Award: OCE-1558809

This project investigated the mechanisms that drive the vertical transport of water, containing nutrients, inside mesoscale ocean eddies, spinning bodies of water that have diameter from 100-200 km. The focus of this study was on warm-core Gulf Stream rings. These are large anticyclonic mesoscale eddies that form from meanders of the Gulf Stream. These warm-core rings are characterized by the accumulation of ware water in their cores. Traditionally, these types of eddies, anticyclones which are defined by their rotation being opposite that of Earth's rotation, have been characterized as areas of low primary production. The advent of satellite observations of the color of the ocean from which we can infer the amount of phytoplankton in the surface waters allowed oceanographers to start to question the previously accepted lack of primary production in these rings. Building on this new information, we developed a numerical simulation of these ring to diagnose which parts of the equations that describe the movement of water in eddies are dominant in the modulation of upwelling and downwelling in eddies. The results indicate the the prevalence of one term over another is very dependent on the scales at which one looks. For example, when looking at these warm-core rings for weeks to months, the upward movement of water resulting from the interaction of the surface currents of the eddy with the wind provides the largest contribution to upwelling. On the other hand, at small time and space scales, as would be observed by a ship occupying a ring for a number of days, the contribution of changes in the shape of the eddy are primarily driving the movement of water up and down. The results of this numerical simulation were presented in the Journal of Physical Oceanography. Last Modified: 09/28/2020 Submitted by: Peter Gaube