用华南暴雨试验雨量资料对TRMM/TMI-85.5 GHz测雨能力的考察

OBSERVATION RESEARCH FOR THE MEASURING RAINFALL CAPACITY OF TRMM/TMI-85.5G BASED ON THE PRECIPITATION DATA DURING THE HEAVY RAIN EXPERIMENT IN SOUTHERN CHINA

利用华南暴雨试验期间稠密的雨量资料对热带测雨卫星(TRMM)微波成像仪(TMI)频率为85.5 GHz(波长0.35 cm)的测雨能力进行了考察。通过TMI-85.5 GHz亮温分布和一小时雨量分布的对比发现,对流性降水的强雨量中心与TMI-85.5 GHz亮温的低值区有很好的对应关系,雨带分布和低亮温分布的位置及形状都很相似, 雨强的大小和亮温的关系也相当密切:雨强越大,亮温值越低。亮温数值和雨强(指每小时雨量,下同)的相关统计进一步表明:雨强的大小与亮温呈明显的负相关,特别是当雨强达到或超过7 mm/h时的相关程度非常显著,从而确认了TMI-85.5 GHz的微波遥感对对流性强降水有较好的测雨能力。

The capacity of Tropical Rainfall Measuring Mission (TRMM) Satellite for measuring rainfall was examined by using TMI-85.5 GHz microwave image data and precipitation data during the heavy rainfall experiment in Southern China. As compared with the distribution of rain amounts in an hour with TBB of 85.5 GHz microwave, it is clear that the center of heavy rain corresponds with an area of low TBB value. The location and shape of TBB distribution is similar to that of precipitation, and the larger rainfall rates, the lower TBB. The statistic analysis shows that the correlation coefficients between TBB and rain rates is negative and significant. Expecially, when the rain rate is over 7 mm/h, the correlation degree between TBB and rain rate is more significaut. The results shows that TRMM/TMI-85.5 G has great ability to measure convective heavy rain.