近50年来黑河流域气温和降水量突变特征分析

Detection of Change Points in Temperature and Precipitation Time Series in the Heihe River Basin over the Past 50 Years

采用Pettitt方法对黑河流域10个气象站点1960年-2009年年平均气温和年降水量资料进行突变分1析98。6研年究,突表变明后:①多气年温平方均面气。温除均野比牛突沟变站前气有温所序增列加在,上19游92站年点存突在变显后著增突温变幅外度,其要余大站于点中气下温游的站突点变的年增份温均幅发度生,突为变前仅有拐子湖站气温呈现上升趋势,而突变后所有站点气温均呈现显著上升趋势;②降水方面。近50年流域降水量上升或者下降变化幅度未达到显著的突变水平。根据Mann-Kendall单调变化趋势分析,托勒和野牛沟两个站点的降水序列呈现显著的上升趋势,根据对年降水量累积距平曲线的分析,流域上游20世纪60年代至70年代末80年代初为少雨期,80年代初至90年代末年降水量和多年平均降水量接近,90年代末至2009年进入多雨期;流域下游年降水量1960年-1981年为多雨期,1981年至20世纪90年代初为少雨期,90年代初至2000年左右又进入多雨期,2000以后进入少雨期。

More attention has been paid to change point analysis in the areas of climate and hydrology due to its increasingly important role in indicating climate change or human activities. In this study, change points of time series of annual temperature and precipitation during the period 1960-2009 at 10 meteorological stations （Ejinaqi, Guaizihu, Dingxin, Jiuquan, Gaotai, Zhangye, Shandan, Tuole, Yeniugou, and Qilian stations） in the Heihe River basin were detected using the Pettitt method. This method can not only detect locations of the change points, but also judge whether a change point is significant or not at a certain significance level. The Heihe River basin, the second largest inland river basin in Northwest China, is located in arid and semiarid regions which are highly sensitive to climate change. Results show that a change point of 1992 in the annual temperature time series was identified at the Yeniugou station, and change points of 1986 in the annual temperature time series occurred at other 9 stations. All the detected change points were remarkable at a 0.05 significance level. Before these change points, only Tuole and Yeniugou stations in the annual temperature time series show increasing trends and the other 8 stations showed decreasing trends, while after the change point, all stations showed increasing trends in the annual temperature. Additionally, average annual temperature after the change point was higher than that before the change point at each station. Concerning annual precipitation, there was no change point found at all stations, which means that the magnitude of changes in the annual precipitation was not significant. Furthermore, trends in the annual precipitation over the past 50 years were analyzed by employing the nonparametric Mann-Kendall test and cumulative departure curves. In terms of the results of the Mann-Kendall test, Tuole and Yeniugou stations in the annual precipitation time series showed remarkable increasing trends, while there was no remarkable monotonous trend detected at other stations. In terms of the results of cumulative departure curves, less precipitation in the upper reaches of the basin appeared from the 1960’s through the end of the 1970’s. More precipitation appeared from the end of the 1990’s through 2009. Across the lower reaches of the basin, the situation was quite different. More precipitation occurred for the periods 1960-1981 and from the 1990’s through 2000, and less precipitation occurred for the rest of study periods.