2009年造成广东深秋一次急降温冷空气的特点

The Analysis of Cold Air Process with Sharp Temperature Drop in Guangdong in Late Autumn 2009

分析2009年11月中旬广东入秋以来最强的一次冷空气的环流形势,结果表明,此次冷空气属于横槽转竖型,乌拉尔山阻塞高压稳定维持使得冷空气在中高纬堆积,横槽转竖后引导下来的冷空气在南岭山脉受到阻挡。分析冷空气的垂直结构发现,本次冷空气较为浅薄,堆积发生在850hPa以下,弱冷空气经过长时间堆积形成较强冷空气,冷空气带来的阴雨天气使得降温以平流降温为主。

Guangdong suffered the strongest cold air process in the early November, 2009. This process had two characteristics of earlier outbreak and stronger intensity than normal. The result of circulation situation analysis shows that, the process followed the pattern of transverse trough downswing ： the cold air accumulated in the areas of middle - high latitude due to the stable blocking high in Ural Mountain, then led by downswing of transverse trough, and finally blocked in the north of Nan - ling Mountain. The vertical structure analysis of cool air mass reveals itself to be a shallow system no higher than the 850 - hPa level but becoming stronger after accumulation. The cloudy and rainy weather also means that the sharp temperature drop mostly result from the cold advection.