大通河流域降水结构的演变特征及其驱动力探究

Study on the Evolution Characteristics and Driving Forces of Rainfall Structure in Datong River Basin

论文以青藏高原大通河流域为例,分别采用基于日、月降雨集中度指标(CI和CIM),表征大通河流域的降水结构特征,并分析其演变特征;采用交叉小波分析探究太阳黑子和大气环流异常指数太平洋10 a涛动(PDO)、厄尔尼诺/南方涛动(ENSO)、北极涛动(AO)与流域降水结构变化的联系。结果表明:1)流域南部的年均CI值高于北部,中部的年均CIM值高于流域其他部分;2)流域年CI值上升趋势明显,而其年CIM值具有明显下降趋势,且两者的一致性被破坏;3)太阳黑子对于流域降水结构影响最为显著,AO和ENSO的影响次之,PDO的影响最弱。研究成果有助于揭示大通河流域降水结构的驱动机理,为其模拟与预测奠定坚实的基础。

In this paper, Datong River Basin in the Qinghai-Tibet Plateau is taken as an example. The characteristics of rainfall structure in Datong River Basin are characterized by daily and monthly rainfall concentration indices（CI and CIM）, and the evolution characteristics of these indices are analyzed. Cross-wavelet analysis is used to investigate the relationship between sunspot, atmospheric circulation anomaly index（PDO, ENSO, Arctic Oscillation） and changes in rainfall structure. The results show that： 1） The annual CI is higher in the south of the basin than in the north, while the annual average CIM is higher in the central part of the basin than in other parts of the basin. 2） The CI value has a slight increasing trend, and the annual CIM value decreased significantly. 3） Sunspot has the most significant effect on the precipitation structure, followed by AO and ENSO, and PDO has the weakest effect.