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theses

The physical oceanography of the Middle Atlantic Bight (MAB) is investigated, with an emphasis on identifying seasonal and alongshore variability within the region. While many previous studies assume uniform values throughout the MAB, and provide only a two-dimensional view of temperature, salinity and circulation, here a fully three dimensional spatial atlas of the MAB is developed for each month of the year. Case studies of the low-salinity coastal plumes, and glider observations near the shelfbreak, highlight the alongshore variability that exists within the MAB. A weighted least squares regression technique is used to map historical temperature and salinity data onto a gridded four dimensional atlas, dubbed MOCHA (The Mid-Atlantic Ocean Climatological and Hydrographic Atlas). MOCHA fields compare well to the input data, to independent datasets, to other climatologies, and even to sophisticated real-time ocean models. MOCHA provides a detailed four-dimensional view of the Middle Atlantic Bight "cold pool". The well-known cycles of the warming of a summer mixed layer with a strong thermocline, and the development and shrinking of the cold pool, are clearly evident in MOCHA fields. Alongshore variations in the extent of the cold pool are observed. A coastal ocean model of circulation and transport is developed using MOCHA as input, calculating box volume budgets of water, heat and freshwater. The seasonal cycles of heat and freshwater budgets are quantified, and the alongshore variability in sea-surface slope and offshore transport is identified. MAB waters, heat and freshwater are both lost and gained across the 85-m isobath along the entire length of the MAB, with the majority of MAB water turning offshore north of Cape Hatteras. Little, if any, of the MAB water volume enters the South Atlantic Bight (SAB), however the location of the offshore turn, and the amount entering and leaving the SAB vary seasonally. Overall, MOCHA provides a much more detailed view of the MAB than previously published, and indicates that there is strong seasonality in temperature, salinity and circulation, along with considerable along-shore variation in properties that should be taken into consideration during future studies.

ETD_7615

Ph.D.

Includes bibliographical references

by Naomi Elisabeth Fleming

doi:10.7282/T3XW4N4M

ETD doctoral

The author owns the copyright to this work.