Underestimated marine stratocumulus cloud feedback associated with overly active deep convection in models
Underestimated marine stratocumulus cloud feedback associated with overly active deep convection in models
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DOI：
10.1088/1748-9326/abfb9e
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发表时间：
2021-07-01
影响因子：
6.7
通讯作者：
Suzuki, K.
中科院分区：
文献类型：
--
作者：
Hirota, N.;Ogura, T.;Suzuki, K.
云反馈仍然是平衡气候敏感性（ECS）不确定性的最大来源。许多研究试图通过提出具有预测未来气候的高技能的可观测指标来缩小云反馈和ECS中的不确定性，称为紧急约束。这些约束通常与云、对流和环流有关，并且相互关联。然而，这些联系的物理解释仍然不清楚。在这里，我们提出了一个新的机制，在多个气候模型的对流和云。一些模式显示，在亚热带低云区，每日时间尺度上的深对流过于活跃，这导致了较弱的下沉逆温和较少量的低空云。这种模式预测较小的短波（SW）云反馈。使用这些地区的降水频率作为紧急约束，封装这一机制，模型与较低的西南云反馈（
Cloud feedback remains the largest source of uncertainty in equilibrium climate sensitivity (ECS). Many studies have attempted to narrow uncertainties in cloud feedback and ECS by proposing observable metrics with high skill at predicting future climate, referred to as emergent constraints. These constraints are often associated with clouds, convection, and circulation, and are interrelated. However, physical explanations for these connections remain unclear. Here, we propose a new mechanism relating convection and clouds across multiple climate models. Some models show overly active deep convection on daily timescales in the subtropical low cloud regions, which contributes to weaker subsidence inversion and smaller amounts of low-level clouds. Such models predict smaller shortwave (SW) cloud feedback. Using precipitation frequency in these regions as an emergent constraint, encapsulating this mechanism, models with lower SW cloud feedback (