Spectral Characterization of Atmospheric Dust from the IR to the UV: A Combined Laboratory and Modeling Study of Composition, Size, and Shape Effects on Dust Optical Properties

大气尘埃从红外到紫外的光谱表征：成分、尺寸和形状对尘埃光学特性影响的实验室和模型联合研究

• 批准号: 0968624
• 负责人: Paul Kleiber
• 金额: $ 38.24万
• 依托单位: University of Iowa
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0968624&HistoricalAwards=false
• 关键词: Spectral; Characterization; Atmospheric; Dust; IR

Mineral dust aerosol plays a critical role in the atmosphere. Dust affects the Earth's radiation balance by direct absorption and scattering of light across the spectrum from infrared (IR) to ultraviolet (UV). Atmospheric dust particles also serve as sites for cloud nucleation indirectly affecting albedo, and as reactive surfaces for tropospheric reactions altering the chemical balance for important gas phase species such as SO2. Correctly modeling the effects of dust in weather, climate, and air quality requires accurate information about dust loading and composition, size and shape (CSS) distributions, as well as proper treatment of dust optical (scattering and absorption) properties. Dust loading and CSS distributions can be obtained by optical remote sensing. However, remote sensing dust retrievals also depend critically on an accurate treatment of aerosol optical properties. Thus, uncertainties in dust optical properties can lead to errors in estimated dust loading, and CSS distributions with deleterious consequences for weather and air quality forecasts and climate modeling.Intellectual merit. We will investigate dust optical properties across the IR-UV spectrum through laboratory measurements and modeling analyses. The study will focus on authentic dust samples. Aerosol extinction and light scattering properties will be analyzed by measurements of particle CSS distributions through real-time in situ single particle time-of-flight mass spectrometry and particle sizing, and various ex situ methodologies. Since the particle CSS distributions will be measured simultaneously with the optical properties, detailed comparisons with theoretical simulations will be possible, with few (or no) adjustable parameters.The main goals of this work are to establish methods for using spectroscopic and polarimetric measurements to infer mineral dust aerosol CSS distributions, and to explore how these distributions may be altered by atmospheric aging. The qualitative insight and quantitative data provided by this work can be incorporated into remote-sensing retrieval algorithms, improving the reliability of aerosol radiative transfer models for dust retrievals and climate forcing calculations, and thus transforming our understanding of the impact of dust on atmospheric chemistry, dynamics, and climate.Broader impacts. The proposed activities offer tremendous opportunities for post-doctoral fellows and students to develop as independent scientists. This research includes aspects of experimental aerosol science, light scattering, spectroscopy, and reaction kinetics studies, combined with an extensive theoretical modeling program. Students participate in all facets of the work, presenting their results at seminars and conferences. The PIs, through a long standing collaboration, have successfully mentored students andpost-doctors at all levels in preparation for professional careers in academia and industry. More than half of the students involved in the research program have been women or from underrepresented minorities. The program also maintains active collaborations with faculty from small colleges in state Iowa, enhancing their research and teaching.

矿物粉尘气溶胶在大气中起着至关重要的作用。尘埃通过从红外(IR)到紫外线(UV)的光谱直接吸收和散射光线，从而影响地球的辐射平衡。大气尘埃颗粒也是间接影响反照率的云核的场所，也是对流层反应的反应面，改变了二氧化硫等重要气相物种的化学平衡。正确模拟粉尘对天气、气候和空气质量的影响需要关于粉尘负荷和成分、大小和形状(CSS)分布的准确信息，以及对粉尘光学(散射和吸收)属性的适当处理。利用光学遥感技术可以获得沙尘负荷和大气中的浓度分布。然而，遥感尘埃的提取也严重依赖于对气溶胶光学性质的准确处理。因此，尘埃光学性质的不确定性可能会导致估计的尘埃载量和css分布的错误，从而对天气和空气质量预报以及气候建模造成有害后果。我们将通过实验室测量和模拟分析，研究尘埃在IR-UV光谱中的光学性质。这项研究将重点放在真实的尘埃样本上。气溶胶消光和光散射特性将通过实时单粒子飞行时间质谱仪和粒子大小测量以及各种非原位方法测量粒子的css分布来分析。由于颗粒的CSS分布将与光学性质同时测量，因此与理论模拟的详细比较将是可能的，只需很少(或没有)可调参数。这项工作的主要目标是建立利用光谱和偏振测量来推断矿物粉尘气溶胶的CSS分布的方法，并探索这些分布如何随大气老化而改变。这项工作提供的定性和定量数据可以纳入遥感反演算法，提高用于沙尘反演和气候强迫计算的气溶胶辐射传输模型的可靠性，从而改变我们对沙尘对大气化学、动力学和气候影响的理解。拟议的活动为博士后研究员和学生提供了作为独立科学家发展的巨大机会。这项研究包括实验气溶胶科学、光散射、光谱学和反应动力学研究的各个方面，并结合广泛的理论模拟程序。学生们参与工作的方方面面，在研讨会和会议上展示他们的成果。通过长期的合作，私人投资机构成功地指导了各级学生和博士后，为在学术界和工业界从事职业生涯做准备。参与该研究项目的学生中，超过一半是女性或来自代表性较低的少数族裔。该项目还与爱荷华州小型学院的教职员工保持积极合作，加强他们的研究和教学。