Recent progress on high wind-speed retrieval from multi-polarization SAR imagery: a review

Synthetic aperture radar (SAR) is a useful instrument for monitoring typhoons, hurricanes, and tropical cyclones from space. In this article, we summarize high wind-speed retrieval and validation methods for multi-polarization SAR. Compared to co-polarized geophysical model functions, we show that a cross-polarized wind-speed retrieval model is potentially able to estimate wind speed under extreme weather conditions. The resulting wind speeds are validated using in situ buoy observations, and airborne Stepped-Frequency Microwave Radiometer (SFMR) and spaceborne scatterometer measurements, as well as the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division's Hurricane Wind Analysis System (H*Wind) data. We also analyse the effect of intense rainfall on SAR-derived winds. The wind-speed retrieval accuracy can be improved in cases where the normalized radar cross sections (NRCSs) are suitably modified in rainfall areas.