Retrieval of the surface wind speed from satellite radio-altimeter data: a review of algorithms

We give a review of surface wind-speed retrieval algorithms using satellite radio-altimeter data and analyze the efficiency of these algorithms. The data processing by new radio altimeters (JASON and ENVISAT) showed that the two-parameter algorithm developed for the satellite “Topex A” effectively operates with the data of the new radio altimeters and exceeds in accuracy the conventional algorithm by 5–10%. We discuss two main reasons for the wind-speed retrieval errors: (i) ambiguous relationship between the wind speed and the backscattering cross section and (ii) regional features of the wave climate formation. Within the framework of a two-parameter algorithm, we propose a new approach for the wind-speed retrieval problem, in which two-mode structures (wind waves and a swell) are taken into account. The data processing confirmed that the new approach allows one to reduce the error related to regional features of the wave climate formation by another 5–7%.