Ocean–atmosphere variability and drought in the insular Caribbean

• Published in: International journal of climatology 2022-08, Vol.42 (10), p.5016-5037
• Main Authors: Moraes, Flávia D. S., Mote, Thomas L., Seymour, Lynne
• Format: Article
• Language: English
• Subjects: Atmospheric forcing; Drought; Drought index; Drying; Earthquakes; El Nino; El Nino phenomena; El Nino-Southern Oscillation event; Environmental hazards; Hazards; Hurricanes; insular Caribbean; North Atlantic Oscillation; Ocean-atmosphere system; scPDSI; Seasonal distribution; seasonal drought; Seasons; Seismic activity; Southern Oscillation; Spatial distribution; Statistical analysis; Teleconnection patterns; teleconnections
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.7517

The insular Caribbean experiences numerous climate and environmental hazards, including but not limited to hurricanes, floods, earthquakes, and drought. While some hazards are well explored in scientific literature, drought is considered one of the neglected hazards because of the lack of studies focusing on its causes and effects. This study identifies the spatial distribution of seasonal drought in insular Caribbean from 1950 to 2017, and its relationship with eastern Pacific (EP) and central Pacific (CP) ENSO, North Atlantic Oscillation (NAO), and Atlantic Meridional Mode (AMM). It brings a new perspective over the region by dividing the Caribbean into Greater Antilles and Bahamas (GA), and the Lesser Antilles (LA) to compare the role of those three teleconnection patterns on drought events over larger versus smaller islands. We used an existing high‐resolution drought atlas (4 km) based on monthly estimates of the self‐calibrating Palmer Drought Severity Index (scPDSI). Results indicate that there is a drying trend in all seasonal‐average scPDSI for both the GA and the LA, but more intense and frequent drought events occur in the LA. The LA is also the region with more widespread drought events, registering 12 years when the mid‐summer dry spell (MSD; July–August) had drought ≥80% of the area, while the GA registered only 2 years of MSD drought that extensive. The peak season AMM had the strongest positive correlation with GA and LA drought during April–November, while NAO was slightly stronger correlated with GA than with LA from July–November. For ENSO, CP El Niño years related stronger with drought in the LA from December–July, while the relationship between the two types of ENSO and the GA was not statistically significant. This effort aims to improve drought forecasts to help the region to better prepare for the prediction of seasonal droughts. Drought is considered one of the neglected hazards in the insular Caribbean because of the lack of studies focusing on its causes and effects. However, this study shows that there is a drying trend in the region since 1950, and the smaller islands are suffering with more frequent, intense, and widespread drought events when compared to the larger islands. Among the teleconnection patterns, the negative phase of Atlantic Meridional Mode is the one most strongly correlated with seasonal drought events.