适用于中尺度系统研究的位涡方程

本文通过推导绝热、无摩擦大气方程组，讨论了新方程组的特点；新方程组中，位温 显式出现在动量方程中，有利于探讨倾斜的等熵面（等位温面）对中尺度系统发生和发展的影响。进一步，利用此新方程组，推导出适用于中尺度系统研究的新的位涡方程，新位涡方程突出的特点是，与中尺度系统发生、发展密切相关的散度项显式出现在方程的右端；这为研究中尺度系统演变过程中，辐合、辐散效应对系统位涡收支的影响、进而研究中尺度系统发生、发展的热、动力学过程提供了方法。

A Modified Potential Vorticity Equation for Mesoscale Systems

A new set of atmospheric equations is derived in an adiabatic, and frictionless atmosphere, and the characteristics of the new equations are discussed. The new set of equations is useful in the evaluation of the potential effect of slantwise isentropic surfaces on the evolution of mesoscale systems since the potential temperature is included explicitly in the dynamic equations of the new set of equations. Further, by using the set of equations derived above, a modified potential vorticity equation more suitable for the study of mesoscale systems is developed, in which the term of divergence is involved explicitly on the right hand side. The new potential vorticity equation can be used in the study of the effect of divergence on the budget of potential vorticity and further in the discussion on the dynamic and thermodynamic processes of mesoscale systems.