3个演变过程不同的东北冷涡结构对比与降水强度差异的成因OA

Using ERA5 reanalysis data from European Centre for Medium-range Weather Forecasts(ECMWF),a comparative analysis was conducted on the thermal and dynamic structural characteristics of three selected Northeast Cold Vortices(NECVs)with different evolution processes,and the causes of differences in precipitation intensity were analyzed.The major results are as follows:three NECVs exhibited distinct surface system developments.NECV1 matured east of Lake Baikal,gradually weakened while moving eastward,with no obvious surface low-pressure system forming during 8-11 September 2021.NECV2 developed through the deepening of a low-level vortex and was accompanied by explosive cyclogenesis at the surface during 7-10 November 2021.NECV3 formed as Typhoon Maysak upper-level circulation merged into a cut-off vortex,with a transitioning extratropical cyclone at the surface during 2-4 September 2020.There are significant difference about structural thermal evolution and cold layer depth among NECVs with vary evolution processes.NECV1 maintained a barotropic cold core structure during its eastward moving,NECV2 evolved from a baroclinic cold core structure to a barotropic cold core structure,and NECV3 transited from a barotropic warm core structure to a barotropic cold core structure.Additionally,the center of the geopotential height and the depth of the cold layer during the mature stage differed among the three NECVs.About vorticity and dynamic structures,all three NECVs exhibited a rotational dynamic structure dominated by positive vorticity.However,differences existed not only in the vertical central height of the positive vorticity area,its distribution relative to the cold vortex axis,and the height of the strong wind belt along the cold vortex periphery,but also the distribution and intensity of the vertical upward motion areas.Under NECV conditions,the generation of heavy precipitation is closely related to the development of surface systems.About baroclinicity,surface cyclogenesis,and jet stream influence,during NECV evolution,strong baroclinicity in the thermal and pressure fields is conducive to surface cyclogenesis.The development of cyclone is related to the intensity and configuration of the Upper-level Jet(ULJ),the position of the cyclone relative to the ULJ,the establishment of the Low-level Jet(LLJ),and the coupling configuration between the ULJ and LLJ.The differences in moisture sources,transport pathways,and moisture transport and concentration mechanisms among the three NECVs result in the differences in precipitation intensity.