2008 Volume 28 Issue 5 Pages 411-426
An extensive study result is presented on the feasibility of SAR estimation of surface wind-speed distribution for coastal lagoon, specifically Lakes Shinji and Nakaumi, Japan. Four satellite-borne SARs, JERS-1, ERS-1, ERS-2 and Radarsat, are used to study the relation between SAR-derived normalized radar cross-section (NRCS) and in-situ surface winds, in order to study the dependence of SAR frequency and incidence angle on the sensitivity of NRCS change to wind speed. It is found that SAR NRCSs have good correlations with the in-situ wind data when C-band and relatively high incidence angle is used and when wind speed is moderate to high, indicating that such SARs have a potential to estimate high-spatial-resolution wind field. On the other hand, peculiar signatures are sometimes found especially when wind speed is low, indicating that the SAR is sensitive to very fine roughness conditions that may be caused by slicks, water flows and/or ship wakes. A simple spatial filtering is also tested to detect such signatures to extract the areas where SAR-estimated wind speed is reliable.