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Predicting in situ pasture quality in the Kruger National Park, South Africa, using continuum-removed absorption features / Onisimo Mutanga in Remote sensing of environment, vol 89 n° 3 (15/02/2004)
[article]
Titre : Predicting in situ pasture quality in the Kruger National Park, South Africa, using continuum-removed absorption features Type de document : Article/Communication Auteurs : Onisimo Mutanga, Auteur ; Andrew K. Skidmore, Auteur ; Herbert H.T. Prins, Auteur Année de publication : 2004 Article en page(s) : pp 393 - 408 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] Afrique du sud (état)
[Termes IGN] azote
[Termes IGN] biochimie
[Termes IGN] carbone
[Termes IGN] forêt tropicale
[Termes IGN] image hyperspectrale
[Termes IGN] parc naturel national
[Termes IGN] paturage
[Termes IGN] phosphore
[Termes IGN] potassium
[Termes IGN] prairie
[Termes IGN] réflectance végétale
[Termes IGN] régression linéaire
[Termes IGN] savane
[Termes IGN] spectroradiomètre
[Termes IGN] zone intertropicaleRésumé : (Auteur) The remote sensing of pasture quality as determined by nitrogen, phosphorous, potassium, calcium and magnesium concentration is critical for a better understanding of wildlife and livestock feeding patterns. Although remote sensing techniques have proved useful for assessing the concentration of foliar biochemicals under controlled laboratory conditions, more investigation is required to assess their capabilities in the field where inconsistent results have been obtained so far. We investigated the possibility of determining the concentration of in situ biochemicals in a savanna rangeland, using the spectral reflectance of five grass species. Canopy spectral measurements were taken in the field using a GER 3700 spectroradiometer. We tested the utility of using four variables derived from continuum-removed absorption features for predicting canopy nitrogen, phosphorous, potassium, calcium and magnesium concentration: (i) continuum-removed derivative reflectance (CRDR), (ii) band depth (BD), (iii) band depth ratio (BDR) and (iv) normalised band depth index (NBDI). Stepwise linear regression was used to select wavelengths from the absorption-feature-based variables. Univariate correlation analysis was also done between the first derivative reflectance and biochemicals. Using a training data set, the variables derived from continuum-removed absorption features could predict biochemicals with R2 values ranging from 0.43 to 0.80. Results were highest using CRDR data, which yielded R2 values of 0.70, 0.80, 0.64, 0.50 and 0.68 with root mean square errors (RMSE) of 0.01, 0.004, 0.03, 0.01 and 0.004 for nitrogen, phosphorous, potassium, calcium and magnesium, respectively. Predicting biochemicals on a test data set, using regression models developed from a training data set. resulted in R2 values ranging from 0. 15 to 0.70. The error of prediction (RSE) in the test data set was 0.08 (+ 10.25% of mean), 0.05 (+ 5.2% of mean), 0.02 (+ 11.11% of mean), 0.05 (+ 11.6% of mean) and 0.03 (+ 15% of mean) for nitrogen, potassium, phosphorous. calcium and magnesium, respectively, using CRDR. When data was partitioned into species groups, the R2 increased significantly to >0.80. With high-quality radiometric and geometric calibration of hyperspectral imagery, the techniques applied in this study (i.e. continuum removal on absorption features) may also be applied on data acquired by airborne and spacebome imaging spectrometers to predict and ultimateIy to map the concentration of macronutrients in tropical rangelands. Numéro de notice : A2004-020 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.11.001 En ligne : https://doi.org/10.1016/j.rse.2003.11.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26548
in Remote sensing of environment > vol 89 n° 3 (15/02/2004) . - pp 393 - 408[article]Mapping the aerodynamic roughness length of desert surfaces from the POLDER/ADEOS bi-directional reflectance product / Béatrice Marticorena in International Journal of Remote Sensing IJRS, vol 25 n° 3 (February 2004)
[article]
Titre : Mapping the aerodynamic roughness length of desert surfaces from the POLDER/ADEOS bi-directional reflectance product Type de document : Article/Communication Auteurs : Béatrice Marticorena, Auteur ; Patrick Chazette, Auteur ; G. Bergametti, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 603 - 626 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] carte thématique
[Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF
[Termes IGN] image ADEOS
[Termes IGN] POLarization and Directionality of Earth's Reflectances
[Termes IGN] poussière
[Termes IGN] réflectance de surface
[Termes IGN] rugosité
[Termes IGN] Sahara, désert du
[Termes IGN] zone arideRésumé : (Auteur) Surface roughness is a key parameter for computing the emissions and for simulating the atmospheric cycle of mineral dust. However its assessment on the basis of field measurements from source areas scattered round the globe requires much effort. Here we investigate the retrieval of the aerodynamic roughness length of and areas using surface bi-directional reflectance products derived from passive multi-directional measurements in the solar spectrum of the POlarization and Directionality of the Earth's Reflectances (POLDER) sensor. The so-called protrusion coefficient (PC) of the surface derived from the POLDER bidirectional reflectance distribution function (BRDF) is well suited to estimate surface roughness. From an appropriate selection of POLDER data, a composite PC dataset has been established over the Sahara and the Arabian Peninsula. We have investigated the relationship between aerodynamic roughness length and PC, and have derived a statistically significant empirical relationship between these two parameters. This relationship is applied to the POLDER-derived PC to map the aerodynamic roughness length of and areas in northern Africa and the Arabian Peninsula at the spatial resolution of POLDER (- 1/16). When degrading these data for global models, we show that the information is essentially preserved at coarser resolutions up to . This map of roughness length derived from the POLDER instrument, and a corresponding map derived from a geomorphologic classification, have been tested by comparing the predicted dust event frequencies obtained using them to dust indices (IDDI) derived from Meteosat IR observations over the Sahara desert. The agreement using the POLDER derived roughness length is at least as good as using the map of roughness length derived from the geomorphologic approach. Our results show promising new prospects for regional and global scale simulations of mineral dust emissions from and regions. Numéro de notice : A2004-065 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000116976 En ligne : https://doi.org/10.1080/0143116031000116976 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26593
in International Journal of Remote Sensing IJRS > vol 25 n° 3 (February 2004) . - pp 603 - 626[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04031 RAB Revue Centre de documentation En réserve L003 Exclu du prêt An autonomous above-water system for the validation of ocean color radiance data / G. Ziborni in IEEE Transactions on geoscience and remote sensing, vol 42 n° 2 (February 2004)
[article]
Titre : An autonomous above-water system for the validation of ocean color radiance data Type de document : Article/Communication Auteurs : G. Ziborni, Auteur ; F. Melin, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 401 - 415 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] Adriatique, mer
[Termes IGN] analyse comparative
[Termes IGN] eaux côtières
[Termes IGN] étalonnage radiométrique
[Termes IGN] exitance spectrale
[Termes IGN] image Aqua-MODIS
[Termes IGN] image Envisat-MERIS
[Termes IGN] image Seawifs
[Termes IGN] luminance lumineuse
[Termes IGN] photométrie
[Termes IGN] radianceRésumé : (Auteur) An operational system for autonomous above-water radiance measurements, called the SeaWiFS Photometer Revision for Incident Surface Measurements (SeaPRISM), was deployed at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea and used for the validation of remote sensing radiometric products in coastal waters. The SeaPRISM data were compared with simultaneous data collected from an independent in-water system for a wide variety of sun elevations along with different atmospheric, seawater, and sea state conditions. The average absolute differences between the above- and in-water determinations of water-leaving radiances (computed linearly) were less than 4.5% in the 412-555-nm spectral interval. A similar comparison for normalized water-leaving radiances showed average absolute differences less than 5.1%. The comparison between normalized water-leaving radiances computed from remote sensing and SeaPRISM matchup data, showed absolute spectral average (linear) differences of 17.0%, 22.1%, and 20.8% for SeaWiFS, MODIS, and MERIS, respectively. The results, in keeping with those produced by independent in-water systems, suggest the feasibility of operational coastal networks of autonomous above-water radiometers deployed on fixed platforms (towers, lighthouses, navigation aids, etc.) to support ocean color validation activities. Numéro de notice : A2004-137 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2003.821064 En ligne : https://doi.org/10.1109/TGRS.2003.821064 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26664
in IEEE Transactions on geoscience and remote sensing > vol 42 n° 2 (February 2004) . - pp 401 - 415[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 065-04021 RAB Revue Centre de documentation En réserve L003 Disponible Systematic corrections of AVHRR image composites for temporal studies / J. Cihlar in Remote sensing of environment, vol 89 n° 2 (30/01/2004)
[article]
Titre : Systematic corrections of AVHRR image composites for temporal studies Type de document : Article/Communication Auteurs : J. Cihlar, Auteur ; R. Latifovic, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 217 - 233 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] correction d'image
[Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF
[Termes IGN] image en couleur composée
[Termes IGN] image Landsat-TM
[Termes IGN] image NOAA-AVHRR
[Termes IGN] réflectance végétaleRésumé : (Auteur) For quantitative studies of vegetation dynamics, satellite data need to be corrected for spurious effects. In this study, we have applied several changes to an earlier advanced very high resolution radiometer (AVHRR) processing methodology (ABC3; [Remote Sens. Environ. 60 (1997) 35; J. Geophys. Res.Atmos, 102 (1997) 29625; Can. J. Remote Sens. 23 (1997) 163]), to better represent the various physical processes causing contamination of the AVHRR measurements. These included published recent estimates of the NOAA-11 and NOAA-14 AVHRR calibration trajectories for channels 1 and 2; the best available estimates for the water vapour, aerosol and ozone amounts at the time of AVHRR data acquisition; an improved bidirectional reflectance algorithm that also takes into consideration surface topography; and an improved image screening algorithm for contaminated pixels. Unlike the previous study that compared the composite images to a single-date AVHRR image, we employed coincident TM images to approximate the AVHRR pixel field of view during the data acquisition. Compared to ABC3, the modified procedure ABOV2 was found to improve the accuracy of AVHRR pixel reflectance estimates, both in the sensitivity (slope) of the regression and in r2. The improvements were especially significant in AVHRR channel 1. In comparison with reference values derived from two full TM scenes, the corrected AVHRR surface reflectance estimates had average standard errors values of + 0.009 for AVHRR C1, + 0.019 for C2, and + 0.04 for NDVI; the corresponding r2 values were 0.55, 0.80, and 0.50, respectively. The changes in ABC3V2 were not able to completely remove interannual variability for land cover types with little or no vegetation cover, which would be expected to remain stable over time, and they increased the interannual variability of mixed forest and grassland. These results are attributed to a combination of increased sensitivity to interannual dynamics on one hand, and the inability to remove all sources of noise for barren or sparsely vegetated northern land cover types on the other. Numéro de notice : A2004-025 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2002.06.007 En ligne : https://doi.org/10.1016/j.rse.2002.06.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26553
in Remote sensing of environment > vol 89 n° 2 (30/01/2004) . - pp 217 - 233[article]Narrowband-to-broadband albedo conversion for glacier ice and snow: equations based on modeling and ranges of validity of the equations / W. Greuell in Remote sensing of environment, vol 89 n° 1 (15/01/2004)
[article]
Titre : Narrowband-to-broadband albedo conversion for glacier ice and snow: equations based on modeling and ranges of validity of the equations Type de document : Article/Communication Auteurs : W. Greuell, Auteur ; J. Oerlemans, Auteur Année de publication : 2004 Article en page(s) : pp 95 - 105 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] albedo
[Termes IGN] éclairement énergétique
[Termes IGN] erreur moyenne quadratique
[Termes IGN] glace
[Termes IGN] image Landsat-TM
[Termes IGN] image NOAA-AVHRR
[Termes IGN] image Terra-MISR
[Termes IGN] image Terra-MODIS
[Termes IGN] neige
[Termes IGN] réflectance
[Termes IGN] transfert radiatifRésumé : (Auteur) In this paper, we propose equations for narrowband-to-broadband (NTB) albedo conversion for glacier ice and snow for four types of satellite sensors : thematic mapper (TM), advanced very high resolution radiometer (AVHRR), moderate resolution imaging spectroradiometer (MODIS), and multi-angle imaging spectroradiometer (MISR). We do this on the basis of spectral albedos and incident spectral irradiances generated with radiative-transfer models of the (sub)surface (a two-stream model) and the atmosphere, respectively. First, we establish equations for reference values of atmospheric components and the surface elevation. These equations describe measurements with root-mean-square differences of ~0.016. We then show that the "reference equations" also perform well when total ozone and aerosol optical depth are changed with respect to the reference. The negative effect of humidity and elevation variations on the performance of the equations can be eliminated by adding a correction term. We argue that narrowband albedos are much less sensitive to variations in the incident spectral irradiance than broadband albedos. Hence, our conclusions about the effects of variations in atmospheric composition and elevation are also valid for equations for NTB conversion proposed in other papers. Numéro de notice : A2004-010 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2003.10.010 En ligne : https://doi.org/10.1016/j.rse.2003.10.010 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26538
in Remote sensing of environment > vol 89 n° 1 (15/01/2004) . - pp 95 - 105[article]Toward universal broad leaf chlorophyll indices using PROSPECT simulated database and hyperspectral reflectance measurements / G. Le Maire in Remote sensing of environment, vol 89 n° 1 (15/01/2004)PermalinkHyperspectral monitoring of physiological parameters of wheat during a vegetation period using AVIS data / N. Oppelt in International Journal of Remote Sensing IJRS, vol 25 n° 1 (January 2004)PermalinkSpectral characteristics and feature selection of hyperspectral remote sensing data / X. Jiang in International Journal of Remote Sensing IJRS, vol 25 n° 1 (January 2004)PermalinkThe EuroSTARRS airborne campaign in support of the SMOS mission: first results over land surfaces / K. Saleh in International Journal of Remote Sensing IJRS, vol 25 n° 1 (January 2004)PermalinkVegetation/SPOT: an operational mission for the Earth monitoring, presentation of new standard product / P. Maisongrande in International Journal of Remote Sensing IJRS, vol 25 n° 1 (January 2004)PermalinkOptical remote sensing / W.G. Egan (2004)PermalinkQuantitative remote sensing of land surfaces / Shunlin Liang (2004)PermalinkIntercalibration of vegetation indices from different sensor systems / M.D. Steven in Remote sensing of environment, vol 88 n° 4 (30/12/2003)PermalinkTraining a neural network with a canopy reflectance model to estimate crop leaf area index / F. Mark Danson in International Journal of Remote Sensing IJRS, vol 24 n° 23 (December 2003)PermalinkFast SAR image restoration, segmentation, and detection of high-reflectance regions / E. Bratsolis in IEEE Transactions on geoscience and remote sensing, vol 41 n° 12 (December 2003)Permalink