Characterization of the Effects of a Severe Drought on Dust Lifting

众所周知，大气中的尘埃颗粒通过吸收和散射辐射以及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尘埃载量的可变性，重要的是研究尘埃气溶胶是如何从地表输送到大气中的，这一过程被称为跃迁。这项奖励将为观察和分析加州欧文斯湖的数据提供资金，欧文斯湖是一个干燥的湖床，被认为是粉尘污染的重要来源。这项研究将寻求确定土壤颗粒分布、结皮土壤、水分和粉尘带电在跃迁中的作用。该项目的长期社会效益是通过在天气和气候系统中更好地反映沙尘，从而改善预报。在短期内，研究人员将与欧文斯山谷空气质量官员合作，提供与健康影响的直接联系，该项目还将有助于对学生的教育和培训。该研究项目将调查在各种天气现象和气候条件下，土壤成分、颗粒分布和土壤水分对跳跃层深度、跳跃强度、跳跃产生的电场和PM2.5气溶胶浓度的影响。该活动主要是观测性的，仪器安装在加利福尼亚州的欧文斯湖咸水游乐场。这项工作的三个主要目标是：1)跳跃和扬尘--继续和改进的测量将被用来检验关于垂直沙尘通量和近地表湿度之间相关性的相互矛盾的假说，2)电场对扬尘的影响-电场数据将被用来检验这样的假说，即电场将跳跃的粒子吸引到表面，抑制随着地表风切变应力的增加而跳跃层深度的增加，3)沙尘天气现象-研究人员将研究从小范围沙尘羽流和涡旋到更大范围沙尘暴的天气现象中跳跃层和扬尘的强度和深度，以准确量化每一种天气现象对沙尘循环的贡献。对流事件掀起的尘埃在细小颗粒中的含量更高的假设也将得到验证。

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.