北京城区与郊区雷暴气候特征及其变化对比分析

利用1961～2007年北京雷暴资料，采用气候倾向率、多项式曲线拟合和Morlet小波分析方法，对北京城区与郊区雷暴气候特征及其变化趋势进行了对比分析。结果表明：1）北京地区雷暴具有明显的月和日变化特征，5月是突增期，9月是陡减期，7月为峰值期。2）初雷日期提前、终雷日期推后和雷暴期延长的趋势，都以城区最为明显。3）城区与郊区年雷暴日数有着截然相反的变化趋势。郊区年平均雷暴日数虽多，但年雷暴日数表现为波动式减少的趋势；城区年平均雷暴日数虽少，但年雷暴日数却呈现出波动式增加的趋势。城区雷暴日数增多趋势可能与城区增温效应以及相对湿度≥85％的日数增加有关；郊区雷暴日数减少可能与其相对湿度呈明显的下降趋势有关。4）城区与郊区年雷暴日数的变化具有多重周期性，其中16～18年的长周期和3～5年的短周期特别明显。

Comparison Analyses of Climate Characteristics of Thunderstorm and Its Variations between Urban and Rural Areas in Beijing

Using thunderstorm data from 1961 to 2007 in Beijing,statistical of tendency rate,polynomial curve fitting,and Morlet wavelet method,comparison analyses of the climate characteristics of thunderstorm and the trend of climate change were given.The results show that: 1)Thunderstorm occurring from March to November had obvious monthly variation and daily variation,which increased abruptly in May,decreased abruptly in September,and reached maximum in July.2)In contrast to the rural area,the urban area had more ...