山西省雷暴天气变化的气候特征分析

掌握山西省雷暴天气的气候变化特征，可以为该区域灾害性天气的预报预测提供参考依据，更有利于科学地指导工农业生产，达到趋利避害的目的。基于1960—2010年山西省71个国家观测站的雷暴资料，通过求线性趋势、滑动t检验、小波分析等气候统计方法，对山西省雷暴天气的时间和空间变化特征进行详细分析。结果表明：山西雷暴总日数分布呈东北多、西南少的格局；1960—2010年71站雷暴总日数变化总体呈下降趋势，无明显的周期性和突变性。山西大部分站点年雷暴日数呈下降趋势，年雷暴日数呈增加趋势且通过显著性检验的站点仅有4个，主要分布在忻州市的西北部。夏季6—8月是雷暴的高发期，约占全年雷暴的76%；4—5月、9—10月出现的雷暴约占24%；11—3月雷暴发生率很小。各月雷暴日数的空间分布特征不尽相同。3—4月雷暴日等值线由纬向转向径向，呈北少南多、西北少东南多的格局；5—6月雷暴日等值线主要以径向分布为主，呈东北多、西南少的格局；7—10月主要以纬向分布为主，呈北多南少的格局；11—2月雷暴日很少，空间分布特征不明显。雷暴过程的日变化显现80%以上的雷暴过程开始在12—20时，结束在13—21时。各时次结束的雷暴次数变化曲线呈现出副峰型，主峰点在16—17时，副峰点突增在20—21时，21—22时陡降。约60%的雷暴持续时长不超过1 h；约39%的雷暴持续时长在2~6 h；1%的雷暴会持续6~19 h；超过19 h的雷暴基本上没有。

Analysis of Climatic Characteristic of Thunderstorm Weather Variations in Shanxi Province

To master climatic characteristic of thunderstorm weather variations in Shanxi Province can provide reference resources for meteorological forecast and industrial and agricultural production. The author carried out the study by using observation data of 71 stations in Shanxi Province from 1960 to 2010 based on statistics methods, such as liner trend, slide test and wavelet analysis. The results showed that thunderstorm days were more in the northeast and fewer in the southwest. The total thunderstorm days of 71 stations presented a declining trend from 1960 to 2010 without remarkable periodicity and mutability. The annual thunderstorm days at most stations had a declining trend, only 4 stations in the northwest of Xinzhou City had an increasing trend. Thunderstorm mainly occurred from June to August in summer, and accounted for 76% of the total number of thunderstorms in a year, while thunderstorm occurring from April to May and from September to October accounted for 24% of the total, there were very few thunderstorm days from November to March. The spatial distribution characteristics of monthly thunderstorm days were different. Monthly thunderstorm days were more in the south and fewer in the north in March, while more in the southeast and fewer in the northwest in April, more in the northeast and fewer in the southwest form May to June, more in the north and fewer in the south form July to October. The daily variation trend of thunderstorms is similar to parabola, 80% thunderstorms started in 12:00-20:00 and ended in 13:00-21:00. The ending variation curve had double peaks, one peak in 16:00-17:00, the other in 20:00-21:00. Thunderstorms lasting for less than an hour accounted for 60%, 2-6 hours for 39%, 6-19 hours for 1%, very few for more than 19 hours.Key words: thunderstorm; variation characteristic; climate