Comparative analysis of the typical cold processes influenced by Kunming quasi-stationary front

Using the ground and conventional radiosonde data and NCEP/NCAR 1°×1°reanalysis data,three typical cold precipitation process influenced by Kunming quasi-stationary front were comparative analyzed in the circulation situation,the quasi stationary front to maintain and dissipation,the precipitation phase changes and other aspects.The results showed that in the high latitudes at 500hPa,the establishment of East Asian Trough and development of ridge behind trough in Baikal Lake to Ural were typical circulation situation occurred cold wave weather in Yunnan.In the high latitude circulation,blocking situation in the presence or absence had a direct relationship in maintaining and dissipation quasi-stationary in the process of cold wave weather.If there was no blocking situation or maintaining,the beginning and the end of the cold weather process was caused by quasi-stationary front westward and back.Accompanied by water vapor condition,precipitation phase was depended on cold air strength and local altitude.The critical judgment indicators of precipitation phase,which were 0℃ layer height(H0) was less than or equal to 260dagpm and potential height difference between 500hPa and 700hPa(H500~700)was less than or equal to 261dagpm had good corresponding relationship with snow area.Due to Yunnan complex terrain,H0 and H500~700 were used in low altitude areas to judge precipitation phase,according to the needs of the local altitude correction.