近35年山西飑线天气的时空分布特征及概念模型

Squall Line Weather in Shanxi Province:Spatial and Temporal Distribution Characteristics and Conceptual Models

为减少飑线天气对农业生产带来的影响,利用山西省气象信息中心1979—2013年信息化产品资料和MICAPS数据资料,对发生在山西境内的飑线进行统计分析。结果表明:山西境内飑线日数具有东部多于西部的空间分布特征;飑线主要发生在4—9月,其中6—7月出现的频次最高;飑线出现时间具有明显的日变化特征,其中16:00—17:00飑线发生的概率最大;近35年山西飑线日数以3.6天/10 a的速率减少;山西飑线的概念模型主要分为2类4型,2类主要是低涡类和西风槽类,4型分别为低涡加冷锋型、低涡无冷锋型、西风槽加冷锋型、西风槽无冷锋型;2类4型概念模型,低层均配合有冷式或暖式切变线;飑线过境时伴随的强对流天气取决于低层的湿度条件,当低层有湿舌相配合时常伴有短历时强降水天气,当低层被干舌控制时常伴有雷暴大风或下击暴流等强对流天气,当低层的温度露点差大于6℃且小于11℃时常伴有雷雨大风和冰雹等强对流天气。

To reduce the damage caused by squall line weather to agricultural production, the statisticalfeatures of squall line weather in Shanxi Province was analyzed based on information products and MICAPSdata of 1979-2013 from Shanxi Meteorological Information Center. The spatial distribution indicated that thedays of squall line weather in the east of Shanxi Province was more than that in the west; squall line mainlyoccurred during April to September, and the highest frequency of squall line was from June to July. There wasan obvious diurnal variation of squall line weather, and the largest probability of squall line occurred at 16：00to 17：00; the rate of squall line reduced by a rate of 3.6 d/10 a in the 35 years. There were two kinds and fourmain types of conceptual models of squall line in Shanxi, the two kinds were low vortex and westerly trough,and the four types were low vortex with cold front, low vortex without cold front, westerly trough with cold frontand westerly trough without cold front. The two kinds and four types of conceptual models were allaccompanied with low-level cold or warm shear line; the severe convective weather depended on the humidityin the low layer when squall line passed, short-time heavy rain occurred when the low level matched with moisttongue, gale and downburst occurred when the low layer was controlled by dry tongue, when the depression ofthe dew point was greater than 6℃ and less than 11℃, thunderstorm and hail occurred.