石家庄暴雪的天气学分型

Synoptic patterns of snowstorms in Shijiazhuang

利用石家庄气象站近58年(1955—2012年)地面降雪观测资料,通过普查近58年期间出现的22次暴雪天气过程,归纳出该地区暴雪天气概念模型,并统计回流降雪预报指标。结果表明:1近地面维持偏东风和中低层出现西南风是石家庄暴雪天气的最主要环流特征;2石家庄暴雪的天气概念模型主要有高压—倒槽型、高压底部型、低涡冷锋型3种,其中高压-倒槽型是当地出现暴雪的主要天气类型;3高压—倒槽型属典型的回流形势,其特点是当地东北方为高压场,西南方为低压倒槽,高低气压差带来偏东风,在高空西南气流的配合下,高低海平面气压场的气压差≥4hPa,可做为预报降雪的重要预报指标。

The current study utilized snow observation data from Shijiazhuang station from 1955 to 2012, investigating the 22 snowstorm weather processes during 58 years. Several synoptic patterns were clarified, which favored the formation and develop- ment of snowstorms during the winter season in Shijiazhuang, and predictive indicators in forecasting Shijiazhuang＇s winter snow- storm weather were counted. The results from Shijiazhuang were obtained as follows： @Close-to-the-ground, easterly winds and low-level, southwest winds were the uppermost circulation characteristics of the snowstorm atmosphere. @The synoptic patterns of snowstorms mainly included high pressure-inverted trough types, at the bottom of high pressure types, and low vortex cold front types. The high pressure^inverted trough type was the principle weather type that occurred during snowstorms. @The high pressure-inverted trough pattern was the typical backflow situation. Under this weather pattern, local northeast was the high pressure field and southwest was the low pressure-inverted trough. The high and low pressure difference formed easterly winds, and coordinated with the high altitude southwest jets when the pressure difference between the high and low sea level pressure fields was greater than or equal to 4 hPa, snow forecast could be considered.