Revisiting the Cox and Munk wave-slope statistics using IASI observations of the sea surface

We use radiances collected from space by the Infrared Atmospheric Sounder Interferometer (IASI) when looking down at ocean surfaces during day to remotely determine probability distribution of wave slopes. This is achieved using about 300 channels between 3.6 and 4.0μm a physically-based approach which properly takes contribution reflected solar radiation into account. Based on 150 millions observations, same number wave-slope probabilities are retrieved for wind speeds (at 10 m) up 15 m/s. revisit discuss methodology proposed Cox Munk (CM) derive their celebrated function (pdf) photographs sun glitter. propose an original robust accurate retrievals 7 parameters appearing in Gram–Charlier representation pdf. Our results mean square slopes (MSSs) fully compatible with those CM, more recent Bréon Henriot, but our lower uncertainties enable point out departures linear wind-speed dependencies slight overestimation upwind MSS described fit CM moderate speed. skewness kurtosis coefficients show clear influences speed, steady decrease former alongwind coefficient being maximal speeds, features that could not due limitations measurements. renormalization procedure employed obtain complete variances truncated pdfs it imposes stringent conditions allow them accurately, wind-dependent values specific local sea state. also provide measurements shifted position most probable slope as well demonstration qualitative change regime updown asymmetry speed increases.