Publication Date

2010-01-01

Availability

Open access

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Physical Oceanography (Marine)

Date of Defense

2010-02-16

First Committee Member

William E. Johns - Committee Chair

Second Committee Member

Kevin D. Leaman - Committee Member

Third Committee Member

Elizabeth M. Johns - Outside Committee Member

Abstract

Windward Passage, which separates the islands of Cuba and Hispaniola, has been recognized as an important inflow channel to the Caribbean Sea for nearly a century. Despite this fact, few direct measurements of the volume transport through the passage exist. In an effort to gain a more comprehensive understanding of the variability, structure, and mean transport associated with flow through Windward Passage, the University of Miami?s Rosenstiel School of Marine and Atmospheric Science (RSMAS) and the National Oceanic and Atmospheric Administration (NOAA)?s Atlantic Oceanographic and Meteorological Laboratory (AOML) conducted a targeted research study of the passage and surrounding region from October 2003 through February 2005. The project deployed a moored current meter array across the passage and conducted four regional hydrographic surveys. Velocity sections collected across Windward Passage during the four cruises from lowered and hull-mounted acoustic Doppler current profilers show a highly variable field dominated by small-scale eddy features and other areas of locally-intensified flow. However, when integrated horizontally across the passage, the resulting transport-per-unit-depth profiles reveal a remarkably robust vertical shear structure. A net inflow of surface and thermocline waters was observed over the four cruises. Beneath these layers, a persistent outflow of intermediate water was found, intensified along the east side of the passage. Deep inflow, just above the sill depth maximum (1680 m), was observed on cruise #1 and, based on data from the moored current meter record, was determined to be a regular flow feature. Together, project velocity sections and water mass analyses of Windward and surrounding passages suggest that Surface Water (SFC), Subtropical Underwater (SUW), and Central Water (CW) primarily arrive at Windward Passage from the east via the Hispaniola Basin. A majority of SFC and SUW enters the Cayman Basin through Windward Passage, while the arriving CW bifurcates, with slightly more than half bypassing the passage and continuing westward north of Cuba. An intermediate water outflow pathway from the Cayman to the Hispaniola Basin via Windward Passage was also observed. Much of this outflow possessed a salinity signature characteristic of upstream inflow regions immediately to the east and south of the Lesser Antilles. Total Windward Passage transport, calculated from the four ship surveys, was found to be an inflow of 3.0 ±2.8 Sverdrups (1 Sv ≡ 10^6 m^3 s^-1). Data from the 16-month moored current meter array yielded a larger mean inflow of 5.0 ±1.6 Sv. These numbers are lower than previous estimates based on regional passage transport differences, and suggest that more transport may be entering the Florida Current system through passages in the Bahamas (the Northwest Providence and Old Bahama Channels) than previously thought, with proportionately less flow entering the system through the Caribbean Sea.

Keywords

Atlantic Inflow; Bahamas Currents; Caribbean Currents; Intra-Americas Sea Circulation; CTD; ADCP; SADCP; LADCP; Mass Transport; Caribbean Circulation; Volume Transport; Atlantic Caribbean Exchange

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