CoAuthors

Jean-François Poustis (CS, France); Danièle Hauser (LATMOS, France); Pierre Dubois (CLS, France); Cédric Tourain (CNES, France); Amanda Gounou (CS, France)

Launched in 2018, the CFOSAT mission provides information at global scale about the sea-state and waves main characteristics such as height, wavelength and direction. This information is derived from the normalized cross-section of the ocean surface radar backscattered signal measured by the on-board SWIM instrument. However, waves main characteristics are not sufficient to accurately describe the sea-state and extra parameters should be considered such as waves mean square slope (mss).


It is well documented that the surface waves slope distribution, hence the mss, can be related to the normalized radar cross-section (NRCS). In this work, we retrieve the “total” mss (i.e., not filtered by the radar wavelength) by inverting SWIM data. We use two models, both dependent on mss: 1/ using a Student law for wave slope distribution instead of the common assumption of Gaussian slope distribution and 2/ using the GO4 model, a expansion of the classic GO2 model. Inferred mss values and their dependance to geophysical parameters (wind speed, ...) are analysed and confronted to results derived from the literature, and their differences are discussed.