In the late spring to summer season of 2023, Canada witnessed unprecedented wildfires, with an extensive burning area and smoke spreading as far as the East Coast of the United States and Europe. Here, using multisource data analysis and climate model simulations, we show that an abnormally warm North Atlantic, as well as an abnormally low Barents Sea ice concentration (SIC), are likely key climate drivers of this Canadian fire season, contributing to ~80% of the fire weather anomaly over Canada from June to August 2023. Specifically, the warm North Atlantic forms an anomalous regional zonal cell with ascending air over the Atlantic and descending air encircling Canada, creating hot and dry local conditions. Meanwhile, reduced Barents SIC leads to a high-pressure center and reinforces the dry northern winds in Canada through Rossby wave dynamics. These exacerbated dry and hot conditions create a favorable environment for the ignition and spread of fires, thus contributing to the prolonged and extreme fire season in Canada. These teleconnections can extend to decadal scales and have important implications for understanding and predicting decadal fire activity in Canada and the surrounding regions.

中文翻译：

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北大西洋和巴伦支海的变率导致加拿大 2023 年极端火灾季节


在 2023 年春末至夏季，加拿大见证了前所未有的野火，燃烧面积大，烟雾蔓延至美国和欧洲东海岸。在这里，使用多源数据分析和气候模型模拟，我们表明异常温暖的北大西洋以及异常低的巴伦支海冰浓度 （SIC） 可能是加拿大火灾季节的关键气候驱动因素，导致 2023 年 6 月至 8 月加拿大火灾天气异常的 ~80%。具体来说，温暖的北大西洋形成了一个异常的区域纬向单体，大西洋上空的上升空气和环绕加拿大的下降空气，创造了炎热干燥的局部条件。与此同时，巴伦支 SIC 的减少导致高压中心，并通过罗斯比波浪动力学加强了加拿大干燥的北风。这些加剧的干燥和炎热条件为火灾的点燃和蔓延创造了有利的环境，从而导致了加拿大漫长而极端的火灾季节。这些遥相关可以扩展到年代际尺度，对于理解和预测加拿大及周边地区的年代际火灾活动具有重要意义。