Re: double tide cause

["Paul O. Johnson" <pojhome@SWBELL.NET>]

John,  there are oceans and there are seas. All the earth's oceans are
larger than any of the its seas. Among the seas, the Gulf of Mexico is the
fifth largest, as I said. It is 54% the size the the largest sea, the
Mediterranean. I objected to your assertation that the Gulf is "fairly
small" in the context of explaining the height of tides on seashores, not on
oceanshores.

Regarding the width of the straits connecting the Gulf to the ocean, I don't
count only that part of the Florida Strait deeper than 200 meters. A hellava
lot of water flows between the ocean and the Gulf at depths less than that.
What's more, the Yucatan Strait does indeed connect the Gulf to the
Caribbean Sea and thence to the ocean past the minor (and open) chain of the
Windward Islands. Considerable water flows between the Gulf and the ocean
via both routes.

The point of all this nitpicking is to question the rationale for your
explanation of the Gulf's attenuated tides. I stand by my position.

Paul O. Johnson

----- Original Message -----
From: "John S. Denker" <jsd@MONMOUTH.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, September 03, 2001 12:34 PM
Subject: Re: double tide cause


> I wrote:
>
> > > You would expect the tides to be somewhat attenuated,
> > > because the Gulf is fairly small, and connected to
> > > the open ocean only by rather narrow straits.
>
> Than at 10:41 AM 9/3/01 -0500, Paul O. Johnson wrote:
>
> > Fairly small? It's the fifth largest sea. See
> > http://www.infoplease.com/ipa/A0001773.html
>
> No, it's not.
>
> 1) First of all, according to that reference, it's ninth... and only half
a
> percent bigger than #10.
>
> 2a) More importantly, nobody cares what it's ordinal rank is.  What
matters
> is its size.  The status of the preceding 6 contenders is
> irrelevant.  Suppose we filled in or chopped up those contenders, so that
> the Gulf ranked third, behind the Pacific and Atlantic.  It would still
> have 50-fold less area and 5-fold less width than the Atlantic, which is
> what most people (especially Floridians) would be comparing it to.
>
> I stand by my assertion that the Gulf is fairly small.  It's endogenous
> tide-driving potential is reduced by a quite noticeable factor.
>
> > Fairly narrow straits? Both the Florida and Yucatan straits are 100 miles
> > wide, See
>
> http://www.reliefweb.int/w/map.nsf/wByCLatest/37DD6CB1016FF5B9852569EA006B9
C
> > B6?Opendocument
>
> 3a) If you count the part of the Strait of Florida that is deeper than 200
> meters, it's a lot less than 100 miles wide.
>
> The Yucatan Channel is wider, but it connects to the Caribbean, not the
> open ocean.
>
> 3b) In any case, how much water do we expect to sluice through such
straits
> during the ~3 hours that the tide is changing?
>
> I remain of the opinion that these straits cause the Gulf to be
> sufficiently decoupled that there is no reason to expect the Gulf coast to
> mimic the US Atlantic coast.
>
> Observations are consistent with this notion:
>    http://www-ocean.tamu.edu/~wormuth/tides/globaltidalpatterns.gif
>
> ======================
>
> Bottom line:  The once-a-day tide-producing potential is only about 2x
> smaller than the more-familiar twice-a-day tide-producing potential.  The
> Gulf appears to have a resonance that responds preferentially to the
> once-a-day component.