Wind Vector and SST Dependence of Ku- and Ka- Band Ocean Surface NRCS at Low Incidence Angles.

This paper presents characterization of collocated Ku- and Ka-band ocean surface normalized radar cross section ( $\sigma^{0}$ ) measurements over nadir-to-18° earth incidence angles using Global Precipitation Measurement (GPM) mission dual frequency precipitation radar (DPR) data. Empirical geophysical model functions (GMF) were derived, and isotopic and directorial sensitivity were evaluated at both bands. Finally, sea surface temperature dependence of radar backscatter were investigated. Ka-band exhibited higher vector wind sensitivity for low-to-moderate wind speeds regime, and the SST effects were also observed to be substantially larger at Ka-band than at Ku-band.