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Investigation of scale dependence and geomorphic stages of evolution through hypsometric analysis: a case study of Sirsa basin, western Himalaya, India / P. Dash in Geocarto international, vol 29 n° 7 - 8 (November - December 2014)  

Public [article]  inGeocarto international > vol 29 n° 7 - 8 (November - December 2014) . - pp 758-777 Titre : Investigation of scale dependence and geomorphic stages of evolution through hypsometric analysis: a case study of Sirsa basin, western Himalaya, India Type de document : Article/Communication Auteurs : P. Dash, Auteur ; S.P. Aggarwal, Auteur ; Narender Verma, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 758-777 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomorphologie [Termes IGN] bassin hydrographique [Termes IGN] carte hypsométrique [Termes IGN] érosion hydrique [Termes IGN] fleuve [Termes IGN] Inde [Termes IGN] représentation du relief Résumé : (Auteur) Hypsometric analysis is an important tool to identify and justify the erosional status, erosional processes, geologic and tectonic influences, and stage of landscape development of a basin. In this study, scale dependence of hypsometric integral (Ea) and hypsometric curve parameters were derived and analysed for various order sub-basins of Sirsa river. Here, Ea of higher order sub-basins are quite scale dependent and controlled by lithology; albeit Ea of all order sub-basins is independent of tectonic uplift. Based on Ea, all fourth and fifth order sub-basins were categorised in three classes. The analysis of hypsometric curve parameters showed that sub-basins of first category (Ea 0.45) are diffusive process dominated and belong to late youth to early mature stage. Numéro de notice : A2014-466 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2013.841772 En ligne : https://doi.org/10.1080/10106049.2013.841772 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74043 [article]

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Separating surface emissivity and temperature using two-channel spectral indices and emissivity composites and comparison with a vegetation fraction method / P. Dash in Remote sensing of environment, vol 96 n° 1 (15/05/2005)  

Public [article]  inRemote sensing of environment > vol 96 n° 1 (15/05/2005) . - pp 1 - 17 Titre : Separating surface emissivity and temperature using two-channel spectral indices and emissivity composites and comparison with a vegetation fraction method Type de document : Article/Communication Auteurs : P. Dash, Auteur ; F. Göttsche, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 1 - 17 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] correction atmosphérique [Termes IGN] données de terrain [Termes IGN] données météorologiques [Termes IGN] éclairement énergétique [Termes IGN] emissivité [Termes IGN] erreur [Termes IGN] image NOAA-AVHRR [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] radiance [Termes IGN] rayonnement infrarouge thermique [Termes IGN] saison [Termes IGN] simulation de surface [Termes IGN] température au sol [Termes IGN] thermal infrared multispectral scanner Résumé : (Auteur) The temperature-independent thermal infrared spectral indices (TISI) method is employed for the separation of land surface temperature (LST) and emissivity from surface radiances (atmospherically corrected satellite data). The daytime reflected solar irradiance and the surface emission at ~3.8 um have comparable magnitudes. Using surface radiances and a combination of day-night 2-channel TISI ratios, the ~3.8 um reflectivity is derived. For implementing the TISI method, coefficients for NOAA 9-16 AVHRR channels are obtained. A numerical analysis with simulated surface radiances shows that for most surface types (showing nearly Lambertian behavior) the achievable accuracy is ~0.005 for emissivity (AVHRR channel-5) and ~1.5 K for LST. Data from the European Centre for Medium-Range Weather Forecasts (ECMWF) is used for calculation of atmospheric attenuation. Comparisons are made over a part of central Europe on two différent dates (seasons). Clouds pose a major problem to surface observations; hence, monthly emissivity composites are derived. Additionally, using TISI-based monthly composites of emissivities, a normalized difference vegetation index (NDVI)-based method is tuned to the particular study area and the results are intercompared. Once the coefficients are known, the NDVI method is easily implemented but holds well only for vegetated areas. The error of the NDVI-based emissivities (with respect to the TISI results) ranges between -0.038 and 0.032, but for vegetated areas the peak of the error-histogram is at ~0.002. The algorithm for retrieving emissivity via TISI was validated with synthetic data. Due to the different spatial scales of satellite and surface measurements and the lack of homogeneous areas, which are representative for low-resolution pixels and ground measurements, ground-validation is a daunting task. However, for operational products ground-truth validation is necessary. Therefore, also an approach to identify suitable validation sites for meteorological satellite products in Europe is described. Numéro de notice : A2005-209 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.12.023 En ligne : https://doi.org/10.1016/j.rse.2004.12.023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27346 [article]