We introduced the first of its kind high-resolution drought dataset for the Caribbean region from 1950 to 2016, using monthly estimates of the “self calibrating” Palmer drought severity index (scPDSI), with the physically based Penman–Monteith approximation for the potential evapotranspiration. Statistically downscaled data products, including reanalysis, are employed to establish an historical baseline for characterizing drought from 1950 to the near present. Since 1950, the Caribbean has been affected by severe droughts in 1974–77, 1997/98, 2009/10, and 2013–16. Results indicate that the 2013–16 drought is the most severe event during the time interval analyzed in this work, which agrees with qualitative reports of many meteorological institutions across the Caribbean. Linear trends in the scPDSI show a significant drying in the study area, averaging an scPDSI change of −0.09 decade−1 (p < 0.05). However, this trend is not homogenous, and significant trends toward wetter conditions in portions of the study area were observed. Results further indicate a strong influence of both tropical Pacific and North Atlantic oceans in modulating drought variability across the study domain. https://journals.ametsoc.org/jcli/article/30/19/7801/342696/Insights-from-a-New-High-Resolution-Drought-Atlas
Climate change impacts on hydroclimate
Climate models project significant drying for the Caribbean as a consequence of increased anthropogenic greenhouse‐gas concentrations. Between 2013 and 2016, virtually, the entire region experienced a Pan‐Caribbean drought, which was unprecedented since at least 1950. We find that human‐caused warming contributed to ~15–17% of drought severity by increasing evapotranspiration rates and accounted for ~7% of land area under drought across the Caribbean. Our results therefore suggest that anthropogenic warming has already increased drought risk in the Caribbean.
From the Figure on the left, (a) scPDSI composite between July 2013 and October 2016, (b) and (c) are the same as (a) but with precipitation and Penman‐Monteith potential evapotranspiration (PET) anomalies, respectively. Both precipitation and PET anomalies are calculated as departures from the 1950–1980 climatology. The Caribbean averaged scPDSI time series is plotted in (d). Negative scPDSI values indicate drought, while positive values are pluvials. Finally, the drought area index between 1950 and 2016 across the Caribbean is plotted in (e). The Pan‐Caribbean drought affected ~98% of land area of the region. scPDSI = self‐calibrating Palmer Drought Severity Index.
Drought dynamics
We use a suite of renalyses and climate models to understand the dynamics underpinning drought in the Tropical Americas.