BAROTROPIC TRANSPORT OF THE ANTARCTIC CIRCUMPOLAR CURRENT MEASURED IN DRAKE PASSAGE
A four-year continuous record of barotropic transport was measured with a line of current and pressure recording inverted echo sounders spanning Drake Passage, November 2007 to November 2011. The four-year mean eastward transport determined from the near-bottom current meter records is 49 Sv with an uncertainty near 5 Sv. This mean transport translates to a mean across-passage eastward bottom-reference velocity of 1.5 cm/s. The annual means are remarkably stable. Summing mean barotropic transport and mean baroclinic transport relative to zero at the seafloor (126 Sv) gives a total transport of 175 Sv through Drake Passage. Thus the barotropic component accounts for 27% of the total. Comparisons of the mean transport determined from current measurements with that from bottom pressure measurements provides an estimate of a 0.06 dbar pressure drop by form drag across the Shackleton Fracture Zone. Barotropic transport fluctuations have temporal standard deviation 18 Sv. Fluctuations with periods greater than 20 days account for 60% of the variance. The temporal standard deviation of baroclinic transport is 9 Sv; therefore, the barotropic component contributes 80% to the total variability.
Tracey, K. L., University of Rhode Island, USA, firstname.lastname@example.org
Donohue, K. A., University of Rhode Island, USA, email@example.com
Watts, D. R., University of Rhode Island, USA, firstname.lastname@example.org
Time: 16:00 - 18:00
Location: Poster/Exhibit Hall
Presentation is given by student: No