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Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates / M.H. Cosh in Remote sensing of environment, vol 92 n° 4 (30 September 2004)  

Public [article]  inRemote sensing of environment > vol 92 n° 4 (30 September 2004) . - pp 427 - 435 Titre : Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates Type de document : Article/Communication Auteurs : M.H. Cosh, Auteur ; Thomas J. Jackson, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 427 - 435 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Advanced Microwave Scanning Radiometer [Termes IGN] analyse comparative [Termes IGN] bassin hydrographique [Termes IGN] étalonnage des données [Termes IGN] humidité du sol [Termes IGN] Iowa (Etats-Unis) [Termes IGN] ligne de partage des eaux [Termes IGN] limite de résolution géométrique [Termes IGN] Soil Moisture Experiment Résumé : (Auteur) Watershed scale soil moisture estimates are necessary to validate current remote sensing products, such as those from the Advanced Microwave Scanning Radiometer (AMSR). Unfortunately, remote sensing technology does not currently resolve the land surface at a scale that is easily observed with ground measurements. One approach to validation is to use existing soil moisture measurement networks and scale these point observations up to the resolution of remote sensing footprints. As part of the Soil Moisture Experiment 2002 (SMEX02), one such soil moisture gaging system in the Walnut Creek Watershed, Iowa, provided robust estimates of the soil moisture average for a watershed throughout the summer of 2002. Twelve in situ soil moisture probes were installed across the watershed. These probes recorded soil moisture at a depth of 5 cm from June 29, 2002 to August 19, 2002. The sampling sites were analyzed for temporal and spatial stability by several measures including mean relative difference, Spearman rank, and correlation coefficient analysis. Representative point measurements were used to estimate the watershed scale (3 25 km) soil moisture average and shown to be accurate indicators with low variance and bias of the watershed scale soil moisture distribution. This work establishes the validity of this approach to provide watershed scale soil moisture estimates in this study region for the purposes of satellite validation with estimation errors as small as 3%. Also, the potential sources of error in this type of analysis are explored. This study is a first step in the implementation of large-scale soil moisture validation using existing networks such as the Soil Climate Analysis Network (SCAN) and several Agricultural Research Service watersheds as a basis for calibrating satellite soil moisture products, for networks design, and designing field experiments. Numéro de notice : A2004-412 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.016 En ligne : https://doi.org/10.1016/j.rse.2004.02.016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26939 [article]