Weak Hadley cell intensity changes due to compensating effects of tropical and extratropical radiative forcing
Weak Hadley cell intensity changes due to compensating effects of tropical and extratropical radiative forcing
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DOI：
10.1038/s41612-022-00287-x
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发表时间：
2022-08-01
影响因子：
9
通讯作者：
Merlis, Timothy M.
中科院分区：
文献类型：
--
作者：
Kim, Doyeon;Kim, Hanjun;Merlis, Timothy M.
哈德利环流对全球二氧化碳浓度增加的响应在空间上是复杂的，具有增强的上升分支和减弱的下降分支。为了更好地理解这些变化，我们考察了哈德利环流对不同纬度带的理想化辐射强迫的敏感性。哈德利环流的响应是由强迫的纬度结构决定的。上升支的加强归因于热带强迫，而下降支的减弱归因于温带强迫。这些直接辐射强迫的哈德利环流响应被大气涡热输送的变化放大，而被总湿稳定性和海洋热吸收的变化部分抵消。辐射反馈通过改变经向大气能量梯度进一步调制哈德利环流的响应。因此，全球变暖下的哈德利环流预测是热带和温带辐射强迫相反的--从而补偿--影响的结果。
The Hadley cell response to globally increasing CO2 concentrations is spatially complex, with an intensified rising branch and weakened descending branch. To better understand these changes, we examine the sensitivity of the Hadley cell to idealized radiative forcing in different latitude bands. The Hadley cell response is, to first order, governed by the latitudinal structure of the forcing. The strengthening of the upward branch is attributed to tropical forcing, whereas the weakening of the descending branch is attributed to extratropical forcing. These direct radiatively-forced Hadley cell responses are amplified by changes in atmospheric eddy heat transport while being partially offset by changes in gross moist stability and ocean heat uptake. The radiative feedbacks further modulate the Hadley cell response by altering the meridional atmospheric energy gradient. The Hadley cell projections under global warming are thus a result of opposing - and thus compensating - effects from tropical and extratropical radiative forcings.