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From: Trevor J. Kenchington (no email)
Date: Sat Aug 16 2003 - 21:16:35 EDT
Fred Hebard wrote:
> Trevor,
>
> Tidal levels may be calculated, but have satisfactory descriptions of
> currents been acheived? I believe George Huxtable was including both
> in his description.
Good point, Fred.
I don't know whether anyone has attempted to model tidal streams in the
ocean. (They are usually tiny: The tidal heights are not great, while
the volume of water needed to make the difference between high water and
low can often move as a current 4,000 metres deep. That means that the
rate of drift is very small.)
Where coastal tidal streams are concerned: Yes, they have been
satisfactorily modelled, in some cases. I'm a tidal enthusiast, not a
tidal expert, and I don't pretend to be up to date with the scientific
literature. However, I'll offer the example of the Canadian Hydrographic
Service's tidal atlases. Those are based entirely on the output from
computer models (at least the Bay of Fundy/Gulf of Maine atlas and the
Strait of Georgia atlas both are -- I think the St.Lawrence River one is
too but I am not fully certain). [CHS publishes only the three tidal
atlases.] Then again, I am not sure to what extent those models use
empirical observations of the tide as input data (rather than just
seabed morphology and astronomic tide-generating forces) so it might be
argued that they do not truly represent observed tidal streams by
calculating from theory alone.
Trevor Kenchington
--
Trevor J. Kenchington PhD
Gadus Associates, Office(902) 889-9250
R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251
Nova Scotia B0J 2L0, CANADA Home (902) 889-3555
Science Serving the Fisheries
http://home.istar.ca/~gadus
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