Asymmetry of free circulations in closed ocean Gyres

作者:LaCasce J H*; Nost O A; Isachsen P E
来源:Journal of Physical Oceanography, 2008, 38(2): 517-526.
DOI:10.1175/2007JPO3789.1

摘要

Steady flows in regions of closed geostrophic contours, such as in ocean basins or over seamounts, are examined by calculating solutions to the nonlinear quasigeostrophic and shallow-water equations with topography. For oceanically realistic choices of parameters, the solutions are asymmetric in that those with cyclonic circulation resemble the topography while those with anticyclonic circulation exhibit small-scale structure and cross-isobath flow. These small-scale structures reflect topographic wave modes, which are stationary with the anticyclonic circulation. The implication of the asymmetry is that random wind forcing is much more likely to excite persistent cyclonic than anticyclonic flow. This may explain why the circulation in the Norwegian and Greenland Gyres is most often cyclonic.

  • 出版日期2008-2
  • 单位中国极地研究中心