非绝热加热对6月东北冷涡形成演变的影响及其可能机制

摘要

Based on the ERA-Interim reanalysis data and the theory of isentropic potential vorticity (IPV)and u-sing 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 forma-tion 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.%利用ERA-Interim再分析资料，基于等熵位涡理论，采用合成分析和动力诊断方法分析了6月东北冷涡演变过程的气候特征，探究非绝热加热对东北冷涡形成和演变的重要影响。结果表明：气候平均东北冷涡形成在中纬度对流层高层，其形成过程表现为等熵位涡“自上而下、自西向东”发展加强，其演变过程与大气非绝热加热的变化密切联系。在东北冷涡形成前，其上空的非绝热加热明显加强；而在东北冷涡形成后，局地对流层中下部非绝热加热迅速发展。可见，东亚中纬度地区的高空非绝热加热是东北冷涡形成和发展的重要因素，而东北地区对流层中部的非绝热加热则是东北冷涡减弱消亡的主要原因。