Downscaling SMOS derived soil moisture for very wet conditions using a physically based approach

A physically based downscaling algorithm, DISPATCH (DISaggregation based on Physical And Theoretical scale CHange), has been used to estimate soil moisture at 1 km scale from coarse resolution SMOS soil moisture estimates over the agricultural site of the CanEx-SM10 campaign. In this paper, we test the applicability of the algorithm and analyze the linearity of the relationship between the soil evaporative efficiency (SEE) and the near-surface soil moisture (SM) for very wet soils. In such conditions, the results show that the linear model is not suitable due to a difficulty in estimating Tsmax (dry edge) within the SMOS pixel. The use of a neighboring area to estimate a reliable value of Tsmax was tested and validated in order to improve the linear model results.