Hurricane Ocean Surface Wind Retrieval from ALOS-2 PALSAR-2 Cross-Polarized Measurements

The relationship between hurricane sea surface wind speed and L-band $\sigma^{0}$ is investigated to enable wind estimation under extreme wind condition based on four the Phased Array type L-band Synthetic Aperture Rader-2 (PALSAR-2) hurricane images and wind speed simultaneously measured by National Oceanic and Atmospheric Administration (NOAA)'s airborne Stepped Frequency Microwave Radiometer (SFMR). It was confirmed that HV $\sigma^{0}$ has a little dependence on the incidence angle and tends to increase without saturation at least up to 55 m/s and an L-band HV geophysical model function (GMF) is constructed using match-ups between HV $\sigma^{0}$ and SFMR wind speed. A comparison between the PALSAR-2-derived and SFMR-measured wind speeds reveals a −0.2m/s bias and 4.1m/s root mean square error (RMSE). The calculated wind speed structure shows the asymmetry wind speed radii which is almost consistent with the best track data.