Potential Vorticity Analysis of Cold Air Activities during the East Asian Summer Monsoon
东亚夏季风时期冷空气活动的位涡分析

Using multi-scale analysis,several indicators of cold air activities during the East Asian summer monsoon (EASM) are compared,and the results show that potential vorticity (PV) is the optimal indicator in tracing cold air activities during EASM. The further study shows that it is best that the low-frequency oscillations of PV (20-80 day and 40-80 day oscillations) represent cold air activities. Then,the source and role of cold air during EASM are studied by use of the indicator,and the process and mechanism...