Academic literature on the topic 'Observations par satellite'
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Journal articles on the topic "Observations par satellite":
1
Joiner, Joanna, Yasuko Yoshida, Philipp Köehler, Petya Campbell, Christian Frankenberg, Christiaan van der Tol, Peiqi Yang, Nicholas Parazoo, Luis Guanter, and Ying Sun. "Systematic Orbital Geometry-Dependent Variations in Satellite Solar-Induced Fluorescence (SIF) Retrievals." Remote Sensing 12, no. 15 (July 22, 2020): 2346. http://dx.doi.org/10.3390/rs12152346.
Abstract:
While solar-induced fluorescence (SIF) shows promise as a remotely-sensed measurement directly related to photosynthesis, interpretation and validation of satellite-based SIF retrievals remains a challenge. SIF is influenced by the fraction of absorbed photosynthetically-active radiation at the canopy level that depends upon illumination geometry as well as the escape of SIF through the canopy that depends upon the viewing geometry. Several approaches to estimate the effects of sun-sensor geometry on satellite-based SIF have been proposed, and some have been implemented, most relying upon satellite reflectance measurements and/or other ancillary data sets. These approaches, designed to ultimately estimate intrinsic or physiological components of SIF related to photosynthesis, have not generally been applied globally to satellite measurements. Here, we examine in detail how SIF and related reflectance-based indices from wide swath polar orbiting satellites in low Earth orbit vary systematically due to the host satellite orbital characteristics. We compare SIF and reflectance-based parameters from the Global Ozone Mapping Experiment 2 (GOME-2) on the MetOp-B platform and from the TROPOspheric Monitoring Instrument (TROPOMI) on the Sentinel 5 Precursor satellite with a focus on high northern latitudes in summer where observations at similar geometries and local times occur. We show that GOME-2 and TROPOMI SIF observations agree nearly to within estimated uncertainties when they are compared at similar observing geometries. We show that the cross-track dependence of SIF normalized by PAR and related reflectance-based indices are highly correlated for dense canopies, but diverge substantially as the vegetation within a field-of-view becomes more sparse. This has implications for approaches that utilize reflectance measurements to help account for SIF geometrical dependences in satellite measurements. To further help interpret the GOME-2 and TROPOMI SIF observations, we simulated cross-track dependences of PAR normalized SIF and reflectance-based indices with the one dimensional Soil-Canopy Observation Photosynthesis and Energy fluxes (SCOPE) canopy radiative transfer model at sun–satellite geometries that occur across the wide swaths of these instruments and examine the geometrical dependencies of the various components (e.g., fraction of absorbed PAR, SIF yield, and escape of SIF from the canopy) of the observed SIF signal. The simulations show that most of the cross-track variations in SIF result from the escape of SIF through the scattering canopy and not the illumination.
2
Frouin, Robert, and Rachel T. Pinker. "Estimating Photosynthetically Active Radiation (PAR) at the earth's surface from satellite observations." Remote Sensing of Environment 51, no. 1 (January 1995): 98–107. http://dx.doi.org/10.1016/0034-4257(94)00068-x.
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Dorf, M., H. Bösch, A. Butz, C. Camy-Peyret, M. P. Chipperfield, A. Engel, F. Goutail, et al. "Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles." Atmospheric Chemistry and Physics 6, no. 9 (June 29, 2006): 2483–501. http://dx.doi.org/10.5194/acp-6-2483-2006.
Abstract:
Abstract. For the first time, results of four stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-borne in situ resonance fluorescence detection of BrO (Triple), (b) balloon-borne solar occultation DOAS measurements (Differential Optical Absorption Spectroscopy) of BrO in the UV, and (c) BrO profiling from the solar occultation SAOZ (Systeme d'Analyse par Observation Zenithale) balloon instrument. Since stratospheric BrO is subject to considerable diurnal variation and none of the measurements are performed close enough in time and space for a direct comparison, all balloon observations are considered with reference to outputs from the 3-D CTM. The referencing is performed by forward and backward air mass trajectory calculations to match the balloon with the satellite observations. The diurnal variation of BrO is considered by 1-D photochemical model calculation along the trajectories. The 1-D photochemical model is initialised with output data of the 3-D model with additional constraints on the vertical transport, the total amount and photochemistry of stratospheric bromine as given by the various balloon observations. Total [Bry]=(20.1±2.5) pptv obtained from DOAS BrO observations at mid-latitudes in 2003, serves as an upper limit of the comparison. Most of the balloon observations agree with the photochemical model predictions within their given error estimates. First retrieval exercises of BrO limb profiling from the SCIAMACHY satellite instrument on average agree to around 20% with the photochemically-corrected balloon observations of the remote sensing instruments (SAOZ and DOAS). An exception is the in situ Triple profile, in which the balloon and satellite data mostly does not agree within the given errors. In general, the satellite measurements show systematically higher values below 25 km than the balloon data and a change in profile shape above about 25 km.
4
Dorf, M., H. Bösch, A. Butz, C. Camy-Peyret, M. P. Chipperfield, A. Engel, F. Goutail, et al. "Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY BrO limb profiles." Atmospheric Chemistry and Physics Discussions 5, no. 6 (December 19, 2005): 13011–52. http://dx.doi.org/10.5194/acpd-5-13011-2005.
Abstract:
Abstract. For the first time, results of all four existing stratospheric BrO profiling instruments, are presented and compared with reference to the SLIMCAT 3-dimensional chemical transport model (3-D CTM). Model calculations are used to infer a BrO profile validation set, measured by 3 different balloon sensors, for the new Envisat/SCIAMACHY (ENVIronment SATellite/SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) satellite instrument. The balloon observations include (a) balloon-borne in situ resonance fluorescence detection of BrO, (b) balloon-borne solar occultation DOAS measurements (Differential Optical Absorption Spectroscopy) of BrO in the UV, and (c) BrO profiling from the solar occultation SAOZ (Systeme d'Analyse par Observation Zenithale) balloon instrument. Since stratospheric BrO is subject to considerable diurnal variation and none of the measurements are performed close enough in time and space for a direct comparison, all balloon observations are considered with reference to outputs from the 3-D CTM. The referencing is performed by forward and backward air mass trajectory calculations to match the balloon with the satellite observations. The diurnal variation of BrO is considered by 1-D photochemical model calculation along the trajectories. The 1-D photochemical model is initialised with output data of the 3-D model with additional constraints on the vertical transport, the total amount and photochemistry of stratospheric bromine as given by the various balloon observations. Total [Bry]=(20.1±2.8)pptv obtained from DOAS BrO observations at mid-latitudes in 2003, serves as an upper limit of the comparison. Most of the balloon observations agree with the photochemical model predictions within their given error estimates. First retrieval exercises of BrO limb profiling from the SCIAMACHY satellite instrument agree to <±50% with the photochemically-corrected balloon observations, and tend to show less agreement below 20 km.
5
Singh, Rakesh Kumar, Anna Vader, Christopher J. Mundy, Janne E. Søreide, Katrin Iken, Kenneth H. Dunton, Laura Castro de la Guardia, Mikael K. Sejr, and Simon Bélanger. "Satellite-Derived Photosynthetically Available Radiation at the Coastal Arctic Seafloor." Remote Sensing 14, no. 20 (October 17, 2022): 5180. http://dx.doi.org/10.3390/rs14205180.
Abstract:
Climate change has affected the Arctic Ocean (AO) and its marginal seas significantly. The reduction of sea ice in the Arctic region has altered the magnitude of photosynthetically available radiation (PAR) entering the water column, impacting primary productivity. Increasing cloudiness in the atmosphere and rising turbidity in the coastal waters of the Arctic region are considered as the major factors that counteract the effect of reduced sea ice on underwater PAR. Additionally, extreme solar zenith angles and sea-ice cover in the AO increase the complexity of retrieving PAR. In this study, a PAR algorithm based on radiative transfer in the atmosphere and satellite observations is implemented to evaluate the effect of these factors on PAR in the coastal AO. To improve the performance of the algorithm, a flag is defined to identify pixels containing open-water, sea-ice or cloud. The use of flag enabled selective application of algorithms to compute the input parameters for the PAR algorithm. The PAR algorithm is validated using in situ measurements from various coastal sites in the Arctic and sub-Arctic seas. The algorithm estimated daily integrated PAR above the sea surface with an uncertainty of 19% in summer. The uncertainty increased to 24% when the algorithm was applied year-round. The PAR values at the seafloor were estimated with an uncertainty of 76%, with 36% of the samples under sea ice and/or cloud cover. The robust performance of the PAR algorithm in the pan-Arctic region throughout the year will help to effectively study the temporal and spatial variability of PAR in the Arctic coastal waters. The calculated PAR data are used to quantify the changing trend in PAR at the seafloor in the coastal AO with depth < 100 m using MODIS-Aqua data from 2003 to 2020. The general trends calculated using the pixels with average PAR > 0.415 mol m−2day−1 at the seafloor during summer indicate that the annual average of PAR entering the water column in the coastal AO between 2003 and 2020 increased by 23%. Concurrently, due to increased turbidity, the attenuation in the water column increased by 22%. The surge in incident PAR in the water column due to retreating sea ice first led to increased PAR observed at the seafloor (∼12% between 2003 and 2014). However, in the last decade, the rapid increase in light attenuation of the water column has restricted the increase in average annual PAR reaching the bottom in the coastal AO.
6
Wang, Dongdong, Shunlin Liang, Ronggao Liu, and Tao Zheng. "Estimation of daily-integrated PAR from sparse satellite observations: comparison of temporal scaling methods." International Journal of Remote Sensing 31, no. 6 (March 26, 2010): 1661–77. http://dx.doi.org/10.1080/01431160903475407.
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Lange, Johannes U., Frank C. van den Bosch, Andrew R. Zentner, Kuan Wang, and Antonio S. Villarreal. "Updated results on the galaxy–halo connection from satellite kinematics in SDSS." Monthly Notices of the Royal Astronomical Society 487, no. 3 (June 7, 2019): 3112–29. http://dx.doi.org/10.1093/mnras/stz1466.
Abstract:
ABSTRACT We present new results on the relationship between central galaxies and dark matter haloes inferred from observations of galaxy abundances and satellite kinematics in the Sloan Digital Sky Survey (SDSS) DR7. We employ an updated analysis framework that includes detailed mock catalogues to model observational effects in SDSS. Our results constrain the colour-dependent conditional luminosity function of dark matter haloes, as well as the radial profile of satellite galaxies. Confirming previous results, we find that red central galaxies live in more massive haloes than blue galaxies at a fixed luminosity. Additionally, our results suggest that satellite galaxies have a radial profile less centrally concentrated than dark matter but not as cored as resolved subhaloes in dark-matter-only simulations. Compared to previous works using satellite kinematics by More et al., we find much more competitive constraints on the galaxy–halo connection, on par with those derived from a combination of galaxy clustering and galaxy–galaxy lensing. This improvement stems from also modelling the abundance of galaxies as well as a larger sample size and more realistic observational uncertainties. We compare our results on the galaxy–halo connection to other studies using galaxy clustering and group catalogues, showing a reasonable agreement between these different techniques. We discuss future applications of satellite kinematics in the context of constraining cosmology and the relationship between galaxies and dark matter haloes.
8
Zheng, Tao, Shunlin Liang, and Kaicun Wang. "Estimation of Incident Photosynthetically Active Radiation from GOES Visible Imagery." Journal of Applied Meteorology and Climatology 47, no. 3 (March 1, 2008): 853–68. http://dx.doi.org/10.1175/2007jamc1475.1.
Abstract:
Abstract Incident photosynthetically active radiation (PAR) is an important parameter for terrestrial ecosystem models. Because of its high temporal resolution, the Geostationary Operational Environmental Satellite (GOES) observations are very suited to catch the diurnal variation of PAR. In this paper, a new method is developed to derive PAR using GOES data. What makes this new method distinct from the existing method is that it does not need external knowledge of atmospheric conditions. The new method retrieves both atmospheric and surface conditions using only at-sensor radiance through interpolation of time series of observations. Validations against ground measurement are carried out at four “FLUXNET” sites. The values of RMSE of estimated and ground-measured instantaneous PAR at the four sites are 130.71, 131.44, 141.16, and 190.22 μmol m−2 s−1, respectively. At the four validation sites, the RMSE as the percentage of estimated mean PAR value are 9.52%, 13.01%, 13.92%, and 24.09%, respectively; the biases are −101.54, 16.56, 11.09, and 53.64 μmol m−2 s−1, respectively. The independence of external atmospheric information enables this method to be applicable to many situations in which external atmospheric information is not available. In addition, topographic impacts on surface PAR are examined at the 1-km resolution at which PAR is retrieved using the GOES visible band data.
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Hendrick, F., B. Barret, M. Van Roozendael, H. Boesch, A. Butz, M. De Mazière, F. Goutail, et al. "Retrieval of nitrogen dioxide stratospheric profiles from ground-based zenith-sky UV-visible observations: validation of the technique through correlative comparisons." Atmospheric Chemistry and Physics Discussions 4, no. 3 (May 25, 2004): 2867–904. http://dx.doi.org/10.5194/acpd-4-2867-2004.
Abstract:
Abstract. A retrieval algorithm based on the Optimal Estimation Method (OEM) has been developed in order to provide vertical distributions of NO2 in the stratosphere from ground-based (GB) zenith-sky UV-visible observations. It has been applied to observational data sets from the NDSC (Network for Detection of Stratospheric Change) stations of Harestua (60° N, 10° E) and Andøya (69.3° N, 16.1° E) in Norway. The information content and retrieval errors have been analyzed following a formalism used for characterizing ozone profiles retrieved from solar infrared absorption spectra. In order to validate the technique, the retrieved NO2 vertical profiles and columns have been compared to correlative balloon and satellite observations. Such extensive validation of the profile and column retrievals was not reported in previously published work on the profiling from GB UV-visible measurements. A good agreement – generally better than 25% – has been found with the SAOZ (Système d'Analyse par Observations Zénithales) and DOAS (Differential Optical Absorption Spectroscopy) balloon data. A similar agreement has been reached with correlative satellite data from HALogen Occultation Experiment (HALOE) and Polar Ozone and Aerosol Measurement (POAM) III instruments above 25 km of altitude. Below 25 km, a systematic overestimation of our retrieved profiles – by up to 50% in some cases – has been observed by both HALOE and POAM III, pointing out the limitation of the satellite solar occultation technique at these altitudes. We have concluded that our study strengthens our confidence in the reliability of the retrieval of vertical distribution information from GB UV-visible observations and offers new perspectives in the use of GB UV-visible network data for validation purposes.
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Hendrick, F., B. Barret, M. Van Roozendael, H. Boesch, A. Butz, M. De Mazière, F. Goutail, et al. "Retrieval of nitrogen dioxide stratospheric profiles from ground-based zenith-sky UV-visible observations: validation of the technique through correlative comparisons." Atmospheric Chemistry and Physics 4, no. 8 (October 21, 2004): 2091–106. http://dx.doi.org/10.5194/acp-4-2091-2004.
Abstract:
Abstract. A retrieval algorithm based on the Optimal Estimation Method (OEM) has been developed in order to provide vertical distributions of NO2 in the stratosphere from ground-based (GB) zenith-sky UV-visible observations. It has been applied to observational data sets from the NDSC (Network for Detection of Stratospheric Change) stations of Harestua (60° N, 10° E) and Andøya (69° N, 16° E) in Norway. The information content and retrieval errors have been analyzed following a formalism used for characterizing ozone profiles retrieved from solar infrared absorption spectra. In order to validate the technique, the retrieved NO2 vertical profiles and columns have been compared to correlative balloon and satellite observations. Such extensive validation of the profile and column retrievals was not reported in previously published work on the profiling from GB UV-visible measurements. A good agreement - generally better than 25% - has been found with the SAOZ (Système d'Analyse par Observations Zénithales) and DOAS (Differential Optical Absorption Spectroscopy) balloons. A similar agreement has been reached with correlative satellite data from the HALogen Occultation Experiment (HALOE) and Polar Ozone and Aerosol Measurement (POAM) III instruments above 25km of altitude. Below 25km, a systematic underestimation - by up to 40% in some cases - of both HALOE and POAM III profiles by our GB profile retrievals has been observed, pointing out more likely a limitation of both satellite instruments at these altitudes. We have concluded that our study strengthens our confidence in the reliability of the retrieval of vertical distribution information from GB UV-visible observations and offers new perspectives in the use of GB UV-visible network data for validation purposes.
Dissertations / Theses on the topic "Observations par satellite":
1
Chen, Hong-Bin. "Simulation d'observations satellitaires passives en micro-onde : influence de la nébulosité et des précipitations sur les températures de brillance : inversion de paramètres nuageux à partir des mesures du sondeur micro-onde Météosat." Lille 1, 1991. http://www.theses.fr/1991LIL10029.
Abstract:
L'utilisation des radiomètres micro-ondes sur un satellite est un moyen puissant d'observation de l'atmosphère et de la surface terrestre. Ce travail décrit la mise au point d'un code numérique pour calculer la température de brillance observée par un radiomètre micro-onde depuis un satellite dans des conditions variées. Ce code est basé sur l'équation de transfert radiatif et dans une hypothèse d'atmosphère plane parallèle. La simulation de la température de brillance nous permet d'effectuer l'étude de sensibilité des signaux micro-ondes aux paramètres des nuages et des précipitations. Cette étude a prouvé la possibilité de retrouver certains de ces paramètres. Puis les algorithmes d'inversion d'essai ont été établis pour remonter à certains paramètres des nuages et à la température de surface de l'océan (en atmosphère nuageuse) à partir des mesures de radiométrie micro-onde. La comparaison entre les valeurs inversées et vraies montre qu'une certaine information concernant les nuages peut être extraite des mesures du sondeur micro-onde Météosat MMS qui est embarqué sur le satellite METEOSAT de seconde génération
2
Artru, Juliette. "Observations au sol ou par satellite et modélisation des signaux ionosphériques post-sismiques." Paris, Institut de physique du globe, 2001. http://www.theses.fr/2001GLOB0006.
Abstract:
Depuis 1960 de fortes perturbations de l'ionosphère consécutives à des tremblements de Terre ont mis en évidence le couplage dynamique entre la Terre solide et l'atmosphère. De nombreuses observations de phénomènes associés ont depuis été réalisées, par des mesures au sol ou par satellite. Nous présentons ici une étude de ces phénomènes, fondée d'une part sur la modélisation de ce couplage par les méthodes sismologiques, d'autre part sur le développement de nouveaux outils d'observation adaptés à ce nouveau champ de recherches. Ce travail s'inscrit dans le cadre de la préparation de la mission DEMETER (microsatellite CNES dédié à l'observation des signaux ionosphériques induits par l'activité sismique ou volcanique, dont le lancement est prévu en 2003). La première partie présente les différentes observations en liaison avec le couplage Terre atmosphère, et leur interprétation. La deuxième partie est dédiée à l'établissement d'une extension des méthodes de calcul de modes propres permettant de calculer des sismogrammes synthétiques pour une source et une station situées soit dans la Terre solide, soit dans l'océan ou l'atmosphère. Les synthétiques calculés par sommation de modes, pour une source sismique, montrent un bon accord avec les données fournies par le sondeur Doppler du CEA. La troisième partie présente les travaux réalisés pour développer de nouveaux outils d'observation dans l'ionosphère, notamment au dessus de zones à forte activité sismique, à partir des réseaux GPS denses, tels ceux de Californie ou du Japon. Nous développons enfin en conclusion les perspectives ouvertes par les signaux sismo-atmosphériques, que ce soit dans les champs de la sismologie ou de l'aéronomie
3
Dartois, Emmanuel. "Les glaces interstellaires : interpretation par simulations en laboratoire des observations du satellite iso." Paris 6, 1998. http://www.theses.fr/1998PA066456.
Abstract:
Je presente dans cette these des resultats obtenus apres analyse des observations par le satellite infrarouge iso (infrared space observatory). Grace a sa couverture spectrale globale du spectre infrarouge (2. 5 a 180 m), iso revolutionne notre comprehension des sources interstellaires. Ces observations sont particulierement interessantes pour la comprehension de la physico-chimie des phases gazeuse et solide (condensee sur les grains de poussiere), a basse temperature, du milieu interstellaire (10 a 50 k). L'objet protostellaire (rafgl7009s) dont nous parlons illustre les proprietes physiques des milieux denses de la galaxie. Les rapports observes entre les phases gazeuse et solide concernant les molecules h 2o, co, co 2 et ch 4 entrainent des implications sur les echanges gaz-grains de ces molecules que nous discutons. Nous detaillons egalement l'evaluation d'une limite superieure sur le rapport deuterium/hydrogene dans les glaces interstellaires et les consequences pour le fractionnement eleve observe dans la phase gazeuse. Pour la premiere fois on a egalement acces aux profils des raies de certains solides inobservables ou tres difficiles a observer depuis le sol. Nous nous attachons plus particulierement au mode 2 de co 2 solide qui presente une sous structure triple dans les observations que l'on interprete par la formation dans les manteaux de glace recouvrant les grains d'une interaction intermoleculaire de type acide-base de lewis. Nous parlerons aussi de la detection du mode longitudinal optique de la glace d'eau vers 230 cm - 1 par comparaison avec un modele simple de transfert radiatif et de la difference d'analyse entre les observations dans l'infrarouge moyen et lointain des glaces interstellaires.
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Yaacoub, Rouba. "Résonance optique par effet tunnel en optique atmosphérique : application aux observations par satellite des gouttelettes de nuages." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1R001.
Abstract:
L'interaction de la lumière avec un diffuseur homogène diélectrique sphérique (par exemple une gouttelette d'eau) de caractéristiques connues (diamètre, indice optique) est traité, en optique atmosphérique, par la théorie de Mie. Cette théorie sert aussi en télédétection pour calculer les propriétés physiques des diffuseurs (problème inverse). Des études récentes ont suggéré fortement qu'un effet tunnel pourrait être important en optique atmosphérique. Une manifestation de cet effet tunnel est la gloire atmosphérique qui est l'irisation circulaire qui se forme autour de l'ombre projetée d'un objet sur un nuage de gouttelettes d'eau. Précisément, la lumière pénètre par effet tunnel dans la gouttelette d'eau et excite résonances aiguës. Selon ces études, la théorie de Mie, telle qu'utilisée en optique atmosphérique, semble négliger ces effets. Nous avons désigné ces resonances par l'acronyme TOR (en anglais: Tunneling Optical Resonance). Dans cette thèse, nous montrons que les TOR peuvent être identifié en utilisant l'équation de Shrödinger à une dimension en introduisant une énergie potentielle effective qui caractérise l'interaction lumière-gouttelette et qui dépend de l'indice optique du diamètre de la gouttelette et de l'énergie incidente. Le premier objectif de cette thèse est d'identifier le concept de l'effet tunnel et montrer la nécessité de l'introduire dans la théorie de Mie. Afin d'atteindre cet objectif, une nouvelle méthode (méthode de la matrice de transfert -- TMM) est développée pour prendre en considération les TOR et identifier les conditions pour lesquelles TOR se produisent. Le deuxième objectif est de comparer cette méthode à celle de la théorie de Mie et d'illustrer les différences entre eux. Nos résultats montrent la similarité entre les deux méthodes en l'absence de TOR et un désaccord autrement. Cette étude est effectuée pour deux cas différents: (1) une seule gouttelette d'eau de diamètre bien déterminée et une énergie incidente précise; (2) une population de gouttelettes de nuage avec un intervalle de diamètres de 5 micron jusqu'à 30 microns pour les énergies incidentes des neuf canaux (de l'IR jusqu'à l'UV) du capteur POLDER. Pour les deux cas les sections efficaces (diffusion, extinction et absorption) et la distribution angulaire de l'intensité diffusée sont comparés en prenant compte les TOR et sans les considérer. Les résultats suggèrent un nouvel aspect pour l'interaction lumière-gouttelette en optique atmosphérique, ce qui pourrait affecter les algorithmes d'inversion en télédétectionThe light interaction with a homogeneous dielectric spherical scatterer (e.g. cloud droplet) of known characteristics (diameter, optical index) is treated, in atmospheric optics, by the Mie's theory. This theory serves, also, in remote sensing to retrieve physical properties of scatterers (inverse problem). Recent studies have showed the importance of tunneling effects in atmospheric optics. They have attribute the implication of tunneling effects in the atmospheric glory which is the circular iridescence that form around the projected shadow of an object on a cloud of water droplets. Precisely, light can penetrate by tunneling into a droplet and produces sharp resonances. According to these studies, the Mie's theory , as used in atmospheric optic, seems to neglect such effects. We have called these resonances by the acronym TOR (Tunneling Optical Resonance). In this thesis, we show that TOR can be solved using a one-dimensional Schrödinger equation with an effective potential energy that characterizes the light-droplet interaction and that depends on the refractive index, diameter of the droplet and the incident light's energy. The first main purpose of this thesis is to identify the concept of tunneling and the necessity to introduce it in the Mie's theory. In order to reach this goal, a new method (called transfer matrix method -- TMM) is developed that takes into account the TOR, and allows the identification of the conditions for which TOR occur. The second main purpose, is to compare this method to the Mie's theory and illustrates the differences between them. Our findings show the similarity of the two methods in the case of non-TOR occurrences and disagreement otherwise. This study is performed upon two different cases: (1) a single droplet with a specific diameter and incident energy; (2) a cloud droplet population with a range of diameters from 5 microns to 30 micron for the incident energies of the nine channels (from IR to UV) of the POLDER sensor. For both (1) and (2), cross sections (scattering, extinction and absorption) and the angular distributions of ²the scattered intensity are compared when taking into account the TOR and without considering them. The results are promising and presents a new aspect for addressing light-droplet interaction in atmospheric optics that may affect the inversion problem treatments in remote sensing
5
Yaacoub, Rouba. "Résonance optique par effet tunnel en optique atmosphérique : application aux observations par satellite des gouttelettes de nuages." Electronic Thesis or Diss., Université de Lille (2018-2021), 2020. http://www.theses.fr/2020LILUR001.
Abstract:
L'interaction de la lumière avec un diffuseur homogène diélectrique sphérique (par exemple une gouttelette d'eau) de caractéristiques connues (diamètre, indice optique) est traité, en optique atmosphérique, par la théorie de Mie. Cette théorie sert aussi en télédétection pour calculer les propriétés physiques des diffuseurs (problème inverse). Des études récentes ont suggéré fortement qu'un effet tunnel pourrait être important en optique atmosphérique. Une manifestation de cet effet tunnel est la gloire atmosphérique qui est l'irisation circulaire qui se forme autour de l'ombre projetée d'un objet sur un nuage de gouttelettes d'eau. Précisément, la lumière pénètre par effet tunnel dans la gouttelette d'eau et excite résonances aiguës. Selon ces études, la théorie de Mie, telle qu'utilisée en optique atmosphérique, semble négliger ces effets. Nous avons désigné ces resonances par l'acronyme TOR (en anglais: Tunneling Optical Resonance). Dans cette thèse, nous montrons que les TOR peuvent être identifié en utilisant l'équation de Shrödinger à une dimension en introduisant une énergie potentielle effective qui caractérise l'interaction lumière-gouttelette et qui dépend de l'indice optique du diamètre de la gouttelette et de l'énergie incidente. Le premier objectif de cette thèse est d'identifier le concept de l'effet tunnel et montrer la nécessité de l'introduire dans la théorie de Mie. Afin d'atteindre cet objectif, une nouvelle méthode (méthode de la matrice de transfert -- TMM) est développée pour prendre en considération les TOR et identifier les conditions pour lesquelles TOR se produisent. Le deuxième objectif est de comparer cette méthode à celle de la théorie de Mie et d'illustrer les différences entre eux. Nos résultats montrent la similarité entre les deux méthodes en l'absence de TOR et un désaccord autrement. Cette étude est effectuée pour deux cas différents: (1) une seule gouttelette d'eau de diamètre bien déterminée et une énergie incidente précise; (2) une population de gouttelettes de nuage avec un intervalle de diamètres de 5 micron jusqu'à 30 microns pour les énergies incidentes des neuf canaux (de l'IR jusqu'à l'UV) du capteur POLDER. Pour les deux cas les sections efficaces (diffusion, extinction et absorption) et la distribution angulaire de l'intensité diffusée sont comparés en prenant compte les TOR et sans les considérer. Les résultats suggèrent un nouvel aspect pour l'interaction lumière-gouttelette en optique atmosphérique, ce qui pourrait affecter les algorithmes d'inversion en télédétectionThe light interaction with a homogeneous dielectric spherical scatterer (e.g. cloud droplet) of known characteristics (diameter, optical index) is treated, in atmospheric optics, by the Mie's theory. This theory serves, also, in remote sensing to retrieve physical properties of scatterers (inverse problem). Recent studies have showed the importance of tunneling effects in atmospheric optics. They have attribute the implication of tunneling effects in the atmospheric glory which is the circular iridescence that form around the projected shadow of an object on a cloud of water droplets. Precisely, light can penetrate by tunneling into a droplet and produces sharp resonances. According to these studies, the Mie's theory , as used in atmospheric optic, seems to neglect such effects. We have called these resonances by the acronym TOR (Tunneling Optical Resonance). In this thesis, we show that TOR can be solved using a one-dimensional Schrödinger equation with an effective potential energy that characterizes the light-droplet interaction and that depends on the refractive index, diameter of the droplet and the incident light's energy. The first main purpose of this thesis is to identify the concept of tunneling and the necessity to introduce it in the Mie's theory. In order to reach this goal, a new method (called transfer matrix method -- TMM) is developed that takes into account the TOR, and allows the identification of the conditions for which TOR occur. The second main purpose, is to compare this method to the Mie's theory and illustrates the differences between them. Our findings show the similarity of the two methods in the case of non-TOR occurrences and disagreement otherwise. This study is performed upon two different cases: (1) a single droplet with a specific diameter and incident energy; (2) a cloud droplet population with a range of diameters from 5 microns to 30 micron for the incident energies of the nine channels (from IR to UV) of the POLDER sensor. For both (1) and (2), cross sections (scattering, extinction and absorption) and the angular distributions of ²the scattered intensity are compared when taking into account the TOR and without considering them. The results are promising and presents a new aspect for addressing light-droplet interaction in atmospheric optics that may affect the inversion problem treatments in remote sensing
6
Tournadre, Benoît. "Heliosat-V ˸ une méthode polyvalente d’estimation du rayonnement solaire au sol par satellite." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM063.
Abstract:
L'éclairement du Soleil à la surface de la Terre est reconnu comme une variable climatique essentielle par l'Organisation Météorologique Mondiale. Sa connaissance est aussi précieuse pour les sciences du climat que pour le développement d'énergies alternatives aux combustibles fossiles, comme le solaire photovoltaïque. La mesure au sol de ce rayonnement est très clairsemée sur la Terre, d'où l'intérêt de méthodes d'estimation basées sur la télédétection par satellite. Combiner les estimations produites à partir de différents satellites en orbite est une voie pour couvrir au mieux l'information sur tout le globe terrestre. De plus, différentes générations de satellites ont produit une imagerie de la Terre depuis plusieurs décennies, permettant d'estimer de longues séries temporelles du rayonnement solaire, voire d'identifier des variations long terme, un objectif récurrent dans l'étude du changement climatique. Depuis plus de trente ans, les méthodes Heliosat permettent cette estimation, mais elles ont été conçues pour être appliquées à un capteur spécifique en orbite géostationnaire et ont des contraintes limitant leurs champs d'application : la nécessité d'utiliser une longue série temporelle passée (Heliosat, Heliosat-2), ou le besoin de mesures multispectrales (Heliosat-4). Ce travail sur le développement d'une méthode Heliosat-V apporte des éléments de polyvalence à l'estimation satellite par les méthodes dites à "indice d'ennuagement", dans l'objectif de tendre vers une donnée homogène du rayonnement solaire issue de mesures de différents instruments satellites. Deux problèmes sont en particulier considérés pour parvenir à cette estimation : la diversité des capteurs en termes de sensibilités spectrales, et l'influence des géométries de visée et d'éclairement solaire sur les mesures satellites. La méthode s'appuie extensivement sur la modélisation du transfert radiatif dans l'atmosphère dans la gamme spectrale 400-1000 nm pour simuler d'une part les mesures de radiomètres satellites en conditions de ciel clair et d'autre part celles en présence d'un nuage optiquement épais. La méthode est testée sur l'imagerie d'un instrument satellite géostationnaire, Meteosat-9/SEVIRI, et de manière plus exploratoire sur celle d'un non géostationnaire, DSCOVR/EPIC. Les résultats sont comparés à des mesures de référence au sol de l'éclairement, et montrent des performances similaires à celles de produits opérationnels d'éclairement solaire. La qualité des estimations dépend cependant du canal spectral utilisé, en particulier de la présence de diffusion ou d'absorption de l'atmosphère claire dans le signal mesuré par satellite. L'accent est aussi mis sur le besoin d'un étalonnage absolu précis des mesures radiométriques satellites pour produire des séries temporelles d'éclairement de surface avec des biais et une dérive temporelle les plus faibles possiblesSolar irradiance at the surface of the Earth is recognized as an essential climate variable by the World Meteorological Organization. Its knowledge is as much important for climate sciences as for the development of energy alternatives to fossil fuels, like solar photovoltaic. Ground measurements of this radiation are very sparse on Earth, explaining the interest for satellite-based remote sensing to estimate it. Combining estimations from different satellites in orbit is a pathway to cover the information on the whole globe. Different generations of satellites also produced a multidecadal imagery of the Earth, making it conceivable to estimate long time series of solar radiation, or even to identify long-term variations, a recurrent objective in the study of climate change. For more than 30 years, Heliosat methods estimate surface solar irradiance from satellite imagery, but they have been designed to be applied to a specific sensor on a geostationary orbit, and have limitations in their scope : the need for a long archive of satellite imagery (Heliosat, Heliosat-2), or else the need for multispectral measurements (Heliosat-4). This work dedicated to the development of a Heliosat-V method brings elements of versatility to the satellite-based estimation from so-called "cloud-index" methods, with the ultimate goal to reach homogeneous data of solar radiation derived from measurements made by different satellite instruments. Two issues are in particular considered here to reach such an estimation: the diversity of sensors in terms of spectral sensitivities, and the influence of viewing and solar geometries on spaceborne measurements. The method extensively deals with radiative transfer modeling in the spectral range 400-1000 nm to simulate on one hand satellite measurements in clear-sky conditions, and on the other hand satellite measurements in the presence of an optically thick cloud. The method is tested on the imagery of a geostationary satellite instrument, Meteosat-9/SEVIRI, and in a more exploratory way, on the non geostationary sensor DSCOVR/EPIC. Results are compared to high quality ground-based measurements of irradiance, and show performances similar to operational satellite products. However, the quality of estimates depends on the spectral channel used, and especially of the presence of clear-sky atmospheric scattering or absorption in the signal measured by the satellite instrument. The accent is also put on the need for an accurate absolute calibration of satellite radiometric measurements in order to produce time series of surface solar irradiance with the smallest biases and temporal drift possible
7
Söhne, Nathalie. "Validation des prévisions de nuages et de précipitations à mésoéchelle par l'observation satellite." Toulouse 3, 2007. http://thesesups.ups-tlse.fr/102/.
Abstract:
Une méthodologie originale combinant l'approche modèle-vers-satellite et le calcul de score a été mise au point pour apporter une évaluation objective et systématique des modèles de mésoéchelle. Cette méthode a été appliquée à trois cas d'étude utilisant le modèle Méso-NH. Le premier cas porte sur la validation d'un ensemble de situations précipitantes contrastées de moyennes latitudes permettant de constituer une base de données. Il montre aussi le lien entre la qualité de la simulation et le type de situation météorologique. Dans le deuxième, un ensemble de simulations est réalisé afin de quantifier l'influence des modifications de l'état initial et de la configuration du modèle sur la prévisibilité d'un événement extrême. Le dernier cas d'étude quantifie la fiabilité d'une série d'un mois de prévisions en Afrique de l'Ouest, et sa variabilité en présence de forçages d'échelle synoptiqueAn original methodology combining the model-to-satellite approach and skill score calculation has been developped in order to objectively evaluate mesoscale models. This method has been applied on three study cases using the Meso-NH model. The first case is about the validation of an ensemble of contrasted precipitating situations, at mid-latitude, used for a data base. It also shows the link between the forecast quality and the meteorological nature of the situation. The second, is an ensemble of forecasts done to quantify the influence on the predictibility of an extreme event when modifications were done on initial conditions and model configurations. The last case allowes to quantify the reliability of a series of AMMA previsions and its variability with synoptic factors
8
Ringard, Justine. "Estimation des précipitations sur le plateau des Guyanes par l'apport de la télédétection satellite." Thesis, Guyane, 2017. http://www.theses.fr/2017YANE0010/document.
Abstract:
Le plateau des Guyanes est une région qui est caractérisée à 90% d’une forêt tropicale primaire et compte pour environ 20% des réserves mondiales d’eau douce. Ce territoire naturel, au vaste réseau hydrographique, montre des intensités pluviométriques annuelles atteignant 4000 mm/an ; ce qui fait de ce plateau une des régions les plus arrosées du monde. De plus les précipitations tropicales sont caractérisées par une variabilité spatiale et temporelle importante. Outre les aspects liés au climat, l’impact des précipitations dans cette région du globe est important en termes d’alimentation énergétique (barrages hydroélectriques). Il est donc important de développer des outils permettant d’estimer quantitativement et qualitativement et à haute résolution spatiale et temporelle les précipitations dans cette zone. Cependant ce vaste espace géographique est caractérisé par un réseau de stations pluviométriques peu développé et hétérogène, ce qui a pour conséquence une méconnaissance de la répartition spatio-temporelle précise des précipitations et de leurs dynamiques.Les travaux réalisées dans cette thèse visent à améliorer la connaissance des précipitations sur le plateau des Guyanes grâce à l’utilisation des données de précipitations satellites (Satellite Precipitation Product : SPP) qui offrent dans cette zone une meilleure résolution spatiale et temporelle que les mesures in situ, au prix d’une qualité moindre en terme de précision.Cette thèse se divise en 3 parties. La première partie compare les performances de quatre produits d’estimations satellitaires sur la zone d’étude et tente de répondre à la question : quelle est la qualité de ces produits au Nord de l’Amazone et sur la Guyane française dans les dimensions spatiales et temporelles ? La seconde partie propose une nouvelle technique de correction de biais des SPP qui procède en trois étapes : i) utiliser les mesures in situ de précipitations pour décomposer la zone étudiée en aires hydro-climatiques ii) paramétrer une méthode de correction de biais appelée quantile mapping sur chacune de ces aires iii) appliquer la méthode de correction aux données satellitaires relatives à chaque aire hydro-climatique. On cherche alors à répondre à la question suivante : est-ce que le paramétrage de la méthode quantile mapping sur différentes aires hydro-climatiques permet de corriger les données satellitaires de précipitations sur la zone d’étude ? Après avoir montré l’intérêt de prendre en compte les différents régimes pluviométriques pour mettre en œuvre la méthode de correction QM sur des données SPP, la troisième partie analyse l’impact de la résolution temporelle des données de précipitations utilisées sur la qualité de la correction et sur l’étendue spatiale des données SPP potentiellement corrigeables (données SPP sur lesquelles la méthode de correction peut s’appliquer avec efficacité). Concrètement l’objectif de cette partie est d’évaluer la capacité de notre méthode à corriger sur une large échelle spatiale le biais des données TRMM-TMPA 3B42V7 en vue de rendre pertinente l’exploitation de ce produit pour différentes applications hydrologiques.Ce travail a permis de corriger les séries satellites journalières à haute résolution spatiale et temporelle sur le plateau des Guyanes selon une approche nouvelle qui utilise la définition de zones hydro-climatiques. Les résultats positifs en terme de réduction du biais et du RMSE obtenus grâce à cette nouvelle approche, rendent possible la généralisation de cette nouvelle méthode dans des zones peu équipées en pluviomètresThe Guiana Shield is a region that is characterized by 90% of a primary rainforest and about 20% of the world’s freshwater reserves. This natural territory, with its vast hydrographic network, shows annual rainfall intensities up to 4000 mm/year; making this plateau one of the most watered regions in the world. In addition, tropical rainfall is characterized by significant spatial and temporal variability. In addition to climate-related aspects, the impact of rainfall in this region of the world is significant in terms of energy supply (hydroelectric dams). It is therefore important to develop tools to estimate quantitatively and qualitatively and at high spatial and temporal resolution the precipitation in this area. However, this vast geographical area is characterized by a network of poorly developed and heterogeneous rain gauges, which results in a lack of knowledge of the precise spatio-temporal distribution of precipitation and their dynamics.The work carried out in this thesis aims to improve the knowledge of precipitation on the Guiana Shield by using Satellite Precipitation Product (SPP) data that offer better spatial and temporal resolution in this area than the in situ measurements, at the cost of poor quality in terms of precision.This thesis is divided into 3 parts. The first part compares the performance of four products of satellite estimates on the study area and attempts to answer the question : what is the quality of these products in the Northern Amazon and French Guiana in spatial and time dimensions ? The second part proposes a new SPP bias correction technique that proceeds in three steps: i) using rain gauges measurements to decompose the studied area into hydro climatic areas ii) parameterizing a bias correction method called quantile mapping on each of these areas iii) apply the correction method to the satellite data for each hydro-climatic area. We then try to answer the following question : does the parameterization of the quantile mapping method on different hydro-climatic areas make it possible to correct the precipitation satellite data on the study area ? After showing the interest of taking into account the different rainfall regimes to implement the QM correction method on SPP data, the third part analyzes the impact of the temporal resolution of the precipitation data used on the quality of the correction and the spatial extent of potentially correctable SPP data (SPP data on which the correction method can be applied effectively). In summary, the objective of this section is to evaluate the ability of our method to correct on a large spatial scale the bias of the TRMM-TMPA 3B42V7 data in order to make the exploitation of this product relevant for different hydrological applications.This work made it possible to correct the daily satellite series with high spatial and temporal resolution on the Guiana Shield using a new approach that uses the definition of hydro-climatic areas. The positive results in terms of reduction of the bias and the RMSE obtained, thanks to this new approach, makes possible the generalization of this new method in sparselygauged areas
9
Avenas, Arthur. "Tropical cyclone dynamics revealed by satellite ocean surface wind speeds observations : the key contribution of the near-core surface wind structure." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0397.
Abstract:
Malgré les avancées dans la prédiction de la trajectoire des cyclones tropicaux et des vitesses de vent dans la région externe, la représentation numérique des vents les plus forts associés aux événements les plus intenses demeure une question ouverte, principalement en raison de la faible taille du cœur du cyclone et de la difficulté à comprendre et résoudre les échanges turbulents entre l’océan et l’atmosphère. Les limitations observationnelles ont longtemps entravé des mesures précises de la surface océanique près de la région centrale dans des conditions de vent extrême, tandis que les satellites géostationnaires aident à caractériser les motifs nuageux mais ne donnent pas d’information directe sur l’interface air-mer. Récemment, le radar à ouverture de synthèse (SAR) a émergé comme une technologie satellitaire prometteuse capable de produire des mesures bidimensionnelles haute résolution des vitesses du vent à la surface de l’océan, grâce à de nouveaux modes d’acquisition et à des développements algorithmiques. Compte tenu de ces nouvelles opportunités d’observation, nous explorons la contribution des caractéristiques structurelles près du cœur, exclusivement discernables à travers des instruments haute résolution, à la dynamique des cyclones. En utilisant un cadre théorique simple et examinant sa cohérence avec les mesures SAR, nous démontrons que les vents en surface près du cœur contrôlent l’évolution de la structure du vent du cyclone. Le cadre développé permet d’illustrer comment les futures mesures des caractéristiques de la couche limite océan-atmosphère pourraient bénéficier du suivi à court et à long terme des cyclones tropicauxDespite advances in predicting the tropical cyclones (TCs) trajectory and outer-core wind speeds, the numerical representation of the strongest winds associated with the most intense events is still an open issue, essentially because of the small radial extent of the TC core and the difficulty in understanding and resolving turbulent air-sea exchanges. Observational limitations have for a long time hindered accurate measurements of the ocean surface near the core region in extreme wind conditions, while geostationary satellites help characterizing the cloud patterns but lack direct information on the air-sea interface. Recently, synthetic aperture radar (SAR) has emerged as a promising satellite technology capable of producing high-resolution two dimensional measurements of the ocean surface wind speeds, thanks to new acquisition modes and algorithmic developments. Given these new observational opportunities, we investigate the contribution of near-core structural features, exclusively discernible through high-resolution instruments, to the TC dynamics. Using a simple theoretical framework and examining its consistency with SAR measurements, we demonstrate that the near-core surface winds modulate the evolution of the TC wind structure. The developed framework allows to illustrate how future measurements of ocean-atmosphere boundary layer characteristics could benefit the short- and long-term monitoring of TCs
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El-Alaoui, Mostafa. "Etude des faisceaux d'ions détectés en région aurorale par le satellite AUREOL-3 : synthèse des observations et apport de la modélisation numérique." Toulouse 3, 1994. http://www.theses.fr/1994TOU30037.
Abstract:
Les resultats amasses pendant plus d'un millier de passages du satellite franco-sovietique aureol-3 au-dessus des regions des hautes latitudes ont ete analyses afin de determiner les proprietes de la precipitation des particules chargees. Cette recherche a permis la decouverte de nombreux faisceaux d'ions energetiques et, pour la premiere fois, leurs proprietes sont decrites en detail. Ces faisceaux sont localises au voisinage de la separatrice entre l'ovale des precipitations aurorales et la calotte polaire; leur caracteristique fondamentale est l'accroissement de leur energie avec la latitude. On demontre en particulier que ces faisceaux, confines en latitude dans une region de moins de 1 degre d'etendue, sont la signature aurorale a basse altitude des faisceaux deja observes par le passe dans les couches limites du feuillet de plasma. A ces faisceaux peut etre associee une region nouvelle qui est aussi mise en evidence et decrite dans ce travail pour la premiere fois: autour de minuit local un minimum prononce de precipitation ionique separe la region aurorale diffuse de la region des faisceaux d'ions et ce minimum correspond partiellement a la region des arcs d'electrons. A partir de l'analyse des equations du mouvement des ions, il est montre que ces faisceaux proviennent des regions tres lointaines de la magnetosphere et transportent des informations fondamentales sur les mecanismes d'accel2ration agissant dans la queue geomagnetique. Au voisinage d'un feuillet neutre les particules executent differentes familles de trajectoires dans l'espace; la physique complexe qui gouverne ce mouvement en presence d'un champ electrostatique de convection et du champ geomagnetique sera discutee puis confirmee et etendue au moyen des simulations numeriques
Books on the topic "Observations par satellite":
1
Harries, John E. Earthwatch: Climate from space. Chichester: Wiley in association with Praxis Publishing, 1995.
2
Harries, John E. Earthwatch: The climate from space. Chichester: Wiley, 1994.
3
Harries, John E. Earthwatch: The climate from space. New York: E. Horwood, 1990.
4
Contribution of satellite observations to the Canadian Global Change Program =: Contribution des observations par satellite au programme canadien des changements à l'échelle du globe. [Ottawa?]: Canada Centre for Remote Sensing, Surveys, Mapping and Remote Sensing Sector, Energy, Mines and Resources Canada, 1989.
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Harries, John E. Earthwatch: The Climate from Space (Ellis Horwood Series in Atmospheric Science). Ellis Horwood, 1991.
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Harries, John E. Earthwatch: The Climate from Space (Ellis Horwood Series in Atmospheric Science). Ellis Horwood, 1991.
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Harries, John E. Earthwatch: The Climate from Space (Wiley-Praxis Series in Remote Sensing). John Wiley & Sons Inc, 1996.
Book chapters on the topic "Observations par satellite":
1
Lukeš, Petr. "Monitoring of Bark Beetle Forest Damages." In Big Data in Bioeconomy, 351–61. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-71069-9_26.
Abstract:
AbstractIn this chapter, we present a multi-source remote sensing approach for country-wise monitoring of bark beetle calamity to support government decision making processes. In the first part, we describe the forest health monitoring system, which is based on the analysis of satellite big data–Sentinel-2 observations collected every five days. We propose an automated processing chain for high-quality cloud-free image synthesis for user-defined acquisition periods. Such a processing chain is applied to yield yearly cloud-free images of the entire Czech Republic from 2015 onwards. Based on this data, we assess forest health trends using Sentinel-2 derived vegetation indices and in situ data of forest status. Finally, we demonstrate the benefits of multi-source remote sensing for timely and objective mapping of bark beetle spread by combining several data sources, including planet high-resolution satellite data, Sentinel-2 forest health maps and other maps of forest conditions. Detected bark beetle sanitary logging and dead standing wood polygons are used by the Ministry of Agriculture of Czech Republic in their decision processes regarding the management of affected forest areas.
2
GILLET-CHAULET, Fabien. "Assimilation de données en glaciologie." In Inversion et assimilation de données de télédétection, 169–200. ISTE Group, 2023. http://dx.doi.org/10.51926/iste.9142.ch5.
Abstract:
De combien et à quelle vitesse les calottes polaires peuvent contribuer au changement de niveau des mers ? » sont les principales problèmes auxquels tendent actuellement de répondre les modèles de calotte polaire. Avec la multiplication des observations par satellite, l’assimilation de données connaît un fort développement en glaciologie afin de mieux comprendre des processus qui, du fait des conditions, sont difficilement observables directement.
3
Ratnakumar, Rahul, and U. Vignesh. "Machine Learning-Based Environmental, Social, and Scientific Studies Using Satellite Images." In AI and Blockchain Optimization Techniques in Aerospace Engineering, 149–63. IGI Global, 2024. http://dx.doi.org/10.4018/979-8-3693-1491-3.ch007.
Abstract:
Satellite images of the entire globe or any given location can be procured quickly with good resolution from any part of the world using thousands of artificial satellites revolving around the Earth. Using advanced AI/ML image processing algorithms, the acquired data can be analyzed to obtain various essential knowledge of any place at any time like the chemical composition of the environment, population density (social), etc. Another prominent field is military, defence, and warfare. Independent hyperspectral image cluster analysis of the world's heavily populated cities like Delhi, Shanghai, etc. has clearly shown the migration of population from rural to the urban. The RS-GIS technology combined with advanced machine learning algorithms predicts that only 50 more years of groundwater supply is left to be harvested. These case observations from different parts of the world show the power and scope of aero-oriented image processing using machine learning algorithms.
4
Wylie, Donald P. "Cirrus and Weather: A Satellite Perspective." In Cirrus. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195130720.003.0010.
Abstract:
Cirrus were originally thought of as benign cloud forms that could be used for predicting the onset of foul weather, such as “mare's tails” and “anvil edges,” but not of great concern because they do not produce any damaging winds or hydrometers. Our original view of cirrus was from the ground, so they were mostly ignored until aircraft started flying in them and making cirruslike contrails in the latter part of World War II. Cirrus limited visibility for the aircraft, and contrails made detection of aircraft from the ground easier. This led to the first studies of cirrus by the Air Force (Stone 1957). Had our first views of earth been from space, cirrus would have been an obvious cloud and often an obstruction to viewing everything else on the planet. Cirrus are difficult to see on visual satellite images, which is deceiving because they reflect enough solar radiation to obscure quantitative measurements of the land and water surfaces. Cirrus are more obvious in window channel infrared images, and they block any sensor that tries to look horizontally through them from either aircraft or satellites. The term “invisible cirrus” originated from an attempt to fly a horizontal viewing sensor on an aircraft for detecting approaching objects (missiles). The sensor was obscured because of its long path length through cirrus, while ground observers did not report the cirrus. Pilots were uncertain whether they were in a cloud or not. The frequency of cirrus reported from satellite data often surprises other scientists. Wylie and Menzel (1999) reported finding cirrus in 25-30% of GOES/VAS (Geostationary Operational Environmental Satellite/Visual spin scan radiometer Atmospheric Sounder) data over the continental United States. A similar satellite instrument flying globally, the HIRS (High Resolution Infrared Radiometer Sounder) on the National Oceanic and Atmospheric Administration (NOAA) satellites, reported cirrus 43% of the time (Wylie and Menzel 1994; Wylie and Menzel 1999). The horizontally viewing SAGE (Stratospheric Aerosol and Gas Experiment) is even more sensitive and reports cirrus in 50-70% of its data (Wang et al. 1996). These numbers should not have surprised people because the compilations of ground-based weather observations by Warren et al. (1988) show cirrus frequencies as high as 75% in Indonesia.
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Polyak, Ilya. "Second Moments of Rain." In Computational Statistics in Climatology. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195099997.003.0010.
Abstract:
The first part of this chapter presents a description of the GATE rain rate data (Polyak and North, 1995), its two-dimensional spectral and correlation characteristics, and multivariate models. Such descriptions have made it possible to show the concentration of significant power along the frequency axis in the spatial-temporal spectra; to detect a diurnal cycle (a range of variation of which is about 3.4 to 5.4 mm/hr); to study the anisotropy (as the result of the distinction between the north-south and east-west transport of rain) of spatial rain rate fields; to evaluate the scales of the distinction between second-moment estimates associated with ground and satellite samples; to determine the appropriate spatial and temporal scales of the simple linear stochastic models fitted to averaged rain rate fields; and to evaluate the mean advection velocity of the rain rate fluctuations. The second part of this chapter (adapted from Polyak et al., 1994) is mainly devoted to the diffusion of rainfall (from PRE-STORM experiment) by associating the multivariate autoregressive model parameters and the diffusion equation coefficients. This analysis led to the use of rain data to estimate rain advection velocity as well as other coefficients of the diffusion equation of the corresponding field. The results obtained can be used in the ground truth problem for TRMM (Tropical Rainfall Measuring Mission) satellite observations, for comparison with corresponding estimates of other sources of data (TOGA-COARE, or simulated by physical, models), for generating multiple rain samples of any size, and in some other areas of rain data analysis and modeling. For many years, the GATE data base has served as the richest and most accurate source of rain observations. Dozens of articles presenting the results of the GATE rain rate data analysis and modeling have been published, and more continue to be released. Recently, a new, valuable set of rain data was produced as a result of the TOGA-COARE experiment. In a few years, it will be possible to obtain satellite (TRMM) rain information, and a rain statistical description will be needed in the analysis of the observations obtained on an irregular spatial and temporal grid.
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Kavouras, Ioannis, Eftychios Protopapadakis, Maria Kaselimi, Emmanuel Sardis, and Nikolaos Doulamis. "Assessing the Lockdown Effects on Air Quality During COVID-19 Era." In Frontiers in Artificial Intelligence and Applications. IOS Press, 2021. http://dx.doi.org/10.3233/faia210095.
Abstract:
In this work we investigate the short-term variations in air quality emissions, attributed to the prevention measures, applied in different cities, to mitigate the COVID-19 spread. In particular, we emphasize on the concentration effects regarding specific pollutant gases, such as carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2). The assessment of the impact of lockdown on air quality focused on four European Cities (Athens, Gladsaxe, Lodz and Rome). Available data on pollutant factors were obtained using global satellite observations. The level of the employed prevention measures is employed using the Oxford COVID-19 Government Response Tracker. The second part of the analysis employed a variety of machine learning tools, utilized for estimating the concentration of each pollutant, two days ahead. The results showed that a weak to moderate correlation exists between the corresponding measures and the pollutant factors and that it is possible to create models which can predict the behaviour of the pollutant gases under daily human activities.
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Adavi, Zohreh, and Robert Weber. "Application of the Total Variation Method in Near Real-Time GNSS Tropospheric Tomography." In International Association of Geodesy Symposia. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/1345_2022_174.
Abstract:
AbstractGNSS tomography is an all-weather remote sensing technique to capture the spatiotemporal behavior of the atmospheric water vapor using the standing infrastructure of GNSS satellites and networks. In this method, the troposphere is discretized to a finite number of 3D elements (voxel) in horizontal and vertical directions. Then, the wet refractivity in these voxels is reconstructed using the Slant Wet Delay (SWD) observations in the desired tomography domain by means of the discrete inverse concept. Due to the insufficient spatial coverage of GNSS signals in the voxels within the given time window, some of the voxels are intersected by a few signals or plenty of signals, and others are not passed by any signals at all. Therefore, the design matrix is sparse, and the observation equation system of the tomography model is mixed-determined. Some constraints have to be applied or external data sources should be added to the tomography problem in order to reconstruct the wet refractivity field. Moreover, the GNSS tomography is a kind of discrete ill-posed problem, as all singular values of the structure matrix (A) in the tomography problem decay gradually to zero without any noticeable gap in the spectrum. Hence, slight changes in the measurements can lead to extremely unstable parameter solutions. In consequence, the regularization method should be applied to the inversion process and ensure a stable and unique solution for the tomography problem. In this research, the Total Variation (TV) method is suggested to retrieve a regularized solution. TV is a nonlinear technique, which resists noise and efficiently preserves discontinuities in the model. This method can also reconstruct the wet refractivity field without any initial field in a shorter time span. For this purpose, observation data from the EPOSA (Echtzeit Positionierung Austria) GNSS network located in the eastern part of Austria is processed within the period DoYs 232-245 in 2019. Then, the TV method is performed in six different tomography windows (10–60 min) with a time step of 10 min by focusing on near-real-time applications. Finally, radiosonde measurements in the area of interest are utilized to compare the estimated wet refractivity field in order to obtain the accuracy of the proposed method.
8
Dolman, Han. "The Hydrological Cycle and Climate." In Biogeochemical Cycles and Climate, 105–28. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198779308.003.0008.
Abstract:
Water is a key part of the Earth system and interacts with climate through a variety of mechanisms. The chapter initially describes the effect of atmospheric moisture on the lapse rate and then discusses cloud formation and the main global reservoirs and fluxes, including precipitation, and discharge into the oceans. Atmospheric transport of water vapour, together with its relation to precipitation, is then discussed. It is shown that meridional transport can occur with a few very strong events, through atmospheric rivers. The difference between evaporation over the ocean and that over land is shown, with the help of data from Earth observation satellites, and the recycling of water is shown to depend very much on locality. Finally, the importance of frozen water on climate is described, using the recent decrease in Arctic sea ice, and the variability in ice sheet extent and consequent sea levels during the Last Glacial Maximum.
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Krawinkel, Thomas, and Steffen Schön. "On the Limits of State-of-the-Art GNSS Receivers in Frequency Transfer." In International Association of Geodesy Symposia. Berlin, Heidelberg: Springer Berlin Heidelberg, 2022. http://dx.doi.org/10.1007/1345_2022_145.
Abstract:
AbstractGNSS frequency transfer (FT) based on precise point positioning delivers instability values down to sub-10−16 between two modern receivers. In the present study we investigate the technical limits such receivers impose on FT by means of a dedicated experiment at Germany’s national metrology institute (PTB). For this purpose, four geodetic receivers, two of the same type each, were all connected to one single antenna and fed by the highly stable UTC (PTB) frequency signal. Since all error sources affecting the satellite signals are the same for all receivers, they cancel out when forming receiver-to-receiver single differences (SDs). Due to the fact that the remaining SD carrier phase ambiguities can be easily fixed to integer values, only the relative receiver clock error remains in the SDs. We assess the instability of three different receiver combinations, two with the same receiver type (intra-receiver) and one with different types (inter-receiver). The intra-receiver pairs reach lower instability values faster than the inter-receiver combination, which is in part caused by the different signal tracking modes of the receivers. To be specific, the 10−18 instability range was only reached by the intra-receiver pairs, whereas the inter-receiver combination already hits its noise floor at about 1.5 ⋅ 10−17. In addition, our analysis of using different observation type combinations only shows small differences regarding the link instability.
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Horning, Ned, Julie A. Robinson, Eleanor J. Sterling, Woody Turner, and Sacha Spector. "Integrating field data." In Remote Sensing for Ecology and Conservation. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780199219940.003.0021.
Abstract:
While the savannah elephant (Loxodonta africana) is listed by the International Union for Conservation of Nature (IUCN) as “vulnerable” because of declining abundance in some regions of Africa (Blanc 2008), populations in some protected areas of South Africa are growing rapidly (van Aarde and Jackson 2007). These populations can cause extensive modification of vegetation structure when their density increases (Owen-Smith 1996; Whyte et al. 2003; Guldemond and van Aarde 2007). Management methods such as culling, translocation, and birth control have not reduced density in some cases (van Aarde et al. 1999; Pimm and van Aarde 2001). Providing more space for elephants is one alternative management strategy, yet fundamental to this strategy is a clear understanding of habitat and landscape use by elephants. Harris et al. (2008) combined remotely sensed data with Global Positioning System (GPS) and traditional ethological observations to assess elephant habitat use across three areas that span the ecological gradient of historical elephant distribution. They explored influences on habitat use across arid savannahs (Etosha National Park in Namibia) and woodlands (Tembe Elephant Park in South Africa and Maputo Elephant Reserve in Mozambique). The researchers focused on three main variables—distance to human settlements, distance to water, and vegetation type. The authors used Landsat 7 ETMþ imagery to create vegetation maps for each location, employing supervised classification and maximum likelihood estimation. Across all sites, they recorded the coordinates of patches with different vegetation and of vegetation transitions to develop signatures for the maps. Elephants do not use all vegetation types, and it can be expedient to focus on presence rather than both presence and absence. Accordingly, the researchers used GPS to record the locations of elephants with the aim of identifying important land cover types for vegetation mapping. The authors mapped water locations in the wet and dry seasons using remotely sensed data and mapped human settlements using GPS, aerial surveys, and regional maps. They tracked elephants with radiotelemetry collars that communicated with the ARGOS satellite system, sending location data for most of the elephants over 24 h, and then remaining quiescent for the next 48 h to extend battery life.
Conference papers on the topic "Observations par satellite":
1
Winker, D. M. "Lidar Observations of Clouds at NASA Langley During ECLIPS Phases I and II." In Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/orsa.1991.owa3.
Abstract:
The Experimental Cloud Lidar Pilot Study (ECLIPS) was formulated in 1988 to explore the feasibility of obtaining a longterm climatology of cloud base height and cloud optical properties using groundbased lidar (WMO, 1988). Data obtained by all participants in ECLIPS will be collected in a single archive to form a database of lidar-derived cloud properties. This archive is being compiled at NASA Langley Research Center and will become part of the NCDC (National Climate Data Center) database when completed. Observations are made coincident with overpasses of the Advanced Very High Resolution Radiometer (AVHRR) instrument carried on the NOAA-10 and NOAA-11 satellites. The ECLIPS archive can then be used as ground validation for satellite retrieval methods, leading to improved predictions of surface energy balance from satellite radiance data.
2
Khan, Muhammad Shadab, Rauno Gordon, Martin Simon, Kristjan Tonismae, Dzmitry Kananovich, Veljo Sinivee, Marko Karm, and Kaarel Repän. "Development and flight results of TalTech University CubeSat mission." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.117.
Abstract:
Student Satellite program at TalTech, Tallinn University of Technology, Tallinn, Estonia was initiated in 2014 with an aim to impart space technology knowledge to the Estonian students as well as assist towards development of new Space Technologies in Estonia. Two 1-Unit CubeSat named Koit and Hämarik that translates respectively as Dawn and Twilight in Estonian are part of the TalTech Satellite Program. The main scientific mission of the CubeSats was to demonstrate Earth observation and Optical Communication technology. Satellites had two types of cameras, an RGB Camera and an NIR Camera to carry out Earth Observation over Estonia. Testing High Speed Optical communication technology from LEO (Low Earth Orbit) was the second major scientific goal and for this purpose the CubeSats had LED (Light Emitting Diode). Koit CubeSat was successfully launched to space on-board Soyuz rocket on July 5, 2019 and Hämarik CubeSat was launched to Space on September 3, 2020 on-board Arianespace Vega Rocket. Koit CubeSat did not contact the Ground station for more than a year since its launch and it was assumed to be lost but on November 21, 2020 it made the first contact with the Ground Station. Hämarik CubeSat was first contacted on November 15, 2020. The team has been successful in updating software of Hämarik and further work is being done on the software with broader functions. Optical communication has not been tested yet because ground station for optical communication has not been developed yet but a good achievement in the path to optical communication was to see the satellites with small hobby telescope and one of the satellite team member was successful to detect the Hämarik CubeSat on 17 August 2021 which was at a distance of about 792 Kilometres. Satellite team is in contact with the Hämarik and has been successful to download a few thumbnails and is working to establish a quick data connection with it and determine its exact position so that the cameras can be focused towards the Earth in order to get the whole images captured by the CubeSat.
3
Zabolotna, Olena, Oleksandr Kryvoshein, and Oleksiy Kryvobok. "Validation of precipitation data of GPM satellite products over Ukraine." In International Conference of Young Scientists on Meteorology, Hydrology and Environmental Monitoring. Ukrainian Hydrometeorological Institute, 2023. http://dx.doi.org/10.15407/icys-mhem.2023.027.
Abstract:
This study provides a description and results of the validation methodology of GPM satellite precipitation data for the territory of Ukraine. Validation was carried out by comparing satellite data with ground weather stations data and included the following stages: data collection and processing, bringing the data to the same spatial and temporal resolution, calculating correlation coefficients and estimation of confusion matrices. Correlation analysis was carried out for two studied periods (the first period - April-September 2020, the second - April-September 2021). Satellite data were provided by the GPM project of NASA and ground data were provided by 155 meteorological stations of the Ukrainian National Hydrometeorological Network. Satellite and ground data were calculated to have the comparable values, that is 12 hours precipitation sums, from 6:00 a.m. to 6:00 p.m. For this, weather stations data were obtained as the sum of the amount of precipitation for this period of the day, and the satellite data that were downloaded for every half an hour as intensity mm/h, were converted into mm/day, thus obtaining the precipitation amount for the specified period of the day. For obtaining reliable results of validation, correlation coefficients were calculated and confusion matrices were built. Confusion matrices are based on the division of precipitation into classes of different intensity. Confusion matrices were calculated for four classes of precipitation (mm): “0-2”, “2-5”, “5-10”, “>10”. Calculations were performed using the software environment for statistical calculations R. The comparison analysis showed that a larger number of stations (117) has a correlation coefficient 0.5 - 0.8. The coefficients of the confusion matrices showed that low-intensity precipitation or “no precipitation”, as well as high-intensity precipitation, are estimated by the satellite with high accuracy in comparison with the ground-based weather station measurements. So, according to the "specificity" indicator, the highest level of correspondence of satellite data (GPM Late, GPM Early) to ground data has precipitation class >”10 mm”. The low value of the "specificity" for the range of 0-2 mm is explained by the fact that satellite methods are able to detect very low values of precipitation intensity, while the station shows their absence - 0 mm. Thus, according to the values of the confusion matrices, we see that a large part of the values of surface observations of precipitation in the range of 0-2 mm are shown by the satellite method as “2-5 mm” class. We can also see that the “2-5 mm” class by satellite has the most confusion with the 0-2 mm class by station (GPM Late, GPM Early). However, based on the high values of the "recall" for the range of 0-2 mm (GPM Late, GPM Early), we can conclude that when the station does not show this amount of precipitation (0-2 mm), then the satellite also shows another class of values. The high values of the coefficient of "precision" show that the satellite measurements are really reliable, that is, the presence or absence of precipitation will be determined precisely, since the highest value of "precision" is typical for low and high amounts of precipitation (on average 0.76 and 0.66, respectively). Heavy precipitation or no precipitation detected by satellites is confirmed by ground stations in most cases.
4
Fomin, Vladimir, Vladimir Fomin, Ludmila Kharitonova, Ludmila Kharitonova, Dmitrii Alekseev, Dmitrii Alekseev, Elena Ivancha, and Elena Ivancha. "MORPHODYNAMICS OF THE BAKALSKAYA SPIT OF THE BLACK SEA." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93fae199c8.45419382.
Abstract:
Studies of shape dynamics of the Bakalskaya Spit based on observation and numerical simulation are carries out. The Bakalskaya Spit is a dynamically active sand formation on the north-west coast of the Crimea Peninsula. Field observations and satellite image analyses showed that the erosion of spit west coast, eastward displacement of spit distal part and separation of distal part from the spit main part are the most significant processes. After the autumn storms in 2010 the isthmus between the distal part of spit and its main part was eroded and had not recovered till now. So the distal part of the Bakalskaya Spit turned into island. Dynamic of sediments depends on wind wave parameters and sea level oscillations. Effect of changing of wind wave direction and storm surge height on erosion and deposition processes in the Bakalskaya Spit region of the Black Sea is studied by using of XBeach numerical model. Dependencies of location and space dimension of erosion and deposition areas of sediments on characteristics of waves and surges are obtained. It is found that the most intensive erosion of spit isthmus occurs in case of wave running from the west in comparison of cases of wave running from the south-west and north-west if there are no surges. Presence of surges may results in increasing or decreasing of erosion process intensiveness depending on wave direction.
5
Fomin, Vladimir, Vladimir Fomin, Ludmila Kharitonova, Ludmila Kharitonova, Dmitrii Alekseev, Dmitrii Alekseev, Elena Ivancha, and Elena Ivancha. "MORPHODYNAMICS OF THE BAKALSKAYA SPIT OF THE BLACK SEA." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431521aa58.
Abstract:
Studies of shape dynamics of the Bakalskaya Spit based on observation and numerical simulation are carries out. The Bakalskaya Spit is a dynamically active sand formation on the north-west coast of the Crimea Peninsula. Field observations and satellite image analyses showed that the erosion of spit west coast, eastward displacement of spit distal part and separation of distal part from the spit main part are the most significant processes. After the autumn storms in 2010 the isthmus between the distal part of spit and its main part was eroded and had not recovered till now. So the distal part of the Bakalskaya Spit turned into island. Dynamic of sediments depends on wind wave parameters and sea level oscillations. Effect of changing of wind wave direction and storm surge height on erosion and deposition processes in the Bakalskaya Spit region of the Black Sea is studied by using of XBeach numerical model. Dependencies of location and space dimension of erosion and deposition areas of sediments on characteristics of waves and surges are obtained. It is found that the most intensive erosion of spit isthmus occurs in case of wave running from the west in comparison of cases of wave running from the south-west and north-west if there are no surges. Presence of surges may results in increasing or decreasing of erosion process intensiveness depending on wave direction.
6
Freudenthaler, Volker, Frank Homburg, and Horst Jäger. "Contrail Observation by Ground-Based Scanning Lidar: Spatial Growth." In Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/orsa.1995.tuc15.
Abstract:
The analysis of satellite data reveals an additional cloud cover due to contrails of 0.4% over mid-Europe (Schumann and Wendling, 1990) and up to 2% over the eastern part of the Atlantic Ocean ( Bakan et.al., 1994). The contrails consist of ice crystals and form from the additional water vapour emitted by high flying aircrafts. Their persistence (up to some hours) depends on the ambient temperature and humidity (Appelman, 1953, Boin and Levkov, 1994). To evaluate the impact of contrails on the earth's radiation budget, their extension and optical parameters must be known. This paper describes a scanning lidar system dedicated to the measurement of contrails, and an analysis of the temporal and spatial evolution of seven contrails.
7
Sambuu, Anna, B. Mongush, and Sh Mongush. "NATURAL AND ANTHROPOGENIC DEGRADATION PROCESSES DESERTED STEPPES OF THE UBSUNUR BASIN." In Land Degradation and Desertification: Problems of Sustainable Land Management and Adaptation. LLC MAKS Press, 2020. http://dx.doi.org/10.29003/m1717.978-5-317-06490-7/240-244.
Abstract:
Steppes in Tuva occupy intermountain basins with altitudes of 550-1200 m above sea level, the lower parts of mountain slopes, and high terraces of river valleys. Large massifs of steppes are typical for the Ulugh-Khem and Ubsunur basins. Studies to assess the state of soil and vegetation cover were conducted in the North-Eastern (Tuva) part of the drainless Ubsunur basin in July-August 1997-2020 using the route method. The location of the basin between the boreal landscapes of Siberia and the desert-steppe landscapes of Central Asia is characterized by a variety of landforms, heterogeneity of soil and vegetation cover, and a unique distribution of climatic factors and geological history. The source material was our own data from soil and geobotanical studies and remote materials from different observation periods. Observation data from different survey years were linked to the Landsat satellite image for July-August 1997-2019. Route studies were carried out on the main geomorphological profiles from the southern foothills of the Western and Eastern Tannu-Ola ranges to the coast of oz. Ubsa-Nur (from North to South). Reference soil sections were laid at key sites, morphological descriptions of soil profiles and horizon-based sampling were carried out. Soil samples were taken to determine the humus content, granulometric composition, size and nature of salinity-the main indicators of soil desertification. Observations also covered the Eastern and Western parts of the basin, which revealed the direction of degradation of desolate steppes in different geomorphological positions of the territory, but also with different nature and intensity of anthropogenic impact.
8
Jäger, H. "Pinatubo Cloud Over Garmisch-Partenkirchen." In Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/orsa.1991.otue18.
Abstract:
The explosive eruptions of the Philippine volcano Pinatubo in mid-June 1991 caused the first major perturbation of the stratosphere since the eruption of the Mexican volcano El Chichón in April 1982. Early groundbased, satelliteborne and in situ observations of the Pinatubo eruption cloud were collected by McClelland et al., 1991. Satellite images from July and August did not show a significant transport of volcanic debris to mid-latitudes, the major part of the cloud was reported to be confined in an equatorial band 15°S to 25°N with the densest part in the 20 to 25 km height range and further layers below 20 km.
9
Fernandez Capon, Lara Pilar, Marco Sobrino Hidalgo, Oriol Milian, Andrea Aguilella Merelas, Arnau Solanellas Bofarull, Marc Badia Ballús, Joan Francesc Muñoz Martin, Juan Adrián Ruiz De Azúa Ortega, Miquel Sureda Anfres, and Adriano José Camps Carmona. "Deployment mechanism for an L-Band Helix antenna on-board the 3Cat-4 1U CubeSat." In Symposium on Space Educational Activities (SSAE). Universitat Politècnica de Catalunya, 2022. http://dx.doi.org/10.5821/conference-9788419184405.072.
Abstract:
Earth Observation (EO) is key for climate and environmental monitoring at global level, and in specific regions where the effects of global warming are more noticeable, such as in polar regions, where ice melt is also opening new commercial maritime routes. Soil moisture is also useful for agriculture and monitoring the advance of desertification, as well as biomass and carbon storage. Global Navigation Satellite System - Reflectometry (GNSS-R) and L-band microwave Radiometry are passive microwave remote sensing techniques that can be used to perform these types of measurements regardless of the illumination and cloud conditions, and -since they are passive- they are well suited for small satellites, where power availability is a limiting factor. GNSS-R was tested from space onboard the UK-DMC and the UK TechDemoSat-1, and several missions have been launched using GNSS-R as main instrument, as CyGNSS, BuFeng-1, or the FSSCAT [1] mission. These missions aim at providing soil moisture [2], ocean wind speed [3], and flooding mapping of the Earth. L-band microwave radiometry data has also been retrieved from space with SMOS and SMAP missions, obtaining sea ice thickness, soil moisture, and ocean salinity data [4]. The 3Cat-4 mission was selected by the ESA Academy "Fly your Satellite" program in 2017. It aims at combining both GNSS-R and L-band Microwave Radiometry at in a low-power and cost-effective 1-Unit (1U) satellite. Moreover, the 3Cat-4 can also detect Automatic Identification System (AIS) signals from vessels. The single payload is the Flexible Microwave Payload 1 (FMPL-1) [5] that performs the signal conditioning and signal processing for GNSS-R, L-Band microwave radiometry and AIS experiments. The spacecraft has three payload antennas: (1) a VHF monopole for AIS signals; (2) an uplooking antenna for the direct GPS signals; (3) a downlooking antenna that captures reflected GPS signals, and for the Microwave Radiometer. The downlooking antenna is a deployable helix antenna called the Nadir Antenna and Deployment Subsystem (NADS) which has a volume of less than 0,3U when stowed, achieving an axial length of more than 500 mm when deployed. As part of this mission, the design of the NADS antenna, its RF performance, as well as the environmental tests performed in terms of structural and thermal space conditions will be presented.
10
Kolev, I., O. Parvanov, B. Kaprielov, and Y. Tomova. "Lidar Cloud Observaion: In Part of Eclips Phase II in the Region of Sofia." In Optical Remote Sensing of the Atmosphere. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/orsa.1993.tuc.8.
Abstract:
The ECLIPS project in which our lidar group also takes part is well described [1]. In general, the main purpose is a ground-based lidar observation of the clouds simultaneously with the NOAA 10 and NOAA 11 meteorological satellites overpassing the same areas to be performed. Essential data are the recorded profiles of the lidar returns from which certain information about the clouds height, optical depth and vertical extinction can be derived.
Reports on the topic "Observations par satellite":
1
Rémy, Elisabeth, Romain Escudier, and Alexandre Mignot. Access impact of observations. EuroSea, 2023. http://dx.doi.org/10.3289/eurosea_d4.8.
Abstract:
The accuracy of the Copernicus Marine Environment and Monitoring Service (CMEMS) ocean analysis and forecasts highly depend on the availability and quality of observations to be assimilated. In situ observations are complementary to satellite observations that are restricted to the ocean surface. Higher resolution model forecasts are required by users of the CMEMS global and regional ocean analysis and forecasts. To support this with an efficient observational constrain of the model forecast via data assimilation, an increase observation coverage is needed, associated with an improved usage of the available ocean observations. This work exploits the capabilities of operational systems to provide comprehensive information for the evolution of the GOOS. In this report, we analyse the use and the efficiency of the in-situ observations to constrain regional and global Mercator Ocean systems. Physical and biogeochemical variables are considered. The in-situ observations are used either to estimate physical ocean state at global and regional scale via data assimilation or to estimate BGC model parameters. The impact of the physical in situ observations assimilated in open ocean and coastal areas is assessed with numerical data assimilation experiments. The experiments are conducted with the regional 1/36° resolution and global 1/12° resolution systems operated by Mercator Ocean for the Copernicus Marine Service. For the global physical ocean, the focus is on the tropical ocean to better understand how the tropical mooring observations constrain the intraseasonal to daily variability and the complementarity with satellite observations and the deep ocean. The tropical moorings provide unique high frequency observations at different depth, but they are far away from each other, so part of the signal in the observation are decorrelated from one mooring to the others. It is only via an integrated approach, as data assimilation into a dynamical model and complementarity with other observing networks that those observations can efficiently constrain the different scales of variability of the tropical ocean circulation. As the satellite observations brings higher spatial resolution between the tropical moorings but for the ocean surface, we show that the tropical mooring and Argo profile data assimilation constrain the larger scale ocean thermohaline vertical structure (EuroSea D2.2; Gasparin et al., 2023). The representation of the high frequency signals observed at mooring location is also significantly improved in the model analysis compared to a non-assimilative simulation. The ocean below 2000 m depth is still largely under constrained as very few observations exist. Some deep ocean basins, as the Antarctic deep ocean, shows significant trend over the past decade but they are still not accurately monitored. Based on the spread of four deep ocean reanalysis estimates, large uncertainties were estimated in representing local heat and freshwater content in the deep ocean. Additionally, temperature and salinity field comparison with deep Argo observations demonstrates that reanalysis errors in the deep ocean are of the same size as or even stronger than the observed deep ocean signal. OSSE already suggested that the deployment of a global deep Argo array will significantly constrain the deep ocean in reanalysis to be closer to the observations (Gasparin et al., 2020). At regional and coastal scales, the physical ocean circulation is dominated by higher frequency, smaller scale processes than the open ocean which requires different observation strategy to be well monitor. The impact of assimilating high frequency and high-resolution observations provided by gliders on European shelves is analysed with the regional Iberic Biscay and Irish (IBI) system. It was found that repetitive glider sections can efficiently help to constrain the transport of water masses flowing across those sections. BGC ocean models are less mature than physical ocean models and some variable dependencies are still based on empirical functions. In this task, Argo BGC profile observations were used to optimize the parameters of the global CMEMS biogeochemical model, PISCES. A particle filter algorithm was chosen to optimize a 1D configuration of PISCES in the North Atlantic. The optimization of the PISCES 1D model significantly improves the model's ability to reproduce the North Atlantic bloom Recommendations on the in-situ network extensions for real time ocean monitoring are given based on those results, and the one also obtained in the WP2, Task 2.2 where data assimilation experiments but with simulated observations where conducted. Argo extension and the complementarity with satellite altimetry was also extensively studied. (EuroSea Deliverable ; D4.8)
2
White, H. P., W. Chen, and S G Leblanc. Satellite observations for detection of dust from mining activities in a caribou habitat, Northwest Territories and Nunavut. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330548.
Abstract:
Diamond mining via open pit mining has been ongoing within the Tlicho region of the Northwest Territories for several decades, which includes the habitat range of the Bathurst Caribou Herd. This has led to the importance of quantitative characterization of the Zone Of Influence (ZOI), where resource development activities may be influencing the natural behaviour of the caribou herd in the tundra environment. As part of better defining and understanding the ZOI in this region, an initiative to evaluate the potential of detecting and mapping mine waste rock dust in the surrounding environment is explored. This dust has been shown to coat foliage near roads, influencing the acidity levels of the surficial soil layer and impacting the foliage distribution. To this end, field spectrometry was acquired at various distances from road ways. Satellite imagery from the Proba-1 CHRIS hyperspectral sensor and the multi-spectral Sentinel-2a system were also acquired of the region. This presentation presents the initial spectral analysis pursued to evaluate the potential to remotely spectrally detect waste rock dust material used in road construction in the surrounding tundra vegetation. Initial analysis of the Proba-1 CHRIS hyperspectral imagery shows spectral indicators of fugitive dust and waste rock easily detects the road and suggests detectable dust concentration above ambient up to a distance of under 1km from the road.
3
Lasko, Kristofer. Incorporating Sentinel-1 SAR imagery with the MODIS MCD64A1 burned area product to improve burn date estimates and reduce burn date uncertainty in wildland fire mapping. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42122.
Abstract:
Wildland fires result in a unique signal detectable by multispectral remote sensing and synthetic aperture radar (SAR). However, in many regions, such as Southeast Asia, persistent cloud cover and aerosols temporarily obstruct multispectral satellite observations of burned area, including the MODIS MCD64A1 Burned Area Product (BAP). Multiple days between cloud free pre- and postburn MODIS observations result in burn date uncertainty. We incorporate cloud-penetrating, C-band SAR-with the MODIS MCD64A BAP in Southeast Asia, to exploit the strengths of each dataset to better estimate the burn date and reduce the potential burn date uncertainty range. We incorporate built-in quality control using MCD64A1 to reduce erroneous pixel updating. We test the method over part of Laos and Thailand during April 2016 and found average uncertainty reduction of 4.5 d, improving 15% of MCD64A1 pixels. A new BAP could improve monitoring temporal trends of wildland fires, air quality studies and monitoring post-fire vegetation dynamics.
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Thoma, David. Landscape phenology, vegetation condition, and relations with climate at Canyonlands National Park, 2000–2019. Edited by Alice Wondrak Biel. National Park Service, June 2023. http://dx.doi.org/10.36967/2299619.
Abstract:
Quantitatively linking satellite observations of vegetation condition and climate data over time provides insight to climate influences on primary production, phenology (timing of growth), and sensitivity of vegetation to weather and longer-term patterns of weather referred to as climate. This in turn provides a basis for understanding potential climate impacts to vegetation—and the potential to anticipate cascading ecological effects—such as impacts to forage, habitat, fire potential, and erosion—as climate changes in the future. This report provides baseline information about vegetation production and condition over time at Canyonlands National Park (NP), as derived from satellite remote sensing. Its objective is to demonstrate methods of analysis, share findings, and document historic climate exposure and sensitivity of vegetation to weather and climate as a driver of vegetation change. This report represents a quantitative foundation of vegetation–climate relationships on an annual timestep. The methods can be modified to finer temporal resolution and other spatial scales if further analyses are needed to inform park planning and management. The knowledge provided in this report can inform vulnerability assessments for Climate Smart Conservation planning by park managers. Patterns of pivot points and responses can serve as a guide to anticipate what, where, when, and why vegetation change may occur. For this analysis, vegetation alliance groups were derived from vegetation-map polygons (Von Loh et al. 2007) by lumping vegetation types expected to respond similarly to climate. Relationships between vegetation production and phenology were evaluated for each alliance map unit larger than a satellite pixel (~300 × 300 m). We used a water-balance model to characterize the climate experienced by plants. Water balance translates temperature and precipitation into more biophysically relevant climate metrics, such as soil moisture and drought stress, that are often more strongly correlated with vegetation condition than temperature or precipitation are. By accounting for the interactions between temperature, precipitation, and site characteristics, water balance helps make regional climate assessments relevant to local scales. The results provide a foundation for interpreting weather and climate as a driver of changes in primary production over a 20-year period at the polygon and alliance-group scale. Additionally, they demonstrate how vegetation type and site characteristics, such as soil properties, slope, and aspect, interact with climate at local scales to determine trends in vegetation condition. This report quantitatively defines critical water needs of vegetation and identifies which alliance types, in which locations, may be most susceptible to climate-change impacts in the future. Finally, this report explains how findings can be used in the Climate Smart Conservation framework, with scenario planning, to help manage park resources through transitions imposed by climate change.
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Thoma, David. Landscape phenology, vegetation condition, and relations with climate at Capitol Reef National Park, 2000–2019. Edited by Alice Wondrak Biel. National Park Service, March 2023. http://dx.doi.org/10.36967/2297289.
Abstract:
Quantitatively linking satellite observations of vegetation condition and climate data over time provides insight to climate influences on primary production, phenology (timing of growth), and sensitivity of vegetation to weather and longer-term patterns of weather referred to as climate. This in turn provides a basis for understanding potential climate impacts to vegetation—and the potential to anticipate cascading ecological effects, such as impacts to forage, habitat, fire potential, and erosion, as climate changes in the future. This report provides baseline information about vegetation production and condition over time at Capitol Reef National Park (NP), as derived from satellite remote sensing. Its objective is to demonstrate methods of analysis, share findings, and document historic climate exposure and sensitivity of vegetation to weather and climate as a driver of vegetation change. This report represents a quantitative foundation of vegetation–climate relationships on an annual timestep. The methods can be modified to finer temporal resolution and other spatial scales if further analyses are needed to inform park planning and management. The knowledge provided in this report can inform vulnerability assessments for Climate Smart Conservation planning by park managers. Patterns of pivot points and responses can serve as a guide to anticipate what, where, when, and why vegetation change may occur. For this analysis, vegetation alliance groups were derived from vegetation-map polygons (Von Loh et al. 2007) by lumping vegetation types expected to respond similarly to climate. Relationships between vegetation production and phenology were evaluated for each alliance map unit larger than a satellite pixel (~300 × 300 m). We used a water-balance model to characterize the climate experienced by plants. Water balance translates temperature and precipitation into more biophysically relevant climate metrics, such as soil moisture and drought stress, that are often more strongly correlated with vegetation condition than temperature or precipitation are. By accounting for the interactions between temperature, precipitation, and site characteristics, water balance helps make regional climate assessments relevant to local scales. The results provide a foundation for interpreting weather and climate as a driver of changes in primary production over a 20-year period at the polygon and alliance-group scale. Additionally, they demonstrate how vegetation type and site characteristics, such as soil properties, slope, and aspect, interact with climate at local scales to determine trends in vegetation condition. This report quantitatively defines critical water needs of vegetation and identifies which alliance types, in which locations, may be most susceptible to climate-change impacts in the future. Finally, this report explains how findings can be used in the Climate Smart Conservation framework, with scenario planning, to help manage park resources through transitions imposed by climate change.
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Hibbert, Angela, Jue Lin, and Begona Pérez Gómez. Automated tide gauge data quality control software and report. EuroSea, 2023. http://dx.doi.org/10.3289/eurosea_d5.7.
Abstract:
The WP5 Coastal Resilience and Operational Services demonstrator aims to design and deploy innovative sea level monitoring systems, integrating their observations with downscaled model forecasts into an alert-based monitoring and forecasting tool (OSPAC) that is design for use by ports and local authorities. As part of this data integration process, sea level observations must be quality-controlled in near real-time, to minimise the risk of false alarms. This has historically been achieved using an established open-source software package (SELENE). Recent progress using automatic quality control (QC) in delayed mode has led to the development of additional functionality that could enhance the SELENE software. At the same time, the delivery of new sea level time series from Global Navigation Satellite Systems (GNSS), provides an additional means of data validation. WP5 aims to enhance the SELENE software by incorporating these enhancements and new data feeds, thereby improving the quality of the OSPAC tool. A delay in the installation of the sea level monitoring systems has led to a corresponding delay in the provision of data inputs to SELENE and subsequently to OSPAC. Some development work has been possible using alternative test time series, but a key implementer in presently taking parental leave, which will delay further development work until October 2023. This deliverable report will be updated thereafter. (EuroSea Deliverable, D5.7)
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Fourrier, Marine. Integration of in situ and satellite multi-platform data (estimation of carbon flux for trop. Atlantic). EuroSea, 2023. http://dx.doi.org/10.3289/eurosea_d7.6.
Abstract:
This report presents the results of task 7.3 on “Quantification of improvements in carbon flux data for the tropical Atlantic based on the multi-platform and neural network approach”. To better constrain changes in the ocean’s capture and sequestration of CO2 emitted by human activities, in situ measurements are needed. Tropical regions are considered to be mostly sources of CO2 to the atmosphere due to specific circulation features, with large interannual variability mainly controlled by physical drivers (Padin et al., 2010). The tropical Atlantic is the second largest source, after the tropical Pacific, of CO2 to the atmosphere (Landschützer et al., 2014). However, it is not a homogeneous zone, as it is affected by many physical and biogeochemical processes that vary on many time scales and affect surrounding areas (Foltz et al., 2019). The Tropical Atlantic Observing System (TAOS) has progressed substantially over the past two decades. Still, many challenges and uncertainties remain to require further studies into the area’s role in terms of carbon fluxes (Foltz et al., 2019). Monitoring and sustained observations of surface oceanic CO2 are critical for understanding the fate of CO2 as it penetrates the ocean and during its sequestration at depth. This deliverable relies on different observing platforms deployed specifically as part of the EuroSea project (a Saildrone, and 5 pH-equipped BGC-Argo floats) as well as on the platforms as part of the TAOS (CO2-equipped moorings, cruises, models, and data products). It also builds on the work done in D7.1 and D7.2 on the deployment and quality control of pH-equipped BGC-Argo floats and Saildrone data. Indeed, high-quality homogeneously calibrated carbonate variable measurements are mandatory to be able to compute air-sea CO2 fluxes at a basin scale from multiple observing platforms. (EuroSea Deliverable, D7.6)
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Ahn, Yushin, and Richard Poythress. Impervious Surfaces from High Resolution Aerial Imagery: Cities in Fresno County. Mineta Transportation Institute, May 2024. http://dx.doi.org/10.31979/mti.2024.2257.
Abstract:
This study investigates impervious surfaces — areas covered by materials with restricted water permeability, such as pavement, sidewalks, and parking lots—due to their crucial role in influencing water dynamics within urban landscapes. The impermeability of these surfaces disrupts natural water absorption processes, resulting in adverse environmental consequences such as increased flooding, erosion, and water pollution. The research employs impervious surface analysis, a method involving the mapping and analysis of these surfaces within specified study areas, including cities, counties, and census tracts. Remote sensing techniques, specifically satellites and aerial imagery, are commonly utilized for the identification and classification of impervious surfaces. In the context of Fresno County, diverse classification methods, encompassing pixel-based, object-based, and deep learning approaches, are employed to classify and evaluate impervious surfaces. Significantly, the deep learning classification method exhibits exceptional performance, achieving an impressive overall accuracy ranging between 85-92%. The study reveals that the estimated percentage of impervious surfaces in Fresno County cities approximates 45%, comparable to the characteristics of medium density residential areas. Noteworthy is the observation in the Fresno/Clovis city area, where the percentage of impervious surfaces escalated from 53% in 2010 (per EnviroAtlas) to 63% in 2020. This 10% increase over a decade closely aligns with concurrent population growth trends in the region. In conclusion, this research underscores the critical significance of comprehending and monitoring impervious surfaces due to their pivotal role in shaping the environmental quality and resilience of urban areas. The insights gleaned from this study provide valuable guidance for the development of effective land use planning and management strategies, specifically tailored to mitigate the adverse impacts of impervious surfaces on the environment and human well-being.
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Ley, Matt, Tom Baldvins, Hannah Pilkington, David Jones, and Kelly Anderson. Vegetation classification and mapping project: Big Thicket National Preserve. National Park Service, 2024. http://dx.doi.org/10.36967/2299254.
Abstract:
The Big Thicket National Preserve (BITH) vegetation inventory project classified and mapped vegetation within the administrative boundary and estimated thematic map accuracy quantitatively. National Park Service (NPS) Vegetation Mapping Inventory Program provided technical guidance. The overall process included initial planning and scoping, imagery procurement, vegetation classification field data collection, data analysis, imagery interpretation/classification, accuracy assessment (AA), and report writing and database development. Initial planning and scoping meetings took place during May, 2016 in Kountze, Texas where representatives gathered from BITH, the NPS Gulf Coast Inventory and Monitoring Network, and Colorado State University. The project acquired new 2014 orthoimagery (30-cm, 4-band (RGB and CIR)) from the Hexagon Imagery Program. Supplemental imagery for the interpretation phase included Texas Natural Resources Information System (TNRIS) 2015 50 cm leaf-off 4-band imagery from the Texas Orthoimagery Program (TOP), Farm Service Agency (FSA) 100-cm (2016) and 60 cm (2018) National Aerial Imagery Program (NAIP) imagery, and current and historical true-color Google Earth and Bing Maps imagery. In addition to aerial and satellite imagery, 2017 Neches River Basin Light Detection and Ranging (LiDAR) data was obtained from the United States Geological Survey (USGS) and TNRIS to analyze vegetation structure at BITH. The preliminary vegetation classification included 110 United States National Vegetation Classification (USNVC) associations. Existing vegetation and mapping data combined with vegetation plot data contributed to the final vegetation classification. Quantitative classification using hierarchical clustering and professional expertise was supported by vegetation data collected from 304 plots surveyed between 2016 and 2019 and 110 additional observation plots. The final vegetation classification includes 75 USNVC associations and 27 park special types including 80 forest and woodland, 7 shrubland, 12 herbaceous, and 3 sparse vegetation types. The final BITH map consists of 51 map classes. Land cover classes include five types: pasture / hay ground agricultural vegetation; non ? vegetated / barren land, borrow pit, cut bank; developed, open space; developed, low ? high intensity; and water. The 46 vegetation classes represent 102 associations or park specials. Of these, 75 represent natural vegetation associations within the USNVC, and 27 types represent unpublished park specials. Of the 46 vegetation map classes, 26 represent a single USNVC association/park special, 7 map classes contain two USNVC associations/park specials, 4 map classes contain three USNVC associations/park specials, and 9 map classes contain four or more USNVC associations/park specials. Forest and woodland types had an abundance of Pinus taeda, Liquidambar styraciflua, Ilex opaca, Ilex vomitoria, Quercus nigra, and Vitis rotundifolia. Shrubland types were dominated by Pinus taeda, Ilex vomitoria, Triadica sebifera, Liquidambar styraciflua, and/or Callicarpa americana. Herbaceous types had an abundance of Zizaniopsis miliacea, Juncus effusus, Panicum virgatum, and/or Saccharum giganteum. The final BITH vegetation map consists of 7,271 polygons totaling 45,771.8 ha (113,104.6 ac). Mean polygon size is 6.3 ha (15.6 ac). Of the total area, 43,314.4 ha (107,032.2 ac) or 94.6% represent natural or ruderal vegetation. Developed areas such as roads, parking lots, and campgrounds comprise 421.9 ha (1,042.5 ac) or 0.9% of the total. Open water accounts for approximately 2,034.9 ha (5,028.3 ac) or 4.4% of the total mapped area. Within the natural or ruderal vegetation types, forest and woodland types were the most extensive at 43,022.19 ha (106,310.1 ac) or 94.0%, followed by herbaceous vegetation types at 129.7 ha (320.5 ac) or 0.3%, sparse vegetation types at 119.2 ha (294.5 ac) or 0.3%, and shrubland types at 43.4 ha (107.2 ac) or 0.1%. A total of 784 AA samples were collected to evaluate the map?s thematic accuracy. When each AA sample was evaluated for a variety of potential errors, a number of the disagreements were overturned. It was determined that 182 plot records disagreed due to either an erroneous field call or a change in the vegetation since the imagery date, and 79 disagreed due to a true map classification error. Those records identified as incorrect due to an erroneous field call or changes in vegetation were considered correct for the purpose of the AA. As a simple plot count proportion, the reconciled overall accuracy was 89.9% (705/784). The spatially-weighted overall accuracy was 92.1% with a Kappa statistic of 89.6%. This method provides more weight to larger map classes in the park. Five map classes had accuracies below 80%. After discussing preliminary results with the parl, we retained those map classes because the community was rare, the map classes provided desired detail for management or the accuracy was reasonably close to the 80% target. When the 90% AA confidence intervals were included, an additional eight classes had thematic accruacies that extend below 80%. In addition to the vegetation polygon database and map, several products to support park resource management include the vegetation classification, field key to the associations, local association descriptions, photographic database, project geodatabase, ArcGIS .mxd files for map posters, and aerial imagery acquired for the project. The project geodatabase links the spatial vegetation data layer to vegetation classification, plot photos, project boundary extent, AA points, and PLOTS database sampling data. The geodatabase includes USNVC hierarchy tables allowing for spatial queries of data associated with a vegetation polygon or sample point. All geospatial products are projected using North American Datum 1983 (NAD83) in Universal Transverse Mercator (UTM) Zone 15 N. The final report includes methods and results, contingency tables showing AA results, field forms, species list, and a guide to imagery interpretation. These products provide useful information to assist with management of park resources and inform future management decisions. Use of standard national vegetation classification and mapping protocols facilitates effective resource stewardship by ensuring the compatibility and widespread use throughout NPS as well as other federal and state agencies. Products support a wide variety of resource assessments, park management and planning needs. Associated information provides a structure for framing and answering critical scientific questions about vegetation communities and their relationship to environmental processes across the landscape.