Aerosols-Climate Interactions: Characterization of Saltation, Dust Lifting, and Dust Electrification in Important Dust Source Regions

气溶胶通过散射和吸收太阳和红外辐射产生直接的气候强迫，通过改变云过程产生间接强迫。由于人类活动导致大气气溶胶浓度显著增加，因此了解气溶胶对气候的影响非常重要。尽管我们对气溶胶-气候相互作用的理解取得了相当大的进展，但矿物粉尘气溶胶的气候强迫仍然是当前气候模式中最不确定的过程之一（IPCC, 2007）。因此，研究扬尘气溶胶的抬升和输送对于准确评估气溶胶气候强迫具有重要意义。理论优点：矿物粉尘气溶胶通过跃迁被提升（喷射到大气中），并通过对流羽流（特别是它们的上升气流）、对流涡旋（尘卷）、沙尘暴（阵风锋扬起的灰尘）和大尺度风（风吹的灰尘）从地表转移出去。到目前为止，大多数研究都集中在沙尘暴和风吹尘埃等大规模过程的扬尘研究上，因为它们是全球气溶胶预算的最重要贡献者。然而，最近的研究表明，对流羽流和涡旋等小规模过程在全球矿物粉尘收支中也起着重要作用。这一结论与西非沙尘“热点”的年沙尘循环变化与干边界层对流产生的小尺度阵风变化密切相关，而与平均地面风变化无关的证据是一致的。为了充分了解气溶胶与气候的相互作用，我们必须了解涉及跃变的基本物理过程及其随土壤和天气条件的变化。该项目将通过研究内华达州的跃迁和扬尘来实现这一目标，该地区普遍存在小规模扬尘过程，欧文斯干湖是美国最重要的粉尘源地区之一。更广泛的影响：该研究有可能对科学和社会产生广泛的影响。除了研究对我们了解全球气候变化至关重要的科学问题外，我们还将把我们的数据和模型提供给科学界。我们有一个教育网站，提供对流羽流、尘卷风和沙尘暴形成的简单物理解释。该网站将包括对内华达州欧文斯干湖的天气和气候的描述。最后，这个项目将有助于培养研究生。

Aerosols produce a direct climate forcing by scattering and absorbing solar and infrared radiation, and an indirect forcing by altering cloud processes. Since human activity causes significant increases in the concentration of atmospheric aerosols, it is important to understand the effects of aerosols on climate. Despite considerable progress in our understanding of aerosols-climate interactions, climate forcing by mineral dust aerosols is still one of the most uncertain processes in current climate models (IPCC, 2007). Therefore, it is important to study the lifting and transport of dust aerosols so that aerosol climate forcing can be assessed accurately. Intellectual merits:Mineral dust aerosols are lifted (ejected into the atmosphere) by saltation and transported away from the surface by convective plumes (in particular, their updrafts), convective vortices (dust devils), dust storms (dust lifting by gust fronts), and large-scale winds (wind-blown dust). So far most research has focused on studies of dust lifting by large-scale processes such as dust storms and wind-blown dust because they are the most important contributors to the global aerosol budget. However, recent studies suggest that small-scale processes such as convective plumes and vortices also play an important role on the global mineral dust budget. This suggestion is consistent with evidence that variations in the annual dust cycle of West African dust "hot spots" are strongly correlated with variations in small-scale wind gusts produced by dry boundary layer convection, but not with variations in the mean surface wind.In order to fully understand aerosols-climate interactions we must understand the basic physical processes involved in saltation and their variability with soil and weather conditions. This project will achieve this goal by studying saltation and dust lifting in Nevada, an area where small-scale dust lifting processes are ubiquitous, the Owens Dry Lake, one of the most important dust source areas in the U.S.Broader impacts:The research has the potential to have a broad impact on science and society. Besides studying an important scientific problem key to our understanding of global climate change, we will make our data and models available to the scientific community. We have an educational website that provides simple physical explanations for the formation of convective plumes, dust devils, and dust storms. The website will include descriptions of the weather and climate of Nevada, the Owens Dry Lake. Finally, this project will contribute to the training of graduate students.