Acoustic current meter data collected in the shallow ( 3m depth) Trinity Bay, (TB a
sub-bay in Galveston Bay), TX, estuary were used to characterize locally generated windwaves.
Significant wave heights, periods, and directions were estimated from dynamic
pressure time-series (P; near bottom) and horizontal current velocities (U, V). Surface wave
spectra were calculated from the pressure time-series and fitted to the empirical shallowwater
Texel, Marsen, and Arsloe wave spectrum. The mean shape parameters used to define
the TB wave spectra were:alpha = 0:016, gamma = 4:26, sigma-a = 0:063, sigma-b = 0:089. Waves heights
were also hindcast using empirical and numerical models. The empirical formulas were
derived from fetch-limited shallow water observations and follow the current proposed
asymptotic limit to wave growth in shallow depth. The depth range for this empirical
formulation is extended from 0.5–2m out to 3.5m. The model does not work for wind
speeds less than 1m/s and during rapid wind direction changes.
The Shallow WAves Nearshore numerical model was implemented in a Galveston Bay
(GB; encompassing TB) computational domain. The model was forced with wind speeds
and directions measured on-site and in four surrounding locations maintained by the NOAA
PORTS. Currents measured on-site in TB and calculated bottom frictions were input homogeneously
in space. The model was run in steady and unsteady conditions, and the
modeled wave spectra were compared to the observations. The modeled wave spectra do
not recreate the observed spectral shape for the steady and unsteady conditions. However,
the total wave energy is represented in the unsteady conditions. In both the steady and unsteady cases, the wave period is underpredicted by one-half times the observed spectra
and the model direction agrees with the observed wave directions.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1175 |
| Date | 15 May 2009 |
| Creators | Dupuis, Keith Wade |
| Contributors | Anis, Ayal |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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