张家口地区雷暴气候统计特征分析

为了深入了解张家口地区雷暴日时空变化特征，为雷电灾害风险评估及防雷减灾工作提供依据，利用1960—2013 年近54 年该地区14 个地面气象观测站的雷暴观测资料，借助数理统计、线性拟合、气候倾向率等方法，对该区域雷暴日分布特征进行统计分析。结果表明：全市大部分区域处于“中雷区”范围，蔚县、怀安、尚义雷暴日数在40 天以上，达到“多雷区”级别；该地区平均年雷暴日大多数年份在30~40 天，年均雷暴日最多年为54.4 天，最少年为28.9 天；年代际分布呈现20 世纪60—70 年代间年均雷暴日缓慢减少，80 年代呈明显偏多，90 年代开始快速减少趋势；夏季雷暴最多，冬季无雷暴。雷暴日数月变化呈单峰抛物线型，其峰值位于7 月。6—10 月间，坝上地区各月月均雷暴日数均大于坝下地区。54年来历史最多月雷暴日数全区14 个观测站均出现在7 月；白天雷暴多于夜间。坝上地区13:00—16:00，坝下地区14:00—18:00 容易发生雷暴。坝上地区雷暴持续时间以＞60 min 的雷暴为多，坝下地区以30 min 以内的雷暴为主。坝上最早雷暴初日与最晚雷暴终日较坝下均有所提前，两区域雷暴初终日及持续期平均状况差异较小。

Analysis on Statistical Characteristics of Thunderstorm in Zhangjiakou

In order to understand the climatic characteristics of thunderstorm in Zhangjiakou region and provide scientific basis for the risk assessment and reduction of thunder and lightning disaster, the thunderstorm bservation data from the 14 ground meteorological stations in Zhangjiakou region in 54 years from 1960 to 2013 were statistically analyzed by mathematical statistics, linear fitting, climate trend rate method and so on. The results showed that: most of the counties in this region were in the moderate thunderstorm range, and Yuxian, Huai'an, and Shangyi county, thunderstorm days were more than 40 days, achieved multi-thunderstorm level. The average annual thunderstorm days in most years were between 30.0 and 40.0 days. They were up to the most of 54.4 days in 1990 and down to the least of 28.9 days in 1972. Decadal variations presented the characteristics of reducing-increasing-reducing again. There was an obvious seasonal thunderstorm, most in summer, no in winter. The monthly thunderstorm day in Zhangjiakou region presented a parabolic unimodal change, its peak value appeared in July. The monthly average thunderstorm days of Bashang area were more than that of Baxia area from June to October. Month with most thunderstorm day was July in 14 observation stations in 54 years. Thunderstorms occurred more during the day than at night, and mainly occurred from 13:00 to 16:00 in Bashang area and from 14 to 18:00 in Baxia area. Most thunderstorms maintained for more than 60 minutes in Bashang area and less than 30 minutes in Baxia area. Both the earliest and the latest day of thunderstorm of Bashang area occurred were ahead of that of Baxia, and there was little difference on the average conditions of beginning and ending of thunderstorms and their duration between the two areas.