Caribbean Sea eddies inferred from TOPEX/POSEIDON altimetry and a 1/6 degrees Atlantic Ocean model simulation

Large cyclonic and anticyclonic eddies are found in the Caribbean Sea. Anal ysis of sea level data from the TOPEX/POSEIDON altimeter shows that the edd ies are quite regular, appearing at near 3-month intervals west of the sout hern Lesser Antilles. These eddies progress westward at average speeds of 1 2 cm s(-1), growing in amplitude up to 20 cm. Many eddies dissipate in the coastal waters of Nicaragua a half year after they appear. A 1/6 degrees x 1/6 degrees general circulation model of the Atlantic is shown to reproduce major features of the eddy life cycle, including their amplitudes, tempora l scales, and propagation speed. Analysis of the model output further sugge sts that the eddies are mainly limited to the thermocline and above, with l ittle phase lag in the vertical. The simulated eddies have sufficiently str ong currents that the horizontal gradient of total vorticity changes sign, suggesting that conversions from mean to eddy kinetic energy may be contrib uting to their growth. Analysis of the simulation links eddies in the Carib bean with eddies formed outside the Caribbean at the confluence of the Nort h Brazil Current and North Equatorial Countercurrent systems.