Meridional location of the Pacific Ocean subtropical gyre

Richard Kleeman, N. H. Naik, M. A. Cane

Research output: Contribution to journalArticle

Abstract

The observed subtropical gyre in the North Pacific shows a shift in meridional location with depth. At shallow levels the density deviation peaks at around 15°N while at deep levels the peak is more like 30°N. It is argued here using analytical solutions to the beta-plane shallow-water equations that such a shift can be explained by the effects of oceanic dissipation processes. These solutions show that the highly damped solution is approximately proportional to Ekman pumping whereas the lightly damped case tends towards the classical Sverdrup solution. In the North Pacific, Ekman pumping peaks near 15°N while the Sverdrup solution peaks at 30°N. It is further demonstrated that 1) density deviations in the upper ocean are more highly influenced by higher order baroclinic modes than those in the deep, which are influenced by the lower modes, and 2) constant dissipation effectively acts much more strongly on the higher order baroclinic modes because of their slower speeds and smaller Rossby radii. These two factors thus explain the observed shift in the gyre with depth.

Original languageEnglish (US)
Pages (from-to)1988-2000
Number of pages13
JournalJournal of Physical Oceanography
Volume30
Issue number8
StatePublished - 2000

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Ekman pumping
baroclinic mode
gyre
dissipation
beta-plane
shallow-water equation
ocean
upper ocean
effect
speed

ASJC Scopus subject areas

  • Oceanography

Cite this

Meridional location of the Pacific Ocean subtropical gyre. / Kleeman, Richard; Naik, N. H.; Cane, M. A.

In: Journal of Physical Oceanography, Vol. 30, No. 8, 2000, p. 1988-2000.

Research output: Contribution to journalArticle

Kleeman, Richard ; Naik, N. H. ; Cane, M. A. / Meridional location of the Pacific Ocean subtropical gyre. In: Journal of Physical Oceanography. 2000 ; Vol. 30, No. 8. pp. 1988-2000.
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