Root-zone plant available water estimation using the SMOS-derived soil water index

摘要: Abstract Currently, there are several space missions capable of measuring surface soil moisture, owing to the relevance this variable in meteorology, hydrology and agriculture. However, Plant Available Water (PAW), which some fields application could be more important than moisture itself, cannot directly measured by remote sensing. Considering root zone as first 50 cm soil, study, PAW at 25 cm integrated between 0 depth was estimated using provided Soil Moisture Ocean Salinity (SMOS) mission. For purpose, Index (SWI) has been used a proxy root-zone involving selection an optimal T (Topt), can interpreted characteristic water travel time. In research, tests correlation coefficient (R), Nash-Sutcliffe score (NS), error estimators bias predictor metrics were applied obtain Topt, making comprehensive study parameter. After analyzing results, differences found Topt obtained R NS decision metrics, that errors bias, but SWI showed good results estimator moisture. This index agreement, with 0.60 0.88. The method tested from January 2010 December 2014, database Measurements Stations Network University Salamanca (REMEDHUS) Spain. estimation agreement situ measurements, following closely dry-downs wetting-up events, ranging 0.92, values lower 0.05 m3m−3. A slight underestimation observed for both different depths; explained pattern SMOS L2 product, line previous studies. Nevertheless, research encouraging improvement estimation. Despite need on issue, show methodology useful applications great interest agriculture hydrology.