remove grande quantidade de dióxido de carbono e o armazena em diferentes partes. Para medir a captura do carbono atmosférico pela vegetação, estimou-se a biomassa vegetal. Este trabalho quantificou a biomassa acima do solo para obtenção do estoque de carbono em diferentes ecossistemas com o uso de sensoriamento remoto na Fazenda Figueira, em Londrina, Paraná. A fazenda possui uma área de 3.686,64 hectares (ha), sendo 1.435,44 ha ocupados por vegetação natural e 1.865,30 ha ocupados por pastagens. A vegetação predominante é a Floresta Estacional Semidecidual (FES), além de apresentar áreas de Floresta Ribeirinha (FR), pastagens, áreas agrícolas e edificações. Para a quantificação da biomassa vegetal aérea, foram estabelecidas 30 parcelas de 300 m2 nas áreas de FES e FR para medição do DAP e foram aplicadas três diferentes equações alométricas. Em relação às gramíneas, foram estabelecidas cinco parcelas de 10mx10m com o capim Tanzânia e, após ciclo de crescimento, foram cortadas subamostras de 1 m2 para cálculo da biomassa. A partir de duas cenas do Landsat-8/OLI, foram gerados quatro Índices de Vegetação: RS, NDVI, EVI e EVI2, referentes a 2014 e 2015. A análise estatística executada foi a correlação de Pearson e a regressão stepwise para selecionar as melhores variáveis. Os resultados mostraram que a maior densidade de espécies foi encontrada na FES do que FR, porém a maior riqueza foi na FR. Ambas florestas apresentaram distribuição diamétrica irregular. Nas três equações alométricas, a biomassa e o estoque de carbono foram maiores na FES do que FR. Em relação aos Índices de Vegetação, os valores de RS, NDVI, EVI e EVI2 foram maiores na FES do que FR e valores foram maiores em 2015 do que 2014. O mesmo ocorreu para os buffers de 50 m e 100 m para todos os índices estudados. A correlação de Pearson mostrou melhor correlação da biomassa florestal total com a equação de Medina Sotomayor com EVI/2015 e a análise de regressão stepwise indicou melhor relação para equação de Burger e Delitti com EVI/2015 (R2 = 0,3742). A biomassa do capim Tanzânia apresentou média de 3,67 Mg.ha-1 e média de carbono de 1,83 MgC.ha-1. Os valores médios dos Índices de Vegetação foram 0,67 para NDVI, 0,58 para EVI, 0,54 para EVI2 e 4,80 para RS. A análise de correlação de Pearson indicou forte correlação negativa da biomassa total de pastagem com todos os índices de vegetação e os valores de buffers de 50 m e 100 m. A análise de regressão stepwise foi significativa com EVI (R2 = 0,9124). A quantificação de biomassa e carbono é importante meio para mitigação climática e as imagens Landsat-8 permitiram diferenciar, por meio de índices de vegetação, as coberturas vegetais da Fazenda Figueira. O sensoriamento remoto tem um bom potencial em estimar a biomassa acima do solo.
Global warming triggers some environmental changes, which are caused by increased concentration of greenhouse gases. Forests have great importance in climate regulation, carbon cycle, and conservation of biodiversity. Vegetation removes and stores large amounts of carbon dioxide. To measure the amount of atmospheric carbon captured by vegetation, biomass is estimated. This study quantified the aboveground biomass for obtaining carbon stocks in different ecosystems by using of remote sensing at Figueira Farm, Londrina, Paraná. The farm has an area of 3686.64 hectares (ha), of which 1435.44 ha are occupied by natural vegetation and 1865.30 ha are occupied by pastures. The predominant vegetation is semideciduous forest (FES), along with areas of riparian forest (FR), pasture, agricultural, and buildings. For quantification of above ground biomass, thirty 300 m2 plots were established in the areas of FES and FR for measurement of DBH and were applied in three allometric equations. In relation to grasses, five 10mx10m plots of Tanzania grass were established and after their growth cycle, five subsamples of 1 m2 were cut into to calculate biomass. From two scenes of Landsat-8/OLI, were generated four vegetation index: SR, NDVI, EVI and EVI2, referring to 2014 and 2015. Pearson correlation and stepwise regression were applied to select the best variables. The results showed that species density in FES was higher than FR, but the greater richness was found in the FR. Both forests had irregular diameter distribution. Using three allometric equations, the above ground biomass and carbon stocks were higher in FES than FR. The vegetation indices, values for SR, NDVI, EVI, and EVI2 were higher in FES than FR and values were higher in 2015 than in 2014. The same difference between FES and FR occurred with buffers of 50 m to 100 m for all indices studied. Pearson correlation analysis showed a better correlation of total forest biomass with the Medina Sotomayor equation with EVI/2015 and stepwise regression analysis indicated a better value to the Burger and Delitti equation with EVI/2015 (R2 = 0.3742). Biomass of Tanzania grass showed an average biomass of 3.67 Mg.ha-1 and average carbon of 1.83 MgC.ha-1. The average vegetation indices were 0.67 for NDVI, 0.58 for EVI, 0.54 for EVI2, and 4.80 for SR. The pearson correlation analysis indicated a strong negative correlation among the total pasture biomass of among the and all vegetation indices and buffers of 50 m and 100 m. The stepwise regression analysis showed significant correlation with EVI (R2 = 0.9124). The quantification of biomass and carbon is an important way of climate mitigation and Landsat-8 images differentiate the vegetation covers of the Figueira Farm, throught vegetation indices. Remote sensing has good potential to provide data for estimating the above ground biomass.

APA, Harvard, Vancouver, ISO, and other styles

38

Coelho, Ana Margarida Matos. "Análise da variabilidade de povoamentos florestais com imagens de satélite." Master's thesis, Universidade de Évora, 2022. http://hdl.handle.net/10174/31716.

Full text

Abstract:

O objetivo deste trabalho foi a análise da variabilidade dos povoamentos florestais no Alto Alentejo, com dados derivados de imagens de satélite, nomeadamente do Sentinel-2. Para a análise da variabilidade dos povoamentos florestais, foi produzido um mapa de uso/ocupação do solo e calculadas métricas de diversidade, ao nível da classe e da paisagem. O mapa de uso/ocupação do solo foi obtido para 5 classes florestais e 1 não florestal, utilizando o algoritmo de classificação Random Forest, com as bandas, os índices de vegetação e os de texturas como variáveis independentes. Neste mapa obteve-se uma precisão global de 89% e um kappa de 86%. A heterogeneidade da paisagem foi avaliada com 11 métricas para o Alto Alentejo e para 4 sub-regiões. A composição e a configuração da paisagem da área estudo é bastante heterogénea. A variabilidade das métricas no Alto Alentejo e entre as regiões evidencia a diversidade dos povoamentos florestais; Analysis of forests stands variability with satellite images ABSTRACT: The objective this study is the analysis of the forest stands variability in Alto Alentejo with data derived from satellite images, namely of Sentinel-2. For the forest stands variability analysis, a soil land use and land cover map was produced and calculated the diversity metrics, at the class and landscape levels. The map was obtained through the classification of the satellite image, with 5 forest classes and 1 non forest class, using the classification algorithm Random Forest, with the bands, the vegetation and the texture indices as independent variables. The soil land use and cover map had global precision of 89% and a Kappa of 86%. The landscape heterogeneity was evaluated with 11 metrics for Alto Alentejo e for 4 sub-regions. The study area composition and configuration is rather heterogeneous. The metrics’ variability in Alto Alentejo and between the sub-regions highlights the diversity of the forest stands.

APA, Harvard, Vancouver, ISO, and other styles

39

Novas, Maria Fátima Bettini. "Mapeamento das estimativas do saldo de radiação e índices de vegetação em área do estado de Alagoas com base em sensores remotos." Universidade Federal de Alagoas, 2008. http://repositorio.ufal.br/handle/riufal/860.

Full text

Abstract:

The balance of radiation at the surface is of great importance in studies related to the flow of heat in the atmosphere, particularly in agricultural crops in areas and basins. This work mapped the components of the radiation balance of the land surface and vegetation indices of the area with the river basin Pratagy in Alagoas, by means of remote sensing data in days of clear sky. In the estimation of the components of the balance of radiation were used data from TM-Landsat 5 and algorithm SEBAL - Surface Energy Balance Algorithm for Land is proposed by Bastiaanssen Land (1995). We analyzed the images of the day 06/11/1990, 09/21/1998 and 09/03/2003. The average value of the Normalized Difference Vegetation Index (NDVI) in 0.633 was 06/11/1990, 0.607 and 0.502 on 09/21/1998 to 09/03/2003, evidencing reduction of vegetation in the area in 1990 to study 1998 and also from 1998 to 2003. The gradual reduction of NDVI that occurred between the years studied, where the low values of 0 - 0.20 are found in more urbanized area, may have resulted from the urbanization process which intensified in these years. The classified image of the subtraction of NDVI between 1990 and 1998, however, demonstrated that in 59.5% of the area in study was little variation in the index. Once in the image of the subtraction of NDVI between 1998 the 2003 evidenced more that in almost 50% of the area in study was loss of vegetation and more spatially distributed in the central part of it. The instantaneous average value of the balance of radiation to the surface (Rn) increased from 1990 to 1998 and decreased between 1998 and 2003, with ranges of 129.6 W/m2 and 77.3 W/m2 respectively. In the classified image subtraction of Rn between 1990 and 1998 found that the increase was well distributed in 93.4% of the area. And the image of the subtraction of Rn between 1998 and 2003 showed that the decrease of Rn was also well distributed spatially in 82.5% of the area. The estimated average snapshot of the surface temperature (Ts) between 1990 and 1998 was an increase in the range of 3.3ºC, while from 1998 to 2003 occurred decrease of 2.7ºC. The gradual increase Ts between 1990 and 1998, where values above 26ºC are found in more urbanized regions of the area under study may have been due to the intensification of the process of urbanization. The analysis of critical areas in relation to the occurrence of loss of vegetation cover has proved that the NDVI is related with the indireta the surface albedo and the Ts, while the Rn with a direct relationship. The analysis of the critical areas of loss or gain of Rn showed that the albedo and Ts almost always act inversely with the Rn and the rates of vegetation directly. It was evident to appropriate employment potential of SEBAL in studies of changes in vegetation and land use in watersheds of scale, since the identification of changes in species can occur by studying the maps of net radiation and rates of vegetation.
O saldo de radiação à superfície é de grande importância em estudos relacionados com o fluxo de calor na atmosfera, particularmente em cultivos agrícolas e em áreas hidrográficas. Neste trabalho são mapeadas as componentes do balanço de radiação à superfície terrestre e índices de vegetação em área com a bacia do rio Pratagy, em Alagoas, por meio de dados de sensores remotos em dias de céu claro. Na estimativa das componentes do balanço de radiação foram utilizados dados do TM-Landsat 5 e o algoritmo SEBAL - Surface Energy Balance Algorithm for Land proposto por Bastiaanssen (1995). Foram analisadas as imagens dos dias 11/06/1990, 21/09/1998 e 03/09/2003. O valor médio do Índice de Vegetação da Diferença Normalizada (IVDN) foi de 0,633 em 11/06/1990, 0,607 em 21/09/1998 e 0,502 para 03/09/2003, evidenciando diminuição de vegetação na área em estudo de 1990 a 1998 e também de 1998 a 2003. A diminuição gradativa do IVDN que ocorreu entre os anos pesquisados, onde os valores baixos de 0 0,20 são encontrados mais na área urbanizada da área, pode ter resultado do processo de urbanização que se intensificou nestes anos. A imagem classificada da subtração do IVDN entre 1990 e 1998, no entanto, demonstrou que em 59,5% da área em estudo ocorreu pouca variação no índice. Já na imagem da subtração do IVDN entre 1998 a 2003 evidenciou que em quase 50% da área em estudo ocorreu perda de vegetação e distribuída espacialmente mais na parte central da mesma. O valor médio instantâneo do saldo de radiação à superfície (Rn) aumentou de 1990 à 1998 e decresceu entre 1998 e 2003, com amplitudes de 129,6W/m2 e de 77,3W/m2 respectivamente. Na imagem classificada da subtração do Rn entre 1990 e 1998 constatou-se que o aumento ocorreu bem distribuído em 93,4% da área estudada. E na imagem da subtração do Rn entre 1998 e 2003 evidenciou que a diminuição do Rn foi também bem distribuída espacialmente em 82,5% da área estudada. O valor estimado médio instantâneo da temperatura da superfície (Ts) entre 1990 e 1998 teve uma elevação na faixa de 3,3ºC, enquanto de 1998 a 2003 ocorreu diminuição de 2,7ºC. O aumento gradativo da Ts entre 1990 e 1998, onde os valores superiores a 26ºC são encontrados mais em regiões urbanizadas da área em estudo pode ter sido devido à intensificação do processo de urbanização. A análise das áreas críticas em relação à ocorrência de perda da cobertura vegetal comprovou que o IVDN tem relação indireta com o albedo da superfície e com a Ts, enquanto com o Rn uma relação direta. A análise das áreas críticas de perda ou ganho de Rn comprovou que o albedo e a Ts quase sempre atuam inversamente com o Rn e os índices de vegetação diretamente. Ficou evidenciada a apropriada potencialidade do emprego do SEBAL em estudos de alterações na vegetação e uso da terra em escala de bacias hidrográficas, uma vez que a identificação em mudanças das espécies pode ocorrer pelo estudo dos mapas de saldo de radiação e de índices de vegetação.

APA, Harvard, Vancouver, ISO, and other styles

40

Rodrigues, Thalita Scharr. "AVALIAÇÃO DE ÍNDICES DE VEGETAÇÃO EM IMAGENS ORBITAIS." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2013. http://tede2.uepg.br/jspui/handle/prefix/159.

Full text

Abstract:

Made available in DSpace on 2017-07-21T14:19:36Z (GMT). No. of bitstreams: 1 Thalita Scharr Rodrigues.pdf: 2564832 bytes, checksum: f5dd6e058b05dbc659cf7c0d5698160c (MD5) Previous issue date: 2013-02-25
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The Remote Sensing has many techniques and technologies which are able to be applied in agriculture. Among these applications are the analysis of images taken by satellites that are in orbit around the Earth. In this work were used orbital images from Landsat 5 TM and 7 ETM+ about the years 2001, 2004 and 2009 in order to analyze the performance of the application of different vegetation indices such as NDVI, NRVI, SAVI, MSAVI2, AVI and TTVI. Statistical techniques were used as well as image processing, such as visual analysis, Histogram, Index Universal Image Quality (IQI) and Mean Square Error. Among the assessment techniques used were the most appropriate visual analysis in conjunction with the application of the IQI and histogram to detect differences in rates of phenological cycles of discrimination agricultural crops, natural vegetation and soils without vegetation. Indexes that showed the lowest performances were CTVI, followed by TTVI and AVI. The application of these vegetation indices enabled the monitoring of land use in the study area over the three years, without the need for continuous trips to the field.Although the spatial resolution is 30 meters, which is considered moderate for the case study, the images from Landsat 5 TM and Landsat 7 ETM were appropriate for this study.
O Sensoriamento Remoto possui diversas técnicas e tecnologias que podem ser aplicadas na Agricultura. Entre essas técnicas está a análise de imagens obtidas por satélites que estão em órbita ao redor da Terra. Nesse trabalho foram trabalhadas imagens orbitais do Satélite Landsat 5 TM e 7 ETM+ dos anos de 2001, 2004 e 2009 de uma região do município de Ponta Grossa, visando analisar o desempenho da aplicação de diferentes índices de vegetação, como o NDVI, NRVI, SAVI, MSAVI2,AVI, CTVI e TTVI. Foram também utilizadas análises estatísticas e técnicas de processamento de imagem, como análise visual, histograma, Índice de Qualidade Universal da Imagem (IQI) e Erro Médio Quadrático. Dentre as técnicas de avaliação utilizadas, as mais adequadas foram a análise visual em conjunto com o histograma e a aplicação do IQI para verificar as diferenças dos índices na discriminação de ciclos fenológicos de culturas agrícolas, vegetação natural e solos sem cobertura vegetal. Os índices que apresentaram os menores desempenhos foram o CTVI, seguido do TTVI e AVI, respectivamente. A aplicação desses índices de vegetação possibilitou o monitoramento do uso do solo da área estudada ao longo dos três anos, sem a necessidade de idas continuas ao campo. Embora a resolução espacial seja de 30 metros, considerada moderada para o estudo de caso, as imagens do Satélite Landsat 5 TM e Landsat 7 ETM+ foram adequadas para o presente estudo.

APA, Harvard, Vancouver, ISO, and other styles

41

Novotný, Jan. "Multispektrální analýza obrazových dat." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228360.

Full text

Abstract:

The airborne hyperspectral remote sensing is used as an approach to monitor actual state of environmental components. This thesis covers priority treatment to analyse of hyperspectral data with the aim of a tree crowns delineation. Specific algorithm applying adaptive equalization and the Voronoi diagrams is designed to subdivide a forest area into individual trees. A computer program executes the algorithm and allows testing it on real data, checking and analyzing the results.

APA, Harvard, Vancouver, ISO, and other styles

42

Alba, Elisiane. "CARACTERIZAÇÃO ESPECTRAL DOS DOSSÉIS E ESTIMATIVA DE VARIÁVEL BIOFÍSICA EM PLANTIOS DE Eucalyptus grandis e Pinus elliottii A PARTIR DE IMAGENS LANDSAT 8/OLI." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/8781.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The area occupied by planted forests has increased significantly in the country, especially with Eucalyptus and Pinus genus. However, the means of determining of dendrometric variables the field are costly, require time and covers small areas. Thus, the orbital products applied in estimating the biophysical variables constitute an important source of data, which facilitate the process of acquiring information of the canopies, being useful, especially, in the planning in order to optimize productivity. This manner, this study aims evaluate the potential of the Landsat 8 satellite images in the differentiation of stage of growth and determining the biophysical variable of Eucalyptus grandis e Pinus elliottii. We used the 221-083 scene of Landsat 8/OLI satellite of the day 30th August 2013, being this converted to surface bidirectional reflectance from the radiometric calibration and, subsequently generated the ARVI vegetation indices, NDVI, NDVI, MVI, NDVI, SAVIL=0.25 SAVIL=0.50 and SR. The spectral behavior of the stands with different ages was established based on the reflectance of the red and near infrared bands. The reflectance of the bands and vegetation indexes was related to the forest volume, analyzing their correlation and adjustment of the data to the regression models, leading to selection of variables through Stepwise method. The Landsat 8 images are sensitive the variations of the characteristics of individuals according to the different growth stages of the forest stands, wherein for E. grandis to 4, 18 and 23 years, the increasing age caused reduction in reflectance in the NIR band and increased in the band Red. However, in stands of P. elliottii it was observed that increasing age led to an increased reflectance in the NIR band and reduction in red band. Correlation analysis between the spectral data and the forest volume of E. grandis showed that SAVIL=0.50 index showed better correlation with forest variable at both ages. The stands of P. elliottii the B5 band showed higher correlation with the volume to 9 years old, however at 10 years of age, the DVI index showed the highest correlation with the forest variable. Regression analysis for E. grandis has exposed the models of best fit, so that at 4 and 18, the equation containing the SAVI index explained 76% and 68% of the variability of the data. At 23 years, the composite model of the SAVI index and B7 band obtained R²aj of 0.67. For P. elliottii the best model to 9 years of age explained 74% of data variability, being this composed of the DVI index and B7 band. Thus, the Landsat 8 / OLI data can be used in forest planning, assisting in forest inventory, as well as knowledge of the individual phases of growth and the identification of forest species.
A superfície ocupada por florestas plantadas tem aumentado significativamente no território nacional, especialmente com os gêneros Eucalyptus e Pinus. Contudo, os meios de determinação das variáveis dendrométricas a campo são onerosos, requer de tempo e abrangem pequenas áreas. Assim, os produtos orbitais aplicados na estimativa das variáveis biofísicas constituem-se de uma importante fonte de dados, os quais facilitam o processo de aquisição de informações dos dosséis, sendo útil, especialmente, no planejamento visando a otimização da produtividade. Desse modo, esse estudo tem por objetivo avaliar a potencialidade das imagens do satélite Landsat 8 na diferenciação do estágio de crescimento e determinação da variável biofísica de Eucalyptus grandis e Pinus elliottii. Utilizou-se a cena 221-083 do satélite Landsat 8/OLI do dia 30 de agosto de 2013, sendo essa convertida para reflectância bidirecional de superfície a partir da calibração radiométrica e, posteriormente gerados os índices de vegetação ARVI, DVI, GNDVI, MVI, NDVI, SAVI25, SAVI50 e SR. O comportamento espectral dos povoamentos com idades distintas foi estabelecido com base na reflectância das bandas do vermelho e infravermelho próximo. A reflectância das bandas e índices de vegetação foi relacionada com o volume florestal, analisando a sua correlação e o ajuste dos dados à modelos de regressão, conduzindo a seleção de variáveis por meio do método Stepwise. A imagem Landsat 8/OLI mostrou-se sensível às variações das características dos indivíduos em função das diferentes fases de crescimento dos povoamentos florestais, sendo que para E. grandis aos 4, 18 e 23 anos, o aumento da idade ocasionou a redução da reflectância na banda B5 e aumento na banda do vermelho. No entanto, em povoamentos de P. elliottii observou-se que o aumento da idade propiciou um aumento da reflectância na banda B5 e redução na banda do vermelho. A análise de correlação entre os dados espectrais e o volume florestal de E. grandis demonstrou que o índice SAVIL=0,50 apresentou melhor correlação com variável florestal em ambas as idades. Para povoamentos de P. elliottii a banda B5 demonstrou maior correlação com o volume aos 9 anos de idade, porém aos 10 anos de idades, o índice DVI apresentou maior correlação com a variável florestal. A análise de regressão para E. grandis expôs os modelos de melhor ajuste, de modo que aos 4 e 18 anos, a equação contendo o índice SAVI explicou 76% e 68% da variabilidade dos dados, respectivamente. Aos 23 anos, o modelo composto pelo índice SAVI e a banda B7 obteve R²aj de 0,67. Para P. elliotti o melhor modelo aos 9 anos de idade explicou 74% da variabilidade dos dados, sendo esse composto pela banda B5, já aos 10 anos o modelo englobou 73% da variabilidade, sendo esse composto pelo índice DVI e a banda B7. Desse modo, os dados Landsat 8/OLI podem ser utilizados no planejamento florestal, auxiliando em inventários florestais, bem como no conhecimento das fases de crescimento dos indivíduos e na identificação de espécies florestais.

APA, Harvard, Vancouver, ISO, and other styles

43

Vasques, Eltiza Rondino. "Qualidade ambiental urbana do Distrito da Liberdade, município de São Paulo (SP)." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-07032018-102753/.

Full text

Abstract:

A urbanização, quando não é devidamente planejada, potencializa impactos ambientais negativos ao ambiente e danos à saúde da população, pois traz consigo mudanças no meio físico e biológico, devido à descaracterização dos cursos dágua, mudança na geomorfologia dos terrenos, impermeabilização dos solos, corte de vegetação, verticalização das construções, entre outros. O conhecimento sobre a qualidade ambiental urbana em cidades já estabelecidas permite identificar os aspectos e impactos ambientais negativos decorrentes das ações humanas, planejar e propor ações de melhoria que favoreçam o bem estar da população e diminuam problemas de saúde causados pela urbanização. Este trabalho objetivou determinar o nível de qualidade ambiental urbana, considerando variáveis que causam impactos ambientais urbanos negativos e positivos, no distrito Liberdade, município de São Paulo, SP. Para a determinação do nível de qualidade ambiental, foram avaliados os seguintes atributos ambientais, adaptados e ampliados a partir de Nucci (1996): usos potencialmente poluidores, tráfego de veículos de passeio e de ônibus, poluição sonora, pontos de alagamentos e enchentes, densidade demográfica, verticalização das edificações, abastecimento de água e coleta de esgotos, coleta de resíduos sólidos, estado das calçadas e presença de espaços livres públicos, áreas verdes, cobertura vegetal e arborização urbana. Para cada um desses atributos, foram determinados índices que permitiram quantificar e indicar o nível de qualidade ambiental dos trechos estudados. Como a presença de um uso potencialmente poluidor interfere no ambiente com diversos impactos ambientais, os usos potencialmente poluidores tiveram maior influência na classificação da qualidade ambiental do distrito. O distrito da Liberdade apresenta, no geral, trânsito moderado em todas as suas ruas e avenidas, na grande maioria das vias do distrito trafegam ônibus e o índice de poluição sonora ultrapassa os níveis de critério de avaliação para ambientes externos determinados pela norma vigente. Os pontos de enchente registrados localizam-se predominantemente ao norte do distrito, próximo ao córrego Moringuinho. O distrito da Liberdade é bastante verticalizado e a tendência é de continuidade deste processo, pois há áreas que estão em processo de regularização para construção de novos edifícios. Em relação ao saneamento básico, 100% da população é atendida por abastecimento de água, 98,5% por coleta e tratamento de esgoto e 100%, por coleta domiciliar de resíduos. A potencialidade média das calçadas é maioria no distrito, as áreas com cobertura vegetal correspondem a 8,3% da área do distrito e o índice de espaços livres públicos é de 2,12 m² por habitante.
Urbanization, when not properly planned, potentiates adverse environmental impacts and damage to the health of the population because it brings with it changes in the biological and physical environment, due to the plugging of watercourses, changes in the geomorphology of the land, soil sealing, vegetation depletion, building verticalization, among other factors. By knowing the urban environmental quality in already established cities, one can identify negative environmental aspects and impacts resulting from human actions, as well as plan and propose improvements that enhance the well-being of the population and reduce health problems caused by urbanization. This work aims to determine the level of urban environmental quality, considering variables that cause negative and positive urban environmental impact, in the district of Liberdade, in the city of São Paulo, State of São Paulo, Brazil. For determining the level of environmental quality, the following environmental attributes were evaluated, adapted and expanded from Nucci (1996): potentially polluting usages; car and bus traffic; noise pollution; inundation and floods; population density; verticalization of buildings and constructions; water supply and sewage collection; solid waste collection; condition of sidewalks; and presence of free public spaces, green areas, vegetation cover and urban forestry. For each of these attributes, indices were determined to quantify and indicate the level of environmental quality of the areas studied. Since the occurrence of a potentially polluting usage interferes with the environment with various environmental impacts, potentially polluting usages have had a major influence on the classification of environmental quality in the district. The District of Liberdade features, overall, moderate traffic in all its streets and avenues, buses travel in most of the district\'s roads, and the pollution index exceeds the levels of assessment criteria for external environments determined by current regulations. Areas in which floods have been recorded are located predominantly in the North of the district, near the Moringuinho stream. The District of Liberdade is predominantly vertical, and this process tends to continue since there are several areas in the process of being regularized for the construction of new buildings. As for sanitation, 100% of the population are served by water supply, 98.5% for sewage collection and treatment, and 100% for household waste collection. The sidewalks in the district are predominantly of medium capability, areas with vegetation cover correspond to 8.3% of the district area, and the index of free public spaces is 2.12 m² per inhabitant.

APA, Harvard, Vancouver, ISO, and other styles

44

Silva, Janilci Serra. "Análise multitemporal do uso e ocupação da terra e identificação de ilhas de calor no município de Paço Lumiar (MA)." Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8935.

Full text

Abstract:

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2017-04-20T11:23:36Z No. of bitstreams: 1 arquivototal.pdf: 8351291 bytes, checksum: 9c34c27730ae5014b89097e887df8ee5 (MD5)
Made available in DSpace on 2017-04-20T11:23:36Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 8351291 bytes, checksum: 9c34c27730ae5014b89097e887df8ee5 (MD5) Previous issue date: 2016-03-31
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The recent process of city urbanization has intensified the changes in the land use and occupation, causing various environmental impacts from the transformation of the natural environment without planning. Among the environmental impacts there is the reduction of vegetation cover areas, occurrence of floods, air pollution and rising temperatures. Urban areas of cities tend to have higher temperatures than the areas to their surroundings and the very urban area, this phenomenon is called heat islands. Various techniques have been used to analyze the influence of the use and occupation of land in the heat island phenomenon, among them stands out the use of geotechnology for the Remote Sensing and Geographic Information Systems (GIS). In this perspective, this study aims to analyze the influence of land use and occupation in the emergence of heat islands in the city Paço do Lumiar – MA. The Delimitation of the study area analyzed in this study area analyzed in this research is justified by the fact present: (1) quick growth of urban population, (2) expansion of the urban network and (3) severe change of use and occupation of land. To develop this research, were adopted using techniques of remote sensing, digital processing of satellite imagery in a GIS environment. These techniques were used to classify the use and occupation of land and estimation of biophysical parameters: vegetation index (NDVI, IVAS and LAI), albedo, surface temperature (°C) and net radiation (W/m²). The results of the land use and occupancy classification showed that in 1988 the urban area occupied a total of 10.84 square kilometers and in 2014 rose to 22.47 km². The albedo values ranged from 0.06 to 1.02. The lowest values of albedo were found in areas with presence of water and vegetation cover higher density and higher values in more densely urbanized areas without vegetation. The analysis of NDVI of the spatio-temporal variation, IVAS and LAI occurred to the surface showed clear reduction of the class of higher values of vegetation, showing the replacement of vegetation by areas with greater urbanization, the lowest values of vegetation indices are observed mainly in the southwest portion of the city, area where are located the most densely occupied neighborhoods, like the Maiobão the neighborhood. It was verified that the surface temperatures showed certain pattern of spatial variation, above all, time. In dates analyzed surface temperature ranged from 23 to 37 °C, the lowest values were observed in class and vegetation water of higher density, showing that areas with greater availability of water and the presence of vegetation. The estimated net radiation revealed that the highest values of net radiation are found on areas with presence of dense vegetation and water bodies and the lowest values in the urban classes and shrub/herbaceous, with values ranging from 450 to 736 W/m² . The results of multi-temporal analysis of the use and occupation of the land made it possible to evaluate the influence of vegetation cover and fragmentation on the urban environment of the study area and contributed to data acquisition for monitoring environmental quality.
O processo de urbanização recente das cidades tem intensificado as modificações do uso e ocupação da terra, ocasionando diversos impactos ambientais oriundos da transformação do meio natural sem planejamento. Dentre os impactos ambientais, destaca-se a redução das áreas com cobertura vegetal, ocorrência de enchentes, poluição do ar e aumento das temperaturas. As zonas urbanas das cidades tendem a apresentar temperaturas mais elevadas do que as áreas ao seu entorno e na própria área urbana, este fenômeno é denominado de ilhas de calor. Várias técnicas têm sido utilizadas para analisar a influência do uso e ocupação da terra no fenômeno de ilhas de calor, entre elas destaca-se o uso das geotecnologias referentes ao Sensoriamento Remoto e aos Sistemas de Informações Geográficas (SIG). Nessa perspectiva, este estudo tem como objetivo analisar a influência do uso e ocupação da terra no surgimento de ilhas de calor na cidade de Paço do Lumiar - MA. A delimitação da área de estudo analisada nesta pesquisa se justifica pelo fato de apresentar: (1) crescimento acelerado da população urbana, (2) expansão da malha urbana e (3) intensa alteração do uso e ocupação da terra. Para desenvolver desta pesquisa, foram adotados o uso de técnicas de sensoriamento remoto, processamento digital de imagens de satélite em ambiente SIG. Essas técnicas foram utilizadas para a classificação do uso e ocupação da terra e estimativa dos parâmetros biofísicos: índices de vegetação (IVDN, IVAS e IAF), albedo, temperatura da superfície (°C) e saldo de radiação (W/m²). Os resultados da classificação de uso e ocupação da terra mostraram que em 1988 a área urbana ocupava um total de 10,84 km² e em 2014 passou para 22,47 km². Os valores do albedo variaram entre 0,061,02. Os menores valores do albedo foram encontrados em áreas com presença de água e com cobertura vegetal de maior densidade e os maiores valores em áreas mais densamente urbanizada e sem cobertura vegetal. A análise da variação espaço-temporais do IVDN, IVAS e IAF ocorridas à superfície, demonstrou clara diminuição da classe dos valores mais elevados de vegetação, evidenciando a substituição da cobertura vegetal por áreas com maior urbanização. Os menores valores dos índices de vegetação são observados principalmente na porção sudoeste do município, área onde estão localizados os bairros mais densamente ocupados, a exemplo o bairro do Maiobão. Pôde-se verificar que as temperaturas de superfície apresentaram certo padrão de variação espacial, sobretudo, temporal. Nas datas analisadas a temperatura de superfície variou de 23 a 37°C, cujos menores valores são observados na classe de água e vegetação de maior densidade, evidenciando que áreas com maior disponibilidade de água e presença de vegetação podem contribuir para a amenização dos efeitos de anomalias térmicas como as ilhas de calor. A estimativa do saldo de radiação revelou que os maiores valores do saldo de radiação são encontrados sobre áreas com presença de vegetação densa e corpos hídricos e os menores valores nas classes urbano e vegetação arbustiva/herbácea, com valores variaram de 450 a 736 W/m². Os resultados da análise multitemporal do uso e ocupação da terra possibilitaram avaliar a influência da cobertura vegetal e sua fragmentação sobre o ambiente urbano da área de estudo e contribuíram para aquisição de dados para monitoramento da qualidade ambiental.

APA, Harvard, Vancouver, ISO, and other styles

45

SILVA, Anderson Santos da. "Estimativa de produtividade da cana-de-açúcar utilizando dados agrometeorológicos e imagens do sensor MODIS." Universidade Federal Rural de Pernambuco, 2016. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/5319.

Full text

Abstract:

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-15T13:14:14Z No. of bitstreams: 1 Anderson Santos da Silva.pdf: 1059889 bytes, checksum: ff989424df01788dbda8e075b1d48a91 (MD5)
Made available in DSpace on 2016-08-15T13:14:14Z (GMT). No. of bitstreams: 1 Anderson Santos da Silva.pdf: 1059889 bytes, checksum: ff989424df01788dbda8e075b1d48a91 (MD5) Previous issue date: 2016-02-26
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
This research is based on estimated and observed agricultural productivity in an area of commercial sugarcane production located at São Francisco’s Agroindustry – AGROVALE S.A., Juazeiro – BA, Brazilian northeast. The new yield estimation models were obtained by multiple linear regression, in which the inputs variables were: irrigation, precipitation, average air temperature, vapor saturation deficit of the air, photoperiod, normalized difference vegetation index (NDVI), leaf area index (LAI) and fractional soil cover (FC). To obtain these models, it was used the statistics program Statística version 10. Futhermore, the meteorological data were obtained from an automatic weather station located at the Farm Brasil Uvas, Juazeiro – BA such as: precipitation (mm), temperature (°C), relative humidity (%), evapotranspiration (mm), current vapor pressure (hPa) and saturation vapor pressure (hPa). The crop yield data and parameters related to crop development were obtained from AGROVALE Agriculture Department. The spectral data, NDVI, IAF and FC, were extracted from MODIS sensor images (Spectroradiometer Imager Moderate Resolution). The data used to models validation were obtained from the same sources previously mentioned. The data were analyzed by mean absolute error (DMA) and mean relative error (DMR). The comparison of yield observed and estimated values showed that the spectral agrometeorological model (SAM) presented the lower and better mean relative error (DMR) with a mean variation of 0.34 %, followed by agrometeorological model with a mean variation of 1.37 % and, finally, the spectral model presented larger mean relatives errors in comparison with other two models, showing a mean variation of 6.58%, approaching AGROVALE’s technicians estimation that presented a mean variation of 6.75%. At the validation’s model for the 2004/2005 crop year, the spectral surpassed the agrometeorological and agrometeorological spectral with average relative errors of 5.05%, while for other models the difference were 15.11% and 16.19%, reflecting a productivity of 93.05 t ha-1 versus 83.19 t ha-1 and 82.13 t ha-1 of agrometeorological and agrometeorologicalspectral models, respectively, for an observed yield of 98 t ha-1. Soon after the 2011/2012 years crop there was a planting renovation with a new variety, with different physiology and consequently a distinct productive power and, from 2013/2014 crop year, the models underestimated the productivity compared to the real. The estimate made by the technicians, based on the crop development since planting until next harvest, showed satisfactory results as well as the tested models.
Esta pesquisa baseou-se na avaliação de produtividade agrícola estimada e observada em uma área de cultivo comercial de cana-de-açúcar localizada na Agroindústria do Vale do São Francisco – AGROVALE S.A., Juazeiro – BA, sertão nordestino. Novos modelos de estimativas de produtividades foram obtidos por regressão linear múltipla utilizando-se, como variáveis de entrada: a irrigação, a precipitação, a temperatura média do ar, o déficit de saturação de vapor do ar, o fotoperíodo, o índice de vegetação por diferença normalizada (NDVI), o índice de área foliar (IAF) e a fração de cobertura do solo (FC). Para obtenção desses modelos utilizou-se o programa estatístico Statística versão 10. Além disso, os meteorológicos foram obtidos na estação meteorológica automática instalada na Fazenda Brasil Uvas, em Juazeiro – BA sendo elas: precipitação, temperatura, umidade relativa, evapotranspiração, pressão atual de vapor e pressão de saturação de vapor. Os dados de rendimento agrícola e parâmetros inerentes ao desenvolvimento da cultura foram disponibilizados pelo Departamento Agrícola da usina AGROVALE. Os dados espectrais: NDVI, IAF e FC foram extraídos de produtos derivados de imagens orbitais do sensor MODIS (Espectrorradiômetro Imageador de Resolução Moderada). Os dados para validação dos modelos também foram obtidos nas mesmas fontes citadas anteriormente. Os dados foram avaliados por meio do cálculo do erro médio absoluto e do erro médio relativo ou percentual. A comparação dos valores observados e estimados de produtividades mostra que o modelo agrometeorológico-espectral (MAE) apresentou as menores e melhores diferenças médias relativas com uma variação média de 0,34%, seguido do modelo agrometeorológico (MA) com uma variação média de 1,37% e por último o modelo espectral (ME) apresentou as maiores diferenças médias relativas, quando comparado com os outros dois modelos obtendo uma variação média de 6,58%, aproximando-se mais da estimativa feita pelos técnicos da usina que apresentou variação média de 6,75%. Na validação dos modelos para o ano-safra de 2004/2005 o espectral superou os agrometeorológico e o agrometeorológico-espectral com diferenças médias relativas na ordem de 5,05% enquanto nos demais modelos as diferenças foram de 15,11% e 16,19%, refletindo numa produtividade de 93,05 t ha-1 contra 83,19 t ha-1 e 82,13 t ha-1 dos modelos agrometeorológicos e agrometeorológico-espectral, respectivamente, para uma produtividade observada de 98 t ha-1. Logo após a safra de 2011/2012 ocorreu uma renovação de plantio com nova variedade, fisiologia diferenciada e, consequentemente, um poder produtivo distinto e a partir da safra de 2013/2014 os modelos subestimaram a produtividade quando comparadas com o real. A estimativa feita pelos técnicos da usina baseada no desenvolvimento da cultura desde o plantio até próximo da colheita, apresentou resultados satisfatórios assim como os modelos testados.

APA, Harvard, Vancouver, ISO, and other styles

46

Swoish, Michael Joseph. "Technological Innovations for Mid-Atlantic Cropping Systems." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/104449.

Full text

Abstract:

Greater projected demand for food, fuel, and fiber will require substantial increases in global agricultural production over the next three decades. Climate change is also forecasted to make weather events more extreme and variable. Efficiency will become more important as demand for food products increases and the availability of fertilizer and land decreases. Technology may be of paramount importance for pushing the boundaries of production while remaining sustainable for generations to come. The first chapter of this dissertation investigated the importance of rate and timing of the plant growth regulator trinexapac-ethyl to malting barley in Virginia. Plant growth regulators can help plants remain upright during strong winds, thereby preserving grain quality and yield. However, this study demonstrated that risks of plant injury also exist. Application should be restricted to fields with greater risk of lodging and made only after the barley crop has broken dormancy and a substantial increase in air temperature is not forecasted in the week following application. Chapter two compared the efficacy of eight vegetation indices calculated from three satellites (Landsat 8, Sentinel 2, and Planet) for estimating cover crop biomass. Cover crops can have beneficial effects on agricultural land as well as groundwater and surface water, but only when adequate biomass is established to reduce erosion and nutrient leaching. Satellite imagery was able to estimate multi-species cover crop biomass more accurately than field-based sensors, although the most accurate vegetation index was dependent upon which satellite was being tested. Chapter three investigated the potential of Arabidopsis thaliana ipk1-, a loss-of-function mutant which exhibits decreased growth at elevated phosphorus concentration, for serving as in indicator of plant available phosphorus. An indicator crop could provide greater spatial resolution compared to soil testing, as well as represent plant available nutrients as opposed to chemically extracted nutrient estimations. Plant response exhibited a quadratic relationship with media P concentration in the range of fertilizer decision making for maize, providing valuable insight for potential yield response in agricultural fields below 'very high' phosphorus concentration.
Doctor of Philosophy
Climate change, increased demand for locally sourced ingredients, and elevated pressure for environmentally responsible practices will make meeting the growing demand for food difficult for farmers to achieve over the next few decades. Similar to many other industries, implementation of advanced technology may be necessary to keep up with agricultural demand. Plant growth regulators are one such technology which when applied to plants can cause them to remain short, decreasing the chance of blowing over during windstorms. However, chapter one of this dissertation concluded that risks of plant injury also exist when applying plant growth regulator on malting barley (for brewing or distilling). Application should be restricted to fields with greater risk of wind damage (e.g. taller barley) and made only after the barley crop begins spring growth and a decrease in air temperature is not forecasted in the week following application. Chapter two compared eight spectral vegetation indices across three satellites with different image resolution for their ability to estimate cover crop biomass. Cover crops protect groundwater and surface water quality, but only when adequate growth is achieved. Satellite imagery was able to estimate multi-species cover crop biomass more accurately than field-based sensors, although the most accurate vegetation index was dependent upon which satellite was being tested. Chapter three investigated the potential of Arabidopsis thaliana ipk1-, a loss-of-function mutant which exhibits decreased growth at elevated phosphorus concentration, as in indicator of plant available phosphorus in soil. An indicator crop could help determine which areas of a field are likely to have increased crop yield if fertilized and which are not. The mutant tested could be useful as an indicator crop given its response to phosphorus concentration, warranting further research with other plant species more appropriate for field use.

APA, Harvard, Vancouver, ISO, and other styles

47

Monteiro, Thereza Rachel Rodrigues. "Uso dos solos, índices de vegetação e degradação na Apa das Onças-PB." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/5863.

Full text

Abstract:

Made available in DSpace on 2015-05-14T12:17:22Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5665085 bytes, checksum: bd60dc545169e5595140b6912f25b1dd (MD5) Previous issue date: 2013-08-19
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Caatinga Biome is little known and has been suffering severe environmental pressures, including in existing protected areas, being the use of geotechnologies of fundamental importance in the deepening of knowledge about that environment. The APA das Onças (São João do Tigre - Paraiba) was chosen for this study because of the diversity of existing ecosystems, associated with the presence of degradation that has systematically changing this area. This research aimed to apply different vegetation indexes to identify areas in APA that show high and low vegetation cover. Soon after this , we applied the NDVI index (Normalized Difference Vegetation) and SAVI (Soil ajusted Vegetation Index), noting which ones would fit the reality seen in the field survey, and subsequently it has identified Anthropization levels that has occurred in this conservation area to eventually create a basemap that guide the interventions for the protection of natural resources present. To achieve these goals were accomplished on-site visits and digital processing of satellite images Lansat 5, TM sensor , for the years 1989, 1992 and 2010 for the identification of landscape units and Anthropization levels. The digital processing of images, it was possible to perform the atmospheric correction, radiance and reflectance in ERDAS 9.3 images to generate the vegetation indexes NDVI and SAVI, and subsequently conference in Excel 2007 spreadsheet. Based on NDVI and SAVI thematic maps generated in Arcgis 9.3, it was identified spatially what would best represent the reality found. The SAVI showed better the biomass reality present in the APA , while the NDVI did not distinguish reliably targets on the surface, confusing which would be degraded area and Caatinga Hiperxerophyle. With SAVI was possible to create a base map of thematic maps of landscape units of the APA , with the following classes : Environmental Degradation , Caatinga Hiperxerophyle , Caatinga hypoxerophytic , Mata Serrana and Brejo de Altitude. In spatio-temporal analysis in images 1989 , 1992 and 2010, it was perceived increase in degraded areas or who have suffered some kind of change in vegetation due to land use for agricultural purposes or due to extraction. The data found indicates the urgent need for the development of intense surveillance actions to curb the changes , while activities should be encouraged to use existing resources on a sustainable basis.
O Bioma Caatinga ainda é pouco conhecido e vem sofrendo fortes pressões ambientais, inclusive nas Unidades de Conservação existentes, sendo o uso das geotecnologias de fundamental importância no aprofundamento do conhecimento sobre esse ambiente. A APA das Onças (município de São João do Tigre - Paraíba) foi escolhida para esse estudo em virtude da diversidade de ecossistemas existentes, associada a presença de degradação que vem alterando sistematicamente essa área. Essa pesquisa objetivou aplicar diferentes índices de vegetação para identificar áreas na APA que apresentem maior e menor cobertura vegetal. Logo após isso, foi aplicado o NDVI (Índice de Vegetação da Diferença Normalizada) e o SAVI (Soil Ajusted Vegetation Index), observando qual deles se adequaria a realidade vista no levantamento de campo, e posteriormente identificou-se os níveis de antropização que têm ocorrido nessa Unidade de Conservação para finalmente, criar uma base cartográfica que orientasse as intervenções de proteção aos recursos naturais presentes. Para alcançar esses objetivos foram realizado visitas in loco e o tratamento digital das imagens de satélite Lansat 5, sensor TM, referentes aos anos de 1989, 1992 e 2010 para a identificação das unidades de paisagem e os níveis de antropização. No tratamento digital das imagens, foi possível realizar a correção atmosférica, a radiância e a reflectância das imagens no Erdas 9.3 para a geração dos índices de vegetação NDVI e SAVI, e subsequentemente, conferência em planilha do Excel 2007.Com base nos mapas temáticos de NDVI e SAVI gerados no Arcgis 9.3, foi identificado espacialmente o que representaria melhor a realidade encontrada. O SAVI apresentou melhor a realidade da biomassa presente na APA, enquanto o NDVI não distinguiu de forma fidedigna os alvos na superfície, confundindo o que seria área degradada e Caatinga Hiperxerófila. Com o SAVI foi possível criar a base cartográfica dos mapas temáticos das unidades de paisagens da APA, com as seguintes classes: Degradação Ambiental, Caatinga Hiperxerófila, Caatinga Hipoxerófila, Mata Serrana e Brejo de Altitude. Na análise espaço-temporal nas imagens de 1989, 1992 e 2010, foi percebido aumento das áreas degradadas ou que sofreram algum tipo de alteração na vegetação em função do uso das terras para fins agropecuários ou devido ao extrativismo. Os dados encontrados indicam a necessidade urgente do desenvolvimento de ações intensas de fiscalização, para coibir as alterações verificadas, ao mesmo tempo que devem ser incentivadas atividades de uso dos recursos existentes em bases sustentáveis.

APA, Harvard, Vancouver, ISO, and other styles

48

Kaptue, Armel. "Cartographie des écosystèmes et paramètres biophysiques satellitaires pour l'étude des flux hydriques sur le continent africain." Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00547510.

Full text

Abstract:

Dans le contexte des changements climatiques, l'objectif du travail effectué est de caractériser l'hétérogénéité du continent africain afin de mieux comprendre et quantifier les processus de surface agissant sur les flux hydriques. Ce travail s'inscrit dans le cadre de la mise à jour de la base de données ECOCLIMAP-I constituée d'une carte d'occupation des sols et des cartes de paramètres biophysiques. Pour cela, on s'appuie sur des données de télédétection acquises par les capteurs de dernière génération MODIS et SPOT/VEGETATION entre 2000 et 2007. Dans un premier temps, deux techniques de classification ont été développées afin de cartographier les différents écosystèmes. L'une, supervisée, a été conduite dans le contexte du programme AMMA afin de discriminer les écosystèmes sur la région ouest-africaine en combinant l'information complémentaire contenue dans les cartes d'occupation du sol GLC2000 et ECOCLIMAP-I par analyse supervisée de l'indice foliaire (LAI) MODIS. L'autre, non supervisée et hybride, utilise les principes de regroupement hiérarchique et dynamique de manière automatique en combinant l'usage du classificateur k-NN et celui de la transformée de Fourier Discrète sur la base des données d'indice de végétation normalisé (NDVI) SPOT/VEGETATION pour identifier les écosystèmes africains. Dans un deuxième temps, des méthodes d'estimation des paramètres biophysiques tels que l'albédo, la fraction de végétation, l'indice foliaire ont été développées et/ou appliquées sur le continent. Une approche statistique permet de déterminer la contribution du sol nu et de la végétation à la constitution de l'albédo de surface comme tel que cela est requis dans les modèles de surface. La méthode a d'abord été appliquée sur la région ouest-africaine et sa robustesse a été prouvée lors de son application à l'intégralité du continent africain. Ces conditions de surface ont ensuite été implémentées dans le modèle de surface ISBA pour reproduire les processus de surface. La sensibilité d'ISBA au forçage physiographique a été étudiée en analysant deux simulations avec le même forçage atmosphérique sur la région ouest-africaine : l'une en utilisant la classification ECOCLIMAP-I et l'autre en utilisant la nouvelle paramétrisation de la surface développée sur la région ouest-africaine. Les flux de chaleur latente et sensible sont principalement pilotés par la fraction de végétation. Le modèle ISBA peut être utilisé pour prédire l'impact d'un changement d'occupation du sol et par conséquent des actions anthropiques sur le bilan hydrique.

APA, Harvard, Vancouver, ISO, and other styles

49

Costa, Laila Hauck. "A avaliação do risco da avifauna em aeródromos públicos: um estudo de caso do Aeroporto Presidente Itamar Franco." Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/6097.

Full text

Abstract:

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-01-16T13:49:44Z No. of bitstreams: 1 lailahauckcosta.pdf: 5163228 bytes, checksum: bbae823dc62d479d390b55e6f4762718 (MD5)
Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-01-23T14:08:23Z (GMT) No. of bitstreams: 1 lailahauckcosta.pdf: 5163228 bytes, checksum: bbae823dc62d479d390b55e6f4762718 (MD5)
Made available in DSpace on 2018-01-23T14:08:23Z (GMT). No. of bitstreams: 1 lailahauckcosta.pdf: 5163228 bytes, checksum: bbae823dc62d479d390b55e6f4762718 (MD5) Previous issue date: 2017-08-31
Perigo da fauna em aeródromos é o risco potencial de colisão de uma aeronave com espécies da fauna. Em todo o mundo, o índice de colisões desta natureza está aumentando. Assim, a presença incontrolada de animais nas imediações das pistas de pousos e decolagens é um dos riscos que as aeronaves enfrentam durante suas operações, principalmente durante a decolagem e aterrissagem, quando há maior possibilidade de colisões. Por este motivo, faz-se necessário implementar ações de controle e manejo da fauna que devem efetivar a redução ou, até mesmo, a interrupção de colisões em aeródromos. Para tanto, deve ser realizada uma avaliação do risco da fauna associada ao aeródromo, de forma a identificar espécies-problema e direcionar a aplicação de recursos para controle das espécies que representam maior risco para as operações do aeroporto. Considerando o maior risco de colisão de aeronaves com aves, o presente trabalho buscou avaliar o risco da avifauna para o Aeroporto Presidente Itamar Franco, um aeroporto estrategicamente localizado na Zona da Mata de Minas Gerais e que atende à região com voos regulares para passageiros e com infraestrutura para logística de carga aérea. Para identificação da avifauna associada a este aeroporto, foi realizado um levantamento bibliográfico que resultou em 185 espécies registradas no ano de 2001, antes da construção do aeroporto, e um levantamento de campo com duração de doze meses, de 2015 a 2016, que teve como resultado o registro de 130 espécies. No mesmo período de 2015 a 2016 também foram identificados os potenciais focos de atração da avifauna tanto no aeroporto como na ASA, que são representados, principalmente, por fontes de alimento às aves. Além disso, através do sensoriamento remoto e da aplicação do índice de vegetação NDVI, foi avaliada a evolução temporal da fragmentação vegetal na ASA do Aeroporto Presidente Itamar Franco, que pode influenciar fortemente a diversidade e o comportamento das espécies de aves na região. Por último, com a aplicação de metodologias propostas na legislação brasileira, foram identificadas as espécies-problema, oito ao total, e, a partir destas informações, foram propostas ações que contribuirão para controle destas espécies.
Wildlife hazard at aerodromes is the potential risk of an aircraft colliding with species, soil or airspace. Across the world, the rate of collisions of this nature is increasing. Thus, the uncontrolled presence of animals in the vicinity of runways is one of the risks that aircraft face during their operations, especially during landing and take-off, when there is a greater possibility of collisions. Because of this, it is necessary to implement actions of wildlife control and management that should effect the reduction or even the interruption of collisions in aerodromes. In order to do so, a risk assessment of the fauna associated with the aerodrome must be carried out in order to identify problem species and to direct the application of resources to control the species that represent greater risk for the airport operations. Considering the greater risk of collision of aircraft with birds, the present work sought to evaluate the risk of avifauna to Presidente Itamar Franco Airport, a strategically located airportin the Zona da Mata of Minas Gerais and that serves the region with scheduled flights for passengers and with infrastructure for air cargo logistics. In order to identify the avifauna associated with this airport, a bibliographic survey was carried out, which resulted in 185 species registered in the year 2001, before the construction of the airport, and work sessions on field lasting twelve months, from 2015 to 2016, which resulted in the registration of 130 species. In the same period from 2015 to 2016, potential sources of avifauna attraction were identified at both the airport and the ASA, which are mainly represented by food sources to birds. In addition, through remote sensing and the application of the NDVI vegetation index, the temporal evolution of plant fragmentation in the ASA of the Presidente Itamar Franco Airport was evaluated, which can strongly influence the diversity and behavior of the bird species in the region. Finally, with the application of methodologies proposed in the Brazilian legislation, the problem species were identified, a total of eight, and, from this information, actions were proposed that will contribute to the control of these species.

APA, Harvard, Vancouver, ISO, and other styles

50

Vinet, Jérôme. "Contribution a la modelisation thermo-aeraulique du microclimat urbain. Caracterisation de l'impact de l'eau et de la vegetation sur les conditions de confort en espaces exterieurs." Nantes, 2000. http://portaildocumentaire.citechaillot.fr/search.aspx?SC=theses&QUERY=cour+ouverte#/Detail/%28query:%28Id:%270_OFFSET_0%27,Index:1,NBResults:1,PageRange:3,SearchQuery:%28CloudTerms:!%28%29,ForceSearch:!t,Page:0,PageRange:3,QueryString:vinet,ResultSize:10,ScenarioCode:theses,ScenarioDisplayMode:display-standard,SearchLabel:%27%27,SearchTerms:vinet,SortField:!n,SortOrder:0,TemplateParams:%28Scenario:%27%27,Scope:%27%27,Size:!n,Source:%27%27,Support:%27%27%29%29%29%29.

Full text

Abstract:

Les grandes villes, en periode estivale, developpent de plus en plus frequemment certains problemes lies au phenomenes d'ilot de chaleur urbain, comme les pics de pollution et la surconsommation energetique due a la climatisation. La mineralisation des villes, en remplacant la vegetation et les zones humides par du beton et de l'asphalte contribue a ces nuisances. Notre objectif est alors de determiner l'impact de la vegetation et des bassins ou jets d'eau sur le microclimat urbain et sur les situations de confort thermique ressenties par un individu. Cette etude fait appel aux techniques de modelisation numerique. Dans la premiere partie, une importante synthese bibliographique permet de faire le point sur des domaines aussi varies que la microclimatologie urbaine, la simulation, l'urbanisme, l'arboriculture et le confort thermique en espace exterieur. Ces informations sont utiles lors de la mise en uvre et de l'interpretation des simulations envisagees. Dans la deuxieme partie, nous detaillons la realisation d'un couplage thermo-aeraulique, base sur deux outils numeriques, solene (logiciel d'ensoleillement et de thermique developpe par le cerma) et n3s (code de mecanique des fluides, developpe par edf). Ce couplage necessite le developpement de programmes specifiques et de procedures d'interfacage. Des elements de validation sur des etudes de cas referencees, ainsi qu'une comparaison avec des mesures in-situ sont presentes. L'application de cette demarche a une etude de cas urbaine, la place du millenaire du quartier antigone a montpellier, permet d'analyser l'impact de la vegetation sur le microclimat urbain et les conditions de confort en espace exterieur. La comparaison de trois situations, l'une sans vegetation, l'autre avec la vegetation actuelle et la derniere avec une vegetation a taille adulte, demontre une evolution notable au cours de annees des conditions microclimatiques et une amelioration sensible des situations de confort.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Vegetation indece'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles