A Two-Pronged Attack on the Problem of Aerosol Climate Forcing

针对气溶胶气候强迫问题的双管齐下

• 批准号: 0601177
• 负责人: Theodore Anderson
• 金额: $ 43.79万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0601177&HistoricalAwards=false
• 关键词: Two; Pronged; Attack; Problem; Aerosol

Essentially all mechanisms by which anthropogenic aerosol is thought to affect climate operate by changing the Earth's albedo (i.e. earth system's reflectivity for solar radiation). High resolution albedo products from satellites are becoming available at the same time that aerosol-sensing satellites are offering an improved ability to delineate the global distribution of anthropogenic aerosol. This suggests that a two-pronged approach to better understanding of aerosol climate forcing may be fruitful - one focused on cause (the global distribution and properties of anthropogenic aerosol), the other on effect (the space/time variability of albedo.) The principle investigators (PIs) are pursuing and integrating these two objectives.Regarding the first objective, the PIs are performing a global reassessment of the sub-micrometer aerosol particle size fraction contribution to aerosol optical depth, building on previous studies by their group. This size fraction represents most of the anthropogenic aerosol. Accurate satellite retrieval of this size fraction is key to empirical assessment of the global distribution of anthropogenic aerosol. Earlier, in collaboration with National Aeronautics and Space Administration (NASA) scientists, they compared satellite to in-situ estimates of aerosol particle loading in this size range. Key activities in the current project include (i) inter-comparing remote retrievals of aerosol characteristics from multiple satellite instruments and ground-based sun photometers, (ii) diagnosis of discrepancies using vertical distribution data from airborne and spaceborne lidar, (iii) global reassessment of submicrometer-size aerosol loading based on analysis of the wavelength dependence of optical depth, and (iv) assimilation of aerosol observations into a chemical transport model in coordination with a separate, NSF-funded, research project for improved estimates of the global distribution of anthropogenic aerosol. Regarding the second objective, the PIs are examining albedo variability at a variety of scales using a new observational tool. They are using downward-looking lidar (airborne and spaceborne) that allows the atmospheric causes of albedo variation to be diagnosed. They are examining the prevalence of states intermediate between traditionally-defined "cloud" and "aerosol" and seeking to detect and quantify the direct and indirect (through impact on haze and cloud properties) influence of anthropogenic aerosol on regional-mean albedo.Broader impacts of the research include its integration with teaching and outreach activities through the University of Washington Department of Atmospheric Sciences. It involves training a post-doctoral scientist and a graduate student. The research is closely coordinated with that of several national laboratories - e.g., National Oceanographic and Atmospheric Administration (NOAA) Pacific Marine Environment Laboratory, NOAA Earth Systems Research Laboratory, NASA Langley Research Center, NASA Goddard Space Flight Center, and NASA Ames Research Center. Improved knowledge of climate forcings derived from this project is essential to improved understanding of climate variability and change.

基本上，人为气溶胶影响气候的所有机制都是通过改变地球的反照率（即地球系统对太阳辐射的反射率）来起作用的。 卫星提供的高分辨率反照率产品正在变得可用，同时气溶胶传感卫星也提高了描绘人为气溶胶全球分布的能力。这表明，采用双管齐下的方法来更好地了解气溶胶气候强迫可能会取得成果 - 一个侧重于原因（人为气溶胶的全球分布和特性），另一个侧重于影响（反照率的空间/时间变化）。主要研究者（PI）正在追求并整合这两个目标。对于第一个目标，PI 正在对亚微米气溶胶粒径进行全球重新评估。 基于他们小组之前的研究，对气溶胶光学深度的分数贡献。该尺寸分数代表了大部分人为气溶胶。对这一尺寸分数的准确卫星反演是对人为气溶胶全球分布进行实证评估的关键。早些时候，他们与美国国家航空航天局（NASA）的科学家合作，将卫星与该尺寸范围内气溶胶颗粒负载的现场估计进行了比较。当前项目的主要活动包括（i）从多个卫星仪器和地面太阳光度计远程检索气溶胶特征进行相互比较，（ii）利用机载和星载激光雷达的垂直分布数据诊断差异，（iii）基于光学深度的波长依赖性分析对亚微米级气溶胶负荷进行全球重新评估，以及（iv）同化 与国家科学基金会资助的一个单独的研究项目协调，将气溶胶观测纳入化学传输模型，以改进对人为气溶胶全球分布的估计。关于第二个目标，PI 正在使用新的观测工具检查各种尺度的反照率变化。他们使用下视激光雷达（机载和星载）来诊断反照率变化的大气原因。他们正在研究传统定义的“云”和“气溶胶”之间状态的流行程度，并寻求检测和量化人为气溶胶对区域平均反照率的直接和间接影响（通过对雾霾和云特性的影响）。该研究的更广泛影响包括将其与华盛顿大学大气科学系的教学和外展活动相结合。它涉及培养一名博士后科学家和一名研究生。该研究与多个国家实验室密切合作，例如国家海洋和大气管理局（NOAA）太平洋海洋环境实验室、NOAA地球系统研究实验室、NASA兰利研究中心、NASA戈达德太空飞行中心和NASA艾姆斯研究中心。通过该项目提高对气候强迫的了解对于提高对气候变率和变化的理解至关重要。