豫西南地区雷暴时空变化特征

Spatiotemporal Variation of Thunderstorm in Southwestern Henan

利用豫西南地区30个观测站55年的雷暴日观测资料,通过数理统计、小波分析和经验正交分解等方法,分析了豫西南地区雷暴日随时间的变化规律及空间分布特征.结果表明:豫西南地区雷暴日年际变化幅度较大,且阶段变化较为明显,雷暴日数呈逐年减少状态,一年中夏季雷暴最多;20世纪60年代至21世纪初,存在着8年左右的短周期和17～19年的长周期;全区雷暴异常变化整体较为一致,受气候特征影响,雷暴日变化以秦岭-淮河线为界有南北差异,还存在着局地变化特征.

Using the observational thunderstorm data of 30 stations in southwestern Henan province during 55 years, the spatiotemporal variation of thunderstorm days in southwestern Henan province are analyzed by means of mathematical statistics, the wavelet analysis and the empirical orthogonal function method. The results indicated that： The inter-annual variation range is bigger and stage change is more obvious, the numbers of thunderstorm days are de- creasing and mostly occur in summer. From 1960s to the early 21st century, there are 8 years short period and 17 - 19 years long period. The anomaly variation of thunderstorms in whole area are consistent, under the influence of climate characteristics, the thunderstorm days change has the north-south differences taking the Qinling Mountains-Huaihe line as a boundary, and meanwhile exist the local features.