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Mapping carbon and water vapor fluxes in a chaparral ecosystem using vegetation indices derived from AVIRIS / D.A. Fuentes in Remote sensing of environment, vol 103 n° 3 (15 August 2006)
[article]
Titre : Mapping carbon and water vapor fluxes in a chaparral ecosystem using vegetation indices derived from AVIRIS Type de document : Article/Communication Auteurs : D.A. Fuentes, Auteur ; John A. Gamon, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 312 - 323 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] circulation atmosphérique
[Termes IGN] dioxyde de carbone
[Termes IGN] données de terrain
[Termes IGN] écosystème
[Termes IGN] image AVIRIS
[Termes IGN] image hyperspectrale
[Termes IGN] indice de végétation
[Termes IGN] réflectance spectrale
[Termes IGN] sécheresse
[Termes IGN] vapeur d'eauRésumé : (Auteur) Using simple models derived from spectral reflectance, we mapped the patterns of ecosystem CO2 and water fluxes in a semi-arid site in southern California during a period of extreme disturbance, marked by drought and fire. Employing a combination of low (not, vert, similar 2 km) and high (not, vert, similar 16 km) altitude images from the hyperspectral Airborne Visible Infrared Imaging Spectrometer (AVIRIS), acquired between April 2002 and September 2003, and ground data collected from an automated tram system, several vegetation indices were calculated for Sky Oaks field station, a FLUXNET and SpecNet site located in northern San Diego County (CA, USA). Based on the relationships observed between the fluxes measured by the eddy covariance tower and the vegetation indices, net CO2 and water vapor flux maps were derived for the region around the flux tower. Despite differences in the scale of the images (from not, vert, similar 2 m to 16 m pixel size) as well as marked differences in environmental conditions (drought in 2002, recovery in early 2003, and fire in mid 2003), net CO2 and water flux modeled from AVIRIS-derived reflectance indices (NDVI, PRI and WBI) effectively tracked changes in tower fluxes across both drought and fire, and readily revealed spatial variation in fluxes within this landscape. After an initial period of net carbon uptake, drought and fire caused the ecosystem to lose carbon to the atmosphere during most of the study period. Our study shows the power of integrating optical and flux data in LUE models to better understand factors driving surface-atmosphere carbon and water vapor flux cycles, one of the main goals of SpecNet. Numéro de notice : A2006-333 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2005.10.028 En ligne : https://doi.org/10.1016/j.rse.2005.10.028 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28057
in Remote sensing of environment > vol 103 n° 3 (15 August 2006) . - pp 312 - 323[article]Mapping the effects of water stress on sphagnum: preliminary observations using airborne remote sensing / A. Harris in Remote sensing of environment, vol 100 n° 3 (15 february 2006)
[article]
Titre : Mapping the effects of water stress on sphagnum: preliminary observations using airborne remote sensing Type de document : Article/Communication Auteurs : A. Harris, Auteur ; R.G. Bryant, Auteur ; A.J. Baird, Auteur Année de publication : 2006 Article en page(s) : pp 363 - 378 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse spectrale
[Termes IGN] canopée
[Termes IGN] eau de surface
[Termes IGN] humidité du sol
[Termes IGN] image aérienne
[Termes IGN] indice d'humidité
[Termes IGN] plante aquatique d'eau salée
[Termes IGN] réflectance spectrale
[Termes IGN] réflectance végétale
[Termes IGN] Royaume-Uni
[Termes IGN] Sphagnum (genre)
[Termes IGN] stress hydrique
[Termes IGN] tourbe
[Termes IGN] zone humideRésumé : (Auteur) Remote sensing of near-surface hydrological conditions within northern peatlands has the potential to provide important large-scale hydrological information regarding ecological and carbon-balance processes occuring within such systems. This article details how field knowledge of the spectral properties of Sphagnum spp., airborne remote sensing data and a range of image analysis approaches may be combined to provide a suitable proxy for near-surface wetness. Co-incident field and airborne remote sensing data were acquired in May and September 2002 over an important UK raised bog (Cors Fochno). A combination of laboratory-tested NIR and SWIR water-based and biophysical spectral reflectance indices were applied to field and airborne reflectance spectra of Sphagnum pulchrum to elucidate changes in near-surface moisture conditions. Field results showed significant correlations between water-based indices (moisture stress index (MSI) and floating water band indices (fWBI980 and fWB1200) and measures of both near-surface volumetric moisture content (VMC) and water-table position. Spectral indices formulated from the NIR (fWBI980 and fWBI1200) proved to be the most useful for indicating near-surface wetness across the widest range of moisture conditions because of their ability to penetrate deeper into the Sphagnum canopy. Correlations between a biophysical index based upon chlorophyll content and both hydrological measures were not significant, possibly due to relatively high levels of surface wetness at the field site in both May and September. S. pulchrum lawns were successfully located and mapped from airborne imagery using the mixed tuned match filtering (MTMF) algorithm. Importantly, MSI derived from airborne data was significantly correlated with both field moisture and the water-table position. Relationships between measures of near-surface wetness and the MSI for naturally heterogeneous canopies were, however, found to be weaker for airborne imagery than for associated field data. This is likely to be a result of the formulation of the MSI itself and the possible preferential detection of "wetter" pixels within the imagery. This effectively reduced the ability of MSI to detect subtle changes in near-surface wetness under high moisture conditions, but would not impede the use of the index under drier conditions. Results from the field data suggest that indices formulated from the NIR may be more suitable for detailed estimations of near-surface and surface wetness at the landscape-scale although reliable hyperspectral data are required to test fully the performance of such indices. The relative merits of using such an approach to determine near-surface hydrological conditions across entire peatland complexes are also discussed. Numéro de notice : A2006-036 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2005.10.024 En ligne : https://doi.org/10.1016/j.rse.2005.10.024 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27763
in Remote sensing of environment > vol 100 n° 3 (15 february 2006) . - pp 363 - 378[article]An empirical investigation of cross-sensor relationships of NDVI and red/near-infrared reflectance using EO-1 Hyperion data / T. Miura in Remote sensing of environment, vol 100 n° 2 (30 January 2006)
[article]
Titre : An empirical investigation of cross-sensor relationships of NDVI and red/near-infrared reflectance using EO-1 Hyperion data Type de document : Article/Communication Auteurs : T. Miura, Auteur ; A. Huete, Auteur ; Hiroki Yoshioka, Auteur Année de publication : 2006 Article en page(s) : pp 223 - 236 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse comparative
[Termes IGN] bande rouge
[Termes IGN] Brésil
[Termes IGN] étalonnage des données
[Termes IGN] filtre passe-bande
[Termes IGN] flore locale
[Termes IGN] forêt tropicale
[Termes IGN] image EO1-Hyperion
[Termes IGN] image hyperspectrale
[Termes IGN] image Landsat-ETM+
[Termes IGN] image Terra-MODIS
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] réflectance spectrale
[Termes IGN] savaneRésumé : (Auteur) Long term observations of global vegetation from multiple satellites require much effort to ensure continuity and compatibility due to differences in sensor characteristics and product generation algorithms. In this study, we focused on the band-pass filter differences and empirically investigated cross-sensor relationships of the normalized difference vegetation index (NDVI) and reflectance. The specific objectives were: 1) to understand the systematic trends in cross-sensor relationships of the NDVI and reflectance as a function of spectral band-passes, 2) to examine/ identify the relative importance of the spectral features (i.e., the green peak, red edge, and leaf liquid water absorption regions) in and the mechanism(s) of causing the observed systematic trends, and 3) to evaluate the performance of several empirical cross-calibration methods in modelling the observed systematic trends. A Level 1A Hyperion hyperspectral image acquired over a tropical forest-savanna transitional region in Brazil was processed to simulate atmospherically corrected reflectances and NDVI for various band-passes, including Terra Moderate Resolution Imaging Spectro-radiometer (MODIS), NOAA-14 Advanced Very High Resolution Radiometer (AVHRR), and Landsat7 Enhanced Thematic Mapper Plus (ETM+). Data were extracted from various land cover types typically found in tropical forest and savanna biomes and used for analyses. Both NDVI and reflectance relationships among the sensors were neither linear nor unique and were found to exhibit complex patterns and band-pass dependencies. The reflectance relationships showed strong land cover dependencies. The NDVI relationships, in contrast, did not show land cover dependencies, but resulted in non-linear forms. From sensitivity analyses, the green peak (550 nm) and red-NIR transitional (680780 nm) features were identified as the key factors in producing the observed land cover dependencies and non-linearity in cross-sensor relationships. In particular, differences in the extents to which the red and/or NIR band-passes included these features significantly influenced the forms and degrees of non-linearity in the relationships. Translation of MODIS NDVI to "AVHRR Iike" NDVI using a weighted average of MODIS green and red bands performed very poorly, resulting in no reduction of overall discrepancy between MODIS and AVHRR NDVI. Cross-calibration of NDVI and reflectance using NDVI-based quadratic functions performed well, reducing their differences to +.025 units for the NDVI and +.01 units for the reflectances; however, many of the translation results suffered from bias errors. The present results suggest that distinct translation equations and coefficients need to be developed for every sensor pairs and that land cover-dependency need to be explicitly accounted for to reduce bias errors. Numéro de notice : A2006-034 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2005.10.010 En ligne : https://doi.org/10.1016/j.rse.2005.10.010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27761
in Remote sensing of environment > vol 100 n° 2 (30 January 2006) . - pp 223 - 236[article]Analysis of the spectral variability of urban materials for classification : A case study over Toulouse (France) / Sophie Lacherade (2005)
Titre : Analysis of the spectral variability of urban materials for classification : A case study over Toulouse (France) Type de document : Article/Communication Auteurs : Sophie Lacherade, Auteur ; Christophe Miesch, Auteur ; F. LemaÎtre, Auteur ; Xavier Briottet , Auteur ; Hervé Le Men , Auteur ; Didier Boldo , Auteur ; Christophe Valorge, Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2005 Collection : International Archives of Photogrammetry and Remote Sensing, ISSN 0252-8231 num. 36-8/W27 Conférence : ISPRS 2005, WG VIII/1, Joint Symposia URBAN - URS 14/03/2005 16/03/2005 Tempe Arizona - Etats-Unis OA ISPRS Archives Importance : 3 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] bande visible
[Termes IGN] classification
[Termes IGN] image proche infrarouge
[Termes IGN] milieu urbain
[Termes IGN] réflectance spectrale
[Termes IGN] Toulouse
[Termes IGN] variabilitéRésumé : (auteur) The automatic classification of urban materials from airborne and spatial acquisitions remains difficult today because of two main reasons: the spatial resolution of the images and the need for pre-processing algorithms to extract ground surface intrinsic properties. This work examines the feasibility of using 8 spectral information distributed in the visible and the near-infrared spectral regions (0.4 - 1 μm), acquired at a 20 cm spatial resolution, for recognizing the urban materials. The motivation for this study is the development of very high spatial resolution sensors which has introduced a promising capability for the study of urban areas. In this study , an experiment campaign took place in Toulouse. The airborne measurements were carried out using 8 cameras associated with 8 narrow filters (30 nm). Ground spectral measurements of Toulouse's urban materials were performed within the configuration of the airborne acquisitions. These measurements allow us to determine and quantify three types of reflectance spatial variability. The results show that urban materials have low reflectances with no significant spectral features and are then difficult to discriminate. To determine which material classes could be discriminate over the 8 spectral bands of the airborne acquisitions, a statistical analysis was performed on the ground measurements. This analysis highlights that 5 material classes could be discriminated from good quality measurements. Numéro de notice : C2005-036 Affiliation des auteurs : MATIS+Ext (1993-2011) Thématique : IMAGERIE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : sans En ligne : https://www.isprs.org/proceedings/XXXVI/8-W27/lacherade.pdf Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100079 Etude phénoménologique du transfert radiatif en milieu urbain : Dimensionnement d'une campagne aéroportée sur Toulouse pour la détermination des réflectances de surface / Sophie Lacherade in Revue Française de Photogrammétrie et de Télédétection, n° 176 (Décembre 2004)
[article]
Titre : Etude phénoménologique du transfert radiatif en milieu urbain : Dimensionnement d'une campagne aéroportée sur Toulouse pour la détermination des réflectances de surface Type de document : Article/Communication Auteurs : Sophie Lacherade, Auteur ; Christophe Miesch, Auteur ; Xavier Briottet , Auteur ; Didier Boldo , Auteur ; Jacques Le Menestrel, Auteur Année de publication : 2004 Article en page(s) : pp 42 - 53 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] acquisition d'images
[Termes IGN] erreur de mesure
[Termes IGN] image aérienne
[Termes IGN] milieu urbain
[Termes IGN] modèle d'inversion
[Termes IGN] modèle de transfert radiatif
[Termes IGN] modèle numérique de surface
[Termes IGN] qualité des données
[Termes IGN] réflectance de surface
[Termes IGN] réflectance spectrale
[Termes IGN] signature spectrale
[Termes IGN] ToulouseRésumé : (Auteur) Ce travail s'inscrit dans le cadre d'une étude portant sur la détermination de la réflectance spectrale des matériaux urbains à partir d'images aéroportées à hautes résolutions spatiale et spectrale dans le domaine réflectif. Cet article présente la campagne expérimentale effectuée pour la validation d'un modèle d'inversion permettant d'extraire ces réflectances à partir de telles prises de vues. Dans un premier temps, une étude phénoménologique réalisée sur un profil de rue à l'aide du modèle de transfert radiatif Amartis a permis, d'une part de comprendre la composition du signal issu de ce milieu urbain et d'autre part d'évaluer l'impact des erreurs d'entrée du modèle (qualité du modèle numérique d'élévation, méconnaissance de certaines réflectances de l'environnement) sur les différentes composantes du signal. Les résultats obtenus ont également contribué à l'établissement des critères de sélection des sites de référence, qui serviront à la validation expérimentale du modèle inverse. La campagne de mesure a été réalisée à l'aide de deux systèmes imageurs aéroportés haute résolution spatiale comportant 8 caméras. Elle a comporté des prises de vues aériennes au-dessus de Toulouse ainsi que des réalités de terrain (mesures de réflectances spectrales, d'éclairements, de luminances et de données météorologiques). Les 8 filtres étroits (30 nm) présents sur les caméras ont été choisis de façon à permettre à la fois une correction atmosphérique (aérosols, vapeur d'eau) et une discrimination des différents spectres de matériaux urbains. Les descriptions ainsi que les premiers résultats de cette campagne sont présentés dans la deuxième partie de l'article. Numéro de notice : A2005-199 Affiliation des auteurs : IGN (1940-2011) Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27336
in Revue Française de Photogrammétrie et de Télédétection > n° 176 (Décembre 2004) . - pp 42 - 53[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 018-04041 RAB Revue Centre de documentation En réserve L003 Disponible Landsat-5 TM reflective-band absolute radiometric calibration / Gyanesh Chander in IEEE Transactions on geoscience and remote sensing, vol 42 n° 12 (December 2004)PermalinkEvaluating airborne hyperspectral imagery for rangeland assessment in south Texas / James H. Everitt in Geocarto international, vol 19 n° 3 (September - November 2004)PermalinkEstimating live fuel moisture content from remotely sensed reflectance / F. Mark Danson in Remote sensing of environment, vol 92 n° 3 (30 August 2004)PermalinkClassification of contamination in salt marsh plant using hyperspectral reflectance / M.D. Wilson in IEEE Transactions on geoscience and remote sensing, vol 42 n° 5 (May 2004)PermalinkSmoothing vegetation spectra with wavelets / K.S. Schmidt in International Journal of Remote Sensing IJRS, vol 25 n° 6 (March 2004)PermalinkUsefulness of spectral reflectance indices as durum wheat yield predictors under contrasting Mediterranean conditions / C. Royo in International Journal of Remote Sensing IJRS, vol 24 n° 22 (November 2003)PermalinkSpectral reflectance characterization of shallow lakes from the Brazilian pantanal wetlands with field and airborne hyperspectral data / L.S. Galvao in International Journal of Remote Sensing IJRS, vol 24 n° 21 (November 2003)PermalinkRelationship between plant spectral reflectances and their image tonal responses on aerial photographs / D.E. Escobar in Geocarto international, vol 17 n° 2 (June - August 2002)Permalinkvol 34 n° 2 - Octobre 1996 - SPECTEL'95 : Propriétés spectrales et télédétection des sols et des roches, [actes], La Serena, 24 - 27 avril 1995 = Spectral properties and remote sensing of soils and rocks = Propiedades espectrales y teledeteccion de los suelos y rocas (Bulletin de Photo interprétation) / Gérard GuyotPermalinkConception et réalisations d'un spectromètre imageur visible - proche infrarouge / J. Romier (1996)Permalink