Merlin O., Chehbouni Abdelghani, Walker J.P., Panciera R., Kerr Y. (2008). A simple method to disaggregate passive microwave-based soil moisture. IEEE Transactions on Geoscience and Remote Sensing, 46 (3), p. 786-796. ISSN 0196-2892.
Titre du document
A simple method to disaggregate passive microwave-based soil moisture
Merlin O., Chehbouni Abdelghani, Walker J.P., Panciera R., Kerr Y.
Source
IEEE Transactions on Geoscience and Remote Sensing, 2008,
46 (3), p. 786-796 ISSN 0196-2892
This paper develops two alternative approaches for downscaling passive microwave-derived soil moisture. Ground and airborne data collected over the Walnut Gulch experimental watershed during the Monsoon'90 experiment were used to test these approaches. These data consisted of eight micrometeorological stations (METFLUX) and six flights of the L-band Push Broom Microwave Radiometer (PBMR). For each PBMR flight, the 180-m resolution L-band pixels covering the eight METFLUX sites were first aggregated to generate a 500-m 'coarse-scale' passive microwave pixel. The coarse-scale-derived soil moisture was then downscaled to the 180-m resolution using two different surface soil moisture indexes (SMIs): 1) the evaporative fraction (EF), which is the ratio of the evapotranspiration to the total energy available at the surface; and 2) the actual EF (AEF), which is defined as the ratio of the actual-to-potential evapotranspiration. It is well known that both SMIs depend on the surface soil moisture. However, they are also influenced by other factors such as vegetation cover, soil type, root-zone soil moisture, and atmospheric conditions. In order to decouple the influence of soil moisture from the other factors, a land surface model was used to account for the heterogeneity of vegetation cover, soil type, and atmospheric conditions. The overall accuracy in the downscaled values was evaluated to 3% (vol.) for EF and 2% (vol.) for AEF under cloud-free conditions. These results illustrate the potential use of satellite-based estimates of instantaneous evapotranspiration on clear-sky days for downscaling the coarse-resolution passive microwave soil moisture
Plan de classement
Etude du micro et phytoclimat / Modélisation [072BCLIGE04]
;
Météorologie / Climatologie [126TELAPP06]
Descripteurs
HUMIDITE DU SOL ; EVAPOTRANSPIRATION ; SURFACE DU SOL ; BILAN ENERGETIQUE ; TELEDETECTION SPATIALE ; HYPERFREQUENCE ; MODELISATION ; ETUDE EXPERIMENTALE
