Program and Agenda

Abstract

FOUR-YEAR OBSERVATIONS OF EDDY HEAT AND MOMENTUM FLUXES ON A SECTION ACROSS DRAKE PASSAGE

The cDrake experiment (11/2007 - 11/2011) moored 20 current- and pressure-recording inverted echo-sounders across Drake Passage with 30-60km spacing. The Shackleton Fracture Zone (SFZ) slants across Drake Passage, intersecting cDrake mid-transect. This array provides full water-column estimates of temperature, density, and cross-frontal velocity to quantify meridional eddy heat and buoyancy fluxes, v’T’ and v’b’. Daily v’T’ time series generate mean values from many brief poleward pulses of growing baroclinic instability. Where cross-frontal heat fluxes are strong, downstream of SFZ in northern Drake Passage, their vertical structure is maximum (75kWm-2) near 300m depth, decreasing to 15kWm-2 between 1300m-3500m depths. Along the southern cDrake transect, upstream of SFZ, heat fluxes are 8 times smaller. Eddy buoyancy fluxes (EBF) have similar structure. Applying quasigeostrophic dynamics to EBF, interfacial form stress (IFS) is estimated; poleward EBF corresponds to downward flux of eastward momentum. Observed IFS structure is nearly uniform vertically (columnar). High northern values (0.6Nm-2) arise from energetic eddies downstream of SFZ, decreasing sharply southward across the Polar Front and SFZ to 0.05Nm-2.

http://www.cdrake.org

Authors

Watts, D. R., University of Rhode Island, USA, randywatts@mail.uri.edu

Tracey, K. L., University of Rhode Island, USA, krltracey@mail.uri.edu

Donohue, K. A., University of Rhode Island, USA, kdonohue@mail.uri.edu

Chereskin, T. K., University of California San Diego, USA, tchereskin@ucsd.edu

Details

Oral presentation

Session #:072
Date: 2/24/2014
Time: 09:30
Location: 323 ABC

Presentation is given by student: No