“等熵思维”到“等熵位涡思维”回顾与讨论

摘要

等熵位涡守恒与中纬度斜压扰动发展之间的诊断关系可用于对气旋发生发展的预报，并作为理解水汽图像的动力学场而在业务上使用。“等熵位涡思维”建立在等熵面分析的“等熵思维”基础上。本文首先依据基础的动力学理论，对等熵面上物理量场的动力学解释和业务应用作回顾和讨论，内容包括：等熵面随高度分布特征、等熵坐标中的垂直速度场、等熵面上水汽输送解释、等熵面上高空急流和锋区的特征等。其次，通过与等熵面物理量场分析和斜压二层模式准地转垂直运动方程的比较，着重回顾和讨论等熵位涡面上的物理量场和业务应用，内容包括：对流层顶定义及其温压湿分布特征、对流层顶等熵位涡面上急流和锋区的特征、对流层顶等熵位涡面上的垂直速度场、“等熵位涡思维”与气旋发展及位涡、水汽图像在改进数值预报模式中的作用等。%The diagnosis relationship between isentropic potential vorticity conservation and baroclinic dis-turbance development has been used in forecasting cyclone development and understanding the dynamic fields of water vapor imagery.“Isentropic potential vorticity thinking”is based on isentropic thinking of isentropic analysis.This paper first reviews and discusses dynamic interpretation and operational applica-tion of isentropic physical fields according to the basic principles of atmospheric dynamics.The contents include isentropic surface distribution with height,vertical velocity in isentropic coordinates,moisture transport on isentropic surface,upper-level fronts and jet stream characteristics on isentropic surface etc. Then,the physical fields and operational applicatoin on isentropic potential vorticity surface are discussed emphatically by comparing with physical fields on isentropic surface and quasi-geostrophic vertical motion equation on baroclinic two-layer model.The contents contain the definition of tropopause and its tempera-ture,pressure and humidity distribution,fronts and jet stream characteristics on tropopause isentropic po-tential vorticity surface,vertical velocity on tropopause isentropic potential vorticity surface,cyclone de-velopment and potential vorticity in accordance with “isentropic potential vorticity thinking”,and how to improve numerical weather prediction model by using water vapor imagery etc.