Trimodal cloudiness and tropical stable layers in simulations of radiative convective equilibrium
Trimodal cloudiness and tropical stable layers in simulations of radiative convective equilibrium
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辐射对流平衡模拟中的三峰云量和热带稳定层
DOI：
10.1029/2007gl033029
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发表时间：
2008
影响因子：
5.2
通讯作者：
Graeme L. Stephens
中科院分区：
文献类型：
--
作者：
D. Posselt;S. C. Heever;Graeme L. Stephens
本文利用一个大范围云系分辨率数值模式，对处于辐射对流平衡的热带环境进行了研究。在对热带温暖海洋(特别是热带西太平洋)对流活动期的观测研究中，我们发现了一种与三个不同稳定层的存在密切相关的三峰云结构，其中包括一个位于零摄氏度附近的显著稳定层。此外，模拟还显示了三个独立的大尺度纬向翻转环流，其中两个环流位于信风逆温层上方，并被冰冻水平稳定层隔开。在平衡状态下，与冻结和融化过程相关的潜热释放与水汽转变的潜热释放相比相形见绌，模拟结果表明，在零度以上存在长波辐射冷却的情况下，这种稳定层可以通过下沉来维持。
In this paper, we examine the tropical environment at radiative convective equilibrium using a large‐domain cloud system resolving numerical model. As in observed studies of convectively active periods over warm tropical oceans (in particular the tropical western Pacific), we find a trimodal cloud structure that is closely associated with the presence of three distinct stable layers, including a prominent stable layer located near the zero‐degree Celsius level. In addition, the simulation exhibits three separate large scale zonal overturning circulations, with two of these circulations located above the trade wind inversion and separated by the freezing level stable layer. At equilibrium, latent heat release associated with freezing and melting processes is dwarfed by that of vapor transitions, and simulation results suggest that this stable layer can be maintained by subsidence in the presence of longwave radiative cooling above the zero‐degree level.