Open-ocean response and normal mode excitation in an eddy-resolving general circulation model
作者:
ArthurJ. Miller,
WilliamR. Holland,
MyrlC. Hendershott,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1987)
卷期:
Volume 37,
issue 4
页码: 253-278
ISSN:0309-1929
年代: 1987
DOI:10.1080/03091928708210099
出版商: Taylor & Francis Group
关键词: Ocean Circulation;mesoscale currents;quasigeostrophic flows;Rossby waves
数据来源: Taylor
摘要:
Analysis of a two-layer, flat-bottom, steady-wind driven, eddy-resolving general circulation model reveals a distinct separation in frequency of baroclinic and barotropic motion in the region distant from the model Gulf Stream. The far-field motions at periods less (greater) than about 100 days are predominantly barotropic (baroclinic), unlike the near-field, eddy-generating, free-jet region which contains barotropic and baroclinic energy throughout the modei frequency range. The far-field barotropic energy produces a peak in the model sea-level spectra between 25 and 50 days with a magnitude comparable to energy levels observed in spectra of sea level from oceanic island tide gauges. The far-field barotropic motion is clearly composed of large-scale, resonant, barotropic normal modes drive by mesoscale activity of the turbulent, free-jet region. Oceanic mesoscale turbulence may therefore provide for planetary normal modes an excitation mechanism distinct from atmospheric forcing. The open-ocean, barotropic, model response is very similar to that of a fluctuating-wind driven model, which suggests that atmospheric and intrinsic forcing of mid-ocean eddies may be of comparable importance.
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