Purpose of Review

We review our understanding of mechanisms underlying the response of (sub)tropical clouds to global warming, highlight mechanisms that challenge our understanding, and discuss simulation strategies that tackle them.

Recent Findings

Turbulence-resolving models and emergent constraints provide probable evidence, supported by theoretical understanding, that the cooling cloud radiative effect (CRE) of low clouds weakens with warming: a positive low-cloud feedback. Nevertheless, an uncertainty in the feedback remains. Climate models may not adequately represent changing SST and circulation patterns, which determine future cloud-controlling factors and how these couple to clouds. Furthermore, we do not understand what mesoscale organization implies for the CRE, and how moisture-radiation interactions, horizontal advection, and the profile of wind regulate low cloud, in our current and in our warmer climate.

Summary

Clouds in nature are more complex than the idealized cloud types that have informed our understanding of the cloud feedback. Remaining major uncertainties are the coupling of clouds to large-scale circulations and to the ocean, and mesoscale aggregation of clouds.

中文翻译：

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当前和温暖气候下亚热带海洋的边界层云和对流

审查目的

我们回顾了对（亚）热带云对全球变暖的响应机制的理解，重点介绍了挑战我们理解的机制，并讨论了解决这些挑战的模拟策略。

最近的发现

湍流解析模型和涌现约束为理论理解提供了可能的证据，即低云的冷却云辐射效应（CRE）随着变暖而减弱：正向低云反馈。尽管如此，反馈的不确定性仍然存在。气候模型可能不足以表示不断变化的海温和环流模式，这决定了未来的云控制因素以及这些因素如何与云耦合。此外，我们不了解中尺度组织对CRE意味着什么，在当前和更温暖的气候中，湿度辐射相互作用，水平对流和风廓线如何调节低云。

概要

自然界中的云要比理想化的云类型复杂得多，因为理想化的云类型有助于我们了解云反馈。剩下的主要不确定因素是云与大规模环流和海洋的耦合以及云的中尺度聚集。