两套土壤湿度再分析资料在黑河流域的对比分析

A Comparative Analysis of Two Soil Moisture Datasets in HeiHe River Basin

利用黑河流域少量观测台站的实测降水和土壤湿度资料,对比分析了欧洲中心ERA40及美国NCEP R—1两套常用的土壤湿度再分析资料在黑河流域的空间分布、年际变化和季节循环特征,结果表明:两套资料在黑河流域均能表现出"南湿北干"的分布格局,湿度高值中心位于祁连山区东南部。以此为中心,土壤湿度从上游山区向中下游递减。ERA40土壤湿度在祁连山区年际变化明显,与降水的响应关系要好于NCEP资料,在中下游站点,NCEP 10 cm层土壤湿度对降水的响应好于ERA40。祁连站ERA40土壤湿度在6～8月接近观测值,在额济纳站两套资料对于土壤湿度的描述都不理想。

The observed station precipitation and soil moisture at a few stations in the Heihe River were compared with reanalysis soil moisture which are obtained from ERA40 and NCEP R-1. The spatial distribution, the interannual variation and seasonal cycle of of soil moisture in Heihe River basin are analyzed. Conclusions are as follows： Soil is wet in the south area and dry in the north area, the center of wet soil is located in the southeast of Qilian Mountain. Interannual variation of ERA40 soil moisture in the Qilian Mountains is very significant and it matches better with the observed precipitation than NCEP R-1, but in the middle and lower reaches sites, NCEP 10 cm soil moisture have a better response with precipitation than ERA40. ERA40 soil moisture is closed to the observed values in Qilian station from June to August, while both datasets have a bad description in Ejina station.