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SMEX02: field scale variability, time stability and similarity of soil moisture / J.M. Jacobs 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 436 - 446 Titre : SMEX02: field scale variability, time stability and similarity of soil moisture Type de document : Article/Communication Auteurs : J.M. Jacobs, Auteur ; B.P. Mohanty, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 436 - 446 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse diachronique [Termes IGN] Argile [Termes IGN] bassin hydrographique [Termes IGN] flore locale [Termes IGN] humidité du sol [Termes IGN] Iowa (Etats-Unis) [Termes IGN] pente [Termes IGN] point de vérification [Termes IGN] précision [Termes IGN] Soil Moisture Experiment [Termes IGN] stabilité dans le temps Résumé : (Auteur) Evaluation of air- or space-bome remote sensors measuring soil moisture requires strategic ground-based sampling. As part of the Soil Moisture Experiment 2002 (SMEX02), daily surface soil moisture sampling at 90-140 locations were conducted in four fields in Walnut Creek watershed, Iowa. Various combinations of soils, vegetation, and topography characterize the fields. Depending on the field's characteristics and soil moisture content, 3 - 32 independent measurements were necessary to capture the field mean volumetric soil moisture with a + 2% bias and 95% confidence interval. Validation of the retrieved soil moisture products from the aircraft microwave instruments using the average of 14 samples per field is more appropriate for dry (25% volumetric soil moisture) range than for intermediate soil moisture range. Time stability analysis showed that an appropriately selected single sampling point could provide similar accuracy across a range of soil moisture conditions. Analyses based on landscape position (depression, hilltop, steep slope, and mild slope) showed that locations with mild slopes consistently exhibit time stable features. Hilltop and steep slope locations consistently underestimated mean field soil moisture. Soils parameters could not be used to identify time stable features as sampling locations with relatively high sand content consistently underestimated the field mean while those locations with relatively high clay content consistently overestimated the field mean. However, the slope position characterization of time stable features was enhanced using soils properties. The mild slope locations having the best time-stable features are those with moderate to moderately high clay content as compare to the field average (28-30% clay). Numéro de notice : A2004-413 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.017 En ligne : https://doi.org/10.1016/j.rse.2004.02.017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26940 [article]