Empirical algorithm developed for SAR/ASAR wave mode data

Kurzfassung

The empirical algorithm CWAVE has been developed to derive integral wave parameters, e.g., significant wave height (SWH), mean wave period and swell wave height, from SAR/ASAR wave mode data. One can obtain full sea state measurements from SAR data using this empirical algorithm, without the need for first guess information. The CWAVE type algorithms implemented on two different kinds of SAR data (i.e., reprocessed ERS-2/SAR wave mode and ENVISAT/ASAR wave mode data), are denoted as CWAVE_ERS and CWAVE_ENV respectively. In the present paper, we demonstrate the development and validation of the CWAVE_ENV algorithm suitable for ENVISAT/ASAR wave mode data. A globally distributed dataset of 25,000 pairs of ASAR wave mode images and collocated ECMWF analysis model results from December, 2006 is used for CWAVE_ENV model parameters tuning. With respect to the CWAVE_ENV empirical algorithm validation, SWH and mean wave period derived from ASAR wave mode data are compared to the ECMWF reanalysis wave model, the German Weather Service (DWD) model forecast results and NOAA buoy measurements. Validation results show that the integrated wave parameters derived by CWAVE_ENV algorithm provide a reliable estimation of significant wave height with scatter index less than 20 %.