Use of the Gibbs thermodynamic potential to express the equation of state in atmospheric models
Use of the Gibbs thermodynamic potential to express the equation of state in atmospheric models
复制标题
使用吉布斯热力学势来表达大气模型中的状态方程
DOI：
10.1002/qj.3020
复制
发表时间：
2017
影响因子：
8.9
通讯作者：
J. Thuburn
中科院分区：
文献类型：
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作者：
J. Thuburn
湿过程的热力学是复杂的，在典型的大气模式中进行了许多近似。然而，它们并不总是以一种自我一致的方式制造，这可能会导致虚假的来源或能量和熵的下沉。确保自洽的一种方法是从一个热力学势导出所有的热力学量，例如吉布斯函数。可以对吉布斯函数进行近似值；这些近似值由所有导出量以一种保证自洽的方式继承。通过一个半隐式、半拉格朗日垂直切片模式的发展及其在标准浮泡试验中的应用，论证了在大气模式中使用Gibbs函数的可行性。通过使用四种不同的状态方程运行测试用例，证明了该方法的灵活性，这些状态方程分别对应于干空气、饱和湿空气、伪不可压缩流体和不可压缩流体。最近提出的将干燥的完全可压缩情况和伪不可压缩情况统一起来的“混合”方程组也很容易适应。
The thermodynamics of moist processes is complicated, and in typical atmospheric models numerous approximations are made. However, they are not always made in a self‐consistent way, which could lead to spurious sources or sinks of energy and entropy. One way to ensure self‐consistency is to derive all thermodynamic quantities from a thermodynamic potential such as the Gibbs function. Approximations may be made to the Gibbs function; these approximations are inherited by all derived quantities in a way that guarantees self‐consistency. Here, the feasibility of using the Gibbs function in an atmospheric model is demonstrated through the development of a semi‐implicit, semi‐Lagrangian vertical slice model, and its application to a standard buoyant bubble test case. The flexibility of the approach is also demonstrated by running the test case with four different equations of state corresponding to dry air, moist air that is saturated, a pseudo‐incompressible fluid, and an incompressible fluid. A recently presented ‘blended’ equation set that unifies the dry fully compressible case and the pseudo‐incompressible case is also easily accommodated.