Synergistic Use of AirMOSS P-band SAR with the SMAP L-band Radar-Radiometer for Soil Moisture Retrieval

We present and discuss an inter-comparison between microwave remote sensing observations from the NASA Soil Moisture Active-Passive (SMAP) mission and those from the NASA Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS). Earth gridded 1, 3, and 9 km AirMOSS and SMAP SAR observations show, in general, a strong correlation (R-2 >= 0.5). However, the correlation degrades at extreme AirMOSS local incidence angles. L-hand brightness temperature from SMAP and P-hand backscatter from AirMOSS are almost uncorrelated (R-2 <= -0.3) and indicate the need for more mathematically comprehensive techniques to merge these datasets to estimate surface soil moisture.