ANALYSES OF HEAVY RAINSTORM IN WARM SECTOR UNDER THE INFLUENCE OF THE LOW-PRESSURE SYSTEM OF QINGHAI-XIZANG PLATEAU

YANG Kang-quan; LU Ping; ZHANG Lin

doi:10.16032/j.issn.1004-4965.2017.03.012

Abstract：An analysis of the meso-convective system in a heavy rain event on 30 to 31 July 2014 in the Sichuan basin is performed by using routine observational data,ground intensive observational data,FY-2E satellite observational data,Doppler radar data and NCEP/NCAR 1 °× 1 ° reanalysis data.(1) There is good correlation between the heavy precipitation and the meso-scale convergence line (MCL):the MCL occurred an hour earlier than the heavy precipitation,which was mainly within the weak cold air of the boundary layer on its left side of the MCL and moved with it.(2) High unstable energy,high low-level humidity,a low lifting condensation level and a deep wet layer were very beneficial to the occurrence of the heavy rain.And adequate water vapor is transported to the heavy rain area and then provided good moisture conditions for the maintenance of the heavy rain.(3) The positive vorticity advection made the low-level low-pressure develop and vertical movement strengthen,and triggered convective activity in the eastward-going process of the plateau vortex,which was the exciting mechanism of heavy rainfall.And the diabatic heating released by rainfall condensation played a feedback role in the maintenance of the heavy rain.