1961-2008年京津冀地区暴雨的气候变化特征分析

摘要

Based on the observational daily precipitation data provided by Beijing, Tianjin and Hebei province Meteorological Bureau during 1961-2008, the characteristics of the climatic variations of stormrain in Beijing-Tianjin-Hebei province region (Jing-Jin-Ji)are analyzed in this paper by using the empirical orthogonal function(EOF)method, Morlet wavelet and Mann-Kendall test. The major results are summarized as follows:the rainstorm precipitation and its frequency show a high consistency distribution which exhibits a significant meridional gradient along the terrain of Jing-Jin-Ji, and appears mainly during late July and early August of the year in climatology. There is a continuously decrease trend in the precipitation of rainstorm in Jing-Jin-Ji since 1960s. Evidence also shows that 1980 is an abrupt change point and an obviously decrease trend of rainstorm in Jing-Jin-Ji occurs in 2000s. Wavelet power spectrum reveals that 2- 4a is a significantly period for rainstorm in Jing-Jin-Ji. The rainstorm in Jing-Jin-Ji shows a consistent change or opposite changes in east and west or in south and north.%利用北京市、天津市和河北省1961—2008年逐日台站降水资料，采用经验正交函数分解（empirical orthogonal function）、Morlet小波、曼-肯德尔（Mann-Kendall）突变检验等方法，统计分析了京津冀地区暴雨量及暴雨频次的气候变化特征。结果表明：气候态下，京津冀地区暴雨量及暴雨频次沿地形呈东南多-西北少的分布型，暴雨发生时间相对集中在7月下旬和8月上旬。1961—2008年京津冀大部分地区暴雨量呈减少的趋势，且在1980年发生显著突变，2000年代以后暴雨量进一步减少。小波功率谱分析结果表明，京津冀地区暴雨量主要存在2~4a的显著主周期。该地区暴雨量EOF展开的前3模态显示，暴雨量主要呈全区一致变化以及东西反向、南北反向的空间变化特征。