Participation in Flame-IV: Understanding Aerosol Absorption in Biomass Burning Plumes Through Measurements of Single-Particle SSA, Coatings, and Brown Carbon

气溶胶通过散射和吸收阳光直接影响地球的辐射平衡，通过改变大气的垂直温度分布和改变云的性质半直接地影响地球的辐射平衡。这些影响的大小是高度不确定的，从而限制了我们对地球气候的理解和预测能力。黑碳(BC)气溶胶对太阳光的吸收被认为是继二氧化碳和生物质燃烧占大气BC的一半以上之后最大的正辐射强迫。描述气溶胶辐射特性的一个关键参数是单次散射反照率(SSA)，它很难从空间可靠地量化，因此，现场测量至关重要。一套仪器将被部署到蒙大拿州米苏拉的火灾科学实验室，对全球重要燃料类型的生物质燃烧排放进行为期4周的调查(题为FLAME-IV(密苏拉第四个火灾实验室))。发射将使用光声吸收光谱仪(PAS)、腔衰减相移光谱仪(CAPS)、热扩散管和气溶胶散射消光比(ASTER)仪器进行表征。气溶胶吸收、半挥发性涂层引起的增强吸收、褐碳、块状气溶胶的SSA和单颗粒的SSA将被量化。生物质燃烧排放的单颗粒SSA分布将提供有关负责吸收的颗粒的大小、特征和混合状态的新信息。这些详细的光学特性将为卫星遥感和气候模型提供信息。项目数据将以易于访问的格式存档，并公开供建模人员和其他人使用。这一成果将有助于就生物质燃烧排放的气候影响做出明智的公共政策决定。该项目将资助2名全日制研究生，并为本科生提供研究机会。这项研究将促进怀俄明大学大气科学系(EPSCoR大学)、火灾科学实验室和参与Flame IV的其他团体之间的合作。结果将在国家会议和同行评议的文献中报告。结果还将被纳入首席调查员部门开设的课程、向社区团体发表的报告，以及为高中生和K-12教师举办的讲习班。

Aerosols impact the radiative balance of the earth directly by scattering and absorbing sunlight and semi-directly by altering the vertical temperature profile of the atmosphere and modifying cloud properties. The magnitudes of these effects are highly uncertain thereby limiting our understanding of and ability to predict earth's climate. Absorption of sunlight by black carbon (BC) aerosols is thought to be the largest positive radiative forcing after carbon dioxide and biomass burning accounts for greater than half of BC in the atmosphere. A key parameter in describing aerosol radiative properties is the single scattering albedo (SSA), which is difficult to reliably quantify from space, thus, making in-situ measurements essential. A suite of instruments will be deployed to the Fire Sciences Laboratory in Missoula, Montana for a 4-week investigation (entitled FLAME-IV (the 4th Fire Lab At Missoula Experiment)) of biomass-burning emissions from globally important fuel types. Emissions will be characterized with a photoacoustic absorption spectrometer (PAS), a cavity attenuated phase shift spectrometer (CAPS), a thermal denuder, and the aerosol scattering to extinction ratio (ASTER) instrument. Aerosol absorption, enhanced absorption caused by semi-volatile coatings, brown carbon, the SSA of the bulk aerosol and the SSA of single particles will be quantified. The single-particle SSA distribution for biomass burning emissions will provide new information regarding the size, character, and mixing state of particles responsible for absorption. These detailed optical properties will inform satellite retrievals and climate models.Project data will be archived in easily accessible formats and available publicly for use by modelers and others. Result will facilitate informed public policy decisions regarding the climatic implications of biomass burning emissions. The project will support 2 full-time graduate students and provide opportunities for undergraduate research. This study will foster collaboration among the Atmospheric Science Department at the University of Wyoming (an EPSCOR University), the Fire Sciences Lab, and other groups participating in Flame IV. Results will be reported at national conferences and in the peer-reviewed literature. Results will also be incorporated into courses offered in the principal investigator's department, presentations to community groups, and workshops for both high school students and K-12 teachers.