On the Increase of Climate Sensitivity and Cloud Feedback With Warming in the Community Atmosphere Models
On the Increase of Climate Sensitivity and Cloud Feedback With Warming in the Community Atmosphere Models
复制标题
社区大气模型中气候敏感性和云反馈随变暖的增加
DOI：
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发表时间：
2020
影响因子：
5.2
通讯作者：
C. Poulsen
中科院分区：
文献类型：
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作者：
Jiang Zhu;C. Poulsen
建模和基于古气候代理的研究表明，平衡气候敏感性（ECS）取决于背景气候状态，但原因尚未完全清楚。在这里，我们通过改变大气 CO2 浓度，研究社区大气模型 (CAM) 版本 4、5 和 6 中 ECS 在大范围全球平均表面温度 (GMST) 上的状态依赖性。我们发现，在所有三个模型中，随着 GMST 的 ECS 均出现了强劲增长，尽管速率不同，这主要归因于高纬度和低纬度地区短波云反馈 (λcld) 的增强。在高纬度地区，增加 GMST 会导致云冰比例减少，削弱由于云冰向液体相变而产生的（负）云相反馈，从而增强 λcld。在低纬度地区，增加 GMST 可能会通过水蒸气的非线性增加来增强 λcld，从而通过热力学和辐射过程导致低云变薄。
Modeling and paleoclimate proxy‐based studies suggest that equilibrium climate sensitivity (ECS) depends on the background climate state, though the reason is not thoroughly understood. Here we study the state dependence of ECS over a large range of global mean surface temperature (GMST) in the Community Atmosphere Model (CAM) Versions 4, 5, and 6 by varying atmospheric CO2 concentrations. We find a robust increase of ECS with GMST in all three models, albeit at different rates, which is primarily attributed to strengthening of the shortwave cloud feedback (λcld) at both high and low latitudes. Over high latitudes, increasing GMST leads to a reduction in the cloud ice fraction, weakening the (negative) cloud‐phase feedback due to the phase transition of cloud ice to liquid and thereby strengthening λcld. Over low‐latitude regions, increasing GMST strengthens λcld likely through the nonlinear increase in water vapor, which causes low‐cloud thinning through thermodynamic and radiative processes.
CMIP6 模型中的高气候敏感性不受古气候支持
影响因子：
30.7
作者：
Zhu, Jiang;Poulsen, Christopher J.;Otto-Bliesner, Bette L.
通讯作者：
Otto-Bliesner, Bette L.