TRMM降雨数据在湖南省长株潭地区的适用性

[目的]基于现有实测降雨数据和TRMM降雨数据,探讨利用TRMM数据估测实际降雨的方法。[方法]利用湖南省长株潭地区12个气象站点观测的降雨数据和TRMM降雨数据,采用相关系数法、误差分析、相对偏差分析等方法,分析长株潭地区2002—2011年TRMM降雨数据的精度。[结果]长株潭地区的TRMM数据和站点数据的拟合程度较好,年降雨量的拟合优度为0.69,春、夏、秋、冬4季降雨量的拟合优度依次为0.68,0.52,0.66,0.34,月降雨量的拟合优度达0.73,各站点月降雨量的拟合优度更好。相对偏差分析与误差分析结果表明TRMM降雨数据普遍低于实测降雨数据,这种偏差主要是因为单个观测站点实际代表面积远小于TRMM单个栅格的代表面积,而相对偏差均为负值则可能是城市的降雨量和雨强大于农村所致。此外偏差和地形起伏存在一定的联系,地形起伏越大的地区偏差越大。[结论]TRMM降雨数据在长株潭地区有一定的适用性,但在使用时需要用观测数据进行必要的修正,TRMM数据也可作为历史降雨观测数据分析的一个参考以提高其空间精度。

Applicability of Precipitation Data from TRMM in Changsha-Zhuzhou-Xiangtan Region, Hunan Province

[Objective] This study aimed to testify the method of estimating the real precipitation with TRMM data with the aid of the observed precipitation and TRMM precipitation from 2002 to 2011.[Methods] The applicability of TRMM precipitation data in Changsha-Zhuzhou-Xiangtan region of Hunan Province from 2002 to 2011 was analyzed based on the precipitation data from 12 rainfall observation stations with the methods of correlation coefficient, error analysis, relative deviation analysis and statistical analysis.[Results] The fitting degree of TRMM data and observation station data in these regions were good. The goodness-of-fit of yearly rainfall was 0.69 and the ones of the spring, summer, fall and winter respectively were 0.68, 0.52, 0.66 and 0.34. The goodness-of-fit of monthly rainfall reached to 0.73 and that of the every station was good too. Methods of relative deviation analysis and error analysis indicated that the TRMM rainfall data was generally lower than the observed precipitation, which was mainly for that the area representativeness of the signal observational station was far smaller than that of the TRMM. This was because of that the cities'' rainfall extensity was stronger than rural area caused by urbanization and that the rainfall observation stations are all located in the edge of cities. The deviation has some definite relations with typographic relief. The more the topographic relief is, the greater the deviation will be.[Conclusion] The TRMM rainfall data has some definite applicability in the region of Changsha-Zhuzhou-Xiangtan region. We can adopt it for different uses but we should have some indispensible correction with observational data. The TRMM data can also be a reference for the use of the limited previously rainfall observation data in order to improve the spatial accuracy.