Overflow into the deep Caribbean

Effects of plume variability

Parker MacCready, William E Johns, Claes G. Rooth, David M. Fratantoni, Roy A. Watlington

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

The deepest connection between the eastern Caribbean and the Atlantic is over the Jungfern-Grappler Sill complex at 1815 m depth. Through these gaps flows the sole source of water for the deep Caribbean, presumably balanced by diffusively driven upwelling elsewhere in the basin. Fourteen-month-long moored observations at the sills in 1991-1992 reveal a mean transport of 0.11±0.05 Sv (1 Sv ≡ 106 m3 s-1) of Atlantic water colder than θ=3.965°C flowing into the Caribbean, one quarter of which comes over the previously unmeasured Grappler Sill. This is about twice the transport seen in previous, shorter experiments. The overflow is highly episodic, with ∼10 "events" per year. The range of overflow density is comparable to the total vertical stratification of the deep Caribbean. A numerical stream-tube model of the overflow plume is run with 13 different initial conditions, representing the observed range of overflow strength and density. Results indicate that much of the overflow only penetrates to 2200-3000 m depth and was dense enough to descend to the bottom of the Caribbean only ∼1% of the time. Combined plume model results are used to drive a model of the basin stratification. A steady balance is found to be possible with small diapycnal diffusivity in the basin, between 0.1 and 0.6 cm2 s-1. The reason for the small diffusivity is that the stratification is essentially built in place by the different detrainment depths, and so less diffusive transformation is needed.

Original languageEnglish (US)
Article number1999JC900206
Pages (from-to)25913-25935
Number of pages23
JournalJournal of Geophysical Research C: Oceans
Volume104
Issue numberC11
StatePublished - Nov 15 1999

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stratification
sill
plumes
plume
diffusivity
basin
cold water
Water
upwelling water
upwelling
tubes
water
effect
experiment
Experiments

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography

Cite this

MacCready, P., Johns, W. E., Rooth, C. G., Fratantoni, D. M., & Watlington, R. A. (1999). Overflow into the deep Caribbean: Effects of plume variability. Journal of Geophysical Research C: Oceans, 104(C11), 25913-25935. [1999JC900206].

Overflow into the deep Caribbean : Effects of plume variability. / MacCready, Parker; Johns, William E; Rooth, Claes G.; Fratantoni, David M.; Watlington, Roy A.

In: Journal of Geophysical Research C: Oceans, Vol. 104, No. C11, 1999JC900206, 15.11.1999, p. 25913-25935.

Research output: Contribution to journalArticle

MacCready, P, Johns, WE, Rooth, CG, Fratantoni, DM & Watlington, RA 1999, 'Overflow into the deep Caribbean: Effects of plume variability', Journal of Geophysical Research C: Oceans, vol. 104, no. C11, 1999JC900206, pp. 25913-25935.
MacCready P, Johns WE, Rooth CG, Fratantoni DM, Watlington RA. Overflow into the deep Caribbean: Effects of plume variability. Journal of Geophysical Research C: Oceans. 1999 Nov 15;104(C11):25913-25935. 1999JC900206.
MacCready, Parker ; Johns, William E ; Rooth, Claes G. ; Fratantoni, David M. ; Watlington, Roy A. / Overflow into the deep Caribbean : Effects of plume variability. In: Journal of Geophysical Research C: Oceans. 1999 ; Vol. 104, No. C11. pp. 25913-25935.
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