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Behavior of a wave-driven buoyant surface jet on a coral reef

Journal of Geophysical Research C: Oceans

By:
, , , and
https://doi.org/10.1002/2016JC011729

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Abstract

A wave-driven surface buoyant jet exiting a coral reef was studied in order to quantify the amount of water re-entrained over the reef crest. Both moored observations and Lagrangian drifters were used to study the fate of the buoyant jet. To investigate in detail the effects of buoyancy and along-shore flow variations, we developed an idealized numerical model of the system. Consistent with previous work, the ratio of along-shore velocity to jet-velocity and the jet internal Froude number were found to be important determinants of the fate of the jet. In the absence of buoyancy, the entrainment of fluid at the reef crest, creates a significant amount of retention, keeping 60% of water in the reef system. However, when the jet is lighter than the ambient ocean-water, the net effect of buoyancy is to enhance the separation of the jet from shore, leading to a greater export of reef water. Matching observations, our modeling predicts that buoyancy limits retention to 30% of the jet flow for conditions existing on the Moorea reef. Overall, the combination of observations and modeling we present here shows that reef-ocean temperature gradients can play an important role in reef-ocean exchanges.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Behavior of a wave-driven buoyant surface jet on a coral reef
Series title:
Journal of Geophysical Research C: Oceans
DOI:
10.1002/2016JC011729
Volume:
122
Issue:
5
Year Published:
2017
Language:
English
Publisher:
American Geophysical Union
Contributing office(s):
Pacific Coastal and Marine Science Center
Description:
22 p.
First page:
4088
Last page:
4109
Other Geospatial:
Moorea Reef