Hydroclimate Variability and Dynamics in the Circum-Caribbean in the Common Era Using New Paleoclimate Records and Model Simulation Experiments

The long-term pattern in the frequency and severity of multi-year drought in the Caribbean is poorly understood. While there is progress in the reconstruction of long-term drought history and dynamical drivers of drought in the continental regions surrounding the Caribbean, there is a gap in data for the Caribbean islands. For Mesoamerica, there is evidence that the mechanisms the drive multi-year drought include changes in moisture transported by winds associated with patterns in sea surface temperature in the tropical Atlantic and Pacific oceans. However, it is unknown whether these patterns are associated with drought in the Caribbean, or if droughts occur in Mesoamerica and the Caribbean at the same time. This project will reconstruct the long-term history of drought in the Caribbean using measurements of blue intensity of Pinus occidentalis Swartz (Hispaniolan pine), an endemic tree species on Hispaniola Island which is known to form annual rings. The project will also conduct climate model experiments to investigate the mechanisms that drive multi-year drought in the circum-Caribbean, and estimate the risk of future multi-year drought. The Broader Impacts include support for undergraduate and graduate student participation in the project and a 5-day workshop on dendrochronology, data science, and modeling at Universidad Autónoma de Santo Domingo. The goal of the project is to collect samples from and measure blue intensity in Pinus occidentalis Swartz from the Dominican Republic to reconstruct past drought. The frequency, duration and magnitude of the past interannual and decadal droughts will be assessed from the new data and the existing drought atlases from North America and Mexico, Caribbean and tropical Americas. Mechanisms for past drought will be investigated with existing climate model ensembles and new simulations with Community Atmospheric Model 6 (CAM6). A hybrid statistical-dynamic approach will be used to estimate future drought risk in the region. The Broader Impacts include support for undergraduate and graduate student participation in the project and a 5-day workshop on dendrochronology, data science, and modeling at Universidad Autónoma de Santo Domingo. 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.