Ocean Circulation Reduces the Hadley Cell Response to Increased Greenhouse Gases
Ocean Circulation Reduces the Hadley Cell Response to Increased Greenhouse Gases
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DOI：
10.1029/2018gl079070
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发表时间：
2018-09-16
影响因子：
5.2
通讯作者：
Polvani, L. M.
中科院分区：
文献类型：
--
作者：
Chemke, R.;Polvani, L. M.
Hadley环流在确定水文循环的强度和位置方面起着重要的作用。气候预测显示，HC减弱，其垂直和纬向范围扩大。预计这些变化将对全球气候产生深远影响。目前的理论HC增加温室气体的反应只占大气和海洋热力学变化，而不是海洋环流的变化。在这里，通过比较完全耦合和平板海洋模式配置的HC响应增加温室气体的海洋环流变化的影响进行检查。通过减少海洋表面和大气的变暖，海洋环流的变化减少了HC对CO2浓度增加的反应。这种减少变暖抑制对流加热，从而减少了HC的减弱和低纬度地区的稳定，从而也减少了纬向（南半球）和垂直HC扩展。简明语言摘要鉴于热带环流在影响低纬度气候方面的重要性，了解热带环流对人为排放的预测响应至关重要。为了充分理解热带环流的响应，必须考虑气候系统不同组成部分之间的内部反馈。在这里，我们研究的影响，在海洋环流的变化，以响应增加温室气体对热带环流。我们发现，海洋环流的行为，以减少热带环流的人为排放的预计响应。这强调了在研究大气层对温室气体增加的长期反应时，使用海洋环流模型的重要性。
The Hadley cell (HC) plays an important role in setting the strength and position of the hydrological cycle. Climate projections show a weakening of the HC, together with widening of its vertical and meridional extents. These changes are projected to have profound global climatic impacts. Current theories for the HC response to increased greenhouse gases account only for atmospheric and oceanic thermodynamic changes and not for oceanic circulation changes. Here the effects of ocean circulation changes on the HC response to increased greenhouse gases are examined by comparing fully coupled and slab ocean model configurations. By reducing the warming of both the sea surface and the atmosphere, changes in ocean circulation reduce the HC response to increased CO2 concentrations. This reduced warming suppresses convective heating, which reduces the weakening of the HC and the stabilization at low latitudes, and thus also reduces the meridional (in the Southern Hemisphere) and vertical HC expansion.Plain Language Summary Given the importance of tropical circulation in affecting low-latitude climate, it is crucial to understand the projected response of tropical circulation to anthropogenic emissions. To fully understand the tropical circulation response, one must account for the internal feedbacks between the different components of the climate system. Here we study the effect of changes in ocean circulation in response to increased greenhouse gases on the tropical circulation. We find that ocean circulation acts to reduce the projected response of tropical circulation to anthropogenic emissions. This emphasizes the importance in using models with ocean circulation, when studying the long-term atmospheric response to increased greenhouse gases.