Global retrieval of surface soil moisture using L-band SMAP SAR data and its validation

摘要: Surface soil moisture retrievals using radar observations have been challenging due to the strong effects by surface roughness and vegetation scattering. Physically-based forward models for scattering are inverted time-series retrieval algorithm systematically correct effect of vegetation. The performed a top 5-cm layer at 3-km spatial resolution L-band data acquired Soil Moisture Active Passive (SMAP) satellite globally every three days from mid-April early July, 2015. These were assessed over 13 rigorously-chosen core validation sites covering wide range biomass types amounts conditions. performance had an accuracy approaching goal 0.063 m3/m3 unbiased-RMSE (root mean square error), near zero bias, correlation 0.56. successful demonstrates that physically-based method is capable characterizing diverse conditions moisture, roughness, on global scale.