Abstract: Based on the equivalent black body temperature at the cloud top derived from FY-2G and the NCEP (National Centers for Environmental Prediction) reanalysis data with resolutions of 1°×1°,a sustained heavy rain in Yangtze-Huaihe river basin on June 16-17,2015 was analyzed.The results show that the intensity of this precipitation is essentially consistent with the evolution of mesoscale convective vortex (MCV) and the southwest jet.The MCV is triggered together by the latent heat release induced by the organized development of convection and the low-level convergence and upper-level divergence.The MCV extends from the lower troposphere to 250 hPa,and the strongest center for vorticity is at the middle-low level of the troposphere.During the mature stage,mesoscale convective system (MCS) can help to stimulate updraft and is a benefit to transport heat and water vapor because the convergence zone of wet Q vector corresponded to the center of positive vorticity,which promoted the development of MCV.The horizontal advection at the middle-lower level contributes negatively to the vorticity during the whole MCV stage.The formation and development of MCV is determined by the horizontal convergence and divergence.Ascending motion of the vortex has a direct impact on the vertical transportation of vorticity and further influences on the development of the vortex in the vertical.

Key words: Mesoscale convective vortex (MCV), Mesoscale convective system (MCS), Wet Q vector, Black body temperature (TBB)