The interaction of recirculation gyres and a deep boundary current
Le Bras, Isabela Astiz
Jayne, Steven R.
Toole, John M.
MetadataShow full item record
KeywordBoundary currents; Meridional overturning circulation; Mesoscale processes; Ocean circulation; Potential vorticity; Quasigeostrophic models
Motivated by the proximity of the Northern Recirculation Gyre and the deep western boundary current in the North Atlantic, an idealized model is used to investigate how recirculation gyres and a deep flow along a topographic slope interact. In this two-layer quasigeostrophic model, an unstable jet imposed in the upper layer generates barotropic recirculation gyres. These are maintained by an eddy-mean balance of potential vorticity (PV) in steady state. The authors show that the topographic slope can constrain the northern recirculation gyre meridionally and that the gyre’s adjustment to the slope leads to increased eddy PV fluxes at the base of the slope. When a deep current is present along the topographic slope in the lower layer, these eddy PV fluxes stir the deep current and recirculation gyre waters. Increased proximity to the slope dampens the eddy growth rate within the unstable jet, altering the geometry of recirculation gyre forcing and leading to a decrease in overall eddy PV fluxes. These mechanisms may shape the circulation in the western North Atlantic, with potential feedbacks on the climate system.
Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 48 (2018): 573-590, doi:10.1175/JPO-D-17-0206.1.
Suggested CitationArticle: Le Bras, Isabela Astiz, Jayne, Steven R., Toole, John M., "The interaction of recirculation gyres and a deep boundary current", Journal of Physical Oceanography 48 (2018): 573-590, DOI:10.1175/JPO-D-17-0206.1, https://hdl.handle.net/1912/10366
Showing items related by title, author, creator and subject.
Potential vorticity structure in the North Atlantic western boundary current from underwater glider observations Todd, Robert E.; Owens, W. Brechner; Rudnick, Daniel L. (American Meteorological Society, 2016-01)Potential vorticity structure in two segments of the North Atlantic’s western boundary current is examined using concurrent, high-resolution measurements of hydrography and velocity from gliders. Spray gliders occupied 40 ...
Spreading of Denmark Strait overflow water in the western subpolar North Atlantic : insights from eddy-resolving simulations with a passive tracer Xu, Xiaobiao; Rhines, Peter B.; Chassignet, Eric P.; Schmitz, William J. (American Meteorological Society, 2015-12)The oceanic deep circulation is shared between concentrated deep western boundary currents (DWBCs) and broader interior pathways, a process that is sensitive to seafloor topography. This study investigates the spreading ...
Yang, Jiayan; Pratt, Lawrence J. (American Meteorological Society, 2014-12)The East Greenland Current (EGC) had long been considered the main pathway for the Denmark Strait overflow (DSO). Recent observations, however, indicate that the north Icelandic jet (NIJ), which flows westward along the ...