Evaluation of the boundary wave number for the two-scale model of backscatter of microwaves in Ka- and Ku-band by the sea surface using the Dual-frequency Precipitation Radar data

Dual-frequency Precipitation Radar (DPR) consists of Ka- and Ku-band radars which operate in scanning mode at low incidence angles. It is installed on the Global Precipitation Measurement (GPM) satellite. Definition of boundary wave number in frameworks of the two-scale model of scattering surface is an important problem for investigation and modelling of radar backscatter from the sea surface. In this research DPR data combined with sea buoys data were used to evaluate slope variance of large-scale (compared to the probing wave length) sea waves along the scanning direction. Then this information was applied to obtain the boundary wave numbers dependences on wind speed for Ka- and Ku-bands. The dependencies were obtained for the case of fully developed sea.