Application Of The Environmental Instability Parameters To Numerical Simulation And Diagnostic Analyses Of Severe Convective Weather

Researches on severe convective weather prediction, including tornado, squall line, thunderstorm, become fatal tasks in meteorological field. With the development of numerical simulation and acquisition, foreign applications of the instability parameters assisting weather prediction improved. To know the environmental instability parameters and their character will undoubtedly be beneficial to severe weather forecasting. Three kinds of environmental parameters are introduced in this paper, inclusive of one concerned with CAPE, one concerned with wind shearing and other concerned with both CAPE and wind shearing.A mesoscale severe convective storm process with tornado and hails occurred on July 12 2004 in Nantong, Jiangsu Province and a squall line occurred on May 5 2005 in Fujian Province were analyzed and simulated in this paper by using conventional observational data and NCEP 1°×1° reanalysis data. Based on numerical simulation results, the parameters BCAPE, NCAPE, SRH, EHI, BRN and SWEAT Index etc. were calculated to discuss their applicability. The results showed that high CAPE and low SRH environment existed over Nantong and contrary over Fujian Area. The parameters and indexes were good indicators for the severe weather including these two severe storms. The parameters changed greatly during the course of severe convective weather. Specially, the indexes concerned with wind shearing, such as SRH, EHI and SWEAT agreed well with observation spatially, and indicated the occurrence of severe convective weather earlier. Wind shearing can affect severe convective weather greatly.