珠江流域极端降雨时空变化规律及气候影响因素研究

Study on Spatial and Temporal Characteristics of Extreme Precipitation and Its Affecting Factors of Climate in the Pearl River Basin

摘要: 依据珠江流域41个气象站1960~2012年的日降雨资料，定义了5个极端降雨指标(极端降雨总量、极端降雨日数、极端降雨平均强度、最大1d降雨量、最大连续3d降雨量)及通过将五者叠加得到的极端降雨综合指数，运用Mann-Kendall及小波分析等方法对珠江流域极端降雨时空变化特征规律及气候影响因子进行了研究。结果表明：1) 珠江流域大部分地区极端降雨呈上升趋势，预示着流域发生洪涝灾害的可能性增加，防洪压力增大。2) 近53年流域极端降雨未发生显著突变。3) 流域极端降雨具有长期记忆性，即未来仍呈不显著增加趋势。4) 流域极端降雨存在2.2~6.5a的主振荡周期，且以短周期演变为主，长周期变化不明显，具有多尺度周期振荡特征。5) 交叉小波分析结果表明，ENSO、太阳黑子活动是珠江流域极端降雨的主要影响因素。

Abstract:  Based on the daily precipitation data at 41 observational stations of the Pearl River Basin from 1960 to 2012, defining five extreme precipitation indices such as total extreme precipitation, extreme rain days, mean intensity of extreme precipitation, maximum 1-day precipitation, maximum consecutive 3-day precipitation and comprehensive index of extreme precipitation, using the methods of Mann-Kendall and Wavelet analysis, the spatial and temporal characteristics of extreme precipitation of the Pearl River Basin are analyzed. The affecting factors of climate are studied as well. The results show that: 1) The extreme precipitation shows an increasing trend in most area of the basin. More flood disasters might occur in the basin; 2) No significant mutation can be identified in these indices in recent 53 years; 3) All the indices have a long-term memory characteristic that future tendency is consistent with those of the past; 4) The extreme precipitation shows complex periodic variations with the primary oscillation periods of 2.2~6.5a; 5) Cross wavelet analysis and coherence analysis show that ENSO and sunspot are the main factors affecting the extreme precipitation in the basin.