北京汛期暴雨气候特征分析

Climatic Characteristics of Rainstorm in Flood Season in Beijing

摘要: 利用北京站(54511)1951~2012年的降水资料、环流特征量资料和历史天气图资料对过去62年北京汛期(6~8月)暴雨气候变化特征以及暴雨产生的天气形势分类进行分析。得出以下结论：1) 北京汛期暴雨累积雨量与汛期累积雨量变化趋势一致，呈逐年减少趋势，汛期暴雨贡献率呈现波动变化；2) 7、8月份的暴雨占前汛期累积雨量的比例呈一定左右的周期变化，未来10年北京可能再次进入暴雨高发期；3) 汛期暴雨频次的小波功率谱显示其存在2~3年和准5年的周期变化，估计2013年暴雨频次有偏少趋势；4) 北京汛期暴雨偏多的年份，副高面积偏大，强度偏强，脊线偏北、偏西，太阳黑子处于非活跃期；暴雨频次较少的年份，副高面积偏小，强度偏弱，脊线偏北、偏西，海温偏低，太阳黑子处于活跃期。

Abstract: Using the data of precipitation, circulation parameters and historic synoptic chart at Beijing station, the climatic characteristics and the classification of weather situation in main flood season at Beijing station in the last 62 years were analysed. The conclusion was expressed as follow. 1) In flood season, the variation trend of accumulated rainstorm rainfall is as same as accumulated rainfall, showing a decreasing trend, and the rainstorm contribution rate shows a wave change. 2) In former flood season, the proportion of rainstorm in July and August shows some periodic changes, and the storm period may be coming in the next 10 years. 3) In flood season, the wavelet power spectrum of storm frequency is a 2 - 3-year period and a qusi-5-year period. According to it, the storm frequency will be on the low side in 2013. 4) In the years of more storms, the Western Pacific Subtropic High Area is larger; the strength is stronger; the ridge is more north and west; and sunspot is in an inactive period. Instead, in the years of fewer storms, the Western Pacific Subtropic High Area is smaller; the strength is weaker; the ridge is more north and west; the temperature is lower; and sunspot is in an active period.