Tides in early February

Orion36

One of the most readable scientific works sent to an Irishman (Robert Boyle) was by John Wallis who put together an account in 1666 -

http://rstl.royalsocietypublishing.org/content/1/1-22/263.full.pdf+html

He discusses the diurnal,monthly an annual components of the tides and one of the nicer observations came from coastal farmers who knew that their lands would more likely be inundated in early February or November than at any other time of the year,something discussed on page 276 of that letter which eventually became one of the first papers presented to the Royal Society.

The annual component of the tides can now be explained in conjunction with the variations in the natural noon cycles due to the planet beginning to speed up after spending 6 months slowing down in its orbital circuit.This is something Wallis noted but couldn't explain no more than his contemporaries could however 21st century visual imaging can now do the job.

If something good comes from the severe flooding in our Southern counties perhaps the reasons why annual high tides occur at just the wrong time allied with these incredibly powerful storms demands a proper explanation and the dynamics behind it.

Joe Public

I heard on the radio today that the particular alignment of the planets at the moment was causing higher tides than usual and rather than calling them "Spring Tides" they were being called "King Tides". I think they were suggesting that the moon wasn't the only influence. Is there any scientific proof for this? Are the planets too far away to have any affect on our tides?

Orion36

Joe Public wrote: »

I heard on the radio today that the particular alignment of the planets at the moment was causing higher tides than usual and rather than calling them "Spring Tides" they were being called "King Tides". I think they were suggesting that the moon wasn't the only influence. Is there any scientific proof for this? Are the planets too far away to have any affect on our tides?

The tides are especially sensitive to the motions of the Earth and the position of the moon,the correlation between the annual high tides and the variations in the length of the natural day were rightly identified by John Wallis even if he and his contemporaries were uncertain as to the reason why the total length of the day varies. This is completely separate effect to the varying lengths of daylight and darkness over the year as the total length of the day from noon to noon is the same in the Northern and Southern hemispheres at the same time and it does take a bit of getting used to.

The Earth starts to slow down presently and as with braking and accelerating,the tides respond to these changes in the orbital component of the Earth's motion. It can be explained visually but generally people are uninterested even when they can see the effects on the streets of Cork,Waterford and the Southern counties.

riffmongous

I'm not sure I understand it yet, could you provide some more information? Maybe a more recent paper on the subject?

Orion36

riffmongous wrote: »

I'm not sure I understand it yet, could you provide some more information? Maybe a more recent paper on the subject?

There are no papers since that article was written in 1666 and particularly the reason why the variations in the total length of the day are connected to the annual high tides which Wallis notes on page 277 -279 of his treatise. The variations in the total length of the day (as opposed to the equable 24 hour day) are due to the braking and accelerating effect of our planet as it makes a circuit of the Sun where the effects are most pronounced in February and November. With these powerful Atlantic storms and the position of the moon all lining up to create the flooding effect in coastal cities and towns,it is well worth the effort to understand why particularly now that areas are prone to flooding as opposed to other times of the year.

The main point is that Wallis admitted that his contemporaries were unsure as to what was behind the variations in the natural noon cycles yet it can be explained today to a 100% certainty using graphics and images.

snowstreams

Are you talking about perigean spring tides?
This is when we have a spring tide at the same time as the moon perigee, so it produces a larger than normal spring tide.
Its only supposed to make a difference of 2 inches or so in Ireland, but still that can make a difference. I think we get 4 of them a year.

Orion36

snowstreams wrote: »

Are you talking about perigean spring tides?
This is when we have a spring tide at the same time as the moon perigee, so it produces a larger than normal spring tide.
Its only supposed to make a difference of 2 inches or so in Ireland, but still that can make a difference. I think we get 4 of them a year.

No.

Apart from being a powerful Atlantic storm with all the effects of a swollen river,the reason there were people swimming in the streets of Cork city is due to a component of the annual orbital motion of the Earth which influences the height of tides at exactly this time of the year,something Wallis noted and correctly correlated to the variations in the natural noon cycles or what amounts to the same thing - the length of the natural day is unequal across the planet as opposed to the equable 24 hour day.

As the Earth experiences its maximum braking in February and acceleration in November,tides show this sensitivity as the annual component and that is why readers really should pay attention to that letter written to Boyle which found itself into public view in the first publication of the Philosophical Transactions.

The idea of the total length of the day being unequal everywhere on the planet is unfamiliar to most readers much less its cause and that is a shame given the effects are readily visible over the last week when extreme weather highlights it. The Leader's question time in the Dail today brought up issues of rising sea levels when clearly the issue is simply a series of unfortunate alignments between a potent storm and the astronomical inputs into the tides.

Popoutman

Orion36 wrote: »

As the Earth experiences its maximum braking in February and acceleration in November,tides show this sensitivity as the annual component
The idea of the total length of the day being unequal everywhere on the planet is unfamiliar to most readers much less its cause

The day (rotation of the earth compared to a fixed point in space, e.g. the star background) is the exact same length all across the earth, and the variance of the day is most certainly not seasonal.

The earth is a solid body, so the length of the rotation period cannot differ from one place to another.

There is absolutely no seasonal variation in the length of the day.

There is no shown coupling between orbital speed (time of year) and rotational speed (length of day).

The length of sunlight is no direct factor in tidal timings.

Maybe you are misunderstanding what is actually going on with the physics of tides. If you need something clarified please don't be afraid to ask and either myself or other experts here should be able to clear up any misconceptions you may have.

To answer the OP: Generally the reason why tides appear to be higher in winter is as a result of the meteorological effects of lower pressure averages, deeper lows, and storm surges pushed ahead of weather systems. Another factor is that towards wintertime, the fact that the moon's altitude at full moon is higher in the sky, closer to overhead, is a factor in annual tide values. The same applies for new moon in summertime but the weather conditions rarely combine to give higher tides.

Orion36

Popoutman wrote: »

The day (rotation of the earth compared to a fixed point in space, e.g. the star background) is the exact same length all across the earth, and the variance of the day is most certainly not seasonal.

The day refers to the return of the Sun to noon hence the fixed point in space for the daily and orbital motions of the Earth happens to be the central Sun so from that standpoint it is easy enough to observe a combination of daily and orbital components causes a variation in the noon cycle to occur,something that was once well known in principle -

"Here take notice, that the Sun or the Earth passes the 12. Signs,or makes an entire revolution in the Ecliptic in 365 days, 5 hours 49 min. or there about, and that those days, reckon'd from noon to noon,are of different lengths; as is known to all that are versed in Astronomy."

http://adcs.home.xs4all.nl/Huygens/06/kort-E.html

I am afraid you did not read what Wallis stated regarding the variations in the total length of the day on page 278 even if he was unfamiliar with the cause just as Huygens was -

http://rstl.royalsocietypublishing.org/content/1/1-22/263.full.pdf+html

The chances are the the vast majority of people haven't heard of the variations in the total length of the day occurring everywhere on the planet each time the Earth turns to the Sun rather than the more familiar seasonal variations between daylight and darkness which is a hemispherical thing and quite separate.

Unless readers want to suffer an assertion binge,I suggest they simply take note of what Wallis states in respect to the variations in the length of the day and where it meshes with annual tides as both involve the orbital speed of the Earth. The present floods have nothing to do with politicians talking about rising sea levels/climate change ,it is strictly an issue of a weather event combining with planetary dynamics to create havoc for people in coastal areas.Once I hear words like 'misconceptions' I switch off as the whole point of the exercise is to make things clearer for readers who might switch on to Wallis's contention that the orbital acceleration and braking of the Earth influences tidal heights and besides,the Irishman Boyle liked it so much he made that private letter public.

What Wallis couldn't explain can be explained today,it requires a little familiarity ,a little discipline and a lot of common sense. I would only be interested in responding to people who are interested and if that doesn't happen then so well and good.

riffmongous

Orion36 wrote: »

and that is why readers really should pay attention to that letter written to Boyle which found itself into public view in the first publication of the Philosophical Transactions.

You're not gkell1 by any chance are you?

Orion36

I do hear politicians raise the idea of the floods and rising sea levels/climate change however it would be occasionally nice to encounter people who are as confident and as comfortable as Boyle and Wallis were in discussing issues where planetary dynamics and terrestrial sciences mesh in an informal way. If people in Cork wish to know why their homes and shops were flooded due to a combination of events then they can discover that they have something in common with the sheep farmers that Wallis encountered when he asked them when they were most wary of the tides and land inundation.

The natural noon variations are central to the topic of the annual highest tides as our planet accelerates and brakes during its annual orbital circuit and especially that period between November and February. The tides being most sensitive to this change point in the direction of the surface rotations which combine to create the varying lengths of natural noon,something Wallis picked up on in principle.

Today it is nearly impossible to find an individual who can read the daily fluctuations in a temperature graph and its correlation to the daily rotation let alone an annual tidal graph and it correlation to the daily and orbital cycles.

http://www.timeanddate.com/weather/ireland/cork/hourly

The reason being that the present mob including most of the 'experts' here,the crowd so vocal on climate change,insist rotations fall out of step with 24 hour days -

" It is a fact not generally known that,owing to the difference between solar and sidereal time,the Earth rotates upon its axis once more often than there are days in the year" NASA /Harvard

When some sane person can switch between temperature graph and that statement and eventually decide it is a junk conclusion then we may talk about tides and planetary dynamics but not before then.

Popoutman

Just to clarify, in case anyone reads this thread in the future; There is no cyclical variation in the length of the day as the year passes. The only change in the length of the day is the gradual lengthening due to the Moon's tidal effects, or once-off changes due to plate tectonics/earthquakes.

Also, the Earth does not experience accelerations and decelerations in November and February - orbital mechanics simply doesn't support the timing or the concept.

Orion36 appears to have had trouble understanding that you need to choose a reference point to count rotations, and the choice of point can affect the numbers that we get. While we rotate ~365 times a year relative to the sun, because we rotate once around the Sun itself, we do ~366 rotations relative to the star background. It's fairly simple mechanics to understand this.

Joe Public

I was getting a bit confused, could this be a factor?

riffmongous

Joe Public wrote: »

I was getting a bit confused, could this be a factor?

These threads show up everyone now and again on the different science forums, always the same hinting and vague style addressed to the 'reader'

http://www.boards.ie/vbulletin/showthread.php?t=2056427954
http://www.boards.ie/vbulletin/showthread.php?t=2056366510&page=4
http://www.boards.ie/vbulletin/showthread.php?p=77961117

Popoutman

Joe Public wrote: »

Are the planets too far away to have any affect on our tides?

I forgot to answer this particular question.

There is a teeny-tiny tidal effect from Venus: it's somewhere in the region of 1/10,000 the effect of the Sun. This Venusian tide peaks when Venus is at inferior conjunction between us and the sun, something that happens about every 1.6 years. Jupiter's tidal effect on the Earth is another 1/10th that of Venus, and is about 13 months long. Compared to the 28 day tidal period due to the moon..

Effectively impossible to measure - local barometric pressure and temperature changes will change the sea level by more.

cerastes

Popoutman wrote: »

I forgot to answer this particular question.

There is a teeny-tiny tidal effect from Venus: it's somewhere in the region of 1/10,000 the effect of the Sun. This Venusian tide peaks when Venus is at inferior conjunction between us and the sun, something that happens about every 1.6 years. Jupiter's tidal effect on the Earth is another 1/10th that of Venus, and is about 13 months long. Compared to the 28 day tidal period due to the moon..

Effectively impossible to measure - local barometric pressure and temperature changes will change the sea level by more.

I was reading through each post to see if anyone answered that chaps question before I said something, while Im not an expert on it, only having read maybe one goodbook on astronomy, Id have considered the effects of the other planets negligible if anything, which is what you seem to be saying.