四川降水相关函数场的分析及其在气象观测站网布局中的应用

Analysis of Correlation Functions of Rainfall over Sichuan Region and Its Application to the Design of Weather Station Network

利用四川省139个台站的逐日降水资料,通过旋转经验正交函数(REOF)方法,将四川地区分为7个区域,分别计算各区域各季节代表月逐日降水的相关函数,推算出相对内插标准误差与相关函数的统计关系,并根据内插标准误差不大于观测标准误差的原则,估算出各区域降水场的最大容许距离。结果表明:盆地西南部布站精度最高,要求≤16 km;其次是盆地东南部,精度≤18 km;阿坝州北部布站精度要求≤19 km;而盆地西北部布站精度要求≤20 km;盆地东北部布站精度要求≤28 km;川西高原的布站精度要求≤33 km;川西南山地的布站精度最低≤42 km。

Based on the daily precipitation data of 139 stations in Sichuan Province from 1961 to 2008,the spatial distribution of precipitation in Sichuan was analyzed by using the rotated empirical orthogonal function（ REOF）,and Sichuan was divided into seven areas. Furthermore,the correlation functions of daily rainfall which were only dependent on the distance between two points over the seven areas for representative months of different seasons were calculated,and the statistical relationships between relative standard error of interpolation and the correlation functions were established. Finally,according to the principle that the standard error of interpolation should not exceed the standard error of observation,the maximum admissible spacing between two stations was estimated in the seven areas. The results show that the highest distributing precision of stations was in the southwest Sichuan basin with the distance between stations being less than 16 km,and secondly that was the southeastern Sichuan basin with the distance between stations being less than18 km. The distance between stations should be less than 20 km in the northwestern Sichuan basin. The northeastern Sichuan basin and the north Aba Prefecture of Sichuan had the same precision in which the distance between stations should be less than 28 km. In the western Sichuan Plateau,the distance between stations should be less than 34 km,and the southwest mountain areas of Sichuan had the lowest distributing scheme precision in which the distance between stations should be less than 42 km.