1961-2013年中国雷暴气候特征及东亚夏季风影响研究

摘要

Using the thunderstorm day data from 722 meteorological stations in China from 1961 to 2013, we have conducted a statistical analysis on the characteristics of spatial and temporal distributions of thunderstorm days and its variation in recent 50 years ,and discussed the effect of East Asian summer mionsoon on the variation of annual awerage thunderstorm days in China. The results show that the thunder-storm region in China can be divided into four, i.e. northern China’s mid-thunderstorm, southern China’s multi-thunderstorm, Tibetan pla-teau multi-thunderstorm and northwestern China’s less-thunderstorm (hereinafter referred to as northern region, southern region, plateau re-gion and northwestern region, respectively). The thunderstorm days are the most in summer but the least in winter, while they are intermediate in spring and autumn, with more in spring than in autumn. In spring and winter most of thunderstorm days occur in the southern region, while in summer and autumn most of them are in the plateau region. The annual average thunderstorm days show a decreasing trend with some fluc-tuation in China in recent 50 years. The trend can be seen at the more than 97.9%of stations, and it is clearer in the southern region than in the northern region. Annual average thunderstorm days in the nationwide and four regions in China has a long oscillation period of 10-13 years and 18 years or so, but a short oscillation period of 4-8 years at different decades, which tends to be more since 2013. There is a clear positive correlation between summer monsoon intensity index and thunderstorm days in China from April to September, and the correlation co-efficient is 0.6589 which passes the test at the 0.001 significance level. The average thunderstorm day from April to September in the strong summer monsoon years is over 25%more than that in the weak ones. There is a significant positive correlation between the weakening of East Asian summer monsoon and the reduction of annual average thunderstorm days.%利用1961―2013年我国722个气象台站雷暴日资料，统计分析了我国雷暴日数的时空分布及其变化特征，同时探讨了东亚夏季风对我国年雷暴日数变化的影响。结果表明：我国雷暴区可分为北方中雷区、南方多雷区、高原多雷区和西北少雷区四个区域；夏季雷暴日数最多，冬季最少，春、秋季居中，春季比秋季多，冬春季雷暴主要发生在南方区，夏秋季主要发生在高原区。我国年平均雷暴日数在波动中总体呈减少趋势，有97.9%以上的台站年平均雷暴日数呈减少趋势，整体上南方区比北方区减少幅度要大。全国及各区年平均雷暴日数变化主要存在10～13 a和18 a左右的长周期振荡，同时在不同年代存在4～8 a短周期振荡。从2013年以来，我国及各区年平均雷暴日数处于相对较多时期。夏季风强度指数与全国4—9月平均雷暴日数存在较好的正相关，相关系数为0.6589，达0.001极显著水平；强夏季风年4—9月雷暴日数比弱夏季风年平均多25%以上。东亚夏季风减弱与我国年雷暴日数减少呈极显著正相关。