Preliminary evaluation of surface clutter for geostationary spaceborne weather radar

Geostationary space-borne weather radar is a future powerful space-borne platform for the surveillance of tropical cyclone with its high performance of high time-space resolution and wide-area coverage. As well as the low orbit space-borne precipitation radar, surface clutter from the mainlobe, sidelobe of radar antenna and range sidelobe of pulse compression will also be a serious problem which would contaminate the weather echoes up to several kilometers above the surface. However, the geostationary platform provides a probability to this radar for surface clutter suppression in the similar methods with ground Doppler weather radar. Before those clutter suppression methods were used, the range area and its influence degree by surface clutter contamination at different incidence angle and the Doppler spectra characters of surface clutter echo and precipitation should be first studied for the geostationary space-borne weather radar. This paper will present a quantitative evaluation with the similar method as TRMM space-borne radar by calculating the contaminated radar range bins according to the geometric relationship between the geostationary satellite and the ground, and by calculating the signal-clutter ratio under the appropriate precipitation and surface scattering model and a realistic antenna pattern. Moreover, an additional work on the evaluation of Doppler spectra character is done for the land and sea surface clutter which is expected for the filter design of surface clutter suppression.