Abstract:

 Using the NCEP/NCAR reanalysis data with 1?×1? spatial resolution, meteorological data from regional automatic weather stations (AWS), FY-2D/2E satellite image and GPS/MET data, three severe convective weather events in different stages of Northeast China cold vortex on June 7 to 18, 2012 over Changchu area were diagnosed and compared. The results show that during the forming stage of Northeast China cold vortex, an isolated-deep-moist convection of meso-β-scale is triggered by the ascending branch of secondary circulation induced by coupled high/low jets. During the developing stage of Northeast China cold vortex, a convective system of meso-α-scale is triggered by invasion of dry-cold air from upper to middle and lower troposphere, so forms an upper dew point front at the same time. During the weakening stage of Northeast China cold vortex, a convective system of meso-β-scale is formed by the weakening of Northeast China cold vortex to an upper trough moving eastward, whose rear part is cold air above the large range of low-level warm and moist air, and surface meso-scale converges in the same time.

Key words:  Northeast China cold vortex, Severe convective weather, Meso-scale convective system