Spectral properties of surface ocean waves from real-aperture radar observations

This paper is on the retrieval of spectral properties of surface ocean waves from the real-aperture radar KuROS carried on an airplane. The system was designed to prepare the satellite mission CFOSAT and to contribute to its validation. In addition, KuROS provides Doppler measurements which are analyzed as Doppler velocity spectra co-located with the wave height spectra derived from intensity measurements. Data have been acquired from 2013 to 2017 in various circumstances including fetch-limited, swell, or mixed sea conditions and under moderate to high wind conditions. In this paper we present results on the directional spectra obtained and on the associated integral parameters such as significant wave height, peak direction, peak wavelength (or frequency), directional and frequency spreads. Comparisons with outputs of the wave model hindcast (MFWAM model) are presented. We also show some results on the Doppler fluctuation spectra.