Wind Speed Retrieval Using L-Band Cross-Poralization Measurements

Abstract

We investigated L-band cross-polarized normalized radar cross section (NRCS) dependence on ocean surface wind for wind speed retrieval. Because it has been reported that the L-band HV NRCS significantly changes due to the Faraday rotation (FR), analysis was conducted on observed NRCS with less influence of FR. About 50,000 match-ups, each consisting of the L-band NRCS, incidence angles, wind speeds and wind directions, were collected from the Phased- Array L-band Synthetic Aperture Radar-2 (PALSAR-2) and scatterometer wind vectors. Based on the match-ups, the L- band HH NRCS dependence on incidence angle and wind vector is modeled for 25 to 40° incidence angles. The derived relation indicates that the wind sensitivity of the L-band HV NRCS is almost equivalent to that of the HH one. Wind speeds are then estimated from the match-ups, based on the derived model function. A comparison with the reference scatterometer winds reveals a 0.37m/s bias and 2.9m/s root mean square (RMS) error.