What drives upwelling patterns in the southeastern Caribbean Sea? Analysis of local an remote sensing data

Digna T Rueda Roa, University of South Florida. collegue of Marine Sciences, digna@marine.usf.edu
Tal Ezer, Old Dominium University, tezer@ccpo.odu.edu
Frank Muller-Karger, University of Massachusetts, fmullerkarger@umassd.edu (Presenting)

About 15 years of data, including Sea Surface Temperature (SST) from AVHRR data, QuikSCAT wind data, and satellite-derived Sea Surface Height (SSH) from Altimetry data, as well as local hydrographic and meteorological data, are analyzed in order to evaluate potential forcing mechanisms for the observed pattern of upwelling along the southeastern Caribbean coast. Strong trade wind-driven upwelling during late winter and early spring has been described before, but secondary upwelling events around June-July when the coastal wind is relatively weak, has not been fully explained yet. The small Antilles experiences a wind speed peak during June-July when the southeastern coast presents a decrease in wind, generating a latitudinal wind speed gradient. Basin-wide analyses show that offshore wind patterns creates strong wind-stress curl that supports an Ekman-driven upwelling maximum during summer, with a pattern that resembles the observed secondary upwelling pattern along the coast. Also, there are seasonal variations in Caribbean eddies with an increasing activity during summer in the Eastern Caribbean. Although the secondary upwelling is short-lived and less intense, together with the main upwelling it extends the presence of cooler waters in the southeastern Caribbean to 7-8 months, with important consequences for biological productivity and fisheries in the region.