SMOS L2 L-band Soil Moisture Retrieval During NAFE’05

Rocco Panciera, Jeffrey Walker, Ed Kim, Jetse Kalma, Jorg Hacker, Olivier Merlin, Kauzar Saleh, Jean-Pierre Wigneron and Jenifer Grant

Power Point Presentation

The National Airborne Field Experiment 2005 (NAFE’05), conducted jointly with ESAS’s CoSMOS campaign, provides a wealth of SMOS-like L-band observations over a variety of land covers and wetness conditions supported by ground measurement of near-surface soil moisture. This study uses the SMOS L2 retrieval algorithm to retrieve soil moisture from L-band brightness temperatures at both 1km and 40km (SMOS footprint) resolution, the latter obtained by aggregation of the 1km brightness temperatures. The performance of the retrieval scheme at different scales is assessed by comparison against ground data of soil moisture. The surface type dependent parameters and ancillary data used to drive the forward modelling of brightness temperature were those currently proposed for SMOS operational soil moisture retrieval. Consequently, this study is amongst the first evaluation of SMOS L2 algorithm with airborne L-band data. This validation exercise gives insight into the accuracy of the forward radiative transfer model parameters, which are still considered preliminary. Moreover, results on upscaling of the surface roughness parameter and the vegetation parameter “b” from tower to aircraft and satellite scales are presented.