Semester of Graduation
Spring 2025
Degree
Master of Oceanography and Coastal Sciences (SOCS)
Department
Oceanography and Coastal Sciences
Document Type
Thesis
Abstract
Every year, strong North African winds across the Sahara loft dust particles and advect them westward within the Saharan Air Layer (SAL). These plumes of dust often reach the Caribbean Sea and can heavily affect regional weather patterns by suppressing convection. When concentrations are high, decreased rainfall can yield negative societal and ecological impacts, potentially leading to drought. The Puerto Rican early rainfall season (ERS), spanning from 1 April through 31 July, overlaps with Saharan dust migration periods, and systematically detecting instances of SAL activity near the island is important for understanding longer-term drought-forcing trends in the region.
Corridors of high-percentile column-integrated dust flux were extracted from the MERRA-2 reanalysis data set to delineate between unique SAL events using methods similar to that of atmospheric river detection. The resulting dataset, lasting from 1980–2023 for the ERS months, reveals high variability in both SAL plume frequency and intensity throughout the tropical Atlantic. The frequency of ERS SAL dust plumes has increased over the 44-year study period by 0.5 days per year. The regions of maximum frequency vary annually and mostly center in the eastern tropical Atlantic. Using convective instability parameters for tropical convection, the influence of the SAL on instability is stronger in the Caribbean than farther west. Rainfall relationships during the ERS are less conclusive, as events often occur independently of the SAL, though strong SAL activity slightly reduces rainfall.
This study develops an objective SAL event database to assess the vulnerability of the Caribbean islands to dust, determine their role as a hydrometeorological forcing mechanism, project future SAL frequency, track prototypical Atlantic migration, and analyze its impact on mesoscale and synoptic convective instability.
Date
4-2-2025
Recommended Citation
Dolce, Charles H., "Identifying Saharan Air Layer Events and their Relationship to Instability and Rainfall Patterns in the Tropical North Atlantic Ocean" (2025). LSU Master's Theses. 6121.
https://repository.lsu.edu/gradschool_theses/6121
Committee Chair
Miller, Paul W.
Included in
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