Estimating RCS of the sea surface perturbed by rain for rainfall rate retrieval

The problem of improving estimates of rainfall intensity over the sea surface through spaceborne rain radars is addressed. The backscattered signal is composed of volumetric contribution due to rainfall and of the sea surface contribution. When trying to estimate the NRCS of the sea surface, one of the major difficulties is that different scale of roughness of the sea surface should be accounted for in the same e.m. model: the larger due to wind and the smaller due to the raindrop splashes. While in the first case several models are available in the literature, in the second case only a few experimental results or theoretical studies are available. In this paper, a model which accounts for the additional roughness due to the effects of the raindrop splashes is analysed. Furthermore, an enhanced algorithm is proposed for retrieving rainfall rate profiles, which utilises the relationship between sea NRCS and rainfall rate.