The Role of Atlantic Versus Pacific Variability on Caribbean Drought

Rainfall across the Caribbean is projected to decrease in the 21st century, a trend that many global climate models agree upon. However, the majority of prior studies of Caribbean rainfall focus on either extreme wet events (e.g. from tropical cyclones) or the mid-summer drought, a feature of the seasonal rainfall cycle that is strongest in the Western Caribbean and Central America. Drought impacts across the Caribbean range from crop loses, increased food costs, and wild fires to severe landslides once the rain returns. Thus it is vital to understand the current large-scale climate drivers of long-term drought in the Caribbean, how these drivers interact, and whether these drivers will remain important in the future. This study uses a combination of observations, reanalysis and global climate model output from the Coupled Model Intercomparison Project phase 5 (CMIP5) to investigate Caribbean drought. Large-scale climate drivers of interest to the region that will be investigated include the drivers from the Pacific (e.g. El Niño Southern oscillation, Pacific-North America pattern, Pacific decadal oscillation) and the Atlantic (e.g. Atlantic multidecadal variability, North Atlantic oscillation) and the gradient between the tropical Pacific and Atlantic. The seasonal impact, timing, stationarity and interaction of these variability modes on Caribbean drought, measured using rainfall, will be investigated in detail for the historical period and future climate projections. The identification of the drivers of Caribbean droughts in observations and climate models allow us to better understand and potentially predict Caribbean droughts now and in the future.