Date of Award

Winter 1986

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Ocean/Earth/Atmos Sciences

Program/Concentration

Oceanography

Committee Director

Donald E. Johnson

Committee Member

Chester E. Grosch

Committee Member

Carvel Blair

Abstract

This study is a comprehensive examination of the tidal circulation of Chesapeake Bay and its major tributaries. Tide and current data, which were observed in Chesapeake Bay by the National Ocean Service during the period from 1972 to 1983, are analyzed and used to construct charts that describe the tide and tidal current. Frictionally damped analytic models are used to: explain the tidal hydrodynamics of the observed tides, determine the location of the quasinodes and antinodes of the M2 and K1 tidal waves, explain the relationship of the tides and tidal currents, and determine if the tide in lower Chesapeake Bay is a Kelvin wave with an amphidromic pattern of cotidal lines. The amplification of constituents as the tide circulates throughout the bay and tributaries is also described and explained.

Tide data from 108 locations throughout the bay and major tributaries, and current meter data from 124 locations in the bay have been analyzed using nonharmonic and harmonic analysis techniques. Cotidal and corange charts have been constructed based on the results of the nonharmonic analysis. Comparable coamplitude and cophase charts for the M2 and K1 tidal constituents have been constructed using the harmonic constants determined during the study. Similarly, the harmonic constants for the M2 tidal current constituent are used to construct cophase and cospeed charts which serve as an approximate description of the tidal current at Maximum Flood.

A one dimensional analytic model of a frictionally damped reflected tidal wave is used to determine whether reflection actually occurs in each basin, where it occurs, and how much the tide is attenuated. Frictional damping coefficients ranging from 2.1 to 3.0 have been determined for the major tributaries and upper bay. It is shown that the tide in the lower bay cannot be modeled properly using a one dimensional analytic model because of its width. A two dimensional analytic model of a reflected Kelvin wave is considered. This model, as well as the charts constructed during this study, indicates the tidal circulation in the lower bay may be an amphidromic system with a virtual amphidrome located onshore to the west of the bay.

The amplification of shallow water constituents is observed to be fairly large near the limit of tide in the major tributaries, but is relatively insignificant elsewhere. This amplification has been shown to be caused by the nonlinear effect of friction on the tide.

DOI

10.25777/gtgr-sv41

Included in

Oceanography Commons

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