大气凝结水汽汇、凝结潜热作用与积云对流参数化  

VAPOR SINK AND LATENT HEAT OF CONDENSATION IN THE ATMOSPHERE AND THE PARAMETERIZATION OF CUMULUS CONVECTION

作　　者：辜旭赞[1] 张兵[1] 

机构地区：[1]中国气象局武汉暴雨研究所,武汉430074

出　　处：《气象学报》2006年第6期790-795,共6页Acta Meteorologica Sinica

基　　金：国家自然科学资金(40575053);湖北省科技攻关计划课题"GRAPES中尺度模式降水预报改进与业务应用研究"(2005AA308B01)。

摘　　要：从引入包含质量(水汽)源、汇的连续方程出发,重新推导出大尺度凝结降水和积云对流凝结降水之水汽汇起作用的热力学方程,从而重新给出气压、气温预报方程及地面气压与高空位势高度预报方程。发现,在此基础上,才能实现凝结3个作用:气块水汽质量流失与气压降低;气块虚温降低;加热气块;和通过大气运动方程,实现大气凝结潜热“热机”作功。这时,对于预报气压、气温场,积云对流参数化方案中的参数在凝结3个作用中保持一致。否则,通过积云对流参数化方案,虽可以近似实现对于预报气压和气温场的凝结3个作用,但不可能调好参数的降水物理特性及其时空分布特征。且对于静力模式预报地面气压和高空位势高度场,不可能实现上述的第一凝结作用。最后表明,当模式分辨率提高到只用降水显式方案、不再用积云对流参数化方案后,则必须引入包含水汽源、汇的连续方程。因在热带海洋面上的水蒸发过程,水汽进入大气将改变地面气压场,且蒸发潜热可分为内潜热(水汽内能)和外潜热(水汽压力能),内潜热立即成为大气热能的一部分,而外潜热直接对大气层作功,使得大气位能增加。文中研究了大气中的大尺度凝结降水和积云对流凝结降水对气压场与位势高度场的影响。一般积云对流参数化方案都已考虑内潜热对大气的加热作用,但还须考虑因凝结与降水造成地面气压场及高空位势高度场的变化,后者应是外潜热作用的结果。在上述研究过程中,必须引入考虑凝结作用的连续方程,且最终可以改变有降水(包括大尺度凝结降水和积云对流凝结降水)发生时的数值预报模式动力框架。Using the continuity equation containing the condensation-precipitation mass sink, we derived the new equation group of thermodynamic equation, and pressure and temperature prediction equations, in which the three effects of condensation within a air parcel, i. e, the lost of water vapor mass, the reduction of virtual temperature, and the warming of air parcel itself, can be simultaneously, really realized. Although the cumulus convection parameterization can be used to approximately realize the three effects of water vapor condensation in prediction pressure and temperature, it can＇t realistically describe the physical properties of air in precipitating process and their spatial/temporal distributions. If the hydrostatic model is used to predict surface pressure and geopotential height fields, then the above first effect of condensation can not be realized. Besides, it is also demonstrated that when the resolution of the prediction model becomes such high （about 1 km） that the cumulus convection parameterization is no longer necessary, then the continuity equation containing the sink and source of vapor must be used. In the evaporation process on the tropical sea surface, the entering into the atmosphere of the water vapor evaporated from sea surface will change the surface pressure field. The ev＇aporation latent heat may be divided into two parts： internal latent heat （internal energy of vapor） and external latent heat （pressure energy of vapor）, the internal latent heat immediately becomes a part of the thermal energy of the atmosphere, while the external latent heat directly does work against the ambient atmosphere, increasing the potential energy of the atmosphere. In this paper we study effects of large scale as well as cumulus convection condensation-precipitation on pressure and geopotential height fields. Generally, the cumulus convection parameterization scheme has taken account the heating effect of internal latent heat, but the changes of surface pressure and geopotential height f

关 键 词：质量源 连续方程 凝结潜热“热机” 积云对流参数化 

分 类 号：P426.6[天文地球—大气科学及气象学]