Simultaneous field experiments with PALSAR observations for soil moisture estimation

We performed three field experiments with PALSAR/polarimetry observations in Ulaanbaatar/Mongolia, Arctic National Wildlife Region (ANWR/ Alaska)/US, and Sendai/Japan, to evaluate soil moisture models. The PALSAR polarimetry observations with off-nadir angle of 21.5deg were done in May 4, 2007, Jul. 29, 2007, and Apr. 14, 2007 in each place. On the other hand, the field experiments were done for May 2-7, 2007, Jul. 28-Aug 4, 2007, and Apr. 14, 2007. The surface parameters derived from field measurements show large dynamic ranges, which are from 4% to 80% for soil moisture value, from 0.16 to 2.22 for surface roughness, and from 1.97 to 8.09 for correlation length. We applied SPM model, X-bragg model, and Oh model in this time. While some discrepancies are appeared, the SPM and Oh models show agreements with absolute/relative sigma⁰ value in some degree. The X-bragg model shows moderate agreement in anisotropy-ks relation.