Meteorological Controls on Dust Emission and Transport in a Closed Basin

就质量而言，尘埃是地球大气中最普遍的气溶胶。由于矿物气溶胶影响水文循环、海洋和陆地的营养收支以及辐射能量收支，因此粉尘在地球天气和气候中起着重要作用。大气总沙尘负荷的很大一部分是由于封闭的地形洼地（封闭盆地）的排放，但对这种地形特征控制沙尘排放的气象过程知之甚少。该项目旨在通过对来自索尔顿盆地的沙尘暴的观测和数值分析，阐明对封闭盆地中粉尘排放和运输的气象控制，从而解决这一认识上的差距。索尔顿盆地是加利福尼亚州东南部一个经常经历沙尘暴的封闭的海平面以下盆地。以前的实地研究侧重于阐明撒哈拉沙漠最大沙尘源内沙尘排放和运输的气象控制，但本文提出的初步结果表明，封闭盆地内沙尘排放和运输的基本气象过程与撒哈拉沙漠广阔沙尘源地区的气象过程非常不同。本项目将重点研究暖风事件对沙尘排放的影响。索尔顿海是一个巨大的浅湖，填满了索尔顿盆地的最低部分，索尔顿盆地是1905年由试图灌溉帝王谷的工程师偶然创造的。2017年颁布的新立法导致索尔顿海的淡水输入大量减少，预计索尔顿海的水位将在未来十年大幅下降，其表面面积可能缩小100至200平方英里。该项目还将阐明海洋干燥对导致沙尘排放的气象过程的影响，并估计不断扩大的干盐湖将如何影响盆地的总沙尘负担。这项研究的更广泛影响集中在利用新的科学发现为政策提供信息，并改善在受影响地区生活和工作的25万人因暴露于空气中粉尘而产生的人类健康结果。科学结果将通过该州的索尔顿海管理计划（SSMP）与利益相关者进行沟通，以便为政策决策提供信息，特别是在旨在减少干燥playa粉尘排放的管理活动方面。此外，将开发和验证WRF-Chem的预报版本，以便提供该地区5天的尘埃浓度预报。这些预报的主要目标是为弱势群体、卫生保健提供者和急救人员提供机会，减轻与当地沙尘暴有关的不利人类健康和安全风险。首席研究员（PI）将与SSMP的公共推广委员会合作，以接触相关利益相关者并提高预测产品的效用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

By mass, dust is the most pervasive aerosol in the Earth's atmosphere. Dust plays an important role in the Earth's weather and climate since mineral aerosols affect the hydrological cycle, oceanic and terrestrial nutrient budget, and radiative energy budget. A large fraction of the total atmospheric dust load is due to emission from closed topographic depressions (closed basins), yet little is known about the meteorological processes controlling dust emission from such topographic features. The project aims to address this gap in understanding by elucidating the meteorological controls on dust emission and transport in a closed basin via observational and numerical analysis of dust storms originating in the Salton Basin, a closed sub-sea level basin in extreme southeastern California that experiences frequent dust storms.Previous field studies have focused on elucidating the meteorological controls on dust emission and transport within the largest dust sources in the Sahara, yet the initial results presented here suggest that the meteorological processes fundamental to dust emission and transport in a closed basin are very different from those over the expansive source regions in the Sahara. This project will focus on the role of warm Foehn events on dust emission. The Salton Sea is the large shallow lake that fills the lowest portions of the Salton Basin, which was accidentally created in 1905 by engineers attempting to irrigate the Imperial Valley. New legislation enacted in 2017 is resulting in a massive reduction in freshwater input to the Salton Sea and it is expected that the level of the Salton will drop so much over the next decade that its surface area may shrink by 100 to 200 square miles. This project will also elucidate the effect of the drying of the Sea on the meteorological processes responsible for dust emission and estimate how the expanding dry playa will influence the total dust burden for the basin.The Broader Impacts of this research center on using the new scientific findings to inform policy and improve human health outcomes from exposure to airborne dust for the quarter-million people living and working in the affected area. Scientific results will be communicated with stakeholders via the state's Salton Sea Management Program (SSMP) in order to inform policy decisions, particularly in terms of those management activities aimed at reducing dust emission from the dry playa. Additionally, a forecast version of WRF-Chem will be developed and validated in order to provide 5-day forecasts of dust concentrations for the region. The main goal of these forecasts will be to afford vulnerable groups, health care providers and first responders an opportunity to mitigate adverse human health and safety risks associated with local dust storms. The Principal Investigator (PI) will work with the SSMP's Public Outreach Committee in order to reach relevant stakeholders and improve the utility of the forecast products.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.