Relationship between circum-Arctic atmospheric wave patterns and large-scale wildfires in boreal summer
Relationship between circum-Arctic atmospheric wave patterns and large-scale wildfires in boreal summer
复制标题
DOI：
10.1088/1748-9326/abf7ef
复制
发表时间：
2021-05
影响因子：
6.7
通讯作者：
T. Yasunari;H. Nakamura;Kyu-Myong Kim;N. Choi;Myong-in Lee;Y. Tachibana;Arlindo M. da Silva
中科院分区：
文献类型：
--
作者：
T. Yasunari;H. Nakamura;Kyu-Myong Kim;N. Choi;Myong-in Lee;Y. Tachibana;Arlindo M. da Silva
对北极及其周边地区严重的野火和相关的空气污染以及相关的气候模式进行长期评估，对于评估健康的人类生活状况至关重要。为了检验这些关系，我们分析了美国国家航空航天局（NASA）现代研究和应用回顾性分析版本2 （MERRA-2）。我们基于这一最先进的大气再分析数据的调查显示，2003-2017年北极地区PM2.5（对应于颗粒有机质[POM]形式中高度升高的有机碳）月平均质量浓度最高的20个月中，有13个月都在夏季（7月和8月），在此期间，POM大于或等于0.5 μ m−3和PM2.5呈正相关。这种相关性表明，北极地区的高PM2.5与大规模野火有关，并以显著的反气旋异常（即顺时针大气环流）为特征，除了欧洲之外，西伯利亚和北美亚极地地区的地表异常温暖和干燥条件。通过对7月和8月平均数据的独立回归分析，在相同的大气变量和符号反转的斯堪的纳维亚模式指数之间也确定了类似的气候模式。我们将这种近期大气环流异常模式命名为环北极波（CAW）模式，它是静止罗斯比波（即大尺度大气波）向东群速传播的一种表现。正如2019年6月下旬观测到的那样，CAW引发了欧洲、西伯利亚、阿拉斯加和加拿大上空暖反气旋异常的同步发展。令人惊讶的是，1980-2017年的扩展回归分析显示，CAW模式在2003年之前并不突出。了解未来气候变化和全球变暖下的CAW模式将有助于更好地预测夏季北极及其周边地区的欧洲热浪和大规模野火与西伯利亚、阿拉斯加和加拿大上空的空气污染同时发生。
Long-term assessment of severe wildfires and associated air pollution and related climate patterns in and around the Arctic is essential for assessing healthy human life status. To examine the relationships, we analyzed the National Aeronautics and Space Administration (NASA) modern-era retrospective analysis for research and applications, version 2 (MERRA-2). Our investigation based on this state-of-the-art atmospheric reanalysis data reveals that 13 out of the 20 months with the highest PM2.5 (corresponding to the highly elevated organic carbon in the particulate organic matter [POM] form) monthly mean mass concentration over the Arctic for 2003–2017 were all in summer (July and August), during which POM of ⩾ 0.5 μg m−3 and PM2.5 were positively correlated. This correlation suggests that high PM2.5 in the Arctic is linked to large wildfire contributions and characterized by significant anticyclonic anomalies (i.e. clockwise atmospheric circulation) with anomalous surface warmth and drier conditions over Siberia and subpolar North America, in addition to Europe. A similar climate pattern was also identified through an independent regression analysis for the July and August mean data between the same atmospheric variables and the sign-reversed Scandinavian pattern index. We named this pattern of recent atmospheric circulation anomalies the circum-Arctic wave (CAW) pattern as a manifestation of eastward group-velocity propagation of stationary Rossby waves (i.e. large-scale atmospheric waves). The CAW induces concomitant development of warm anticyclonic anomalies over Europe, Siberia, Alaska, and Canada, as observed in late June 2019. Surprisingly, the extended regression analysis of the 1980–2017 period revealed that the CAW pattern was not prominent before 2003. Understanding the CAW pattern under future climate change and global warming would lead to better prediction of co-occurrences of European heatwaves and large-scale wildfires with air pollution over Siberia, Alaska, and Canada in and around the Arctic in summer.