Validation of MSWEP daily and extreme precipitation of the Taihu Lake Basin in Jiangsu ProvinceEI北大核心CSCD

基于1979—2019年江苏省太湖流域雨量站实测降水资料,综合解析了全球性降水资料MSWEP(multi-source weighted-ensemble precipitation)对日降水量和各历时极值降水量的表征能力。结果表明:MSWEP对研究区日降水量总体上有较强的解释能力,但在山丘区较集中的湖西区和以水域为主的太湖区两个水利分区的精度相对较差,同时MSWEP难以捕捉到暴雨等级的日降水事件;MSWEP可大致反映研究区各历时极值降水量的空间分布格局,但在细节特征上与地面降水场仍有一定差异;随着历时增加,MSWEP极值降水量的精度不断提高,MSWEP对15 d及更长历时极值降水量具有较强的定量表征能力;MSWEP日降水量和极值降水量的误差与降水强度之间均有显著的线性负相关性,存在较明显的“低值高估、高值低估”现象,且MSWEP的精度与空间尺度有关;在研究区面平均尺度上,由于降水量的空间均化效应和尺度不匹配性的消除,MSWEP对日降水量和极值降水量的表征能力明显优于栅格尺度。

Validation of MSWEP daily and extreme precipitation of the Taihu Lake Basin in Jiangsu Province

Based on precipitation observations from rain gauges in the Taihu Lake Basin in Jiangsu Province from 1979 to 2019, the ability of MSWEP (multi-source weighted ensemble precipitation) to characterize daily and extreme precipitation with different durations was comprehensively analyzed. Results show that, in general, MSWEP can well reflect daily precipitations in the study area; however, its accuracy is relatively poor in the Huxi and Taihu Lake sub-areas, where hilly area is concentrated and water body is dominated, respectively, and it is difficult for MSWEP to capture rainstorm events on daily scale. MSWEP can roughly reflect the spatial structure of extreme precipitation with different durations in the study area, but there are some differences between MSWEP and gauge observations in details. With the increase of duration, the fitting accuracy of MSWEP extreme precipitation is improved, and MSWEP has a strong ability in characterizing extreme precipitation with a duration of 15 d or even longer. There is a significant linear negative correlation between the errors of MSWEP daily precipitation and extreme precipitation and precipitation intensity, and there are obvious phenomena of "lowvalue overestimation and high-value underestimation". Moreover, the accuracy of MSWEP is remarkably correlated with spatial scale. On the mean areal scale of the study area, the ability of MSWEP in characterizing daily precipitation and extreme precipitation is higher than that on the grid scale because of the spatial homogenization effect and the elimination of spatial scale mismatching. © 2023, Editorial Board of Water Resources Protection. All rights reserved.