Meteorological Controls on Dust Emission and Transport in a Closed Basin

点击翻译按钮获取中文摘要

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.