Abstract:
Based on the ERA-Interim reanalysis data and the theory of isentropic potential vorticity (IPV) and using methods of composite technology and dynamical diagnosis,climatic characteristics of cold vortexes over Northeast China in June as well as the important effects of diabatic heating on their formation and evolution were analyzed.The results show that climatic mean cold vortex over Northeast China forms in the upper troposphere at the middle latitudes,characterized by IPV strengthening from upward to downward and from the west to the east,which is closely related to variation of the atmospheric diabatic heating.Before cold vortex forms,diabatic heating at the upper levels is evidently strengthened,while as it forms,the local diabatic heating in the middle and lower troposphere rapidly enhances.Consequently,diabatic heating in the upper troposphere greatly determines the formation and development of cold vortex over Northeast China,and diabatic heating in the middle troposphere is the major reason to the delay of cold vortex over Northeast China.