CFSR、ERA-Interim再分析降水数据在高寒山区径流模拟中的适用性

Application of CFSR and ERA-Interim Reanalysis Data in Runoff Simulation in High Cold Alpine Areas

为能更好地在严重稀缺资料地区开展水文水资源相关方面的工作,以天山西部山区的喀什河流域为典型研究区,基于1990~2000年现有的实测水文气象站点资料、CFSR与ERA-Interim数据,通过对比流域内两再分析降水数据空间分布情况、水文站点处实测与两再分析数据的降水时间序列变化及两再分析降水数据经过一定处理后驱动VIC模型所得的径流过程与实测径流过程三个方面,并评价了各再分析降水数据在喀什河流域的适用性。结果表明,两再分析降水分布符合山区大于平原、东部多于西部的规律,符合实际地理分布特点。流域内ERA-Interim年降水范围较为合理,而CFSR年降水范围则不太符合现实情况;两再分析降水数据春夏秋三季降水分布较为一致,其中ERA-Interim降水在流域内的高值区随季节变化较为明显,CFSR降水可能由于数据集本身或分辨率较低的缘故导致变化不为明显。冬季降水可能由于所针对的对象并非高寒区及冬季固液态降水的转化关系未深究这两个因素而较为反常。此外,CFSR降水高估了ERAInterim弱降水区,低估了其强降水区;研究区内CFSR降水存在高估实际降水的现象,而ERA-Interim降水存在低估强降水的现象;ERA-Interim在两套水文参数下均具有较为良好的模拟效果,且ERA-Interim数据在喀什河流域具有更好的适用性。

In order to better study of hydrology and water resources in seriously lack of data area,the VIC model has been built in the west Tianshan Mountains based on the data of hydrometeorology record,CFSR and ERA-Interim during the period from 1990 to 2000.This paper analyzes the suitability of two reanalysis data from two aspects:comparing the precipitation between CFSR and ERA-Interim on temporal-spatial distribution and the results of runoff simulation based on each reanalysis data.The results show that the precipitation of each reanalysis data has similar features with each other:the amount of precipitation in mountainous area is higher than that of plain area;the amount of precipitation in east area is higher than that of west.This law is suitable for the geographic feature in that area.The precipitation range of ERA-Interim is reasonable,but the precipitation range of CFSR is quite unreasonable.The spatial distribution of each type reanalysis data is much similar on spring,summer and autumn.The area with high precipitation of ERA-Interim is changed obviously in different seasons,but the area with high precipitation of CFSR has an inconspicuous change in different seasons because of the property and the resolution of this data.In addition,CFSR precipitation overestimates the ERA-Interim precipitation in low precipitation area and underestimates the ERA-Interim precipitation in high precipitation area.CFSR precipitation overestimates the real precipitation in study area,and ERA-Interim precipitation underestimates the real heavy precipitation.After the same way to calibrate the precipitation of each reanalysis data,4results of monthly runoff simulation have been simulated by VIC model with two optimal hydrological parameters.ERA-Interim data has much better applicability in Kashi basin.