洞庭湖流域径流变化过程及其对ENSO和东亚季风的响应

Variation Processes of Runoff and Responses to ENSO and the East Asian Summer Monsoon in the Dongting Lake Basin

依据1951~2017年洞庭湖流域四水逐年径流资料,运用滑动平均、Mann-Kendall趋势检验和小波分析等方法,探讨洞庭湖流域四水径流变化过程及其对ENSO和东亚夏季风的响应.结果表明:(1)径流量表现出丰枯交替的年际变化,湘潭站、桃源站径流量呈不显著的增加趋势,桃江站、石门站径流量呈不显著的减少趋势;(2)径流量呈现间歇式周期振荡,以2~4a年际振荡为主,在该年际尺度上径流量对ENSO和东亚夏季风的响应具有显著的滞后性.(3)在年际和年代际尺度上径流量对ENSO和东亚夏季风联合作用的响应有所增强,这可能与“ENSO-反气旋/气旋-西太平洋副热带高压-东亚夏季风”耦合系统有关.

Based on the annual runoff data from four hydrological stations of Xiangtan,Taoyuan,Taojiang and Shimen in the Dongting Lake basin from 1951 to 2017,the five annual moving average,the Mann-Kendall trend test and the wavelet analysis have been used to explore the variation process of runoff from four rivers in the Dongting Lake basin and response to ENSO and the East Asian Summer Monsoon.The results show that runoff exhibits interannual variation of alternating abundance and depletion,with a non-significant increasing trend at Xiangtan and Taoyuan hydrological stations and a non-significant decreasing trend at Taojiang and Shimen hydrological stations.Runoff exhibit an intermittent periodic oscillation,with dominating interannual oscillation of 2-4 a,and responses to ENSO and the East Asian Summer Monsoon are more sensitive in this interannual scale,accompanying significant lags.The responses to the combined effect of ENSO and the East Asian summer monsoon are enhanced in the interannual and interdecadal scales,which may be related to the coupled system of“ENSO-Anticyclone/cyclone-Western Pacific subtropical high-East Asian summer monsoon”.