Files
Abstract
The limited groundwater capacity of Puerto Rico makes rainfall critically important. In the past, rainfall perturbations for the island led to droughts that resulted in water rationing and threatened the biodiversity of the island’s tropical rainforest in the Luquillo Mountains. Rainfall suppression can occur during the early rainfall season (ERS) from Saharan Air Layer influences on thermodynamics. Global Climate Models (GCM) predict droughts to continue but are too coarse to provide a regional analysis for Puerto Rico. GCM output from European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5) and Coupled Model Intercomparison Project Phase 5 (CMIP5) were dynamically downscaled with the Weather Research and Forecasting Model. Analysis periods consisted of a historical period from 2014–2018 and future periods from 2045–2049 and 2085–2089. Future aerosol measurements and atmospheric patterns support longer dust intrusions into the Caribbean. In the Luquillo Mountains, between the historical and end-century periods ERS rainfall decreases significantly with (80%) and without (63%) dust. The most significant declines occur by the end of the mid-century. Similarly, convective potential decreases, but May and June remain the most convective months of the dust season.