SGER: Exploration of a Tracer Patch in the Tropical Atlantic and Caribbean Sea

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

Exploration of a Tracer Patch in the Tropical Atlantic and Caribbean Sea J. Ledwell WHOI Sampling of a tracer patch released in 2001 in the tropical Atlantic Ocean and Caribbean Sea is proposed. The main goals of the sampling are to quantify the surprisingly large zonal dispersion of the tracer in the tropical Atlantic, and to measure the diapycnal diffusivity of the tracer in the pycnocline of the Caribbean, where susceptibility to salt fingering is nearly as great as east of Barbados, but where thermohaline staircases are rare. Other important goals are to determine the nature of the apparent sinking of the tracer distribution in the staircase region east of Barbados, to obtain a 2-year measurement of the diapycnal diffusivity there, and to determine the westward extent of the tracer patch at 2 years. Exploration of zonal dispersion in both the Atlantic and Caribbean will provide unique data with which to compare models of ocean circulation, and may help to improve knowledge of shear across the subtropical front. Measurement of diapycnal diffusivity in the Caribbean will improve parameterizations of mixing as a function of density ratio, i.e., as a function of temperature and salinity gradients, in salt-finger favorable regions with high shear. The nature of the survey is exploratory in all of its goals, and furthermore, the request for support is temporally urgent because of the speed with which the tracer patch will spread and be swept through the region of the study. Sampling should be done in 2003.