Dynamics of atmospheres with a non-dilute condensible component
Dynamics of atmospheres with a non-dilute condensible component
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具有非稀释可凝成分的大气动力学
DOI：
10.1098/rspa.2016.0107
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
F. Ding
中科院分区：
文献类型：
--
作者：
R. Pierrehumbert;F. Ding
最近发现的大量系外行星的特征多样性为地球物理流体动力学开辟了大量肥沃的新领域，特别是当流体流动与新型热力学、辐射传递或化学相结合时。在本文中，我们调查这些新的领域之一-大气的气候动力学与非稀释可凝结成分，定义为大气的可凝结成分的情况下，在某些层内的大气质量构成了相当大的一部分。非稀释动力学可以发生广泛的可冷凝物，一般适用于传统的可居住区的内外边缘附近，并与失控的温室现象。它也适用于各种各样的其他行星环境。我们首先提出了一些分析结果，开发了一些关键功能的非稀释大气，然后显示了如何在模拟中表现出这些功能的一般循环模型，适合处理非稀释大气。我们发现，非稀释的大气层有微弱的水平温度梯度，即使是快速旋转的行星，他们的环流主要是正压的。随着大气变得更加非稀释，可冷凝组分的相对湿度趋于100%，这对失控的温室阈值具有重要意义。非稀释大气表现出许多有趣的有组织的对流特征，对此还没有足够的理论认识。
The diversity of characteristics for the host of recently discovered exoplanets opens up a great deal of fertile new territory for geophysical fluid dynamics, particularly when the fluid flow is coupled to novel thermodynamics, radiative transfer or chemistry. In this paper, we survey one of these new areas—the climate dynamics of atmospheres with a non-dilute condensible component, defined as the situation in which a condensible component of the atmosphere makes up a substantial fraction of the atmospheric mass within some layer. Non-dilute dynamics can occur for a wide range of condensibles, generically applying near both the inner and the outer edges of the conventional habitable zone and in connection with runaway greenhouse phenomena. It also applies in a wide variety of other planetary circumstances. We first present a number of analytical results developing some key features of non-dilute atmospheres, and then show how some of these features are manifest in simulations with a general circulation model adapted to handle non-dilute atmospheres. We find that non-dilute atmospheres have weak horizontal temperature gradients even for rapidly rotating planets, and that their circulations are largely barotropic. The relative humidity of the condensible component tends towards 100% as the atmosphere becomes more non-dilute, which has important implications for runaway greenhouse thresholds. Non-dilute atmospheres exhibit a number of interesting organized convection features, for which there is not yet any adequate theoretical understanding.