黄河流域降水格局及影响因素

Spatio-temporal patterns of precipitation and its possible driving factors in the Yellow River Basin

黄河流域位于干旱、半干旱与半湿润过渡地带,是中国重要的经济地带和生态屏障,研究流域降水时空格局及其对多驱动因素的响应具有重要意义。本文分析了近70年降水的时空格局规律、多尺度特征以及降水对不同气象要素与环流因子的响应。结果表明:黄河流域降水量呈下降趋势,降水变率为-0.88 mm/10a,而上游地区呈增加趋势。流域降水存在显著的年周期尺度;年际周期尺度为主导模态,集合经验模态分解(EEMD)的累积方差贡献率为94.85%。偏小波相干性(PWC)分析表明蒸散量为降水多尺度特征的主导气象因素,气象因素主要调制降水的季节性与年周期,环流因子主导降水的年际和年代际周期;不同类型因素的耦合可以增强对降水在所有周期尺度的解释能力。

The Yellow River Basin is located in the arid,semi-arid and semi-humid transition zone,which is an important economic zone and ecological barrier in China.It’s of great significance to study the spatio-temporal pattern of precipitation and its response to multiple driving factors.In this paper,the spatio-temporal pattern,multi-scale characteristics and response of precipitation to different factors are analyzed.The precipitation showed a decreasing trend,with a decreasing rate of-0.88 mm/10a,while the precipitation in the upper reaches showed an increasing trend.The annual time scale was significant and the cumulative variance contribution rate of ensemble empirical mode decomposition(EEMD)was 94.85%.The partial wavelet coherence(PWC)analysis showed that evaporation was the dominant meteorological factor,meteorological factors mainly affected the seasonal and annual periods and circulation factors mainly dominated the inter-annual and decadal periods of precipitation.The synergistic effects of different types of factors can enhance the explanatory ability of precipitation at all time scales.The study is significant for understanding the precipitation variability and promoting the ecological protection and high-quality development of the basin.