A radar-radiometer surface soil moisture retrieval algorithm for SMAP

A soil moisture retrieval algorithm is presented whereby both radar and radiometer measurements are used simultaneously in an optimization scheme to retrieve for surface soil moisture in the presence of vegetation. Further, using fine-resolution radar measurements, a disaggregated brightness temperature product at the radar resolution is developed to reconcile the spatial resolution discrepancy between the two measurements. Numerical simulations are performed to synthesize SMAP data, and then via the method of Simulated Annealing, optimization is accomplished to retrieve high resolution soil moisture.