Faculty of Engineering, Hokkaido University, Kita-13 Nishi-8, Kita-ku, Sapporo, 060-8628, Japan.
Arctic Research Center, Hokkaido University, Kita-21 Nishi-11, Kita-ku, Sapporo, 001-0021, Japan.
Sci Rep. 2018 Apr 25;8(1):6413. doi: 10.1038/s41598-018-24335-w.
To identify the unusual climate conditions and their connections to air pollutions in a remote area due to wildfires, we examine three anomalous large-scale wildfires in May 2003, April 2008, and July 2014 over East Eurasia, as well as how products of those wildfires reached an urban city, Sapporo, in the northern part of Japan (Hokkaido), significantly affecting the air quality. NASA's MERRA-2 (the Modern-Era Retrospective analysis for Research and Applications, Version 2) aerosol re-analysis data closely reproduced the PM variations in Sapporo for the case of smoke arrival in July 2014. Results show that all three cases featured unusually early snowmelt in East Eurasia, accompanied by warmer and drier surface conditions in the months leading to the fires, inducing long-lasting soil dryness and producing climate and environmental conditions conducive to active wildfires. Due to prevailing anomalous synoptic-scale atmospheric motions, smoke from those fires eventually reached a remote area, Hokkaido, and worsened the air quality in Sapporo. In future studies, continuous monitoring of the timing of Eurasian snowmelt and the air quality from the source regions to remote regions, coupled with the analysis of atmospheric and surface conditions, may be essential in more accurately predicting the effects of wildfires on air quality.
为了识别由于野火而导致偏远地区的异常气候条件及其与空气污染的关系，我们研究了 2003 年 5 月、2008 年 4 月和 2014 年 7 月在东亚发生的三次异常大规模野火，以及这些野火的产物如何到达日本北部（北海道）的一个城市札幌，显著影响空气质量。美国宇航局的 MERRA-2（现代回顾分析研究和应用，版本 2）气溶胶再分析数据密切再现了 2014 年 7 月烟雾到达时札幌的 PM 变化。结果表明，所有三个案例都表现出欧亚大陆异常早的融雪现象，同时在火灾发生前的几个月里，地表条件更加温暖和干燥，导致土壤持久干燥，并产生有利于野火活动的气候和环境条件。由于盛行异常的天气尺度大气运动，这些火灾产生的烟雾最终到达了一个偏远地区——北海道，并使札幌的空气质量恶化。在未来的研究中，对欧亚大陆融雪时间和来自源地区到偏远地区的空气质量进行持续监测，并结合大气和地表条件的分析，可能对于更准确地预测野火对空气质量的影响至关重要。
