Retrieve optical depth using microwave vegetation indices from WindSat data

Obtaining reliable vegetation optical depth (
^τ
, tau) is essential for vegetation parameter estimation and soil moisture retrieval. In this paper, a lookup table method was developed to retrieve optical depth using MVIs, which can derive the optical depth and single scattering albedo simultaneously without any auxiliary data. The lookup table method is based on the relationship of the single scattering albedo and optical depth at two adjacent frequencies, respectively. The relationships are explored by using a large simulation database generated using a physical model. Then, a lookup table will be established according to the relationships. Following this, we will validate this method and analyze the source of errors.