应用GMS5多通道云图估计降水技术的研究

Study of Rainfall Estimate Technique with GMS-5 Data

对近两年来 5～ 8月中国东部地区 1 2 0多个测站雨量观测资料和对应 4 40 0多幅GMS 5四个通道云图的研究发现 :红外亮温的时间、空间变率、红外和水汽通道亮温差等云图衍生资料对消除卷云 ,弥补夜间缺少可见光云图的不足起到明显作用。从而 ,应用双判据双重MOS多元回归法建立四通道云图因子、衍生因子与降水量之间的回归方程 ,进行 6小时分级降水估计。为了进一步消除厚卷云和特殊地形的影响 ,提出使用逐日实时资料自动建立多元回归方程估计降水量 ,从而对双判据双重MOS多元回归法估计结果进行校正。上海中心气象台的业务使用表明 ,总体估计的准确率达 70 %左右。

Through the study of six-hour raingauge data from about 120 stations in East China and the corresponding 4400 multi-channel cloud imagines of GMS-5 during the summer of 2001—2002, it is found that the temporal and spatial variation of the TBB and its gradient of the infrared channel, the TBB difference between the infrared and the vapor channel have certain function to eliminate error caused by cirrus, even to solve the absence of visible-channel data. Based on the study above, the rainfall estimate equations between six-hour rainfall and GMS-5 data are obtained by using double-judging & double-MOS regression method, which can be used to estimate six-hour rainfall. In order to further eliminate error caused by deep cirrus or special terrain, a day-by-day rainfall estimate equation by using real-time data is set up. The operational application in Shanghai Meteorological Center shows that its average estimate accuracy reaches about 70%.