A Model Study of the Chemistry of Biomass Burning Smoke Plumes Constrained by Aircraft Data

生物质燃烧是大气中痕量气体和颗粒的主要来源，但目前的模型尚未捕捉到导致臭氧和二次有机气溶胶(SOA)大量形成的过程，这些过程通常在排放后的头几个小时观察到。该项目将开发一种新的最先进的模拟框架，将气体和气溶胶相光化学模拟的最新进展纳入到高分辨率拉格朗日弥散模型中。新的模拟框架将根据两个北美烟羽的化学演化的详细测量进行评估。这将使以下科学问题得以解决：*是什么导致在新鲜的生物质烟羽中观察到高臭氧和羟基自由基(OH)浓度？*烟羽中SOA的来源是什么？*烟雾气溶胶对光解率以及烟羽中的光化学有什么影响？2006年墨西哥Milagro(大城市倡议本地和全球研究观测)活动和2009年加州圣路易斯·奥比斯波生物燃烧(SLOBB)实验对年轻的生物质燃烧烟羽进行的飞机测量提供了全面的痕量气体和气溶胶演变数据，包括首次在生物质燃烧羽流中原位观测到的OH，因此是评价模型开发的理想方法。这些羽流的化学演化将使用新版本的气溶胶模拟程序(ASP)进行模拟，该程序将纳入半经验二维挥发性基组(2D-VBS)方案，该方案已成功用于模拟墨西哥城的SOA形成。这一更新版本的ASP将被纳入由天气研究和预报(WRF)模式的高分辨率输出驱动的混合单粒子拉格朗日积分轨迹(HYSPLIT)扩散模式的增强版本中。在飞机和GOES卫星观测的约束下，这些组合模型将被用来研究烟雾中臭氧和二氧化硫的形成。这项研究将导致对生物质燃烧对气候、空气质量和人类健康影响的更基本的了解。在这项工作中使用WRF-HYSPLIT框架模拟大气扩散，将有助于今后将该模式纳入现有预报系统模式。该项目将在一名专门测量生物质燃烧烟羽中微量气体的学术科学家和两名私营部门科学家之间建立合作，一名专门研究烟羽内的大气化学模型，另一名专门模拟大气羽流的扩散。这项工作还将刺激和支持WRF和ASP模式的继续发展，这些模式是在以前NSF的支持下开发的。两名研究生将接受使用开发的模型的培训，这将使他们有机会在非学术环境中与科学家合作。

Biomass burning is a major source of trace gases and particles to the atmosphere, but current models have not yet captured the processes that lead to the significant formation of ozone and secondary organic aerosol (SOA) that is often observed in the first few hours after emission. This project will develop a new state-of-the-art modeling framework that incorporates recent advances in modeling gas- and aerosol-phase photochemistry into a high resolution Lagrangian dispersion model. The new modeling framework will be evaluated against detailed measurements of the chemical evolution of two North American smoke plumes. This will allow the following science questions to be addressed: * What causes the high ozone and hydroxyl radical (OH) concentrations observed in fresh biomass smoke plumes? * What are the sources of SOA within the smoke plumes? * What is the impact of smoke aerosols on photolysis rates, and hence photochemistry, within the smoke plumes?The aircraft measurements of young biomass burning smoke plumes from the 2006 MILAGRO (Megacity Initiative Local and Global Research Observations) campaign in Mexico and the 2009 San Luis Obispo Biomass Burning (SLOBB) experiment in California provide comprehensive trace gas and aerosol evolution data, including the first in situ observations of OH in biomass burning plumes, and are thus ideal to evaluate the model development. The chemical evolution of these plumes will be modeled using a new version of the Aerosol Simulation Program (ASP) that will incorporate the semi-empirical two-dimensional Volatility Basis Set (2D-VBS) scheme that has been used successfully to model SOA formation in Mexico City. This updated version of ASP will be incorporated into an enhanced version of the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) dispersion model driven by high-resolution output from the Weather Research and Forecasting (WRF) model. The combined models, constrained by aircraft and GOES satellite observations, will then be used to study the formation of O3 and SOA within the smoke plumes.This research will lead to a better fundamental understanding of the climate, air quality, and human health impacts of biomass burning. Use of the WRF-HYSPLIT framework for modeling atmospheric dispersion in this work will facilitate the future inclusion of the model into the existing forecasting system models. This project will establish collaboration between an academic scientist specializing in the measurement of trace gases in biomass burning smoke plumes and two private sector scientists, one specializing in the modeling of atmospheric chemistry within smoke plumes and one specializing in modeling the dispersion of atmospheric plumes. The work will also stimulate and support the continued development of the WRF and ASP models, which were developed with previous NSF support. Two graduate students will be trained to use the developed models, which will give them the opportunity to work with scientists in a non-academic environment.