ERA-5降水数据在雨量站稀疏地区的适用性研究--以缅甸密支那流域为例

Research on applicability of ERA-5 precipitation data in basins with spare rain-gauge coverage:case of Myitkyina Basin in Myanmar

为探究降水产品在雨量站稀疏地区的适用性,选择位于缅甸的密支那流域作为研究流域,以雨量站数据作为参考数据,评估了ERA-5再分析降水数据的精度;并使用ERA-5数据率定和驱动CREST模型,探究了该数据应用于径流模拟的可行性。结果表明:在整个研究区域内,ERA-5数据和雨量站数据之间的相关程度高,差距较小;而在径流模拟方面,ERA-5数据可以较好地模拟中低水位的日径流过程,对于高水位流量则存在着一定的低估,但不同观测时段的NSCE系数均在0.7以上,总体而言精度仍较高;对于月径流量,该数据在不同观测时段的NSCE系数均大于0.85,相关系数均在0.9以上,能够较好地描述径流的年内变化特征。因此,ERA-5降水数据在一定程度上可以代替雨量站数据作为研究区域的降水数据来源,应用于流域水资源管理、水利工程设计等领域。

In this paper,we evaluated the accuracy of the ERA-5 reanalysis precipitation data based on rain-gauge data,and then used ERA-5 to calibrate and drove CREST model to explore the applicability of the data for streamflow simulation at Myitkyina Basin in Myanmar.The results showed that the deviation between ERA-5 data and rainfall station data was small and the correlation degree was high in regional scale.In terms of streamflow simulation,ERA-5 data could better simulate the low and medium daily streamflow,but there was a certain underestimation for the high streamflow.However,the NSCE coefficients of different observation periods were all above 0.7,and the overall accuracy was still high;for the monthly streamflow,the NSCE coefficients of ERA-5 data at different observation periods were all above 0.85,and the correlation coefficients were all above 0.9,which could better describe the annual variation characteristics of runoff.Therefore,ERA-5 precipitation data could replace the ground station data to some extent as the precipitation data source of the study area for water resources management and hydraulic engineering design.