Effects of Extra-Tropical Fires on Trace Gases and Aerosols

该项目将调查自1997年以来北方火灾排放对对流层中微量气体和气溶胶的影响。近年来的北方大火对大气中一氧化碳和气溶胶的丰度造成了很大的扰动，对氮氧化物和臭氧也产生了影响。大气化学和传输的三维模式(GEOS-Chem)将被用来分析这些火灾的半球尺度影响。模式模拟将由同化的气象场驱动，以考虑输送的年际变化。这项工作将采用两个独立得出的北部地区火灾气体和气溶胶物种的月度排放清单。在量化北方火灾排放的影响方面，一个关键的不确定性是缺乏对排放到大气中的高度的了解。来自Terra航天器上的多角度成像光谱仪(MISR)的数据将被分析，以确定自2000年以来西伯利亚大火排放的喷射高度，并将这些高度与燃烧面积、燃料消耗和当时的气象联系起来。模型模拟将通过地面站和遥感的气体测量进行评估，包括对流层污染的测量(MOPITT)一氧化碳(CO)数据和气溶胶的中分辨率成像光谱仪(MODIS)数据。火灾区域、燃料装载量和排放系数的数据将被用来协调自下而上的火灾排放量估计值与3-d模型计算结果和大气观测结果施加的约束。北方火灾的气溶胶分布(黑碳和有机碳)和由此产生的气溶胶光学厚度将被用来计算极端火灾年与低火年相比的瞬时辐射强迫。需要了解这些火灾排放的影响，以确定自然过程在导致美国和其他地方的空气质量恶化以及影响气候方面所起的作用。这个项目将支持一名博士后。这项研究的参与者将通过参加专业会议和与来自其他学科的同事的互动来关注这项工作的更广泛的影响。

This project will investigate the impacts of boreal fire emissions since 1997 on trace gases and aerosols in the troposphere. Large boreal fires in recent years caused large perturbations to the atmospheric abundance of carbon monoxide and aerosols, with effects on nitrogen oxides and ozone as well. A three-dimensional model of atmospheric chemistry and transport (GEOS-Chem) will be used to analyze the hemispheric-scale impacts of these fires. Model simulations will be driven by assimilated meteorological fields to allow for interannual variability in transport. This work will employ two independently derived monthly emissions inventories of gas and aerosol species for boreal fires. A key uncertainty in quantifying the effects of boreal fire emissions is lack of knowledge of the heights at which the emissions are injected into the atmosphere. Data from the Multi-angle Imaging SpectroRadiometer (MISR) on board the Terra spacecraft will be analyzed to determine the injection heights of emissions from Siberian fires since 2000, and to relate the heights to area burned, fuel consumed, and prevailing meteorology. The model simulations will be evaluated with measurements of gases from surface stations, and from remote sensing, including Measurements of Pollution In The Troposphere (MOPITT) data for carbon monoxide (CO) and moderate resolution imaging spectroradiometer (MODIS) data for aerosols. Data for the areas of fires, fuel loading, and emission factors will be used to reconcile bottom-up estimates of fire emissions with constraints imposed by the results of the 3-d model calculations and atmospheric observations. The aerosol distributions (black carbon and organic carbon) and resulting aerosol optical depths from the boreal fires will be used to calculate the instantaneous radiative forcing for extreme fires years compared to low fire years. Understanding the impacts of emissions from these fires is required to determine the role that natural processes play in causing degradation of air quality in the United States and elsewhere, and in influencing climate.This project will support a post-doctoral student. Participants in this research will be focusing on the broader implications of this work by participating in professional meetings and though interactions with colleagues from other disciplines.