Diagnostic Analysis of a Southwest Gale Process at Zhaotong Airport

The extreme southwest gale weather process at Zhaotong Airport on March 19,2019 was analyzed by using observational data、conventional meteorological observation data and NCEP reanalysis data.The results show that:during this gale weather,the surface pressure field is a typical "high east and low west" ,and Zhaotong Airport is under the control of southwest airflow in front of the high air trough,the southwest jet stream over the airport provides a powerful force for the winds to guide and accelerate the movement of the surface atmosphere,which has a basic circulation background for generating southwest gale.The analysis of physical quantity field shows that the deep convergence movement in the upper layer causes the forced downdraft in the vertical direction,and the cold advection in the whole layer further strengthens the downdraft,which makes the momentum of the upper layer pass down,accelerates the airflow movement near the ground,and forms the strong wind.