Retrieval of Ocean Wave Parameters Using Envisat Advanced Synthetic Aperture Radar Data and Its Verification Analysis

Abstract

Based on MPI iterative retrieve algorithm, we retrieve the 2-D (two-dimensional) ocean wave spectrum by using Envisat ASAR wave mode Single Look Complex (SLC) imageries. The first guess spectrum is a necessary input item to run this MPI algorithm. In this paper, the first guess spectrum was calculated with reanalyzing wind data of ECMWF (European Centre for Medium-Range Weather Forecasts) and NCEP (National Centers for Environmental Prediction) as input wind stress of WAM Model. The Significant Wave Heights (SWHs) retrieved from the first guess spectrum as well as the best fit spectrum corresponding to ECMWF and NCEP wind field respectively are compared with the measurement data from buoys all over the world ocean. The comparison shows that the SWHs retrieved by ECMWF wind are less than field measurement buoy data in general, while the SWHs retrieved by NCEP wind are greater than those buoy data, but the mean SWHs of them fit with the field buoy data are better than whichever pro. However, the MPI algorithm makes the retrieved SWHs more accurate in comparison with the first guess spectrum derived from either ECMWF or NCEP wind field. Moreover, the relative error of the MPI method is improved by ∼12 percent with respect to the first guess spectrum.