Aimed at Graham E really Teri
--
Freddie
Pontesbury
Shropshire
102 m AMSL
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Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
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On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


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Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Graham
Penzance

Graham Easterling Wrote in message:
On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Thanks Graham. I had noticed that high tides get later as you go
East - hence my question, as I would've anticipated Penzance
being later than St Marys, but it is a few minutes
earlier.

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


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On Wednesday, July 27, 2016 at 9:40:04 AM UTC+1, Freddie wrote:
Graham Easterling Wrote in message:
On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Thanks Graham. I had noticed that high tides get later as you go
East - hence my question, as I would've anticipated Penzance
being later than St Marys, but it is a few minutes
earlier.

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
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Yes, it is typically just 2-3 minutes earlier. You get some tidal swirling around Bays & Headlands, so although the tide does move east, with an irregular coast it can be quite variable from place to place.

Sennen, near Land's End, is 10 minutes earlier than Penzance, so I've often thought Scilly appears a bit late, but the tide is for St Mary's Harbour. It is an area enclosed by islands & reefs, so there is a delay in the high tide. I'm sure if tide tables were available for the western rocks, high tide would be 15 mins or so earlier than Penzance

It is for a similar reason the high tide in Truro is several minutes later than Falmouth.

Graham

Graham Easterling Wrote in message:
On Wednesday, July 27, 2016 at 9:40:04 AM UTC+1, Freddie wrote:
Graham Easterling Wrote in message:
On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Thanks Graham. I had noticed that high tides get later as you go
East - hence my question, as I would've anticipated Penzance
being later than St Marys, but it is a few minutes
earlier.

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Yes, it is typically just 2-3 minutes earlier. You get some tidal swirling around Bays & Headlands, so although the tide does move east, with an irregular coast it can be quite variable from place to place.

Sennen, near Land's End, is 10 minutes earlier than Penzance, so I've often thought Scilly appears a bit late, but the tide is for St Mary's Harbour. It is an area enclosed by islands & reefs, so there is a delay in the high tide. I'm sure if tide tables were available for the western rocks, high tide would be 15 mins or so earlier than Penzance

It is for a similar reason the high tide in Truro is several minutes later than Falmouth.

Thanks Graham. Lots of complexity with an indented coastline such
as Cornwall!

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
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On 27/07/2016 09:29, Graham Easterling wrote:
On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Graham
Penzance


I thought Brian Cox came up with the most understandable reason behind
why 2 tides a day, on his otherwise BBC1 travalogue/anthropology series.
Earth rotates once a day relative to the sun, moon rotates approximately
once a day round the Earth , so why 2 tides per day.
Just wish I could remember exactly how it goes, the moon's and Sun's
gravity on the Earth and the centrifugal force associated with the
spinning Earth and the "roundabout" effect and which forces balance out
in the mix.

On Wednesday, 27 July 2016 14:10:00 UTC+1, N_Cook wrote:
On 27/07/2016 09:29, Graham Easterling wrote:
On Wednesday, July 27, 2016 at 7:56:40 AM UTC+1, Freddie wrote:
Freddie Wrote in message:

Aimed at Graham E really. Why is the Penzance high tide time a few
minutes later than high tide at St Marys? I thought it would be
the other way round...

--
Freddie
Pontesbury
Shropshire
102 m AMSL
http://www.hosiene.co.uk/weather/
http://twitter.com/PontesburyWx for hourly updates


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Freddie, I assume you expected to tides to move from east to the west for purely astronomical reasons? If the Earth contained no land, this would be the case. However, the distribution of land makes a huge difference. If you take an estuary like the Severn, the tide cannot really move westwards towards Cornwall - where's the water going to come from?

Another important affect on tides is the Coriolis force.

Because the Earth contains large land masses & fairly well separated Oceans, the astronomical affects of the Sun & Moon result in the water slopping around in the oceans, similar to water in a bath. In addition the Coriolis force makes the tides rotate around centres of rotation (amphidromic points) where there is basicallly no tide. The tidal range increases the further you get from one of these points.

In south west England the tides get later, & bigger as you head east.
So in St Ives for today - high tide 5.6m - 10:33
Weston-Super-Mare high tide 10.4m - 11:56
Some of the highest tides in the world are in the Severn Estuary, as the tidal 'wave' becomes compressed & surfable http://i.dailymail.co.uk/i/pix/2014/...00_964x994.jpg

Bit of simplified overview, but still very different with images you get of the sea levels bulging towards & away from the moon.

Graham
Penzance


I thought Brian Cox came up with the most understandable reason behind
why 2 tides a day, on his otherwise BBC1 travalogue/anthropology series.
Earth rotates once a day relative to the sun, moon rotates approximately
once a day round the Earth , so why 2 tides per day.
Just wish I could remember exactly how it goes, the moon's and Sun's
gravity on the Earth and the centrifugal force associated with the
spinning Earth and the "roundabout" effect and which forces balance out
in the mix.

Why can't the experts on the other plaice help you with this?

On 27/07/2016 14:25, Weatherlawyer wrote:
On Wednesday, 27 July 2016 14:10:00 UTC+1, N_Cook wrote:

I thought Brian Cox came up with the most understandable reason behind
why 2 tides a day, on his otherwise BBC1 travalogue/anthropology series.
Earth rotates once a day relative to the sun, moon rotates approximately
once a day round the Earth , so why 2 tides per day.
Just wish I could remember exactly how it goes, the moon's and Sun's
gravity on the Earth and the centrifugal force associated with the
spinning Earth and the "roundabout" effect and which forces balance out
in the mix.

Why can't the experts on the other plaice help you with this?


There's something fishy about that...

--

Paul Hyett, Cheltenham

SNIP

I thought Brian Cox came up with the most understandable reason behind
why 2 tides a day, on his otherwise BBC1 travalogue/anthropology series.
Earth rotates once a day relative to the sun, moon rotates approximately
once a day round the Earth , so why 2 tides per day.

Well, no, that isn't really the reason for 2 tides a day.

The tides are mainly down to the moon. Without going into detail, if the Earth was all ocean, this would result in 2 high tides. One facing the moon, the on the other opposite side. It's because the moon is the dominant influence that the tides slip each day, by just under 1 hour on average (though with a variation) in synch with the moon.

The suns influence on this cycle is to produce Spring Tides when all 3 bodies are aligned (new & full moon), with Neaps in between.

In addition the moons distance from Earth influences the size of the tide, as does the angle of the Earth to the sun, the sun's biggest influence near the equinox.

Because of the land masses, the actual picture is much more complex, as you know as in your part of the UK there a 4 high tides a day.

Graham
Penzance. Strange conditions for my daily swim. Sea 19C, air 19C humidity 95% with a very light mizzle. It made it feel warm warm despite the lack of sunshine.