CAREER: From Dust to Drought: Understanding the Multi-Scale Relationship between the Saharan Air Layer and Caribbean Water Stress

Louisiana State University, Baton Rouge LA

Investigators

Abstract

The Saharan Air Layer (SAL) is a well-known meteorological phenomenon where dry air and dust from the Saharan Desert is advected across the Atlantic Ocean. The SAL has received significant scientific attention due to the role that it plays in air quality and inhibiting tropical cyclone formation. Recent work has also shown that the SAL can impact drought in the Caribbean. This project will address the factors that lead to the development of drought in the Caribbean, with a specific focus on Puerto Rico. The societal impact of this project is significant because the Caribbean Islands rely heavily on regular precipitation to meet agricultural, ecological, and municipal water needs. The lead researcher is a founding member of the Caribbean drought resource group SECARIBE and will share research findings with local water managers and operational weather forecasters. There is also a significant education and outreach component to the project with a two-week intensive summer course, aerosol workshop, participation in the Ocean Commotion K-8 event, and development of an interest segment with a local television station. The goal of this project is to address the question of how Saharan dust affects water stress in the insular Caribbean region. This project will pioneer three major innovations: (1) Develop a multi-decade dataset of SAL events and their morphological behavior; (2) Assess the morphological behavior in (1) as a function of the embedded dust load; and (3) Determine evaporative demand in the SAL destination region as a function of the dust load. Whereas previous research expressly considers dust as a rainfall suppressant, this is the first effort to extend the dust-warming effect to surface drought dynamics via evaporative demand. This project will use climatological analyses and numerical modeling using WRF-Chem to address three main hypotheses: 1) SALs are more frequent and/or stronger during drought years in the Caribbean, 2) Suspended dust within the SAL actively influences SAL evolution across the Atlantic, and 3) Dust-driven warming increases near-SAL evaporative demand, promoting flash drought. This project is jointly funded by Physical and Dynamic Meteorology, the Established Program to Stimulate Competitive Research (EPSCoR), and Climate and Large-scale Dynamics. 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.