近35a山西飑线天气的时空分布特征及概念模型

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年～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16-17时飑线发生的概率最大；近35年山西飑线日数以3.6天/10年的速率减少；山西飑线的概念模型主要分为两类四型,两类主要是低涡类和西风槽类,四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；两类四型概念模型,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。

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

To reduce the damage of agriculture caused by the squall line weather, the information-baseSdata from 1979 to 2013 from Shanxi Meteorological Information Center and MICAPS data is used and statistical analysis of the squall line weather in Shanxi Province was done. The results show that: The spatial distribution characteristic presents that the days of squall line is more in the east than in the west of Shanxi Province. Squall line mainly occurred among April to September, the highest frequency of squall line appears in June to July. The appearance of squall line weather has obvious diurnalSvariationSfeatures and the largest incidence of squall line is during 16:00-17:00 o’clock. Days and stations of the squall line in Shanxi reduced with the rate of 3.6 days every 10 years nearly 35 years. There are four main types of conceptual models of squall line in Shanxi. They are respectively the model of low vortex with cold front, low vortex without cold front, westerly trough with cold front, and westerly trough without cold front. Four types of concept model are all combined with low-level cold or warm shear line. Which kind of severe convective weather will happen while the squall line transits depends on the humidity conditions of low layer. Short-time heavy rain will happen when the low level is matched with moist tongue, and gale and downbursts will happen when the low layer is controlled by dry tongue. When the depression of the dew point of low layer is greater than 6 ℃ and less than 11 ℃, it is often accompanied by thunderstorm and hail.