Sea surface height and significant wave height estimations in the calm semienclosed Celebes Sea

Satellite altimeters measure the travel time of microwave pulses from the satellite and the sea surface at nadir, in which homogeneous reflections are assumed. However, this assumption often fails in coastal areas where various sources of inhomogeneous microwave reflections, such as lands, ships, and smooth water in ports. Areas with smooth sea surface called “slicks” are present not only in coastal areas but also in the middle of calm seas away from lands, which decrease the quality of altimeters' estimations of the sea surface height, significant wave height, and wind speeds. In this chapter, we introduce new data processing algorithms called “subwaveform retrackers” to eliminate reflected microwave echoes from these contamination sources. We show practical examples of retrackers with Jason-2 data in the Celebes Sea.