Re: Tidal Oceanic Bulge - A Progress Report

[brian whatcott <inet@intellisys.net>]

I wrote to one or two people who attempt to answer scientific questions
posed on the net. Here is an extract of two conversations.


At 08:01 4/2/98 -0500, you wrote:
> Brian,
>
> We are not experts in this area.
> Look here. These sites may help.
>
> http://topex-www.jpl.nasa.gov/discover/oc_tides.html
> http://www-geology.ucdavis.edu/~GEL217/Montague/gpsimp.html
>
> Steve Baumann
> Steve Baumann <baumann@fi.edu>

> Stephen H. Baumann
> Director of Educational Technology
> The Franklin Institute Science Museum
> 222 N. 20th St.
> Philadelphia, PA 19103
> 215-448-1206
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>
[Extract from the Topex web site]

A significant accomplishment of TOPEX/Poseidon is that its data have been used
to produce the most accurate global maps of tides. As a result, tides can
now be
predicted everywhere in the deep ocean with an accuracy of 2 centimeters (see
example below). Once TOPEX/Poseidon measurements of sea have been corrected
for the influences of tides, the data are used for the study of ocean
circulation.

This level of accuracy is necessary to understand many oceanic and geodetic
processes: tides are important for navigation especially in coastal
regions; tides slow up the rotation of the moon around the Earth and cause
the moon to keep the same face toward the Earth; the weight of the tides
depresses the sea floor, disrupting measurements of gravity on land; and
finally, tides change the orbits of artificial satellites, such as the
Hubble Space Telescope and TOPEX/Poseidon.

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> Chuck,
> There is an ongoing discussion on the phys-l list
>
> The topic, which is a subject of disagreement, is about
> the objective measures available which support the
> commonly held concept that the Earth's Oceanic tidal 
> bulges lead the line joining the moon and the Earth.
> This is the concept used to explain day length changes, 
> Moon orbit changes etc.




Brian - You over-estimate my knowledge! I am not an expert in ocean 
remote sensing in any way. My guess is that the only remote sensing tool 
that would be relevant is radar, which can map ocean tides. I do not know 
the relevant literature, however. I suggest you visit the Scripps Inst. 
of Oceanography web page and find some name there to ask. Sorry! And good 
luck! Chuck

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Charles A. Wood                    Tel: 701-777-3167
Space Studies                      FAX: 701-777-3711
Univ. of North Dakota              VolcanoWorld: volcano.und.edu
Grand Forks, ND 58202-9008         Space Studies: www.space.edu
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

I will attempt to reach someone at Scripps.
I will admit to considerable disappointment at the NASA JPL Topex
presentation at the above-mentioned URL. Their radar imagery essentially
provides a similar graphic global presentation of the tidal time and 
range that Jim used - but prefaces it with the stock description of 
the process as though it were a meridional progression, while it 
confirms in fact that the major oceanic basins see a rotating tide 
(with a range of roughly one meter). 
I can see why Jim would become impatient.

Whatcott    Altus OK