A dual-frequency approach for improving the accuracy of altimeter-measured sea surface wind speed

This study aims to demonstrate the feasibility of using simultaneous measurements of Ku and C band radar cross sections (σ _Ku⁰ and σ_C⁰) from TOPEX altimetry to enhance the performance of existing wind speed algorithms. A simple scheme of σ_C⁰/σ _Ku⁰ adjustment is proposed, assuming that altimeter-measured radar cross sections of Ku and C bands follow a “standard” relationship for various wind speeds under normal conditions. Rain-induced systematic deviations of σ_C ⁰/σ_Ku⁰ with respect to their “standard” positions are observed and corrected using the proposed scheme. Validation of the authors´ results against the Japan Meteorological Agency (JMA) buoy observations suggests that the dual-frequency scheme is an effective approach in improving altimeter-measured sea surface wind speeds