Investigation of C-band altimeter cross section dependence on wind speed and sea state

Wind and wave impacts on C-band altimeter backscatter data are presented using data collected from the TOPEX/POSEIDON platform. The compilation of a large global data set of TOPEX observations collocated with NASA scatterometer (NSCAT) wind speed estimates is used to propose an algorithm for wind speed retrieval using both cross section and significant wave height observations. Evidence of sea state impact on radar backscatter is further analyzed through comparison with National Oceanographic Data Center (NODC) buoy spectral wave measurements. For wind speeds above 6 m(.)s(-1) and global mean sea state conditions, altimeter and buoy-derived slope variance estimates exhibit high correlation in their wind speed and sea state dependencies. Results suggest that the C-band instrument may be used to derive new data on the degree of development of the sea state.