陕西省雷暴的气候特征

Climatic Characteristic of Thunderstorm in Shaanxi Province

利用陕西省78个代表站1961-2002年月雷暴日数资料和运用数理统计及旋转经验正交函数分解(REOF)等方法,对陕西雷暴的时空特征及其演变规律进行了诊断分析.结果表明:陕西省年平均雷暴日数为25.3天,呈现南北多、中部少的分布特点;全年中6～8月为雷暴集中期;近42年来雷暴的发生有逐渐减少的变化趋势.REOF分解将陕西雷暴异常划分为3个区,关中区雷暴频数为减少趋势,陕南区呈现陕南区呈现由多-少-多的变化趋势,陕北区为缓慢增多趋势.各区雷暴异常变化还存在年代际、年际差异.

Using the data of the thunderstorm days of 78 stations in Shaanxi province from 1961 to 2002 and applying the REOF analysis method, the basic climatic characteristics of thunderstorm in Shaanxi province are analyzed. The main results are as follows: The annual averaged days of thunderstorm in Shaanxi province are 25.3 days. Thunderstorm mainly occurs from June to August, and its seasonal distribution have the single peak characteristics. Analyses indicate that the general trend of the annual mean thunderstorm in Shaanxi have been reducing in the last 42 years.However, the thunderstorm frequencies under different geographical regions are different from each other.