Analysis on the Mesoscale Characteristics of a Severe Convection Process over Western Sichuan Plateau
Based on conventional observation data,regional automatic station data,Doppler weather radar products,FY4A satellite cloud images,NCEP 1°×1° reanalysis data and so on,the environmental conditions and mesoscale convective characteristics of a strong convective weather in Ganzi Prefecture on July 21,2016 were analyzed.Results are as follows:(1)The shear line of the plateau moved eastwards,accompanied by the diffusion of cold air in the middle and upper layers and the northward movement of warm and wet air in the lower layers.The combination of the systems made the whole layer form an unstable structure of"upper-layer-cold and the lower-lay-er-warm"and strong vertical wind shear,which was conducive to the occurrence of strong convection.(2)The typical MCS structure could be identified on the satellite cloud image,and its convective center strength TBB was below-70℃.The convective centers with TBB≤-70℃corresponded well with the strong convective weather area,which had a good indication for the forecast.(3)The strongest value of radar echo intensity could reach above 60 dBZ,and the maximum echo top height could reach above 16km.Weak mesoscale cyc-lones could be identified in the radial velocity diagram of radar.The maximum liquid water content accumulated vertically in the atmo-sphere exceeded 55 kg·m-2,which provided abundant water vapor conditions for the occurrence of heavy precipitation.
Western Sichuan PlateauStrong convectionMesoscale convective cloud clusterMonomer storm
NETL
NSTL
万方数据
