Sea-ice loss and radiative feedbacks have been proposed to explain Arctic amplification (AA)—the enhanced Arctic warming under increased greenhouse gases, but their relationship is unclear. By analyzing coupled CESM1 simulations with 1%/year CO₂ increases, we show that without large sea-ice loss and AA, the lapse rate, Planck, and surface albedo feedbacks are greatly reduced, while the positive water vapor feedback changes little. The positive Arctic lapse rate feedback, which results from enhanced surface warming rather than the high stability of Arctic air, and changes in atmospheric energy transport across the Arctic Circle are a result, not a cause, of AA; while the water vapor feedback also plays a minor role. Instead, AA results from enhanced winter oceanic heating associated with sea-ice loss that is aided by a positive surface albedo feedback in summer and positive cloud feedback in winter.

中文翻译：

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海冰损失对北极气候反馈的影响及其对北极放大的作用

已经提出海冰损失和辐射反馈来解释北极放大（AA）——在温室气体增加的情况下北极变暖加剧，但它们之间的关系尚不清楚。通过分析耦合 CESM1 模拟与 1%/年的 CO ₂增加，我们表明在没有大量海冰损失和 AA 的情况下，递减率、普朗克和表面反照率反馈大大降低，而正水汽反馈变化很小。正北极递减率反馈是由于地表变暖增强而不是北极空气的高度稳定性导致的，北极圈内大气能量传输的变化是 AA 的结果，而不是原因；而水汽反馈也起次要作用。相反，AA 是由与海冰损失相关的冬季海洋加热增强引起的，而夏季正表面反照率反馈和冬季正云反馈有助于增加 AA。