Diagnostic Analysis on a Regional Rainstorm Weather in North-central Henan Province

[Objective] The research aimed to analyze a regional rainstorm weather process in north-central Henan Province.[Method] Based on the conventional meteorological observation data and the rainfall data of Henan Meteorological Observatory,the atmospheric thermodynamics and dynamics diagnosis analysis on a rainstorm weather process in north-central Henan Province on July 19,2010 was carried out.The characteristics of physical quantity field and the evolution of weather situation in north-central Henan Province when the rainstorm happened were studied.[Result] West Pacific subtropical high strengthened to extend westward.The dynamic lifting of low vortex at the middle and low layers and the strong water vapor transportation of southwest low-level jet caused the regional rainstorm weather process in north-central Henan Province.The diagnosis results of physical quantity showed that the deep moisture layer and the sustained water vapor convergence provided the plentiful water for rainstorm.The advection center of positive vorticity developed and spread from northwest to southeast,which was favorable for the development of vertical movement.The structure maintenance of positive vorticity at the middle and low layers and negative vorticity at the middle-upper level provided the power condition for the rainstorm generation.The pumping and suction effect of convergence at the middle and low layers and divergence at the high layer was favorable for the strengthening of vertical ascending motion at the low layer.The lifting effect of dew point front at the middle and low layers triggered the release of unstable energy.The confrontation of warm and cold air currents was one of the important reasons for the regional rainstorm.TBB characteristic analysis showed that TBB was from-60 to-50 ℃ in north-central Henan Province in the whole strong precipitation time,and the moving speed was equal to that of southwest vortex.The low value belt of TBB corresponded with the rainstorm occurrence zone in Henan,and the minimum value center of TBB was basically consistent with the strongest centre of precipitation.[Conclusion] The research provided the scientific basis for the short-term forecast of rainstorm.