The Atmospheric Pathway of the Cloud-Radiative Impact on the Circulation Response to Global Warming: Important and Uncertain
The Atmospheric Pathway of the Cloud-Radiative Impact on the Circulation Response to Global Warming: Important and Uncertain
复制标题
云辐射对全球变暖环流响应影响的大气路径：重要且不确定
DOI：
10.1175/jcli-d-18-0810.1
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发表时间：
2019
影响因子：
4.9
通讯作者：
G. Papavasileiou
中科院分区：
文献类型：
--
作者：
A. Voigt;Nicole Albern;G. Papavasileiou
以前的工作表明，响应全球变暖的年平均纬向平均大气环流的向极扩展受到云的变化及其对地面和大气的辐射加热的强烈调制。在这里，一个层次和一个全球气候模式的集合被用来研究大气云辐射加热的变化在没有海表面温度（SST）的变化，这被称为云辐射影响的大气路径的环流影响。对于MPI-ESM模式，大气路径约占总云辐射影响的一半，实际上占总环流响应的一半。大气云辐射加热的变化在对流层的低层和高层都很大。然而，由于SST是规定的大气路径是由上层对流层云辐射加热的变化，这在很大程度上是由于高层云的向上移动。通过大气路径的向极环流扩张和对流层上层云辐射加热的变化在三个全球模型中定性地是稳健的，但它们的大小变化了3倍。这些震级差异的很大一部分与当今气候中高层云对对流层上部的辐射加热有关。与观测结果的比较突出了模型在代表高层云辐射加热方面的不足，并表明减少这些不足有助于改善对区域气候变化的预测。
Previous work showed that the poleward expansion of the annual-mean zonal-mean atmospheric circulation in response to global warming is strongly modulated by changes in clouds and their radiative heating of the surface and atmosphere. Here, a hierarchy and an ensemble of global climate models are used to study the circulation impact of changes in atmospheric cloud-radiative heating in the absence of changes in sea surface temperature (SST), which is referred to as the atmospheric pathway of the cloud-radiative impact. For the MPI-ESM model, the atmospheric pathway is responsible for about half of the total cloud-radiative impact, and in fact half of the total circulation response. Changes in atmospheric cloud-radiative heating are substantial in both the lower and upper troposphere. However, because SST is prescribed the atmospheric pathway is dominated by changes in upper-tropospheric cloud-radiative heating, which in large part results from the upward shift of high-level clouds. The poleward circulation expansion via the atmospheric pathway and changes in upper-tropospheric cloud-radiative heating are qualitatively robust across three global models, yet their magnitudes vary by a factor of 3. A substantial part of these magnitude differences are related to the upper-tropospheric radiative heating by high-level clouds in the present-day climate. A comparison with observations highlights the model deficits in representing the radiative heating by high-level clouds and indicates that reducing these deficits can contribute to improved predictions of regional climate change.