E_(CAP)等环境参数在强对流天气分析中的应用

Application of Environmental Parameters E_(CAP) and I_(EH) to the Analyses of the Severe Convective Weather

引入大气热力学变量密度温度Tρ,采取与实际大气较为相符的可逆饱和湿绝热抬升过程,利用MM5V3.5模式输出资料,计算了对流有效位能ECAP。在此基础上,介绍了能量螺旋度指数IEH。分析了2003年7月江淮梅雨暴雨等强对流天气发生过程中对流有效位能ECAP及能量螺旋度指数IEH的量值变化。结果表明:ECAP、IEH等参数对强风暴的发生发展有一定的指示作用,值得在业务工作中推广应用。

This paper discusses a approach of computing the ECAP in detail, by adopting me MMSV3.5 output data,introducing an atmospheric thermodynamic variable,density temperature Tp, and according to the reversible saturated moist adiabatic process in the environmental atmosphere. Based on this, the energy-helicity parameter IEH is introduced. Besides, through analyzing the value variations of the ECAe and IE, parameters in the “03.7 ”Jianghuai Meiyu period severe convective process,it is found that ECAP and IEH parameters are usefull in the prediction of the severe storm＇s occurrence and development, and worth noting in operational predictions.