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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]Resolution dependent errors in remote sensing of cultivated areas / M. Ozdogan in Remote sensing of environment, vol 103 n° 2 (30/07/2006)
[article]
Titre : Resolution dependent errors in remote sensing of cultivated areas Type de document : Article/Communication Auteurs : M. Ozdogan, Auteur ; Curtis E. Woodcock, Auteur Année de publication : 2006 Article en page(s) : pp 203 - 217 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] analyse de sensibilité
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] Chine
[Termes IGN] cultures
[Termes IGN] distribution spatiale
[Termes IGN] erreur de classification
[Termes IGN] image Ikonos
[Termes IGN] limite de résolution géométrique
[Termes IGN] précision infrapixellaire
[Termes IGN] seuillage d'image
[Termes IGN] surface cultivée
[Termes IGN] variogrammeRésumé : (Auteur) Remote sensing has become a common and effective method for estimating the areal coverage of land cover classes. One class of particular interest is agriculture as area estimates of cultivated lands are important for purposes such as estimating yields or irrigation needs. The synoptic coverage of satellite imagery and the relative ease of automated analysis have led to widespread mapping of agriculture using remote sensing. The accuracy of area estimates derived from these maps is known to be related to the accuracy of the maps. However, even in the situation where the map is very accurate, errors in area estimates may occur. These errors result from the behavior of the distribution of subpixel proportions of cultivated areas, and how that behavior changes as a result of sensor spatial resolution and class definitions. The sensitivity of estimates of cultivated areas to sensor spatial resolution and to the choice of threshold used to define cultivated land is explored in six agriculturally distinct locations around the world. Using a beta model for the distribution of subpixel proportions that is parameterized using variograms, it is possible to model the distribution of subpixel proportions for any spatial resolution. When the spatial resolution is small with respect to the spatial structure of the landscape (as measured by the variogram range) use of any class definition threshold produces an estimate very close to the true area coverage. On the other hand, as the resolution becomes coarse in relation to the variogram range, the subpixel proportions are no longer concentrated at the extremes of the distribution and the difference between the estimated and the true area has greater sensitivity to the selected threshold used to define classes. Thus, for the cases examined here, both the resolution and the class definition threshold have a strong influence on area estimates. The spatial resolutions where errors can be large depend on landscape spatial structure, which can be quantified using variograms. The net effect is that for the same spatial resolution, some places will exhibit much larger errors in area estimates than others. For the site in the Anhui province of China, where agricultural fields are very small (0.07 ha on the average), area estimates are highly sensitive to class definition thresholds even at the relatively fine resolution of 45 m. Conversely, in California (USA) spatial resolutions as coarse as 500 m can be used to reliably estimate cultivated areas. Results also suggest that the proportion of the total area that is cultivated significantly influences the accuracy of area estimates. When the area proportion is low, the class definition threshold must also be low to achieve an accurate area estimate. Conversely, in areas dominated by agriculture, a very stringent class definition of cultivated lands is required for accurate area estimates. While explored in the context of estimation of cultivated areas, the findings presented here are generic to the problem of area estimation using remote sensing. Copyright Elsevier Numéro de notice : A2006-321 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.04.004 En ligne : https://doi.org/10.1016/j.rse.2006.04.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28045
in Remote sensing of environment > vol 103 n° 2 (30/07/2006) . - pp 203 - 217[article]Application of multiple endmember spectral mixture analysis (MESMA) to AVIRIS imagery for coastal salt marsh mapping: a case study in China Camp, CA, USA / L. Li in International Journal of Remote Sensing IJRS, vol 26 n° 23 (December 2005)
[article]
Titre : Application of multiple endmember spectral mixture analysis (MESMA) to AVIRIS imagery for coastal salt marsh mapping: a case study in China Camp, CA, USA Type de document : Article/Communication Auteurs : L. Li, Auteur ; S.L. Ustin, Auteur ; M. Lay, Auteur Année de publication : 2005 Article en page(s) : pp 5193 - 5207 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse de mélange spectral d’extrémités multiples
[Termes IGN] analyse discriminante
[Termes IGN] analyse multibande
[Termes IGN] bande infrarouge
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] carte de la végétation
[Termes IGN] image AVIRIS
[Termes IGN] littoral
[Termes IGN] marais salé
[Termes IGN] plante halophileRésumé : (Auteur) Multiple endmember spectral mixture analysis (MESMA) was applied to the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) imagery of a salt marsh in China Camp at San Pablo Bay, California, A nine-endmember set representing materials within the scene was used including: two Salicornia and two soils, and Grindelia, Spartina, dry grass, water and shade. The resultant abundance maps were used to investigate the spatial distribution of the marsh vegetation species, Salicornia virginica, Grindelia Stricta and Spartinafoliosa. The Spartina abundance map exhibited a well-defined zone bordering the water and the lower marsh, which is in good agreement with the field observations made in 2002. Comparison of the Salicornia map with all six field global positional system (GPS) polygons indicates Salicornia was classified with high accuracy. The proposed approach did a good job in classifying Spartina and Salicornia which cover 93.81% of the total marsh. The Grindelia fraction image underestimates in some areas, while in other areas it shows false detection. This misclassification is attributed to the spectral similarity between Grindelia and Salicornia and to the small patch size of Grindelia. Further work is required to solve this confusion. Numéro de notice : A2005-514 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160500218911 En ligne : https://doi.org/10.1080/01431160500218911 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27650
in International Journal of Remote Sensing IJRS > vol 26 n° 23 (December 2005) . - pp 5193 - 5207[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-05231 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Estimating sub-pixel surface roughness using remotely sensed stereoscopic data / A. Mushkin in Remote sensing of environment, vol 99 n° 1-2 (15 November 2005)
[article]
Titre : Estimating sub-pixel surface roughness using remotely sensed stereoscopic data Type de document : Article/Communication Auteurs : A. Mushkin, Auteur ; A.R. Gillepsie, Auteur Année de publication : 2005 Article en page(s) : pp 75 - 83 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse infrapixellaire
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] désert
[Termes IGN] image Terra-ASTER
[Termes IGN] Israël
[Termes IGN] modèle stéréoscopique
[Termes IGN] ombre
[Termes IGN] radiance
[Termes IGN] rugosité du solRésumé : (Auteur) Surface roughness at the scale of 10-2-10-1 m can be estimated using the ratio (RR) between surface-reflected solar radiance measured from two view angles at nearly the same time. As RR is primarily a function of the difference between effective sub-pixel shading observed from the two view-angles, the divergence from unity RR values, which are expected for smooth Lambertian surfaces (they have no shadows), was found to be proportional to roughness at the 10-2-10-1 m scale of geomorphic desert surfaces. Ground-based RR values at 1-m resolution, as well as remotely acquired RR values at 4-, 15- and 50-m resolutions, were compared with observed surface roughness in two hyperarid test sites, located in Death Valley, California, USA and the southem Negev Desert in Israel. The ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) 15-m stereoscopic capability is identified as an effective resource for obtaining relative subpixel surface-roughness estimates that are largely independent of surface composition and relatively insensitive to atmospheric effects. Numéro de notice : A2005-441 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2005.02.018 En ligne : https://doi.org/10.1016/j.rse.2005.02.018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27577
in Remote sensing of environment > vol 99 n° 1-2 (15 November 2005) . - pp 75 - 83[article]Spatio-temporal dynamics in California's central valley: empirical links to urban theory / C. Dietzel in International journal of geographical information science IJGIS, vol 19 n° 2 (february 2005)
[article]
Titre : Spatio-temporal dynamics in California's central valley: empirical links to urban theory Type de document : Article/Communication Auteurs : C. Dietzel, Auteur ; Martin Herold, Auteur ; J.J. Hemphill, Auteur ; K.C. Clarke, Auteur Année de publication : 2005 Article en page(s) : pp 175 - 195 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG
[Termes IGN] analyse spatiale
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] classification barycentrique
[Termes IGN] croissance urbaine
[Termes IGN] densité de population
[Termes IGN] échelle géographique
[Termes IGN] modèle conceptuel de données spatio-temporelles
[Termes IGN] population urbaine
[Termes IGN] spatial metrics
[Termes IGN] urbanisation
[Termes IGN] villeRésumé : (Auteur) This paper explores an addition to theory in urban geography pertaining to spatio-temporal dynamics. Remotely sensed data on the historical extent of urban areas were used in a spatial metrics analysis of geographical form of towns and cities in the Central Valley of California (USA). Regularities in the spatiotemporal pattern of urban growth were detected and characterized over a hundred year period. To test hypotheses about variation over geographical scale, multiple spatial extents were used in examining a set of spatial metric values including an index of contagion, the mean nearest neighbor distance, urban patch density and edge density. Through changes in these values a general temporal oscillation between phases of diffusion and coalescence in urban growth was revealed. Analysis of historical datasets revealed preliminary evidence supporting an addition to the theory of urban growth dynamics, one alluded to in some previous research, but not well developed. The empirical results and findings provide a lead for future research into the dynamics of urban growth and further development of existing urban theory. Numéro de notice : A2005-047 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810410001713407 En ligne : https://doi.org/10.1080/13658810410001713407 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27185
in International journal of geographical information science IJGIS > vol 19 n° 2 (february 2005) . - pp 175 - 195[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-05021 RAB Revue Centre de documentation En réserve L003 Disponible 079-05022 RAB Revue Centre de documentation En réserve L003 Disponible A new method for the specification of geographic footprints in digital gazetteers / J.P. Wilson in Cartography and Geographic Information Science, vol 31 n° 4 (October 2004)PermalinkExamining the effect of spatial resolution and texture window size on classification accuracy: an urban environment case / D. Chen in International Journal of Remote Sensing IJRS, vol 25 n° 11 (June 2004)PermalinkWavelet transform applied to EO-1 hyperspectral data for forest LAI and crown closure mapping / R. Pu in Remote sensing of environment, vol 91 n° 2 (30/05/2004)PermalinkEffect of grain size on remotely sensed spectral reflectance of sandy desert surfaces / G.S. Okin in Remote sensing of environment, vol 89 n° 3 (15/02/2004)PermalinkStrategies for integrating information from multiple resolutions into land-use/land-cover classification routines / D.M. Chen in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 11 (November 2003)PermalinkAssessing vulnerability to earthquake hazards through spatial multicriteria analysis of urban areas / T. Rashed in International journal of geographical information science IJGIS, vol 17 n° 6 (september 2003)PermalinkMeasuring the physical composition of urban morphology using multiple endmember spectral mixture models / T. Rashed in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 9 (September 2003)PermalinkSpatial metrics and image texture for mapping urban land use / Martin Herold in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 9 (September 2003)PermalinkLand-cover change monitoring with classification trees using Landsat TM and ancillary data / J. Rogan in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 7 (July 2003)PermalinkSAR monitoring of progressive and seasonal ground deformation using the permanent scatterers technique / C. Colesanti in IEEE Transactions on geoscience and remote sensing, vol 41 n° 7 (July 2003)Permalink