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AGU: Geophysical Research Letters

 

Keywords

  • Meridional Overturning Circulation
  • Antarctic Circumpolar Current
  • MOC-ACC interaction

Index Terms

  • Oceanography: General: Arctic and Antarctic oceanography
  • Oceanography: General: Numerical modeling
  • Oceanography: Physical: Deep recirculations
  • Oceanography: Physical: General circulation

Abstract

Interhemispheric influence of surface buoyancy conditions on a circumpolar current

Neven S. Fučkar

Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, New Jersey, USA

Geoffrey K. Vallis

Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, New Jersey, USA

NOAA Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA

This study shows that the surface buoyancy conditions in the Northern Hemisphere may influence the stratification and transport of the Antarctic Circumpolar Current (ACC). We use a course-resolution ocean general circulation model (OGCM) in an idealized single-basin configuration with a circumpolar channel. A decrease in the magnitude of the surface temperature meridional gradient in the Northern Hemisphere reduces production of the deep water, affecting the interhemispheric Meridional Overturning Circulation (MOC) and deepening the thermocline in both hemispheres. The induced change of stratification in the Southern Hemisphere circumpolar region increases the zonal volume transport of circumpolar current because of an increase in the local meridional density gradient and the associated thermal wind shear, which is the dominant baroclinic component of the total volume transport. The result is robust to variations in the background vertical mixing and the parameterization scheme for mesoscale eddies.

Received 14 April 2007; accepted 25 June 2007; published 24 July 2007.

Citation: Fučkar, N. S., and G. K. Vallis (2007), Interhemispheric influence of surface buoyancy conditions on a circumpolar current, Geophys. Res. Lett., 34, L14605, doi:10.1029/2007GL030379.

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