Plateau Atmospheric and Environment Key Laboratory of Sichuan Province, College of Atmosphere Sciences, Chengdu University of Information Technology, Chengdu 610225, China.
State Key Laboratory of Severe Weather (LASW) and Key Laboratory of Atmospheric Chemistry (LAC), Chinese Academy of Meteorological Sciences, CMA, Beijing 100081, China.
Sci Total Environ. 2021 Mar 25;762:144586. doi: 10.1016/j.scitotenv.2020.144586. Epub 2020 Dec 17.
Carbonaceous aerosols and gaseous pollutants emitted from wildfires play a crucial role in both the global climate system and regional air quality. Here, using multisource satellite and ground-based observations combined with reanalysis data, we investigate the three-dimensional evolution of biomass-burning emissions from a forest wildfire event in Liangshan, Southwest China, which occurred from 29 March to 1 April 2020. The meteorological field analysis showed that the negative anomaly of relative humidity and precipitation, as well as the positive anomaly of near-surface wind speed, created favourable conditions for the occurrence and spread of this wildfire event. During the fire, satellite observations suggested a maximum fire radiation power of over 100 MW. In addition, there were significant short-term effects of fire activity on regional air quality, with downwind surface PM concentrations at the Xichang site reaching a maximum of approximately 470 μg·m on March 31. Driven by a southwesterly airflow, large amounts of smoke aerosols were transported rapidly to downstream areas, significantly deteriorating air quality, with the maximum value of the aerosol optical depth (AOD) exceeding 2. Moreover, the quantitative evaluation based on Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) reanalysis showed that the instantaneous maximum values of the column mass concentration of black carbon (BC) and organic carbon (OC) reached 9.8 g·m and 1.8 g·m during the fire respectively. Further analysis suggested that the interaction between the lower and upper atmosphere constrained the smoke aerosols to altitudes below approximately 5 km, which was also supported by the vertical distribution of elevated smoke aerosols observed by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP).
生物质燃烧排放物的三维演变
来自野火的碳质气溶胶和气态污染物在全球气候系统和区域空气质量中都起着至关重要的作用。在这里，我们利用多源卫星和地面观测以及再分析数据，研究了 2020 年 3 月 29 日至 4 月 1 日发生在中国西南凉山的森林野火事件中生物质燃烧排放物的三维演变。气象场分析表明，相对湿度和降水的负异常以及近地表风速的正异常为这场野火的发生和蔓延创造了有利条件。在火灾期间，卫星观测表明火灾辐射功率最大值超过 100MW。此外，火灾活动对区域空气质量有显著的短期影响，西昌站点下风面 PM 浓度在 3 月 31 日达到约 470μg·m 的最大值。受西南气流驱动，大量烟雾气溶胶迅速输送到下游地区，空气质量显著恶化，气溶胶光学深度（AOD）的最大值超过 2。此外，基于现代回顾分析研究和应用，版本 2（MERRA-2）再分析的定量评估表明，火灾期间柱质量浓度的黑碳（BC）和有机碳（OC）的瞬时最大值分别达到 9.8g·m 和 1.8g·m。进一步分析表明，大气低层和高层之间的相互作用将烟雾气溶胶限制在大约 5km 以下的高度，这也得到了云气溶胶激光雷达与正交偏振（CALIOP）观测到的抬升烟雾气溶胶垂直分布的支持。
