Variation in tides

n cook wrote:

http://geography.berkeley.edu/people...am/2%20Literat
ure.pdf

File Not Found. The file you have requested does not exist on this
server.
The Berkeley Geography Website was moved to a new server on February 4,
2006. Some personal accounts have not yet been moved, and some will be
closed.

Weatherlawyer wrote in message
oups.com...

n cook wrote:


http://geography.berkeley.edu/people...am/2%20Literat
ure.pdf

File Not Found. The file you have requested does not exist on this
server.
The Berkeley Geography Website was moved to a new server on February 4,
2006. Some personal accounts have not yet been moved, and some will be
closed.


The usenet 80 column limit perhaps.

I just downloaded and pdf-text converted the relevant page with mamgled
maths

page 42
reference to the phenomenon of "Perigean Spring Tides" (Wood 1976).
As noted before, tidal amplitude (and therefore range) is relatively large
during syzygy (period = ½ synodical month = 14.765294... MSD) and during
lunar perigee (period = 1 nodical month = 27.212220... MSD).
As is often the case with natural phenomena with independent origins, the
ratio of these periods (and hence their frequencies and angular speeds) is
an irrational number (T /T = 1.842985...).
Therefore, syzygy and lunar perigee will periodically approach and converge
(i.e. "beat"), but will literally never exactly coincide.
Their closest convergence during a beat will vary, and the strength of the
perigean spring tides will therefore also vary.
Wood, after an exhaustive historical and theoretical review of the
phenomenon (1976), classified perigean spring tides as 1) perigean (closest
coincidence is 6.5-23° geocentric longitude = moderately large amplitude);
2) proxigean (3.25-6.5°); and 3) extreme proxigean ( 3.25° coincidence =
greatest amplitude).
He also calculated the primary frequency sets that govern the closeness of
convergence during beats, based on the !! recognition that beats will occur
when n T (n+1) T , where n is an integer and T and T !! 1 2 1 2 are the
periods of the interacting waves.
When T T is irrational, there is no integer n 1/ 2 satisfying this
equation, but there will be sets of integers that satisfy the approximation
to any desired coincidence.
Using this method, Wood recognized major frequencies at multiples of about
31 years as well as shorter and longer frequencies and beats.
Wood and others researching extreme tides have noted that other cycles, at
other irrational period ratios, also generate beats and/or modulate the
magnitude of the beats generated by the syzygy and lunar perigee cycles
(Pugh 1987).
This means that the temporal structure of tidal beats, and therefore the
temporal patterns of the high tides that most influence marshes, is quite
complex.

Roger Hamlett wrote:

It is wrong to think of the tides as being caused by the Moon 'pulling'.
The key is that the whole 'Earth-Moon' system, is orbiting around their
common mass centre (actually inside the Earth). In it's simplest form, the
bit of the Earth closest to the Moon, gets pulled more, and bulges upwards
towards the Moon, but at the same time, the part furthest away, gets
pulled less, and with the centripetal effect, bulges up in the opposite
direction. Worse, the actual 'tides', lag the pull, and can get
accelerated/decelerated by the local geography, so (for example), there
are places that actually get four tides (or more!) a day, as the water
takes different routes round the local land masses.

Where can I see a page or two on this non Newtonian physics that shows
how a mass 1/4 of a million miles away can have more effect on tiny
particulates than a mass 81 times greater and no distance at all? Got a
link?

Weatherlawyer wrote:
n cook wrote:


http://geography.berkeley.edu/people...Roam/2%20Liter
at
ure.pdf

File Not Found. The file you have requested does not exist on this
server.
The Berkeley Geography Website was moved to a new server on February 4,
2006. Some personal accounts have not yet been moved, and some will be
closed.

You need to rebiuld the URL as it is split across two lines and not all of
it is
showing as a link.

Try this:
URL:
http://geography.berkeley.edu/people...Roam/2%20Liter
ature.pdf
and it should work.


--
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WIMBORNE http://www.wessex-astro.org.uk/ Wessex Astro Society's Website
Dorset UK Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

JRS: In article , dated Fri, 7 Jul 2006
12:17:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
Dr John Stockton wrote in message
...
JRS: In article , dated Thu, 6 Jul 2006
06:44:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
According to a local old sea dog, there is a 50 year cycle to the height
of
tides superimposed on the usual new/full moon / sun distance, cyclic
variation.

http://geography.berkeley.edu/people...am/2%20Literat
ure.pdf

URLs that may line-wrap should be quoted as in sig below, though just
... generally suffices. Please read the newsgroup FAQ on formatting
of News replies, and/or the UK hierarchy's guidance in news:uk.answers.

has mention of a 31 year cycle on top of the perigean cycles but the maths
is all rather daunting, nice to see reference to one of my favourite words ,
as a word that is, syzygy unfortunately not even any use in Scrabble- too
many "y"s 3 not 2.

But is there any reference to the cycle having been noticed by tidal
observers?

What's the biggest-scoring legal move in Scrabble?


To another article :

There is no Usenet 80-column limit in the sense you mention. There is a
convention on ordinary text having a 72-character margin, but longer
lines can be transmitted if required. Writers/readers may need to
adjust their settings or get better software.

This paragraph will be transmitted as one very very very very very very very very very very very very very very very very very very very very very very very very very long line, but nowhere near the limit, if any, of this software; I set the right margin at one fathom.

--
© John Stockton, Surrey, UK. Turnpike v4.00 MIME. ©
Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms & links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.

Dr John Stockton wrote in message
...
JRS: In article , dated Fri, 7 Jul 2006
12:17:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
Dr John Stockton wrote in message
...
JRS: In article , dated Thu, 6 Jul 2006
06:44:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
According to a local old sea dog, there is a 50 year cycle to the
height
of
tides superimposed on the usual new/full moon / sun distance, cyclic
variation.


http://geography.berkeley.edu/people...oam/2%20Litera
t
ure.pdf

URLs that may line-wrap should be quoted as in sig below, though just
... generally suffices. Please read the newsgroup FAQ on formatting
of News replies, and/or the UK hierarchy's guidance in news:uk.answers.

has mention of a 31 year cycle on top of the perigean cycles but the
maths
is all rather daunting, nice to see reference to one of my favourite
words ,
as a word that is, syzygy unfortunately not even any use in Scrabble- too
many "y"s 3 not 2.

But is there any reference to the cycle having been noticed by tidal
observers?

What's the biggest-scoring legal move in Scrabble?


To another article :

There is no Usenet 80-column limit in the sense you mention. There is a
convention on ordinary text having a 72-character margin, but longer
lines can be transmitted if required. Writers/readers may need to
adjust their settings or get better software.

This paragraph will be transmitted as one very very very very very very
very very very very very very very very very very very very very very very
very very very very long line, but nowhere near the limit, if any, of this
software; I set the right margin at one fathom.

--
© John Stockton, Surrey, UK. Turnpike v4.00
MIME. ©
Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms &
links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm,
etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail
News.


I've been playing with freeware WXTide32 tide calculator, I've no idea what
underlying equations it uses.
I've old tide tables for 1989 and 1992 and also looking at current
predictions the results all agree to no more than 4 minutes out in time of
highs and lows or 0.1m in predicted heights.
I've run it for all days from 1980 to 2020 and most years the maximum high
tide is one or more 5.1m but in all those 40 years no 5.2m or higher
predicted for my nearest "station" of Portsmouth. I was expecting to see
some sort of cyclic nature to the extreme peaks.
My concern is marine flooding to low lying coastal area, but as it stands
low barometric pressure, analysing past flooding events, seems to have more
influence than astronomic tides.

Hi many thanks for helping me with the 2 tides not 1 so helping you out with
scrabble this links shows the record legal score for 1 play

http://www.fun-with-words.com/scrabble.html

regards Paul
"n cook" wrote in message
...
Dr John Stockton wrote in message
...
JRS: In article , dated Fri, 7 Jul 2006
12:17:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
Dr John Stockton wrote in message
...
JRS: In article , dated Thu, 6 Jul 2006
06:44:04 remote, seen in news:uk.sci.astronomy, n cook
posted :
According to a local old sea dog, there is a 50 year cycle to the
height
of
tides superimposed on the usual new/full moon / sun distance, cyclic
variation.


http://geography.berkeley.edu/people...oam/2%20Litera
t
ure.pdf

URLs that may line-wrap should be quoted as in sig below, though just
... generally suffices. Please read the newsgroup FAQ on formatting
of News replies, and/or the UK hierarchy's guidance in news:uk.answers.

has mention of a 31 year cycle on top of the perigean cycles but the
maths
is all rather daunting, nice to see reference to one of my favourite
words ,
as a word that is, syzygy unfortunately not even any use in Scrabble-
too
many "y"s 3 not 2.

But is there any reference to the cycle having been noticed by tidal
observers?

What's the biggest-scoring legal move in Scrabble?


To another article :

There is no Usenet 80-column limit in the sense you mention. There is a
convention on ordinary text having a 72-character margin, but longer
lines can be transmitted if required. Writers/readers may need to
adjust their settings or get better software.

This paragraph will be transmitted as one very very very very very very
very very very very very very very very very very very very very very very
very very very very long line, but nowhere near the limit, if any, of this
software; I set the right margin at one fathom.

--
© John Stockton, Surrey, UK. Turnpike v4.00
MIME. ©
Web URL:http://www.merlyn.demon.co.uk/ - FAQqish topics, acronyms &
links;
Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm,
etc.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail
News.


I've been playing with freeware WXTide32 tide calculator, I've no idea
what
underlying equations it uses.
I've old tide tables for 1989 and 1992 and also looking at current
predictions the results all agree to no more than 4 minutes out in time of
highs and lows or 0.1m in predicted heights.
I've run it for all days from 1980 to 2020 and most years the maximum high
tide is one or more 5.1m but in all those 40 years no 5.2m or higher
predicted for my nearest "station" of Portsmouth. I was expecting to see
some sort of cyclic nature to the extreme peaks.
My concern is marine flooding to low lying coastal area, but as it stands
low barometric pressure, analysing past flooding events, seems to have
more
influence than astronomic tides.

In message . com,
Weatherlawyer writes

I have been working on the time of the phase and its influence on the
weather for quite some time now and consider myself to be a bit of an
expert on the influence

Whatever the coincidentae are for all the proceeding posts (and it is
useful and interesting work) the fact remains that "pull" is not the
way that the moon affects the hydrology of this planet at all.

All we have, since the days of Kelvin and Doogeson, are the factors
that are involved. So far, the theory and laws concerning tides are
elusive.

While there is a repeatable pattern (and every port is different, some
being so closely related that one can be (as they are) used as a datum
for others) there is a stage in the function of gravity on tides, that
has yet to be discovered.

Until tidal theory is addressed in light of the fundamental laws of
mechanics, that stage never will be.


And your evidence for any of the above is... ?

It's been known for years (centuries ?) that there are all sorts of
resonance effects governing ocean tides, not to mention the fact that
they are caused by two bodies dragging water around a body with various
irregularly shaped land masses.
One of the most entertaining accounts of this I know of is Fritz
Lieber's novel "The Wanderer", where the situation is complicated by the
appearance of an Earth-mass body near the Moon prompting one character
to exclaim "At last, a really challenging example of the three-body
problem" :-)

Jonathan Silverlight wrote:

they are caused by two bodies dragging water around a body with various
irregularly shaped land masses.
One of the most entertaining accounts of this I know of is Fritz
Lieber's novel "The Wanderer", where the situation is complicated by the
appearance of an Earth-mass body near the Moon prompting one character
to exclaim "At last, a really challenging example of the three-body
problem"

When you use emoticons it means the joke needs explaining. When the
joke needs...
Ah never mind. Never mind the drivel, can you have a stab at explaining
the mechanics?

I want to know how the moon can drag a particle up from the earth
considering the masses and distances involved. And why if it works on
volumes with very little gravity of their own, it doesn't have the same
effect on more imposing particulate.

Besides which, if the three body problem is in a constant state of flux
as one planet invokes movement on another, how does the distant planet
affect subdivisions of the other.

And another thing: If the moon can raise water on the earth, why can't
the earth raise sand on the moon? IIRC a crystal of silicon dioxide or
whatever sand is, is some 3 times more dense than water but the moon's
gravity is 1/6th.

I would have thought that on the theory most here are defending
(without the benefit of a schoolboy's primer may I add) the moon would
have tidal mountains and hills.

Weatherlawyer wrote:

And another thing: If the moon can raise water on the earth, why can't
the earth raise sand on the moon?

It does, or else how is the moon's rotation locked to the earth ?

Steve