Thermodynamic Consistency of the Anelastic Approximation for a Moist Atmosphere
Thermodynamic Consistency of the Anelastic Approximation for a Moist Atmosphere
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DOI：
10.1175/2007jas2475.1
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发表时间：
2008-08
影响因子：
3.1
通讯作者：
O. Pauluis
中科院分区：
文献类型：
--
作者：
O. Pauluis
摘要 本文的主要目标是验证滞弹性近似对于具有复杂状态方程的流体（例如潮湿空气或海水）的使用。非弹性近似基于可压缩流体运动方程在密度方面的主阶展开。其在大气流动中的应用基于将相变视为外部能源的干框架。然而，浑浊的空气更准确地描述为两相流体，其中冷凝水和水蒸气处于热力学平衡。热力学平衡将描述湿空气热力学状态所需的状态变量数量减少到三个，并导致饱和点状态方程的偏导数不连续。此处通过将大气密度视为湿绝热参考剖面的小扰动，并使用 mo...
Abstract The primary goal of this paper is to validate the use of the anelastic approximation for fluids with a complex equation of state such as moist air or seawater. The anelastic approximation is based on a leading-order expansion of the equations of motion for a compressible fluid in terms of density. Its application to atmospheric flows has been based on a dry framework that treats phase transitions as an external energy source. However, cloudy air is more accurately described as a two-phase fluid in which condensed water and water vapor are in thermodynamic equilibrium. Thermodynamic equilibrium reduces to three the number of state variables necessary to describe the thermodynamic state of moist air, and leads to a discontinuity in the partial derivatives of the equation of state at the saturation point. A version of the anelastic approximation for a moist atmosphere is derived here by considering the atmospheric density as a small perturbation from a moist-adiabatic reference profile, and using mo...