三峡库区降水量的空间插值方法及时空分布

三峡库区是一个特殊的地理单元，分析库区降水的时空特征具有重要意义。利用三峡库区及周边46个气象站点资料，分别采用反距离加权法、样条函数法、普通克里金法、协同克里金法等4种空间插值方法，对三峡库区1961~2005年45年间的年平均降水量、月平均降水量进行了空间插值模拟与交叉检验，并对三峡库区降水量的时空分布特征进行了分析。检验结果表明，考虑高程的协同克里金法整体插值效果要优于其他3种插值法。但通过站点误差分析，协同克里金法并非对每一个站点的插值精度都高。研究发现，在剔除其中2个高海拔站点的情况下，可以显著提高协同克里金的空间插值效果。由插值得到的三峡库区降水分布图可知，大部分区域的年平均降水量处于 1000~1200 mm ，而年内降水分配不均匀，夏季降水约占年降水量的45%。

SPATIAL INTERPOLATION METHODS AND TEMPORAL SPATIAL DISTRIBUTION OF PRECIPITATION IN THE THREE GORGES RESERVOIR AREA

It is important for studying the temporal spatial characteristics of precipitation in the Three Gorges Reservoir Area because of its special geographical position in China.In this paper,Inverse Distance Weighted,Spline,Ordinary Kriging and Co Krigings methods were respectively employed to interpolate the annual and monthly average precipitation of 46 weather stations in and around the Three Gorges Reservoir Area from 1961~2005.Then the results of the four interpolators were assessed under cross validation,and the temporal spatial distribution of precipitation was analyzed.The validating criterions indicated that the Co Kriging which taken into account the elevation,performed better than the other three methods.However〖,based on the analysis of station error,we found that this method couldn't guarantee the error of all stations less than other methods.It showed that the precision of Co Kriging interpolator would increase,when two weather stations at high elevation were eliminated.Through analyzing the temporal spatial distribution of precipitation in the Three Gorges Reservoir Area,the annual average precipitation is 1000~1200 mm in most area,and more than 45% of the annual precipitation concentrated in the summer.