Sea ice and atmospheric circulation shape the high-latitude lapse rate feedback
Sea ice and atmospheric circulation shape the high-latitude lapse rate feedback
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DOI：
10.1038/s41612-020-00146-7
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发表时间：
2020-10-22
影响因子：
9
通讯作者：
Kushner, Paul J.
中科院分区：
文献类型：
--
作者：
Feldl, Nicole;Po-Chedley, Stephen;Kushner, Paul J.
北极地区人为气候变化的放大被广泛归因于海冰反照率反馈及其伴随的吸收太阳辐射的增加，以及大气变暖的垂直结构对地球发出的长波辐射的影响。后一种错误率反馈在高纬度地区受到无数本地和远程影响，其相对贡献仍然无法量化。在这里，对高纬度递减率反馈的不同控制被划分为“上”和“下”贡献，它们起源于将高纬度下对流层与大气层其余部分分开的特征气候等熵面上方和下方。这种分解阐明了极地海洋上空的正高纬度递减率反馈是如何主要作为大气对当地海冰丧失的反应而产生的，并因向极地大气能量输送的增加而在亚极地纬度减少。高纬度递减率反馈的本地驱动分量的分离进一步揭示了它和海冰反照率反馈如何作为一种耦合机制在季节周期中共同主导北极的放大。
Arctic amplification of anthropogenic climate change is widely attributed to the sea-ice albedo feedback, with its attendant increase in absorbed solar radiation, and to the effect of the vertical structure of atmospheric warming on Earth's outgoing longwave radiation. The latter lapse rate feedback is subject, at high latitudes, to a myriad of local and remote influences whose relative contributions remain unquantified. The distinct controls on the high-latitude lapse rate feedback are here partitioned into "upper" and "lower" contributions originating above and below a characteristic climatological isentropic surface that separates the high-latitude lower troposphere from the rest of the atmosphere. This decomposition clarifies how the positive high-latitude lapse rate feedback over polar oceans arises primarily as an atmospheric response to local sea ice loss and is reduced in subpolar latitudes by an increase in poleward atmospheric energy transport. The separation of the locally driven component of the high-latitude lapse rate feedback further reveals how it and the sea-ice albedo feedback together dominate Arctic amplification as a coupled mechanism operating across the seasonal cycle.