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Re: Bulges



On Thu, 6 Mar 1997, David Bowman wrote:

Therefore it is no wonder that Jim doesn't see any
evidence of a tidal bulge in the oceanic tidal data that he has ammassed.
The contribution of the (highly underdamped) oceans to the tidal bulge is too
small to show up in the time series for the ocean level at a typical
coastline which is dominated by other undamped resonant/sloshing and
continental reflection effects as well as extraneous wind effects, seasonal
ocean current effects, etc. I suspect that if the time series for the ocean
height in the middle of an ocean was Fourier analyzed and its power spectrum
taken, that there would be a significant spike located at the lunar driving
frequency which would correspond to the presence of at least some of the
tidal bulge being present in the oceans.

I don't understand this. The time series for the ocean height at
virtually *any* location--in the middle of the ocean, near a coast line,
or even within highly protected bays--is, I believe, *overwhelmingly*
dominated by spikes at the lunar and solar driving frequencies, isn't it?
If anyone expects to find evidence against the tidal bulge theory in a
lack of these components, I think they will be sorely disappointed.

(Lest anyone misconstrue my remarks here, this is decidedly not to say
that the *presence* of these components argues *for* the oversimplified
tidal bulge model.)

John
----------------------------------------------------------------
A. John Mallinckrodt email: mallinckrodt@csupomona.edu
Professor of Physics voice: 909-869-4054
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web: http://www.sci.csupomona.edu/~mallinckrodt/