SPATIAL DISTRIBUTION AND SEASONAL VARIABILITY OF THE RAINFALL OBSERVED FROM TRMM PRECIPITATION RADAR (PR) IN THE SOUTH CHINA SEA AREA(SCSA)

High resolution PR rainfall data, which is collected by the Tropical Rainfall Measurement Mission (TRMM), is used to study the spatial distribution and seasonal variability of the rainfall in SCSA. Annual mean field shows that the rainfall distribution is highly non-uniform. In general, rainfall in southern SCSA is higher than that in northern SCSA and rainfall in eastern SCSA is higher than that in western SCSA. Restricted by the land topographies, heavy rainfall mainly occurs at the sidehill of more than 500 m. On the side facing the air current with full water vapor, the rainfall is much higher than the other side. PR's monthly mean rainfall fields show that the rainfall in SCSA has significant seasonal variability, and the monsoons push the heavy rainfall belt northward in summer and southward in winter. Compared with that of CPC Merged Analysis of Precipitation (CMAP), PR rainfall has similar scale and spatial features. However, PR rainfall fields imply more mesoscale information, and reveal more details of the effect of the mountains. Compared with the observed rainfall at the observation stations, time series of PR's monthly mean rainfall are well consistent with the gauges measurement. As a result, the PR measurement can be widely used to study the regional rainfall.