A warming Arctic is expected to exacerbate wildfires in Siberia, potentially creating a critical feedback to the Arctic climate change. However, our understanding of these fire-climate interactions remains limited. This study investigated changes in East Siberian wildfires and their influence on fire emissions, aerosol optical depth (AOD), and the surface clear-sky insolation across the Siberian Arctic from 2000 to 2020 using satellite observations. Our analysis reveals a substantial increase in wildfires, with fire counts doubling (a 114% increase) and fire radiative power surging by 8.4 × 10 MW compared to the early 21st century. Over 93% of this increase occurred during the boreal summer months. These intensified wildfires led to a significant rise in aerosol emission (organic carbon, PM2.5, and black carbon) exceeding 75% in East Siberia. Consequently, fire-season AOD in the Siberian Arctic increased by 33% (6.0 × 10), with 85% (5.1 × 10) attributable to wildfire changes. The wildfire-associated increase in AOD resulted in enhanced clear-sky dimming of 4.1 ± 3.2 W m across the Siberian Arctic from 2000 to 2020. These findings suggest a critical feedback mechanism: a warming Arctic drives increased wildfires in Siberia, which in turn significantly impact the Arctic surface radiative budget through enhanced clear-sky dimming. Future simulations and projections for the Arctic should prioritize incorporating the feedback effects of intensifying wildfires.

中文翻译：

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夏季野火增加是 2000 年至 2020 年西伯利亚北极地区晴空变暗的主要驱动因素


北极变暖预计将加剧西伯利亚的野火，可能对北极气候变化产生重要的反馈。然而，我们对这些火灾与气候相互作用的理解仍然有限。本研究利用卫星观测调查了 2000 年至 2020 年东西伯利亚野火的变化及其对火灾排放、气溶胶光学深度 (AOD) 以及西伯利亚北极地区表面晴空日照的影响。我们的分析显示，与 21 世纪初相比，野火大幅增加，火灾数量增加了一倍（增加 114%），火灾辐射功率激增 8.4 × 10 MW。超过 93% 的增长发生在北方夏季。这些加剧的山火导致东西伯利亚气溶胶排放（有机碳、PM2.5和黑碳）大幅增加超过75%。因此，西伯利亚北极火灾季节的 AOD 增加了 33% (6.0 × 10)，其中 85% (5.1 × 10) 归因于野火变化。 2000 年至 2020 年间，与野火相关的 AOD 增加导致西伯利亚北极晴空变暗增强，幅度为 4.1 ± 3.2 W m。这些发现表明了一个关键的反馈机制：北极变暖导致西伯利亚野火增加，进而显着通过增强晴空调光影响北极表面辐射预算。未来对北极的模拟和预测应优先考虑加剧野火的反馈效应。