Arctic amplification dominated by temperature feedbacks in contemporary climate models
Arctic amplification dominated by temperature feedbacks in contemporary climate models
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DOI：
10.1038/ngeo2071
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发表时间：
2014-03-01
影响因子：
18.3
通讯作者：
Mauritsen, Thorsten
中科院分区：
文献类型：
--
作者：
Pithan, Felix;Mauritsen, Thorsten
气候变化在北极地区被放大。在过去的暖期(1)和冰期(2)以及历史观测(3，4)和气候模型实验(5，6)中都发现了北极的放大现象。与温度、水蒸气和云层有关的反馈效应被认为是北极变暖加剧的原因，但地表反照率反馈--冰雪融化时表面对太阳辐射的吸收增加--常常被认为是主要因素(7-10)。然而，在没有冰雪覆盖变化的模型中也发现了北极的放大(11，12)。在这里，我们分析来自耦合模式相互比较项目第五阶段档案的气候模式模拟，以量化各种反馈的贡献。我们发现，在模拟中，对北极放大的最大贡献来自温度反馈：与北极相比，随着地表变暖，更多的能量在低纬度辐射回太空。这种影响既可以归因于高纬度和低纬度地区升温的垂直结构不同，也可以归因于温度较低时单位升温单位发射的黑体辐射增加较小。我们发现，地表反照率反馈是北极放大的第二个主要贡献者，其他贡献要小得多，甚至与北极放大相反。
Climate change is amplified in the Arctic region. Arctic amplification has been found in past warm(1) and glacial(2) periods, as well as in historical observations(3,4) and climate model experiments(5,6). Feedback effects associated with temperature, water vapour and clouds have been suggested to contribute to amplified warming in the Arctic, but the surface albedo feedback-the increase in surface absorption of solar radiation when snow and ice retreat-is often cited as the main contributor(7-10). However, Arctic amplification is also found in models without changes in snow and ice cover(11,12). Here we analyse climate model simulations from the Coupled Model Intercomparison Project Phase 5 archive to quantify the contributions of the various feedbacks. We find that in the simulations, the largest contribution to Arctic amplification comes from a temperature feedbacks: as the surface warms, more energy is radiated back to space in low latitudes, compared with the Arctic. This effect can be attributed to both the different vertical structure of the warming in high and low latitudes, and a smaller increase in emitted blackbody radiation per unit warming at colder temperatures. We find that the surface albedo feedback is the second main contributor to Arctic amplification and that other contributions are substantially smaller or even oppose Arctic amplification.