The impacts of cloud-radiative changes on poleward atmospheric and oceanic energy transport in a warmer climate
The impacts of cloud-radiative changes on poleward atmospheric and oceanic energy transport in a warmer climate
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DOI：
10.1175/jcli-d-20-0949.1
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发表时间：
2021-07
影响因子：
4.9
通讯作者：
Yong-Jhih Chen;Yen‐Ting Hwang;P. Ceppi
中科院分区：
文献类型：
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作者：
Yong-Jhih Chen;Yen‐Ting Hwang;P. Ceppi
基于理论和气候模式实验，以往的研究表明，预测未来纬向能量输送和纬向平均地表温度变化的大部分不确定性可以归因于云反馈。为了研究辐射和动力调整如何改变云辐射变化对能量传输的影响，本研究在一个完全耦合的气候模式CESM中应用了云锁定技术。在全球变暖条件下，云辐射变化对纬向能量输送的影响在两半球是不对称的。在北方半球，云辐射变化对能量输送的影响很小，因为89%的云致加热是通过增加出射长波辐射来平衡的。另一方面，在南半球，云引起的大气和海洋动力学变化导致向极地的能量输送增强，这是变暖下能量输送增加的主要原因。我们的实验强调，由温度变化引起的本地长波辐射调整可以部分抵消云辐射变化对能量输送的影响，使估计的影响小于在以前的研究中直接集成云辐射变化所获得的影响。研究还表明，云辐射对温度和能量输送的影响可以显着调制的海洋环流，这表明在估计云辐射变化对气候系统的影响时，考虑大气-海洋耦合的必要性。
Based on theory and climate model experiments, previous studies suggest most of the uncertainties in projected future changes in meridional energy transport and zonal mean surface temperature can be attributed to cloud feedback. To investigate how radiative and dynamical adjustments modify the influence of cloud-radiative changes on energy transport, this study applies a cloud-locking technique in a fully-coupled climate model, CESM. Under global warming, the impacts of cloud-radiative changes on the meridional energy transport are asymmetric in the two hemispheres. In the Northern Hemisphere, the cloud-radiative changes have little impact on energy transport, because 89% of the cloud-induced heating is balanced locally by increasing outgoing longwave radiation. In the Southern Hemisphere, on the other hand, cloud-induced dynamical changes in the atmosphere and the ocean cause enhanced poleward energy transport, accounting for most of the increase in energy transport under warming. Our experiments highlight that the local longwave radiation adjustment induced by temperature variation can partially offset the impacts of cloud-radiative changes on energy transport, making the estimated impacts smaller than those obtained from directly integrating cloud-radiative changes in previous studies. It is also demonstrated that the cloud-radiative impacts on temperature and energy transport can be significantly modulated by the oceanic circulation, suggesting the necessity of considering atmospheric-oceanic coupling when estimating the impacts of cloud-radiative changes on the climate system.