Characterization of the Effects of a Severe Drought on Dust Lifting

严重干旱对扬尘影响的表征

• 批准号: 1526444
• 负责人: Nilton Renno
• 金额: $ 67.2万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1526444&HistoricalAwards=false
• 关键词: Characterization; Effects; Severe; Drought; Dust

Dust particles in the atmosphere are known to affect weather and climate through the absorption and scattering of radiation and through their ability to affect cloud processes. In order to better understand the variability of dust loading in the atmosphere it is important to study how dust aerosols are transported from the surface to the atmosphere, a process known as saltation. This award will provide funding for observations and analysis of data from the Owens Lake playa in California, a dry lake bed that is known as a significant source of dust pollution. The research will seek to determine the roles of soil particle size distribution, crusted soil, water content, and dust electrification in saltation. The long-term societal benefits of the project are through better representation of dust in the weather and climate system, thereby improving forecasts. In the shorter-term the researchers will work with the Owens Valley air quality officer, offering a direct link to health effects, and the project will also contribute to the education and training of students.This research project will investigate the effects of soil composition, particle size distribution, and soil water content on the depth of the saltation layer, the intensity of saltation, the electric fields generated by saltation, and the PM2.5 aerosol concentration as a function of wind shear stress in a variety of weather phenomena and climate conditions. The campaign is primarily observational, with instrumentation residing in the Owens Lake salty playa in California. The three main objectives of the work are in the following areas: 1) Saltation and dust lifting - Continued and improved measurements will be used to test competing hypotheses about the correlation between vertical dust flux and near surface humidity, 2) Effects of electric fields on dust lifting - Electric field data would be used to test the hypothesis that electric forces attract saltating particles toward the surface, inhibiting increases in the depth of the saltation layer with increases in wind shear stress at the surface, and 3) Dusty weather phenomena - The researcher will study the intensity and depth of the saltation layer and dust lifting in weather phenomena ranging from small-scale dusty plumes and vortices to larger-scale dust storms to accurately quantify the contributions from each to the dust cycle. The hypothesis that dust lifted by convective events is much richer in fine particles will also be tested.

众所周知，大气中的尘埃粒子通过吸收和散射辐射以及通过它们影响云过程的能力来影响天气和气候。为了更好地了解大气中粉尘负荷的可变性，研究粉尘气溶胶如何从地表输送到大气中是很重要的，这一过程被称为跃变。该奖项将为观察和分析来自加利福尼亚州欧文斯湖playa的数据提供资金，欧文斯湖是一个干燥的湖床，被称为粉尘污染的重要来源。该研究将试图确定土壤粒度分布、结壳土壤、含水量和粉尘电气化在跃变中的作用。该项目的长期社会效益是通过更好地代表天气和气候系统中的尘埃，从而改进预报。在短期内，研究人员将与欧文斯谷空气质量官员合作，提供与健康影响的直接联系，该项目还将有助于学生的教育和培训。本课题将研究在多种天气现象和气候条件下，土壤成分、粒径分布和土壤含水量对跃变层深度、跃变强度、跃变电场以及PM2.5气溶胶浓度与风切变应力的关系。该活动主要是观测性的，仪器驻留在加利福尼亚州的欧文斯湖盐湖上。这项工作的三个主要目标是在以下领域：1)跃变和扬尘——持续和改进的测量将用于测试关于垂直尘埃通量与近地表湿度之间相关性的竞争性假设。2)电场对扬尘的影响——电场数据将用于测试这样的假设，即电场吸引跃变粒子向地表移动，抑制随着地表风切变应力的增加而增加的跃变层深度。3)沙尘天气现象。研究人员将研究小尺度沙尘羽流和涡旋到大尺度沙尘暴等天气现象中跃变层的强度和深度以及沙尘抬升，以准确量化每种天气现象对沙尘循环的贡献。关于由对流事件扬起的尘埃含有更丰富的细颗粒的假设也将得到验证。