735 / 2024-09-19 10:59:41

ENSO Modulates Mean Currents and Mesoscale Eddies in the Caribbean Sea and its Downstream Regions

ENSO,Ocean Currents,Caribbean Sea ,Northwestern Atlantic,Mesoscale Eddies

Although El Niño-Southern Oscillation (ENSO) and its global impacts through teleconnections have been studied for decades, the specific connection between ENSO and the mean currents and mesoscale eddies in the Caribbean Sea remains an open question. In this study, by analyzing satellite observations and several ocean reanalysis data, we identify a strong link between ENSO and the variability of mean currents and eddies in the Caribbean on interannual timescales. During strong El Niño events, we observe an increase in north-south sea surface height differences, which leads to stronger mean currents in the Caribbean Sea, with the reverse occurring during La Niña events. Eddy kinetic energy is modulated by ENSO through eddy-mean flow interactions, primarily via baroclinic instability, which releases the available potential energy stored in the mean currents to mesoscale eddies. Additionally, ENSO's influence on the mean currents and eddies in the Caribbean Sea propagates downstream, leading to interannual variations in the Gulf Stream and associated eddies. These findings suggest some level of predictability for mean currents and eddies in the Caribbean and its downstream regions, especially during strong El Niño and La Niña events. Given the similarities between our study regions and the Northwestern Tropical Pacific Ocean, including the South China Sea, it may be beneficial to evaluate existing studies or conduct similar investigations in the Northwestern Tropical Pacific.