Document Type

Article

Publication Date

7-2017

Publication Title

Deep Sea Research Part I: Oceanographic Research Papers

Keywords

Undercurrent, Surface undercurrent, Western boundary current, Alongshore pressure gradient, Ekman transport, Bottom boundary layer

ISSN

0967-0637

Volume

125

First Page

94

Last Page

105

Abstract

A suite of long-term in situ measurements in the Straits of Florida, including the ADCP bottom moorings at an 11-m isobath and 244-m isobath (Miami Terrace) and several ADCP ship transects, have revealed a remarkable feature of the ocean circulation - southward flow on the western, coastal flank of the Florida Current. We have observed three forms of the southward flow - a seasonally varying coastal countercurrent, an undercurrent jet attached to the Florida shelf, and an intermittent undercurrent on the Miami Terrace. According to a 13-year monthly climatology obtained from the near-shore mooring, the coastal countercurrent is a persistent feature from October through January. The southward flow in the form of an undercurrent jet attached to the continental slope was observed during five ship transects from April through September but was not observed during three transects in February, March, and November. This undercurrent jet is well mixed due to strong shear at its top associated with the northward direction of the surface flow (Florida Current) and friction at the bottom. At the same time, no statistically significant seasonal cycle has been observed in the undercurrent flow on the Miami Terrace. Theoretical considerations suggest that several processes could drive the southward current, including interaction between the Florida Current and the shelf, as well as forcing that is independent of the Florida Current. The exact nature of the southward flow on the western flank of the Florida Current is, however, unknown.

Comments

©2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).

Additional Comments

FAU subcontract #: NR993/97-305 (ONR # N00014-98-1-0861; ONR award #: N00014-02-1-0950; NOAA grant #: NA08NOS4730409; ONR award #: N00014-10-1-0938; CIMAS award #: S15-01/AC55653 (NOAA NA10OAR4320143); University of Miami/Gulf of Mexico Research Initiative award #: S120021

ORCID ID

0000-0001-6519-1547

DOI

10.1016/j.dsr.2017.05.002

Peer Reviewed

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