The climate time scale in the approach to radiative‐convective equilibrium
The climate time scale in the approach to radiative‐convective equilibrium
复制标题
辐射对流平衡方法中的气候时间尺度
DOI：
10.1002/jame.20049
复制
发表时间：
2013
影响因子：
6.8
通讯作者：
K. Emanuel
中科院分区：
文献类型：
--
作者：
T. Cronin;K. Emanuel
本文讨论了表面边界条件(固定表面温度与相互作用表面温度)对辐射-对流平衡(RCE)的长时间尺度逼近的重要性。利用一个简单的地气相互作用的线性化双变量模式，我们得到了τC的解析表达式，它是一个长的气候松弛时间尺度，即使在地表热容为零的极限情况下，它也比Tompkins和Craig(1998B)的任何一个混合时间尺度都要长得多。结果表明，τC的大小是大气与表面耦合的内在属性，而不仅仅是表面热惯性的结果。当表面热容较低时，由于湿气对大气有效热容的影响，τC可能会比预期的长几倍。我们还表明，在表面温度和表面热容的范围内，τC的理论表达式可以很好地预测具有全物理特性的单柱模型中的最佳指数弛豫时间尺度。
In this paper, we discuss the importance of the surface boundary condition (fixed versus interactive surface temperature) for the long time scale of approach to Radiative‐Convective Equilibrium (RCE). Using a simple linearized two‐variable model for surface‐atmosphere interaction, we derive an analytic expression for τC, a long climate relaxation time scale that remains well defined and much longer than either mixing time scale of Tompkins and Craig (1998b), even in the limit that the heat capacity of the surface vanishes. We show that the size of τC is an intrinsic property of the coupling between the atmosphere and surface, and not a result of the thermal inertia of the surface alone. When the surface heat capacity is low, τC can be several times longer than expected, due to the effects of moisture on the effective heat capacity of the atmosphere. We also show that the theoretical expression for τC is a good predictor of best fit exponential relaxation time scales in a single‐column model with full physics, across a range of surface temperatures and surface heat capacities.