The Trouble with Water: Condensation, Circulation and Climate
The Trouble with Water: Condensation, Circulation and Climate
复制标题
DOI：
10.1140/epjp/s13360-020-00493-7
复制
发表时间：
2020-06
期刊：
影响因子：
--
通讯作者：
G. Vallis
中科院分区：
文献类型：
--
作者：
G. Vallis
本文在基本层面上讨论了地球物理流体动力学和气候中与空气中水分的存在、它的凝结和潜热的释放有关的几个问题。我们的主要焦点是地球的大气层，但我们也讨论了这些问题可能如何在其他行星上表现出来，特别是在土卫六上，甲烷扮演着水的角色。地球物理流体动力学传统上关注于理解动力气象学和海洋学的基础上的最基本的问题。具有一点讽刺意味的是，按照惯例，这门学科主要考虑的是“干”流体，这意味着它不会过多地关注相变。从另一方面来说，这个主题通常被认为是枯燥的，因为它不考虑被认为与现实世界相关的问题，比如云或降雨，而这些问题通常是复杂的数值模型的领域。这些模型通常依赖于未解析过程的参数，这些参数可能工作得很好，但通常具有半经验基础。随之而来的基础和应用之间的二分法阻碍了取得既有科学理解的可靠基础又与地球气候相关的进展，特别是在水分方面。这种二分法还阻碍了在理解其他行星气候方面的进展，在这些行星上，观测不足以调整地球天气和气候模型所依赖的参数，需要更根本的方法。在这里，我们讨论关于水分问题的四个不同的例子：相对湿度和云量的确定；水蒸气的输送及其在全球变暖下可能的变化；潮湿的浅水方程和马登-朱利安振荡；以及其他行星上的水文循环。
This article discusses at a basic level a few of the problems that arise in geophysical fluid dynamics and climate that are associated with the presence of moisture in the air, its condensation and release of latent heat. Our main focus is Earth’s atmosphere, but we also discuss how these problems might manifest themselves on other planetary bodies, with particular attention to Titan where methane takes on the role of water. Geophysical fluid dynamics has traditionally been concerned with understanding the very basic problems that lie at the foundation of dynamical meteorology and oceanography. Conventionally, and a little ironically, the subject mainly considers ‘dry’ fluids, meaning it does not concern itself overly much with phase changes. The subject is often regarded as dry in another way, because it does not consider problems perceived as relevant to the real world, such as clouds or rainfall, which have typically been the province of complicated numerical models. Those models often rely on parameterizations of unresolved processes, parameterizations that may work very well but that often have a semiempirical basis. The consequent dichotomy between the foundations and the applications prevents progress being made that has both a secure basis in scientific understanding and a relevance to the Earth’s climate, especially where moisture is concerned. The dichotomy also inhibits progress in understanding the climate of other planets, where observations are insufficient to tune the parameterizations that weather and climate models for Earth rely upon, and a more fundamental approach is called for. Here, we discuss four diverse examples of the problems with moisture: the determination of relative humidity and cloudiness; the transport of water vapor and its possible change under global warming; the moist shallow water equations and the Madden–Julian Oscillation; and the hydrology cycle on other planetary bodies.