中国雷电事件的时空分布特征

Spatial and Temporal Characteristics of Thunderstorm in China

根据1970—2006年全国847站逐日雷暴日资料,统计分析了中国雷电事件的时空分布特征及雷电在发展阶段和消退阶段的路径变化。结果表明:全国雷电主要有4个多发区:南方区、高原区、北方区和新疆区;全国雷电日数呈下降趋势,高原区和南方区的下降趋势更明显;南方的雷电最早是3月份从江南中部往西往南辐射,然后再往北发展,高原的雷电由四川南部往北往西发展,而北方的雷电从华北东北部往东往南扩展。随着副高的季节性北跳三个区域的雷电在7月份连成一片,全国雷电范围达到最大,8月第2旬随着副高南撤各雷电区开始逐渐撤退,直到10月第1旬。全国雷电大都发生在4—9月午后到深夜(12—24时),其中15—17时和19—20时存在两个峰值,南方雷电发生时间最长,尤其是华南区雷电发生在3—9月,并有三个峰值,而北方区(包括新疆)雷电发生时间较短,主要集中在夏季,发生时段较晚,发生频次也明显偏低。雷电的时空分布及演变特征为雷电的落区预报提供了宏观的气候背景。

By using 1970 - 2006 observed thunderstorm data from 847 stations in China, the spatial and temporal characteristics of thunderstorm in China and the variation of thunderstorm track in development and attenuation phases were demonstrated. Results show that thunderstorm in China were mainly concentrated over 4 regions： south area, plateau area, north area and Xinjiang. Annual mean thunderstorm days decreased recent years, and the decreasing trend is obvious over south area and plateau area. Thunderstorms over south area were spread from the central part of south of Yangtze River to the westward and southward, and then to northward; thunderstorms of plateau stretched from south of Sichuan to the northward and westward; thunderstorms of north area stretched from the northeast of North China to eastward and southward. In July the thunderstorm of the above 3 areas connected together and the extension and frequency of thunderstorm in China reached maximum due to the seasonal shift of subtropical high toward the north. Thunderstorms began to withdraw along with the shift of subtropical high toward the south from the second ten-days of August to the first ten-days of October. Thunderstorms usually began at 12：00-24：00 from April to September with two maxima at 15：00- 17：00 and 19：00 -20： 00, and the duration of thunderstorm over south area, especially over South China, is longest from March to September with three maxima, while over north area, including Xinjiang, the duration is shorter concentrating in summer with later maximum time and lower frequency. Analysis of the spatial and temporal characteristics and evolution of thunderstorm in China provides a macroscopicaUy climatic background for the potential prediction of thunderstorm. The relationship between the evolution of thunderstorm and atmospheric circulation and system will be studied in the near future.