Measuring Vortex Force and Turbulence Fluxes in the Oceanic Surface Boundary Layer

University Of Washington, Seattle WA

Investigators

Abstract

0002331 Lien/UW The intent of this study is to use a novel instrument, the Electromagnetic Vorticity Meter, to directly measure the flow vorticity which, in combination with the Stokes drift associated with the surface waves, gives rise to the "vortex force," identified by theoretical explanations of roll vortices in the mixed layer (Langmuir cells) as the primary cause of these vortices. An additional objective is to determine which component of vorticity, vertical or horizontal, is most critical for Langmuir cell formation and hence distinguish between competing theories. The vorticity measurements will be supplemented with observations of temperature, salinity and turbulence parameters. While theories of Langmuir cells have existed for a long time, direct verification of their central hypotheses with field observations has been lacking because of the difficulty of directly measuring vorticity in the mixed layer. This study holds out the possibility of being able to make such measurements. A better understanding of Langmuir cells will help oceanographers develop a clearer picture of mixing in the upper few meters of the ocean and may lead to improved representations of such mixing in computer models of oceans and climate.