Internal variability in a coupled general circulation model in radiative‐convective equilibrium
Internal variability in a coupled general circulation model in radiative‐convective equilibrium
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DOI：
10.1002/2017gl073658
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发表时间：
2017-05
影响因子：
5.2
通讯作者：
D. Coppin;S. Bony
中科院分区：
文献类型：
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作者：
D. Coppin;S. Bony
使用指定的海面温度（SST）在非旋转辐射对流平衡（RCE）中运行的数值模型表明，对流可以自发地聚集成干燥和潮湿的区域，并且对流聚集倾向于随温度增加而增加。使用耦合到海洋混合层的大气环流模式，我们表明，在RCE耦合的海洋-大气系统表现出一些内部的变化。这种变化是由平均表面温度、SST梯度和对流聚集之间的相互作用引起的，其时间尺度与海洋混合层的深度成正比。对于10 m以上的海洋层，对流聚合的变化发生在年际时间尺度上，并且对流聚合的变化与表面温度的变化几乎是异相的。耦合的RCE框架可能有助于理解热带海洋-大气系统的某些内部变率模式，如厄尔尼诺南方涛动。
Numerical models run in non‐rotating radiative‐convective equilibrium (RCE) using prescribed sea surface temperatures (SSTs) show that convection can spontaneously aggregate into dry and moist areas, and that convective aggregation tends to increase with temperature. Using a general circulation model coupled to an ocean mixed layer, we show that in RCE the coupled ocean‐atmosphere system exhibits some internal variability. This variability arises from the interplay between mean surface temperature, SST gradients and convective aggregation, and its timescale is proportional to the depth of the ocean mixed layer. For an ocean layer deeper than 10 m, the variability occurs at the interannual timescale, and variations of convective aggregation are almost out of phase with those of surface temperature. The coupled RCE framework might be relevant to understand some internal modes of variability of the tropical ocean‐atmosphere system such as El Niño Southern Oscillation.