Abstract. The Last Interglacial period (129–116 ka BP) is characterized by a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the pre-industrial period. In particular, these changes amplify the seasonality of the insolation in the high latitudes of the northern hemisphere. Here, we investigate the Arctic climate response to this forcing by comparing the CMIP6 lig127k and pi-Control simulations performed with the IPSL-CM6A-LR model. Using an energy budget framework, we analyse the interactions between the atmosphere, ocean, sea ice and continents. In summer, the insolation anomaly reaches its maximum and causes a near-surface air temperature rise of 3.2 °C over the Arctic region. This warming is primarily due to a strong positive surface downwelling shortwave radiation anomaly over continental surfaces, followed by large heat transfers from the continents back to the atmosphere. The surface layers of the Arctic Ocean also receives more energy, but in smaller quantity than the continents due to a cloud negative feedback. Furthermore, while heat exchanges from the continental surfaces towards the atmosphere are strengthened, the ocean absorbs and stores the heat excess due to a decline in sea ice cover. However, the maximum near-surface air temperature anomaly does not peak in summer like insolation, but occurs in autumn with a temperature increase of 4.0 °C relative to the pre-industrial period. This strong warming is driven by a positive anomaly of longwave radiations over the Arctic ocean enhanced by a positive cloud feedback. It is also favoured by the summer and autumn Arctic sea ice retreat (−1.9 × 10⁶ and −3.4 × 10⁶ km² respectively), which exposes the warm oceanic surface and allows heat stored by the ocean in summer and water vapour to be released. This study highlights the crucial role of the sea ice cover variations, the Arctic ocean, as well as changes in polar clouds optical properties on the Last Interglacial Arctic warming.

中文翻译：

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了解末次间冰期北极变暖的能量预算方法

摘要。最后一次间冰期 (129–116 ka BP) 的特征是强烈的轨道强迫，与工业化前时期相比，这导致日照的季节和纬度分布不同。特别是，这些变化放大了北半球高纬度地区日照的季节性。在这里，我们通过比较 CMIP6 lig127k和pi - Control来研究北极气候对这种强迫的反应使用 IPSL-CM6A-LR 模型进行的模拟。使用能源预算框架，我们分析了大气、海洋、海冰和大陆之间的相互作用。在夏季，日照异常达到最大值，导致北极地区近地表气温上升 3.2 °C。这种变暖主要是由于大陆表面强烈的正地表下行短波辐射异常，随后是大量热量从大陆传回大气。由于云的负反馈，北冰洋的表层也接收到更多的能量，但数量少于大陆。此外，虽然从大陆表面到大气的热交换得到加强，但由于海冰覆盖的减少，海洋吸收并储存了多余的热量。然而，最大近地表气温异常并不像日照那样在夏季达到峰值，而是出现在秋季，温度比工业化前时期升高了 4.0 °C。这种强烈的变暖是由正云反馈增强的北冰洋长波辐射的正异常驱动的。也受到夏秋季北极海冰退缩的青睐（−1.9 × 10⁶和 −3.4 × 10 ⁶  km ² )，暴露了温暖的海洋表面，并允许夏季海洋储存的热量和水蒸气被释放。这项研究强调了海冰覆盖变化、北冰洋以及极地云光学特性变化对最后一次间冰期北极变暖的关键作用。