低空西南急流与冷锋快速南移的关系

The Relationship between Southwesterly Low level Jet and Fast Southerly Movement Cold Front

该文提出了冷锋的不连续传播是引起冷锋快速南移的直接原因的观点，即主冷锋南侧的锋生及其发展代替了主冷锋。在南方的锋生过程中，西南低空急流起了重要作用，其作用表现在两个方面：（１）低空急流向北的暖湿输送；（２）急流北侧形成的低涡环流西侧的偏北气流有利于冷空气南下。这两股不同性质的气流交汇的结果引起了锋生。关于冬半年低空急流的形成，文中也作了初步的讨论。

It is suggested that uncontinuous propagation of cold front is the direct cause of fast southerly movement of cold fronts,i.e.,as a result of frontogenesis in the southern part of the cold front and its evolution,the new frontogenetical front takes the place of the cold front in north China.The southwesterly low level jet plays important roles in the frontogenesis process,these roles are:(1)northerly warm wet transportations in the low level jets;and (2) the jets can induce low vortices in the north of jets,and northerly air current of west of the vortices is favourable to southward movement of cold air mass.The result of interaction of the air currents which possess distinct property induces frontogenesis.The caues of the low level jets formation in winter are also preliminarily discussed.It shows that they are different from those in the summer.