Spinup of a submesoscale eddy in the TOGA COARE intensive flux array during the spindown of an intense eastward jet

During the TOGA COARE Intensive Observing Period, an energetic, surface-int ensified, submesoscale cyclonic eddy was observed in the near-equatorial we stern Pacific warm pool. The eddy appeared to have been generated as part o f the spindown of a strong eastward surface jet forced by the December 1992 westerly wind burst. Because of its potential impacts on the long-term hea t, salt, and momentum budgets of the warm pool, the authors provide a thoro ugh description of the evolution of the surface jet and the development of the eddy in the present study. Both the isopycnal surface fit and the zerot h-order dynamic balance confirm the existence of the eddy. Surface layer co nvergence and northward inertial motion are suggested to be the main causes of the negative eddy vorticity, and it is likely that the eddy drew its en ergy from the decaying surface jet. This study indicates that in the near-e quatorial region the inertial motion has a decreasing meridional spatial sc ale with time, (betat)(-1), due to the beta effect, which increases the Ros sby number of the decaying jet and generates the nonlinearity.