A Wind Field Retrieval Method for Scatterometer Based on the Distribution Characteristic of its Objective Function

Aiming at the problem of high directional ambiguity in the nadir region of conically scanning scatterometer, taking SeaWinds as an example and in consideration of its objective function distribution characteristic, a modified wind field retrieval method suitable for this kind of scatterometer is presented in this paper, which is designed based on the traditional maximum likelihood wind vector retrieval algorithm and circle median filter algorithm. This method attempts to enhance the accuracy in selecting the true wind direction by extending the possible range of wind direction and allowing them to be taken into account in the ambiguity removal. Two hundred of SeaWinds Level 2A data files and some corresponding colocated buoy data are used to validate this retrieval method. The experimental results indicate that the retrieval method is feasible due to its capability of effectively improving the directional ambiguity existing in the nadir region without any external reference data to aid in wind field initialization.