三江源地区温度和降水量空间插值方法比较

Comparison of Spatial Interpolation Methods on Temperature and Precipitation of Sanjiangyuan Region

以获取三江源地区1971～2000年的各月降水及平均气温的栅格数据为目的,选取青海省及其周边共58个基准气象站点的气候数据,结合100 m×100 m分辨率的数字高程模型(DEM)数据,采用协同克里格(Co-Kriging,COK)和薄盘光滑样条函数(Thin plate smoothing splines,TPS)2种方法进行气温及降水的空间插值。用广义交叉验证(General cross validation,GCV)的最小统计误差筛选最佳模型,用均方根预测误差(RMSE)和平均绝对误差(MAE)比较2种方法的精度。结果表明,①不论是COK还是TPS,引入协变量后模型插值结果的精度更优;②TPS的插值效果显著优于COK:对月均温模型,TPS的RMSE值比COK提高了69.48%,MAE验证指标提高了70.56%;而对于月降水模型,TPS的RMSE值比COK提高了28.07%,MAE值提高了29.06%。

In order to get the spatial grid data of monthly precipitation and monthly average temperature of Sanjiangyuan region,the Co-Kriging（COK） and thin plate smoothing splines（TPS） interpolation methods were applied by using the climate data in 1971-2000 of 58 meteorological stations around Qinghai province and the 3 arc-second digital elevation model（DEM） data.The performance was evaluated by the smallest statistical errors by general cross validation（GCV）.Root-mean squared predicted errors（RMSE） and mean absolute errors（MAE） were used to compare the performance of the two methods.The result showed that： ① After combing covariates into the models,both methods performed better;② The performance of TPS was significantly better than COK： for monthly average temperature,the RMSE derived from TPS was 69.48% higher than COK,as MAE increased by 70.56%;And for monthly precipitation,the RMSE derived from TPS was 28.07% higher than COK,as MAE increased by 29.06%.