1965年至2005年泾河流域极端降水事件的变化趋势分析  

Analyzing Variation Trends in Extreme Precipitation Events in the Jing River Watershed during 1965-2005

作　　者：李志[1] 刘文兆[2] 郑粉莉[2] 

机构地区：[1]西北农林科技大学资源环境学院,杨凌712100 [2]中国科学院水利部水土保持研究所,杨凌712100

出　　处：《资源科学》2010年第8期1527-1532,共6页Resources Science

基　　金："十一五"科技支撑计划项目(编号:2006BAD09B09);西北农林科技大学基本科研业务费青年项目(编号:Z109021002)

摘　　要：极端降水事件是导致黄土高原水土流失的主要原因之一,分析其变化趋势可为该区的生态建设提供重要的参考信息。选取泾河流域为研究区域,基于Mann-Kendall和小波分析等方法,分析了1965年-2005年极端降水事件的降水量、降水天数、降水强度和严重干旱次数等的变化趋势、突变、年代际变化和振荡周期等。结果表明,泾河流域极端降水事件的整体变化趋势不显著,但其发生频率和强度等都可能呈上升趋势,且存在空间差异,流域中下游呈上升趋势而流域西南部和北部呈下降趋势。各指标均呈波动变化,但基本都在1985年以后呈上升趋势,且在2000年左右发生多次上升突变;波动周期为2～3a,7～8a,13a和17a。尽管变化趋势不显著,但极端降水事件的各指标都趋于升高,表明未来极端降水事件可能对泾河流域的水土保持工作造成更加严重的威胁。Extreme climate events often cause more damages to society and ecosystems than do simple shifts in the mean values, and the impacts of extreme precipitation events are one of the most critical reasons causing severe soil and water loss over the Loess Plateau. Therefore, variations trends in extreme precipitation events need to be reasonably assessed, which can provide meaningful information on regional ecological conservation. The authors performed a study on the Jing River watershed using daily precipitation data from 18 meteorological stations during 1965-2005. Extreme precipitation events were defined in terms of percentile values. Indices, such as amount, frequency, intensity and severe drought frequency, were used to quantify the extreme precipitation events. The Mann-Kendall test and wavelet analysis method were employed to analyze the monotonic trend, abrupt change, interdecadal change and the period of each index. Results showed that the mean annual amount of extreme precipitation events was 143.9 mm/a, accounting for 27% of the total amount of annual precipitation. The mean annual frequency, intensity and maximum daily amount of extreme precipitation events were 3.6 d/a, 39.8 mm/d and 52.3 mm/d, respectively; while the mean annual frequency of severe drought was 7.4 times/a. Most stations in the Jing River watershed had no significant monotonic trend in each selected index of extreme precipitation events; however, the frequency and intensity of extreme precipitation events tended to increase. Furthermore, the variation trends in extreme precipitation events exhibited spatial variability, which might be caused by the integrated effects of terrain, meteorological conditions and global warming. Specifically, there was a positive trend in extreme precipitation events in the middle and lower reaches of the river that was generally in line with the dominant change trends; while a negative trend in extreme precipitation events in the southwestern and northern watershed was detected, which was opposite to the do

关 键 词：黄土高原 泾河流域 极端降水事件 MANN-KENDALL 小波分析 

分 类 号：P333.1[天文地球—水文科学]