Rozprawy doktorskie na temat „Vegetation”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Vegetation”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Eliasson, Jacob. "Vegetation på dammar". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66827.
Pełny tekst źródłaGreen, Janet Alexis. "An application of predictive vegetation mapping to mountain vegetation in Sweden". Texas A&M University, 2005. http://hdl.handle.net/1969.1/3089.
Pełny tekst źródłaLloyd, D. "An evaluation of small scale shortwave vegetation index imagery for vegetation mapping". Thesis, University of Bristol, 1988. http://hdl.handle.net/1983/d1ea0ff2-2c0d-4b41-849c-bd8ce3c3649f.
Pełny tekst źródłaRoderick, 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.
Pełny tekst źródłaRoderick, 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.
Pełny tekst źródłastructural 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.
Helt, Michael F. "Vegetation identification with Lidar". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Sep%5FHelt.pdf.
Pełny tekst źródłaMöller, Ingo. "Studien zur Vegetation Nordwestspitzbergens". [S.l. : s.n.], 1999. http://www.sub.uni-hamburg.de/disse/133/Disse.pdf.
Pełny tekst źródłaSchmidt, Peter A., i Dirk Wendel. "Überblick zur Vegetation Sachsens". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-77542.
Pełny tekst źródłaSmith, R. I. L. "Ecology of Antarctic vegetation". Thesis, University of Aberdeen, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.593458.
Pełny tekst źródłaTEALDI, STEFANO. "River - Riparian Vegetation Interactions". Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2497016.
Pełny tekst źródłaCohen, Yoav. "A comparison between vegetation indices for measuring vegetation dynamics resulting from climate variations /". [Beer Sheva] : Ben Gurion University of the Negev, 2008. http://aranne5.lib.ad.bgu.ac.il/others/CohenYoav.pdf.
Pełny tekst źródłaCutler, Nick. "High-latitude vegetation dynamics : 850 years of vegetation development on Mt Hekla, Iceland". Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/2485.
Pełny tekst źródłaRushworth, Garry. "Late Quaternary vegetation history of Craven, Yorkshire Dales". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/6286.
Pełny tekst źródłaFreund, Anne. "Verlauf von Patienten mit infektiöser Endokarditis der linksseitigen Nativklappen und isolierten großen Vegetationen". Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-202542.
Pełny tekst źródłaWang, Li-Fang Ph D. Massachusetts Institute of Technology. "Monte Carlo simulation model for electromagnetic scattering from vegetation and inversion of vegetation parameters". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38923.
Pełny tekst źródłaIncludes bibliographical references (p. 171-185).
In this thesis research, a coherent scattering model for microwave remote sensing of vegetation canopy is developed on the basis of Monte Carlo simulations. An accurate model of vegetation structure is essential for the calculation of scattering from vegetations, especially those with closely spaced elements in clusters. The Monte Carlo approach has an advantage over the conventional wave theory in dealing with complex vegetation structures because it is not necessary to find the probability density functions and the pair-distribution functions required in the analytic formulation and usually difficult to obtain for natural vegetation. To achieve a realistic description of the vegetation structure under consideration, two methods may be employed. One method requires the specification of the number of each type of component and the relative orientations of the components. In a structural model which incorporates this method, the detailed features can be preserved to the desired level of accuracy. This structural model is applied to two types of vegetation- --rice crops and sunflowers.
(cont.) The developed structural model for rice crops takes into account the coherent wave interactions made prominent by the clustered and closely spaced structure of rice crops, and is validated with the ERS-1 and RADARSAT data. It is utilized to interpret the experimental observations from the JERS-1 data, such as the effects of the structure of rice fields, and to predict the temporal response of rice growth. The structural model developed for sunflowers is validated using the airborne Remote Sensing Campaign Mac-Europe 91 multi-frequency and multi-polarization data acquired for sunflower fields at the Montespertoli test site in Italy. Another method to characterize vegetation structure uses growth rules. This is especially useful in modeling trees, which are structurally more complex. The Lindenmayer systems (L-systems) are utilized to fully capture the architecture of trees and describe their growth. Monte Carlo simulation results of the scattering returns from trees with different structures and at different growth stages are calculated and analyzed. The concept of the "structure factor" which extracts the structural information of a tree and and provides a measure of the spatial distribution of branches is defined, and computed for trees with different architectures.
(cont.) After study of the forward scattering problem in which the scattering coefficients are determined on the basis of known physical characteristics of the scattering objects or medium, the inverse scattering problem is considered in which the characteristics of the scattering objects or medium are to be calculated from the scattering data. In this thesis research, neural networks are applied to the inversion of geophysical parameters including soil moisture and surface parameters, sunflower biomass, as well as forest age (or equivalently, forest biomass). They are found to be especially useful for multi-dimensional inputs such as multi-frequency polarimetric scattering data. For the inversion of soil moisture and surface parameters, neural networks are trained with theoretical surface scattering models. To retrieve the sunflower biomass, neural networks are trained with the scattering returns obtained from the developed vegetation scattering model based on the Monte Carlo approach. To assess the performance of the use of experimental data to train the neural networks, the polarimetric radar data acquired by the Spaceborne Imaging Radar-C (SIR-C) over the Landes Forest in France are utilized as the training data to retrieve the forest age. Different combinations of backscattering data are used as input to the neural net in order to determine the combination which yields the best inversion result.
by L-i-Fang Wang.
Ph.D.
Street, Lorna Elizabeth. "Carbon dynamics in Arctic vegetation". Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5651.
Pełny tekst źródłaQuesada, carlos Alberto Nobre. "Soil Vegetation Interactions Across Amazonia". Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503277.
Pełny tekst źródłaLiu, David. "Flow through Rigid Vegetation Hydrodynamics". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35068.
Pełny tekst źródłaMaster of Science
Steiner, Arnold J. "Die Vegetation der Gemeinde Zermatt /". [S.l.] : [s.n.], 1999. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Pełny tekst źródłaDiGirolamo, Paul A. "A comparison of change detection methods in an urban environment using LANDSAT TM and ETM+ satellite imagery a multi-temporal, multi-spectral analysis of Gwinnett County, GA 1991-2000 /". unrestricted, 2005. http://etd.gsu.edu/theses/available/etd-07242006-110800/.
Pełny tekst źródłaTitle from title screen. Zhi-Yong Yin, committee chair; Paul Knapp, Truman Hartshorn, committee members. Electronic text (135 p. : col. ill., col. maps)) : digital, PDF file. Description based on contents viewed Aug. 2, 2007. Includes bibliographical references (p. 125-133).
Silva, Rui Pedro Guerreiro Duarte Rivaes. "Predicting the effects of climatic change on mediterranean riparian vegetation using a dynamic vegetation model". Master's thesis, ISA, 2010. http://hdl.handle.net/10400.5/2883.
Pełny tekst źródłaThe present master's thesis, had as its main objective the application of a dynamic model of riparian habitats in a case study with pronounced mediterranean characteristics. he vegetation model used is based on the existence of water conditions (water height and distance to water) suitable for the development of each type of riparian vegetation in different stages of their development, modeling annually its space-time evolution. The rules underlying the model take into account the height of the flow, the shear stress and duration of flooding. The modeling of vegetation held in ArcGIS environment, bases on three general ohases: initial creation of landscape, simulation of temporal and spatial evolution of vegetation and the presentation of annual results.
Sadler, Rohan. "Image-based modelling of pattern dynamics in a semiarid grassland of the Pilbara, Australia /". Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0155.
Pełny tekst źródłaPaula, Isabela Fernanda Moraes de. "Cobertura vegetal das regiões urbanas de Juiz de Fora - MG". Universidade Federal de Juiz de Fora (UFJF), 2017. https://repositorio.ufjf.br/jspui/handle/ufjf/5915.
Pełny tekst źródłaApproved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-11-09T14:05:14Z (GMT) No. of bitstreams: 1 isabelafernandamoraesdepaula.pdf: 8651561 bytes, checksum: 51b9a252199579213a423569927ae229 (MD5)
Made available in DSpace on 2017-11-09T14:05:14Z (GMT). No. of bitstreams: 1 isabelafernandamoraesdepaula.pdf: 8651561 bytes, checksum: 51b9a252199579213a423569927ae229 (MD5) Previous issue date: 2017-07-27
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A cobertura vegetal, entendida como o conjunto das tipologias arbórea, arbustiva e rasteira, constitui um importante elemento a compor os centros urbanos em função dos diversos benefícios de cunho ecológico, social e estético que proporcionam. Nesse sentido, o conhecimento de sua ocorrência no espaço torna-se fundamental tanto para se identificar as funcionalidades destes no meio quanto para se instituir políticas ambientais que visem melhorias na sua disposição. Sendo assim, considerando a relevância deste recurso natural, esta pesquisa buscou identificar a vegetação existente nas Regiões Administrativas do município de Juiz de Fora. Os resultados obtidos demonstram uma distribuição destituída de homogeneidade, evidenciando maiores fragmentos nas áreas periféricas e reduzidos remanescentes no sentido noroeste-sudeste, revelando um processo de uso e ocupação da terra mais intenso nesses locais. Nota-se, dessa forma, a ocorrência de manchas de vegetação mais pontuais e espaçadas nesses trechos, típicas da categoria Isolated, definida pelo pesquisador Jim como dominante de áreas impermeabilizadas, enquanto nas áreas próximas as bordas dos limites, encontram-se o tipo Connected, caracterizado pela presença de verde urbano mais contíguo e de maiores extensões. Tais aspectos refletem diretamente nos resultados dos índices de cobertura vegetal obtidos, no qual a Região Centro abrange os menores valores em relação as demais. No que se refere aos espaços de integração urbana e espaços livres de construção, observa-se escassez do elemento vegetativo nesses sistemas, visto que o primeiro abrange menos de 2,1% das regiões e o segundo menos de 1,5%, o que demonstra a necessidade de melhorias nesses ambientes, de forma a contribuir mais efetivamente ao bem estar humano.
The vegetal covering, understood as a set of arboreal typology, creeper shrub, consists of an important element that composes the cities and provide a lot of befits such as ecological, social, and esthetical. In this way, the knowledge about vegetal covering throughout the cities is an important issue in order to identify its best features for communities as well as to promote environmental policies for improves the vegetal covering displacement around cities. Thus, regarding the relevance of this natural resource, the aim of this work was identify the vegetal covering that exists at administrative regions of Juiz de Fora city. On the one hand the results shown that the vegetal covering is homogeneity distributed with larges fragments at peripheral regions. On the other hand a small remaining of vegetal covering was found at northwest and southeast regions of city which reveal an intensive process of use and occupation of the ground. Thus, we found sparse and punctual vegetal stains at downtown, typical of isolated category, defined by researcher Jim as impermeable dominants areas. While at cities’ board areas, it can be found connected type vegetal covering which is characterized by continuous green urban presence with larger extension. Such issues reflect directly at vegetal covering index results we have found, in which the downtown indexes are smaller than others regions evaluated. As far as urban spaces of integration as well as building free regions are concerned we can observe scarce vegetative elements. At urban spaces of integration we find only 2,1 % of regions have vegetative elements, while at building open spaces has 1,5 % as well. Therefore, the results have shown that there are demands for improvements in these environments in order to contribute effectively for the human well-being.
Arain, Muhammad Altaf. "Spatial aggregation of vegetation parameters in a coupled land surface-atmosphere model". Thesis, The University of Arizona, 1994. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0049_m_sip1_w.pdf&type=application/pdf.
Pełny tekst źródłaIslamovic, Azra. "Bumblebee (Bombus spp.) occurrence in relation to vegetation height, variation in vegetation height and flower abundance". Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-108671.
Pełny tekst źródłaR, A. Majdaldin, B. A. Osunmadewa, E. Csaplovics i D. Aralova. "Remote sensing-based vegetation indices for monitoring vegetation change in the semi-arid region of Sudan". SPIE, 2016. https://tud.qucosa.de/id/qucosa%3A35109.
Pełny tekst źródłaHall, Stuart. "Vegetation change and vegetation type stability in the Cape of Good Hope Nature Reserve 1966 - 2010". Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/26385.
Pełny tekst źródłaBerglund, Mattias. "Semiautomatisk spridning av vegetation i dataspel". Thesis, University of Skövde, School of Humanities and Informatics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-43.
Pełny tekst źródłaDagens spel kräver hela tiden mer resurser i en konstant växande och mer detaljerad spelvärld. Det är därför intressant att titta på alternativ till att designers manuellt placerar ut innehåll i en värld. Problemet som tas upp är om det är möjligt att kombinera generering av procedurellt innehåll i form av en skog med att låta en användare kunna påverka denna generering. Problemet delas upp i två delar där en utveckling av en arkitektur sker genom att utvärdera existerande skogsmodeller och sedan implementera arkitekturen. Slutligen sker en utvärdering av modellen genom att analysera ett antal scenarier. Resultaten visar att det är möjligt att låta en användare kunna påverka en evolvering av en skog genom att ändra egenskaper på ett specifikt område, men påverkas i stor grad av hur pass komplex skogsmodellen är. Arbetet visar att det är möjligt att enkelt kunna styra och påverka generering av procedurellt innehåll.
Maurice, Christian. "Landfill gas emission and landfill vegetation". Licentiate thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17271.
Pełny tekst źródłaHuthoff, Fredrik. "Modeling hydraulic resistance of floodplain vegetation". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/58016.
Pełny tekst źródłaWalmsley, Clive Andrew. "The ecology of shingle-beach vegetation". Thesis, University of East Anglia, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525009.
Pełny tekst źródłaSchofield, James Edward. "Vegetation succession in the Humber wetlands". Thesis, University of Hull, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395518.
Pełny tekst źródłaFlechard, Christophe R. "Turbulent exchange of ammonia above vegetation". Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243639.
Pełny tekst źródłaMasterman, Richard. "Vegetation effects on river bank stability". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358028.
Pełny tekst źródłaBenhouhou, Salima S. "Vegetation studies in the Algerian Sahara". Thesis, University of Sheffield, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308145.
Pełny tekst źródłaDavies, Julia Jacqueline. "Vegetation experiments on lime spoil rehabilitation". Thesis, University of Ulster, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268592.
Pełny tekst źródłaStrawbridge, Fiona. "Passive microwave remote sensing of vegetation". Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242948.
Pełny tekst źródłaTanino, Yukie 1980. "Aquatic gravity currents through emergent vegetation". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/26712.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 109-112).
Differential heating and cooling can generate density-driven, lateral exchange flows in aquatic systems. Despite the ubiquity of wetlands and other types of aquatic canopies, few studies have examined the hydrodynamic effects of aquatic vegetation on these currents. This study investigates the dynamics of lock-exchange flows, a particular class of density currents, propagating through rigid emergent vegetation. First, previous mathematical formulation is extended to develop theoretical models of vegetated lock-exchange flows. The regime in which stem drag is inversely proportional to velocity is considered as a special case. Lock-exchange flows were generated in a laboratory flume with rigid cylindrical dowels as model vegetation. Experimental observations were consistent with the theory. Under high stem drag or low stem Reynolds number conditions, the interface deviated from the well-documented block profile associated with unobstructed lock-exchange flows and approached a linear profile. Criteria are developed to categorize all flow conditions as inertial or non-inertial and the interface profile as linear, transitional, or non-linear, respectively, based on (a) the evolution of the velocity of the leading edge of the undercurrent and (b) the interface shape. Finally, the present model is enhanced to account for wind forcing and bed friction to better describe conditions found in nature. The theory highlights the sensitivity of currents to wind forcing.
by Yukie Tanino.
S.M.
McIntosh, Brian S. "Rule-based modelling of vegetation dynamics". Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/12619.
Pełny tekst źródłaLevy, Peter E. "Carbon dioxide exchange of Sahelian vegetation". Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/12411.
Pełny tekst źródłaGebrehiwot, Worku Zewdie. "Climate, land use and vegetation trends". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-209668.
Pełny tekst źródłaFerreira, Carla Sofia Borges Pinto da Cruz. "Temporary ponds vegetation and dynamics:SW Portugal". Doctoral thesis, ISA, 2010. http://hdl.handle.net/10400.5/2862.
Pełny tekst źródłaFernandes, Royston. "Wind erosion in presence of vegetation". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0194.
Pełny tekst źródłaAtmospheric mineral dust resulting from aeolian soil erosion affects the Earth system. Their size-distribution (PSD) plays a key role on atmospheric radiation balance, cloud formation, atmospheric chemistry, and the productivity of terrestrial and marine ecosystems. However, climate models still fail to reproduce accurately the suspended dust PSD. This is explained by the poor representation of the dust emission mechanisms and the associated surface wind speed in these large-scale models. This is particularly true in the presence of surface roughnesses such as vegetation in semiarid regions. This thesis aims at improving the understanding of dust emission in semi-arid environments, characterized by heterogeneous surfaces with sparse seasonal vegetation. To this end, a combination of numerical and field experiments was employed, with investigations progressing from a bare erodible soil to surfaces with sparse vegetation.A review of the existing dust emission schemes showed ambiguities in the parametrization of the processes influencing the emitted dust. A sensitivity analysis, using a 1D dust dispersal model, demonstrated (i) the importance of surface dust PSD and inter-particle cohesive bond parametrization on the emitted dust PSD, and (ii) the importance of the deposition process on the net dust flux PSD. Based on this analysis, a new emission scheme was incorporated into a 3D erosion model, coupled with a Large Eddy Simulation (LES) airflow model, and evaluated first on a bare surface against the WIND-O-V’s 2017 field experiment in Tunisia. The model was able to reproduce the near-surface turbulent transport dissimilarity between dust and momentum observed during the experiment. This means that momentum and dust are not always transported by the same turbulent eddies. The model demonstrated that the main cause of this dissimilarity is the dust emission intermittency, which varies as a function of wind intensity and fetch.The role of sparse vegetation on the net emitted dust flux was then explored using the WIND-O-V’s 2018 experiment, conducted at the same site as the 2017 experiment. The resulting field measurements were used to evaluate the 3D erosion model, including vegetation characteristics. A comparison between the 2017 and 2018 experiments confirmed that sparse vegetation reduces dust emission by increasing the erosion threshold friction velocity, which depends on vegetation characteristics and wind direction relative to the vegetation arrangement. During the 2018 experiment, the net emitted dust flux PSD varied continuously, unlike the 2017 experiment, with a progressive impoverishment in coarse particles (1.50 μm). This impoverishment was found independent of the vegetation, and resulted from the depletion of coarse particles at the surface due to longer emission periods in 2018 without surface tillage or precipitation. This non-influence of vegetation on the dust flux PSD was validated by the similarity of the dust flux PSD at the beginning of the 2018 experiment, when the vegetation was at its maximum height, with the one of the 2017 experiment without vegetation. It was further confirmed by the simulations that demonstrated (i) negligible re-deposition of coarse particles on to vegetation during emission events, and (ii) negligible effect of the turbulence induced by the vegetation on the PSD of the net emitted dust flux.Our 3D erosion model appears as a promising tool for characterizing dust emissions over heterogeneous surfaces typical of semi-arid regions and for deriving dust emission schemes for climate models as a function of surface roughness properties
Shannon, Debbie Anne. "Atmosphere-vegetation interactions over South Africa". Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/22109.
Pełny tekst źródłaThis study examines the sensitivity of the atmospheric circulation to vegetation change over South Africa in the context of the portended global warming. This is achieved using a vegetation model driven by climate change information and subsequently incorporated within a general circulation model (GCM). The stand-alone vegetation model is driven using precipitation, temperature and relative humidity derived from downscaling using artificial neural networks. The vegetation model is then run with perturbed precipitation, temperature and relative humidity from downscaled model data from lxCO₂ and 2xCO₂ GCM simulations. The resultant vegetation perturbation response to climate change is then examined and incorporated into the GCM in order to ascertain the atmospheric sensitivity to vegetation changes. The off-line results of the vegetation model indicate a moderate degree of sensitivity of the vegetation to perturbations in precipitation, temperature and relative humidity. The general trend in response to the CO₂ climate is a westwards and altitudinal shift of lowland vegetation over the eastern part of the country, and a southwards and eastwards shift of the more dryland vegetation in the west. These shifts are in accordance with expected responses, since lowland vegetation responds more to temperature changes and the dryland vegetation to precipitation changes. Nonetheless, the use of the model provides a physically justifiable scenario on which to base the GCM studies, and at a finer resolution than otherwise available. A GCM simulation with the perturbed vegetation was then performed using sea surface temperature boundary conditions for 1980 and compared to an identical GCM run without the perturbation. 1980 was chosen since this year does not represent either a strong El Niño or La Niña year. The atmospheric sensitivity to the vegetation perturbation has been examined in terms of climatic variables such as temperature, precipitation, pressure, specific humidity, horizontal divergence, and sensible and latent heat fluxes. The results show that the atmosphere is quite sensitive to relatively small vegetation changes. Atmospheric response to vegetation perturbations indicates greater sensitivity over the NW and SE regions of southern Africa. The perturbation indicates a reduction in precipitation over the SE interior, related to less moisture feeding in over the interior from the SE Indian Ocean. Wind speed changes over the adjacent ocean were also evident, and are probably related to the changes in the South Atlantic and Indian high pressures. A southwards extension of the Hadley Cell was also suggested, as well as changes in sensible and latent heat fluxes, relating to precipitation and temperature changes. It is suggested that changes may be in response to the general drying out of the country and the associated increase in aridity. This research forms the preliminary investigation for further work incorporating the atmospheric perturbation response back into driving the vegetation model in order to examine the direction of the feedback -- whether this is positive or negative in the longer term. Thus, this study has demonstrated that the atmosphere is significantly sensitive to vegetation changes over South Africa and reinforces the need for improved land surface parameterization schemes and vegetation models in general circulation models.
Ohanyan, Vahe A. "Computer Models for Vegetation Diversity Analysis". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1328879870.
Pełny tekst źródłaBorgelt, Jan. "Terrestrial respiration across tundra vegetation types". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-132765.
Pełny tekst źródłaHester, Alison Janet. "Vegetation succession under developing birch woods". Thesis, University of Aberdeen, 1988. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU010074.
Pełny tekst źródłaEklund, 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.
Pełny tekst źródłaA 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.
Baierle, Heinz Ullrich. "Vegetation und Flora im südwestlichen Jordanien /". Berlin [u.a.] : Cramer, 1993. http://www.gbv.de/dms/bs/toc/126235503.pdf.
Pełny tekst źródłaSantini, Gonzalez Bianca Ariana. "Plant functional traits and vegetation strategies". Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/12119/.
Pełny tekst źródła