TRMM卫星降雨雷达观测的南海降雨空间结构和季节变化

利用热带降雨计划卫星(TRMM)获得的雷达降雨资料，对南海及其周边区域(简称南海地区)降雨的空间分布和季节特征进行了研究。结果表明：南海地区的降雨在空间上分布很不均匀，同时具有显著的季节变化。除了副高活动、季风潮、冬季冷涌和热带低压活动等天气过程，南海周边广泛分布的山地地形对该地区的降雨分布也产生强烈影响，降雨呈现南部高于北部、东部高于西部的分布特征?与CAMP和台站资料相比，PR观测具有更丰富的空间结构，能够更好地体现降雨随时间和空间变化的特征、反映高大的山地地形对降雨分布的影响。

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.