雷暴天气是甘肃武威市多发的灾害性天气之一。利用1961~2010年武威市5个气象站雷暴资料，以及2001~2010年4~10月逐日NCEP再分析资料，分析了武威市雷暴天气的时空分布特征及变化趋势，并依据气流的南北配置方法对雷暴天气进行了环流分型。结果表明：受海拔高度和地形地势的影响，武威市雷暴具有明显的地域特征，南部天祝山区雷暴日数远大于其他各地，占雷暴总日数的40.6%。年际、年代际雷暴日数总体呈减少趋势，其中，天祝的减少趋势尤为显著，其递减率为-5.819 d/10 a，年雷暴日数的时间序列存在着7~8 a的准周期变化。一年内，6~8月是雷暴的高发期，雷暴日数占全年总日数的70.8%~78.6%。雷暴的日变化特征明显，12~22时为其多发时段，集中发生时段为13~17时，雷暴的平均持续时间为10~40 min。武威市雷暴天气环流形势可分为西北气流型、西南气流型和西风气流型3类。其中，西北气流型，高空冷平流深厚且移速缓慢，最有利于强对流天气发生，雷暴发生比例最高；西南气流型，系统过境后无残余的冷空气滞留，不利于强对流天气发生，雷暴发生比例最低；西风气流型，高空低涡位置较偏北，冷空气较强，较利于强对流天气发生，雷暴发生比例相对较高。%Thunderstorm is one of the most frequently disastrous weather in Wuwei of Gansu Province. The temporal and spatial distri-bution characteristics and changed trend of thunderstorm weather were analyzed by using the statistical methods based on thunderstorm data from 5 meteorological stations in Wuwei city during 1961-2010,firstly. Combined the daily NCEP reanalysis data with 6 h tem-poral and 1° × 1° spatial resolution from April to October during 2001 -2010,the circulation pattern of thunderstorm weather were summarized through north-south airflow configuration. Results showed that the spatial distribution of thunderstorm weather in Wuwei was regionally obvious due to the altitude and topography,and the thunderstorm days in Tianzhu of southern mountain area was far more than those in other parts,which accounted for 40. 6% of the total thunderstorm days during 1961 -2010. The annual and decadal changes of thunderstorm days appeared declining tends on the whole,the declining trend in Tianzhu was most significant,and the cli-matic linear tendency was -5. 819 d/10 a. The quasi-period of thunderstorm days in Wuwei was seven to eight years. The thunder-storm in Wuwei mainly occurred from June to August,which accounted for 70. 8% to 78. 6% of the annual total thunderstorm days. Additionally,the daily changes of thunderstorm weather in Wuwei were significant,mainly occurred from 12:00 to 22:00,especially from 13:00 to 17:00,and the average durations were 10 to 40 minutes. Regional characteristic of thunderstorm weather was very obvi-ous,and the thunderstorm days reduced rapidly with the increase of thunderstorm station numbers. The circulation pattern of thunder-storm weather was divided into three categories in Wuwei city,i. e. northwest airflow,southwest airflow and westerly airflow types. To the thunderstorm with northwest airflow type,the cold advection on upper level was deep and slow-moving,which was beneficial to the occurrence of strong convective weather,the proportion of thunderstorm was the most. The cold air didn’t remain after the weather system passed through Wuwei for the southwest airflow type,which wasn’t conductive to the occurrence of strong convective,the pro-portion of thunderstorm was the least. The location of the upper vortex was to the north and the cold air was stronger for the westerly air-flow type,which was more advantageous to strong convective weather occurrence,the proportion of thunderstorm was relatively higher.
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