广东省1999—2013年雷电活动特征的分析

以1999—2013年广东省雷电定位资料作为数据来源,采用数理统计方法、Sql server数据库技术和GIS技术,统计分析雷电时空分布特征。研究表明,全省雷电活动频繁,规律性强,每年有数百万次雷电发生,具有明显的区域性特征。以广州为中心的珠三角区域和湛江局部地区雷电密度分布密集,粤东和粤西则分布相对稀疏,全省平均雷电密度为16.25次/(km2·年),其中广州最高,达30.96次/(km2·年),韶关最小,为9.52次/(km2·年);全省平均雷电流为25.29 k A,其中珠海最高,达33.7 k A,湛江最小,为22.3 k A;月分布主要集中在5—9月,占总数的89.5%,时段分布则在午后至傍晚13:00—19:00,占总数的62.0%。闪电以负闪为主,占93.01%,正闪占6.99%。

Analysis of Lightning Activity of Guangdong Province from 1999 to 2013

Based on the observations of a national base observation station at Dianbai County from 2006 to 2013, this paper analyzes the characteristics of the variation of acid rain in the county and studies the relationships between meteorological conditions and the acid rain. The results are shown as follows. For the eight years of acid rain studied, the mean value of pH is 4.51, the minimum is 2.92 and the monthly mean pH is between 4.0 and 5.3, with January having the highest acidity, 4.11. By seasonal distribution, winter is the season with most frequent occurrence of acid rain, followed in turn by autumn and summer. It is known from the monthly distribution over the eight years that acid rain frequency is higher in January to March and October to December, both more than 80%. Besides, the monthly mean pH value is generally in positive correlation with monthly mean rainfall. It is known by analyzing the relationships between acid rain intensity and rainfall intensity that the former first decreases and then increases with the increase of the latter. In Dianbai county, it is most likely to have acid rain when there is easterly wind. Wind speed and acid rain frequency are both unimodal. With the increase of wind speed, the likelihood for acid rain to happen first increases and then decreases gradually.