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binntho

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Re: Tides
« Reply #100 on: August 04, 2020, 03:08:36 AM »
John, you keep claiming that the tides move a lot of water = and I men a lot. Your posts imply  at least hundreds of km3 if not thousands. This should be easily verifiable, these seas have been measured for decades if not centuries.

In "The 2020 melting season" thread yesterday I posted links to two recent research papers, one that specifically measured tidal movement in the Nares strait which I estimated to be in the range of 5 km3 twice daily, very insignificant at the scale of the Arctic ocean, but big enough to cause tidal currents to be visible along the coast of Greenland.  (First post)

But the tidal effect in the Nares is quite big - the tidal effect elsewhere is very small, and within the Arctic ocean itself it is not really discernible. Another paper I linked to yesterday measured current flows in the Fram strait. They are strong, and they vary, but there is no tidal factor mentioned, simply because the tides do not effect the flow of water throught the Fram strait. (Second post)

So I challenge you to show one single paper that measures or calculates the phenomena you keep posting about. Specifically you keep making statements that imply the movement of vast amounts of water with the all the turbulence and whatnot that such movement would induce. But you show no evidence whatsoever!

John, making repeated claims about strange phenomena that nobody else sees or can measure, is called pseudoscience. And Oren, I challenge you to be stricter in moderation here - John should not be allowed to post pseudoscientific claims on the main threads as if they were accepted science. Until he can bring evidence, as in real life measurements or scientifically sound modelling and calculations, the whole tidal fixation has to be deemed pseudoscience.

Comments like "I believe tides play a very important role in the Arctic" are not helpful here. If you think they are so very important, where is the evidence? Where are the scientific papers about this important role? What are the physics behind it, and how does it work, and how comes nobody has measured it or written about it?
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Rod

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Re: Tides
« Reply #101 on: August 04, 2020, 03:58:16 AM »

So I challenge you to show one single paper that measures or calculates the phenomena you keep posting about. Specifically you keep making statements that imply the movement of vast amounts of water with the all the turbulence and whatnot that such movement would induce. But you show no evidence whatsoever!

Tides stir up deep Atlantic heat in the Arctic Ocean

Quote
Researchers have identified how warm Atlantic water that is flowing deep into the Arctic Ocean is mixing with colder waters above to contribute to sea-ice loss in the Arctic. The results, published this week in the journal Nature Geoscience, show that tidal flows in the Arctic are causing deep, warm water (originating from the Gulf Stream) to mix with cold, fresh water lying above, in turn contributing to melting the floating sea-ice.

                                                                 .   .   . 

Quote
We studied the warm body of water from the Atlantic that represents the largest oceanic input of heat into the Arctic – it is four degrees Celsius warmer than the surrounding water, and it is the warmest it has been in nearly two thousand years. The top of the warm layer sits at depths between 40 and 200 m, and its heat slowly diffuses upwards into the cold, fresher water above, but sometimes this movement of heat can be greatly accelerated by turbulence which drives mixing. We have found that tides are producing significant amounts of turbulence over steep sea bed topography, and so are greatly enhancing the upward movement of heat in these regions. In areas where tidal currents interact with steep sea bed slopes, this process causes mixing of the warmer waters with the over-lying colder waters, and this in turn can generate 'hotspots' for sea-ice melt or thinning.

https://www.google.com/amp/s/phys.org/news/2015-02-tides-deep-atlantic-arctic-ocean.amp


oren

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Re: Tides
« Reply #102 on: August 04, 2020, 04:15:25 AM »
Quote
If you think tides are so very important, where is the evidence?
I have seen enough RAMBB and Mosaic animations showing effects of tides, including in the CAA where the tides break some of the fast ice. It is clear to me that tides add kinetic energy to the system, and also do move water around, presumably by ratcheting on the bathymetry and/or on Coriolis effects.
By how much? I have no clue. Scientific papers? I welcome them.

Quote
John should not be allowed to post claims on the main threads as if they were accepted science
I admit I have trouble sometimes following John's hydrological explanations, though I've been reading them for years. It can be very profound or it can be wrong, I am mostly unable to judge. Over time I have poked some questions and have gleaned some insights but not enough. This is why I encourage debates to be held on the Tides thread, to shed light on this important issue.
As for moderation, where I judge claims to be unsupported I will tend to act. However where I judge posts to be harmless (i.e. no specific claims can be discerned, or writeup is too esoteric to be controversial) I will tend to keep them even when I can't judge them.
If you have trouble with specific posts that you believe cause some harm, please do use Report to Moderator and explain. I always pay attention to these reports, and often act on them.

binntho

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Re: Tides
« Reply #103 on: August 04, 2020, 06:59:47 AM »
Oren, thanks for the reply. But the examples you give and we all have seen do not imply a "very important role" outside of a very small area, i.e. the Nares, the Lincoln Sea coast of Greenland, and some areas in the CAA. So yes, in certain isolated places the tides do impart kinetic energy. That does not equate to a "very important role" for the entire Arctic.

Rod, the article you linked to is excellent and I must admit that it surprises me that the weak Arctic tides (as they point out themselves) can have so profound an impact. But the article does no no way whatsoever support John's various claims.

To repeat: The article does not support John's posts.
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binntho

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Re: Tides
« Reply #104 on: August 04, 2020, 07:03:31 AM »
Oren, here is a recent example from the main thread. One I replied to on the main thread, but would have ignored in this thread.

My take on the loss of ice north of Greenland is tidally forced Atl. entering by Svalbard enhancing the existing current towards Nares of the same waters but pushing more forcefully along the shelf creating turbulence/vortices which overspill onto the shelf. Not all of it makes it through to the Canadian side but may force it's way through in the two or three days left of peak tidal movement, after that the rotating ice should close the gap. Similarly the lighter fraction of Atl. waters is creating more turbulence along Barents shelf as it pushes east causing more melt/retreat there.

He does start with "my take" but for those unfamiliar with the steady stream of pseudoscience from him it may create the impression that totally freeform musings without scientific grounding are allowed as part of normal discourse.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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blumenkraft

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Re: Tides
« Reply #105 on: August 04, 2020, 07:05:47 AM »
Quote from: Oren
This is why I encourage debates to be held on the Tides thread, to shed light on this important issue.

+1

He is onto something IMHO. I also don't understand it completely quite yet, but i would like to.
« Last Edit: August 04, 2020, 07:26:19 AM by blumenkraft »

binntho

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Re: Tides
« Reply #106 on: August 04, 2020, 07:08:15 AM »
Rod, further to your article. In the Abstract they say:

Quote
Vertical mixing is generally weak within the Arctic Ocean basins, with very modest heat fluxes...

but that at certain isolated locations

Quote
... geographically limited observations have indicated substantially enhanced turbulent mixing rates over rough topography.

and

Quote
We identify tides as the main energy source that supports the enhanced dissipation

So in geographically isolated regions, heat flux is enhanced by tidal-induced turbulence. But there is no indication that this is a widespread phenomenon and if it has any measurable impact on the total sea ice cover. I exptect it does, there are polynia and bites that are suspiciously ice free, and some of them may be caused by this effect. But without the full article, it's very hard to say.

And again, the article does in no way whatsoever support John's claims.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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binntho

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Re: Tides
« Reply #107 on: August 04, 2020, 07:09:18 AM »
This is why I encourage debates to be held on the Tides thread, to shed light on this important issue.

+1

He is onto something IMHO. I also don't understand it completely quite yet, but i would like to.
I think it was Oren who said that - and yes, debates about tides are interesting. But battling pseudoscientists with fixed ideas is not good for the blood pressure!  8)
because a thing is eloquently expressed it should not be taken to be as necessarily true
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binntho

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Re: Tides
« Reply #108 on: August 04, 2020, 07:16:23 AM »
Searching for an open-source copy of Rod's article I found the following:

Tidal Conversion and Mixing Poleward of the Critical Latitude (an Arctic Case Study)

It's an interesting article, and in the abstract they say that although tidal energy is a major source of turbulence mixing in the world's oceans, north of the "critical latitude", Coriolis forces make propagation of linear tides impossible.

Quote
... much of the Arctic Ocean is north of the critical latitude, beyond which the type of
 nternal tide that is believed to drive mixing across other major oceans on the planet cannot occur.

So effectively, John's ideas are shot down - the Coriolis force precludes the effects he thinks he is seeing.

Other than that the article seems to be saying the same thing as the one Rod pointed out, that in spite of this, some turbulence does occur:

Quote
However, new evidence has been found that suggests that the tide might be important in driving mixing in certain areas of the Arctic Ocean.
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blumenkraft

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Re: Tides
« Reply #109 on: August 04, 2020, 07:29:52 AM »
I think it was Oren who said that - and yes, debates about tides are interesting. But battling pseudoscientists with fixed ideas is not good for the blood pressure!  8)

Sorry, fixed. Hadn't had my first coffee yet. ;)

On your point though, it's not pseudoscience. It's talking about observations made. This is 100% legit.

binntho

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Re: Tides
« Reply #110 on: August 04, 2020, 08:05:08 AM »
I think it was Oren who said that - and yes, debates about tides are interesting. But battling pseudoscientists with fixed ideas is not good for the blood pressure!  8)

Sorry, fixed. Hadn't had my first coffee yet. ;)

On your point though, it's not pseudoscience. It's talking about observations made. This is 100% legit.

Writing from the land of coffee, I fully appreciate your need for the fix!

But I disagree that it is not pseudoscience if it is based on observations. We can all observe things, but the science bit is in the underlying mechanisms, forces and processes.

Two recent examples are a gif John posted which showed ice moving back and forth north of Svalbard, along with claims about tidal movements (in an area almost totally devoid of tidal effect) while the obvious explanation was that it was wind driven!

And the other example is that the gap opening up north of Greenland is somehow due to tidal forcings while again it is obviously due to winds and warm air advection.

So he sees things and uses his imagination to come up with pseduoscientific explanations. Science is when you have numbers, measurements, quantifiable observations and verifiable predictions. He has none of that.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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KiwiGriff

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Re: Tides
« Reply #111 on: August 04, 2020, 08:09:30 AM »

I am with binntho... Again.
Tides are not a significant influence in the Arctic ocean.
In deeper water over 20m or so tidal flows do not have much if any effect.
Wave and swell action are far more significant at such depths.
Fifty odd years of pissing around in boats and  many hours scuba diving reinforces my views.
Unless tidal flows are constrained by topography the effects  are insignificant.
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uniquorn

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Re: Tides
« Reply #112 on: August 04, 2020, 09:24:30 AM »
In my humble opinion, mosaic buoys are showing tidal movement that affects melt. They have been showing it ever since the project started. Tidal movement is less detectable further north. Some people see it, some don't, and some don't want to see it.
The ICEX buoys may show it too when I zoom in on them later.
« Last Edit: August 04, 2020, 09:48:44 AM by uniquorn »

binntho

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Re: Tides
« Reply #113 on: August 04, 2020, 09:46:14 AM »
In my humble opinion, mosaic buoys are showing tidal movement that affects melt. They have been showing it ever since the project started. Tidal movement is less detectable further north. Some people see it, some don't, and some don't want to see it.
The ICEX buoys may show it too when I zoom in on them later.

There are two statements here that would need substantiation:

1) The buoys show tidal movement.
2) The tidal movement affects melt.

Perhaps some data to support these statements?
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uniquorn

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Re: Tides
« Reply #114 on: August 04, 2020, 09:50:26 AM »
Wasn't this enough for 1)?
Perhaps JayW's gif, also northern Laptev, from jul19 2020 for 2)
Both already on this thread.
« Last Edit: August 04, 2020, 10:12:21 AM by uniquorn »

blumenkraft

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Re: Tides
« Reply #115 on: August 04, 2020, 09:54:49 AM »
Perhaps some data to support these statements?

Uniquorn's posts are 99.9999% data. Valuable data mind you! Telling him to post data is a bold move. Not at all a clever move, but a bold one.

binntho

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Re: Tides
« Reply #116 on: August 04, 2020, 10:11:37 AM »
Wasn't this enough for 1?
https://forum.arctic-sea-ice.net/index.php/topic,3030.msg260724.html#msg260724
Good animation. I've not been following this thread, trying to keeping my bloodpressure down, but the tidal movement is very clear. Five days (less 2 hours) with 10 loops. Total distance travelled is 67km and the magnitude of each sideways movement is around 1km to each side.

Not very much, and perhaps not unexpected over deep ocean. Do you see something similar over other parts of the Arctic or only over the Lomonosov?

This of course does not in any way substantiate what John has been claiming.
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uniquorn

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Re: Tides
« Reply #117 on: August 04, 2020, 10:17:18 AM »
mosaic buoys over the yermak plateau from the mosaic thread.

rammb of yermak/fram. I'm not claiming that is all tidal but similar movement suggest a tidal contribution.
« Last Edit: August 04, 2020, 10:27:22 AM by uniquorn »

binntho

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Re: Tides
« Reply #118 on: August 04, 2020, 11:01:19 AM »
The tidal movement in the first gif was a measly 1km per 6 hours, and the same the other way Average speed 4.5 cm/s, significantly lower than in the Nares strait. Unless there are great differences in the rate of movement from one area to another, I can't really see it affecting the ice at all. In other words, the ice probably simply shifts back and forth by a tiny amount, with far less effect than a moderate wind would have.
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uniquorn

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Re: Tides
« Reply #119 on: August 04, 2020, 11:03:19 AM »
Understood, we disagree.  :) Thank you for accepting that there is some tidal movement. My interest is mostly at the shelf breaks, where that measly movement might be amplified by the rapid change in depth.
« Last Edit: August 04, 2020, 11:08:58 AM by uniquorn »

johnm33

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Re: Tides
« Reply #120 on: August 09, 2020, 04:20:37 PM »
John, you keep claiming that the tides move a lot of water = and I men a lot. Your posts imply  at least hundreds of km3 if not thousands. This should be easily verifiable, these seas have been measured for decades if not centuries.

In "The 2020 melting season" thread yesterday I posted links to two recent research papers, one that specifically measured tidal movement in the Nares strait which I estimated to be in the range of 5 km3 twice daily, very insignificant at the scale of the Arctic ocean, but big enough to cause tidal currents to be visible along the coast of Greenland.  (First post)

But the tidal effect in the Nares is quite big - the tidal effect elsewhere is very small, and within the Arctic ocean itself it is not really discernible. Another paper I linked to yesterday measured current flows in the Fram strait. They are strong, and they vary, but there is no tidal factor mentioned, simply because the tides do not effect the flow of water throught the Fram strait. (Second post)

So I challenge you to show one single paper that measures or calculates the phenomena you keep posting about. Specifically you keep making statements that imply the movement of vast amounts of water with the all the turbulence and whatnot that such movement would induce. But you show no evidence whatsoever!

John, making repeated claims about strange phenomena that nobody else sees or can measure, is called pseudoscience. And Oren, I challenge you to be stricter in moderation here - John should not be allowed to post pseudoscientific claims on the main threads as if they were accepted science. Until he can bring evidence, as in real life measurements or scientifically sound modelling and calculations, the whole tidal fixation has to be deemed pseudoscience.

Comments like "I believe tides play a very important role in the Arctic" are not helpful here. If you think they are so very important, where is the evidence? Where are the scientific papers about this important role? What are the physics behind it, and how does it work, and how comes nobody has measured it or written about it?
"keep claiming" I did once estimate the amount of water I thought moved through the Norwegian/Greenland seas as best I recall it was a similar order of magnitude to your paper says moves through Nares so unless you can be specific I don't know what you're talking about.
On the south west coast of Svalbard I would anticipate the norhward flowing current to somewhat flatten against the shelf, as it has to shed about 4mph for every deg. it moves north and as it's essentially weightless it moves here more like a vertical stream which accounts for the turbidity. I don't use 'coriolis force' to think with since it is deemed to be fictional, instead I use tangential speed and assume some ongoing normalisation to 'current' latitude this means of course that any waters flowing out from the Arctic will naturally have a lower inherent tangential speed will lose ground turn right and explore the Greenland fjords rather than the S.W. Svalbard coast.
from the paper " It is not  entirely  clear to  what  extent  the  increased  heat  transport  toward  the  Arctic  is  related to  a strengthening of the Atlantic Meridional Overturning Circulation [32], to an increase in temperature or in volume of  the  AW  [4,33],  or,  instead, to  the  variability  of  the AW  transport along the two preferential pathways (Barents Sea and Fram Strait branches, [33]). Notably, the AW heat transport [29,34] can affect air temperature especially during winter [35], which in turn has direct effects on the dense water formation around the Spitsbergen margin. "
Personally i think the prime suspect is the gradual overcoming of the inertia of the Arctic ocean, that is it begins to wake from a long slumber and currents push more easily into it and in turn force out Arctic waters, but bear in mind this is just from observation and thought so in some sense 'made up'.
I have tried to find a paper which quantifies the amount of water moved around by tides in the Atlantic without success, even tried a calculation myself but didn't find the number credible so if anyone knows of such a paper I'd be grateful, or even an apropriate search term would help.
    Now although I have read quite a bit about tides in the last few years i found nothing that elucidates your insight "The physics of course is that the tidal effect is caused by expansion of water in the deep ocean at lower latitudes, with minimal actual movement of water except where coastal obstruction creates a local height/gravity imbalance (a fancy way of saying "downward slope")."  from do you know of a paper?

binntho

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Re: Tides
« Reply #121 on: August 09, 2020, 07:04:51 PM »
I don't use 'coriolis force' to think with since it is deemed to be fictional,

Well, that says it all. John, please stop posting until you have learned some science!
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uniquorn

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Re: Tides
« Reply #122 on: August 09, 2020, 08:50:01 PM »
https://en.wikipedia.org/wiki/Fictitious_force
Quote
Fictitious force
From Wikipedia, the free encyclopedia
A fictitious force (also called a pseudo force,[1] d'Alembert force,[2][3] or inertial force[4][5]) is a force that appears to act on a mass whose motion is described using a non-inertial frame of reference, such as an accelerating or rotating reference frame. An example is seen in a passenger vehicle that is accelerating in the forward direction - passengers perceive that they are acted upon by a force in the rearward direction pushing them back into their seats. An example in a rotating reference frame is the force that appears to push objects outwards towards the rim of a centrifuge. These apparent forces are examples of fictitious forces.

The fictitious force F is due to an object's inertia when the reference frame does not move inertially, and thus begins to accelerate relative to the free object. The fictitious force thus does not arise from any physical interaction between two objects, such as electromagnetism or contact forces, but rather from the acceleration a of the non-inertial reference frame itself, which from the viewpoint of the frame now appears to be an acceleration of the object instead, requiring a "force" to make this happen. As stated by Iro:[6][7]

    Such an additional force due to nonuniform relative motion of two reference frames is called a pseudo-force.
    — H. Iro in A Modern Approach to Classical Mechanics p. 180

Assuming Newton's second law in the form F = ma, fictitious forces are always proportional to the mass m.

The fictitious force on an object arises as an imaginary influence, when the frame of reference used to describe the object's motion is accelerating compared to a non-accelerating frame. The fictitious force "explains," using Newton's mechanics, why an object does not follow Newton's laws and "floats freely" as if weightless. As a frame can accelerate in any arbitrary way, so can fictitious forces be as arbitrary (but only in direct response to the acceleration of the frame). However, four fictitious forces are defined for frames accelerated in commonly occurring ways: one caused by any relative acceleration of the origin in a straight line (rectilinear acceleration);[8] two involving rotation: centrifugal force and Coriolis force; and a fourth, called the Euler force, caused by a variable rate of rotation, should that occur.

Gravitational force would also be a fictitious force based upon a field model in which particles distort spacetime due to their mass, such as general relativity.
Quote
Fictitious forces and work

Fictitious forces can be considered to do work, provided that they move an object on a trajectory that changes its energy from potential to kinetic. For example, consider a person in a rotating chair holding a weight in their outstretched hand. If they pull their hand inward toward their body, from the perspective of the rotating reference frame, they have done work against the centrifugal force. When the weight is let go, it spontaneously flies outward relative to the rotating reference frame, because the centrifugal force does work on the object, converting its potential energy into kinetic. From an inertial viewpoint, of course, the object flies away from them because it is suddenly allowed to move in a straight line. This illustrates that the work done, like the total potential and kinetic energy of an object, can be different in a non-inertial frame than an inertial one.


Gravity as a fictitious force
Main article: General relativity
The notion of "fictitious force" comes up in Einstein's general theory of relativity.[17][18] All fictitious forces are proportional to the mass of the object upon which they act, which is also true for gravity.[19] This led Albert Einstein to wonder whether gravity was a fictitious force as well. He noted that a freefalling observer in a closed box would not be able to detect the force of gravity; hence, freefalling reference frames are equivalent to an inertial reference frame (the equivalence principle). Following up on this insight, Einstein was able to formulate a theory with gravity as a fictitious force and attributing the apparent acceleration of gravity to the curvature of spacetime. This idea underlies Einstein's theory of general relativity. See Eötvös experiment.

johnm33

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Re: Tides
« Reply #123 on: August 09, 2020, 10:14:00 PM »
"Fictitious force" my point is that's a headful of itself, so to be able to think about it I take the tangential speed at 60N [500mph] -the same at the pole [0mph] divide that into the mileage, 2000 and get about 4mph to shed/gain per deg. of N/S movement which is just the inertial component, very real and very simple. The angular momentum component I address in a different manner assuming that any movement N/S is going to force a rotation in any current, somewhat like the magnetic force around an electric cable, but which apparently can come to dominate temporarily the motion of the current when a change of direction is forced, whatever that forced change is. Thus if it turns right into a fjord turbulence, if it is forced to flatten against a shelf vortices form in the vertical current, and if it meets a wall of water, going north it will form vortices which try to go up and south the opposite. The angular momentum is interesting but the inertia if it is not going into motion where it actually is is forcing motion somewhere in the direction it's headed, thus as the Arctic 'wakes' the currents in the Norwegian sea will more closely approach that 4mph, which makes the inertia more significant, i think?

binntho

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Re: Tides
« Reply #124 on: August 10, 2020, 06:41:19 AM »
Uniqorn, you have just demonstrated how truly lost poor John is. But if he wants to continue free-form fantasy postings in this thread he is welcome. But the "real"  threads are not the place for pseudoscience.
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KiwiGriff

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Re: Tides
« Reply #125 on: August 10, 2020, 07:49:10 AM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JC011009
Abstract
Seismic reflection imaging of mixing processes in Fram Strait
Quote
The West Spitsbergen Current, which flows northward along the western Svalbard continental slope, transports warm and saline Atlantic water (AW) into the Arctic Ocean. A combined analysis of high‐resolution seismic images and hydrographic sections across this current has uncovered the oceanographic processes involved in horizontal and vertical mixing of AW. At the shelf break, where a strong horizontal temperature gradient exists east of the warmest AW, isopycnal interleaving of warm AW and surrounding colder waters is observed. Strong seismic reflections characterize these interleaving features, with a negative polarity reflection arising from an interface of warm water overlying colder water. A seismic‐derived sound speed image reveals the extent and lateral continuity of such interleaving layers. There is evidence of obliquely aligned internal waves emanating from the slope at 450–500 m. They follow the predicted trajectory of internal S2 tidal waves and can promote vertical mixing between Atlantic and Arctic‐origin waters.
Well above my pay grade but I think relevant to the discussion.


Illustration of Tidal influences in the arctic .
From
Ocean Tide Influences on the Antarctic and Greenland Ice Sheets
Laurie Padman  Matthew R. Siegfried  Helen A. Fricker
First published: 08 January 2018

 
Figure 1

Global tidal properties derived from the TPXO‐7.2 global inverse tide model, an update to Egbert and Erofeeva (2002). (a) Tidal range (m), defined as maximum surface tide height minus minimum height over 1 year. Sites identified as 1–6 show locations for which the sea surface height amplitudes for the major tidal constituents are given in Table 1. (b) Mean tidal current (m s−1), defined as the annual average of instantaneous tidal speed, |u | = (u 2 + v 2)1/2, where u and v are east and north components of tidal velocity. (c) Tidal form factor, F  = (amp(ζ K1) + amp(ζ O1))/(amp(ζ M2) + amp(ζ S2)), where amp(ζ X) is the surface height amplitude of tidal constituent X . Small values of F indicate that tides are semidiurnal (two high and low waters per day); large values indicate tides are diurnal dominated, for example, in the Pacific sector along the Antarctic coast. Maps are on a Miller cylindrical projection to emphasize the polar regions.


 
Animals can be driven crazy by placing too many in too small a pen. Homo sapiens is the only animal that voluntarily does this to himself.
Notebooks of Lazarus Long.
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johnm33

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Re: Tides
« Reply #126 on: August 10, 2020, 09:07:47 AM »
Play the game not the man Binntho, now stop playing for time and back this up  "The physics of course is that the tidal effect is caused by expansion of water in the deep ocean at lower latitudes, with minimal actual movement of water except where coastal obstruction creates a local height/gravity imbalance (a fancy way of saying "downward slope")." 
or shut up.
Maybe i should take Mark Twains advice.

binntho

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Re: Tides
« Reply #127 on: August 10, 2020, 09:20:59 AM »
KiwiGriff posted three images above, and the first two are of particular interest - they show how very small and insignificant a factor the tides really are in the Arctic.

The first image shows the tidal effect - the Arctic is basically void of tidal effect compared with other oceans, the only one that gets near is the Mediterranean.

The second image shows tidal currents, and again the Arctic is basically a non-starter.

Now just to be clear, the following has already been established in eariler discussions and links to papers: There is a tidal effect in the Arctic. It is very small, perhaps 5 to 20 cm, and with a lateral fluctuation of perhaps 1km. Which is basically nothing. But in certain spots, the bathymetry combined with the very small tidal effect does increase turbulence enough so that warm waters do rise to the surface in these locations, and thus have an outsized effect on warming. Although this effect is apparently real, I've seen no quantification of it - so it could be totally insignificant in the larger scheme of things, or it could have a small but discernible effect on the total ice cover in the Arctic.

John's ideas have been about "tidal surges" and tidal currents somehow pushing their way through the Arctic, creating large and easily visible effects over large areas. Which is totally unfounded and not supported at all by any evidence.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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oren

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Re: Tides
« Reply #128 on: August 10, 2020, 09:26:09 AM »
Binntho your last two posts were unhelpful. If you want to counter some of John's arguments please respond with focused questions/criticism/rebuttal of very specific points, not in generalities "oh dear John is lost" as these cannot convince anyone of anything and are frowned upon.
Also it seems to me that while you have raised some good points, you need to respond to John's counter of your own point about tidal expansion of water.

Edit: your previous two posts, this was typed while you made a new one.

binntho

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Re: Tides
« Reply #129 on: August 10, 2020, 09:31:18 AM »
Binntho your last two posts were unhelpful. If you want to counter some of John's arguments please respond with focused questions/criticism/rebuttal of very specific points, not in generalities "oh dear John is lost" as these cannot convince anyone of anything and are frowned upon.
Also it seems to me that while you have raised some good points, you need to respond to John's counter of your own point about tidal expansion of water.

Edit: your previous two posts, this was typed while you made a new one.

Oren, no. There should be no need or requirement to argue with someone who does not have the basic knowledge to understand the science behind his own claims or the counterarguments made by others.

John's total lack of knowledge exposes his own persona to attack. The claims he makes are so totally wrong and so totally lacking in supporting evidence that there is not point in arguing factually with him.

But still I have done so repeatedly, again and again, and it should not be my responsibility to keep pseudoscientific claptrap away from the main forums. That is why I have made the simple requirement that he be banned from posting to the main forum, and then he can pollute this thread to his own hearts content.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

oren

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Re: Tides
« Reply #130 on: August 10, 2020, 10:38:56 AM »
No binntho, you have not been convincing enough for your requirement to be fulfilled. You have taken the original stance a long time ago that "tides do nothing" and are meaningless except maybe to slosh some water back and forth a bit, something which was obviously wrong even for the layman, and you only give way (and even that, barely) when presented with insurmountable evidence to the contrary. Thus you have been biased since the beginning, in my judgment. Admittedly, it appears to the layman's eyes that John's stance is that "tides do everything", which is also dubious at face value. However, to refute and rebutt you must delve down to very specific details. You have partially done that but then you resort to generalities again. That no one else has joined the debate on "your" side should give pause as well. I am willing to bet the truth is somewhere in the middle, but I lack the knowledge and even worse, the time, to delve into this issue and judge it by myself to my own satisfaction.

blumenkraft

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Re: Tides
« Reply #131 on: August 10, 2020, 11:29:14 AM »
Binnthos starting point was 'no vertical movement caused by tides'. Give him some time, he'll come around.

johnm33

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Re: Tides
« Reply #132 on: August 10, 2020, 11:38:13 AM »
"tides do everything" no far from it my point is they are gradually doing more, and more, and that their effects, mainly in forcing currents, are becoming increasingly visible, i was genuinely worried i was stating the obvious, clearly not, but if you review my posts and not the cartoonish caricatures of them that should be clear. Whatever you see that cannot be explained by the weather can be explained by whats happening in the awakening ocean, and sometimes the ocean provides a simpler explanation for those things assigned to the weather.
You used the ratchet analogy where i use the flywheel, the flywheel being the currents the tides giving them a gentle push, and depending on the atmospheric set up different currents get that gentle push. For instance on the 26th i predicted/guessed that the forcing would be along the northern shelf of Greenland and clear the shelf, then the atmospherics changed and the incoming was redirected but not altogether and a limited but increased flow of incoming Atl. waters continues, imho, to skirt the shelf of the CAA and begins to penetrate the channels.
 Your call Oren I can continue with my own efforts to understand/make a fool of myself in public or private, because it may not look like it but I'm trying to find out why I'm wrong, so far without success and if even the rational don't 'get' what i'm saying then i question it's value.

oren

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Re: Tides
« Reply #133 on: August 10, 2020, 11:51:02 AM »
Please do continue in public John. This is an important issue and deserves research and discussion. Lacking the time and the background, how will I ever get to a semblance of knowledge without the efforts of others on this forum? I greatly appreciate your points even though I often have trouble understanding or corroborating them.
To be clear binntho, please continue as well, but discuss the subject. More details, less name calling please. Atrack each specific point as you see fit, leaving biases aside.

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Re: Tides
« Reply #134 on: August 10, 2020, 12:51:44 PM »
Oren and bk,

This is both a matter of scale and and of change.

Some months ago we had a similar disagreement related to geothermal heat gradients in NE Greenland. This "constant" turned ot to have a miniscule impact on glacier melting in Greenland.

Now, we are discussing another "constant" - the tides in the Arctic Ocean. Binntho argues that it has a minuscule impact on the sea ice changes in the Arctic Ocean, which I tend to agree with.

Instead of putting Binntho into the "defence corner", it would be more convincing to ask others to provide some solid evidence, why the tides should have changed recently, and how these changes could have possibly affected the Arctic Sea extent.

Mark Tough

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Re: Tides
« Reply #135 on: August 10, 2020, 01:27:04 PM »
Just about to post something similar and as a very long lurker - I don't post that often.

A few points hopefully balanced  :)

- Unless the moon starts a slow drift to or from our earth, tides are a known constant
- Apogee and Perigee are two of my favourite words, so we know tides have extreme variants in a year, although known ones
- Extreme Low tides are ice tongue killers and that's when massive glaciers lose their support
-I expect that's when fast ice is also more likely to fail (sorry no citation) but again it's a known constant
-binntho - appreciate your steely gaze and as steely protection of the forum and the main threads from deniers and shall we say pseudo scientific word bloat - keep it real
-johnm33 - you are not that, your posts are valid
-Tides - Every 6 hours and 25 minutes there is a low or high tide that will break things, but again we know that.

Off Topic, I live in Maroubra, Sydney - fortunately near the beech. In Covid times it has been wonderful taking a walk on the headlands or a run on the beach where I live. Never in all my days here have I seen bigger surf and Winter Storms (4 to date) massive oceans and I go and watch in awe at high tide - tides matter and they devastate but we know where the moon is, it hasn't gone from 250 to 410 PPM Carbon, now that I'd say is a factor  :D

 

binntho

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Re: Tides
« Reply #136 on: August 10, 2020, 01:43:06 PM »
Oren and blumenkraft, this is simply a question of scale and perception.

My stance has always been, from the very start, that tides are almost exclusively a vertical movement with a small lateral factor mostly in coastal waters. I started posting on this subject as a response to a user that seemed to think that the tides caused a MASSIVE lateral movement of water. I can't remember if it was Johnm at the time, but it was e.g. the claim that there was a "tidal surge" into the Artic! Other of his postings have been along the same lines, he seems to think that the tides move SIGNIFICANT amounts of water laterally.

That is simply wrong. There is a very small and generally totally insignificant lateral movement out in the open ocean. But some people think that what they experience along the coast is what happens out in the open ocean. And this is wrong. It has always been wrong. It does not become less wrong by people showing anectdotal evidence of lateral movement along coasts and in narrow sounds and straits. It does not become less wrong by people describing how the tidal movement can cause localized turbulence where bathymetry allows, with surprisingly large knock-on effects.

The main point is: Tides are almost exclusively a vertical movement.

In the context of the first postings, I stated this more categorically - the tides are exclusively a vertical movement. This is true both when we think about the tidal pull as of itself, and also when we consider that probably 99.9% or more of the measurable movement is vertical. The lateral component is a miniscule part of the whole.

The reason I was so categorical was that the poster I was rebutting seemed to think that there was a largescale lateral movement pushing significant amounts of water around. Which is of course wrong.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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johnm33

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Re: Tides
« Reply #137 on: August 10, 2020, 02:05:50 PM »
" why the tides should have changed recently," I recall mentioning this a few times but since the ice has been cleared from the Barents sea they no longer inhibit tidal ingress, thus more water has found it's way into the Arctic proper and more has been forced out as a consequence, so they're the flywheel, that consequential forcing needs to be measured by others since all i can do is look at the available models.
Iirc i was the first here to point out the coincidence of the ice edge and the Barents shelf, what i thought then was being caused by waves i now suspect is caused by vortices generated by currents moving along the shelf and when the tides run the vorticity of those currents increase, or at least that's what the models seem to depict. Thus the tidal action liberated by the loss of Barentz ice now acts to maintain that loss.
 I also suspect the tides have been changing since Lomonosov had an ice sheet resting on it and will continue to change until lake Elgygytgyn [?] has an equible climate.

binntho

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Re: Tides
« Reply #138 on: August 10, 2020, 02:08:47 PM »
Johnm points a finger at the main point a few posts back, he found the following statement that I made earlier,
Quote
"the physics of course is that the tidal effect is caused by expansion of water in the deep ocean at lower latitudes, with minimal actual movement of water except where coastal obstruction creates a local height/gravity imbalance (a fancy way of saying "downward slope")

He wants me to substantiate this, because if true, his whole understanding of tides collapses. But this is actually fairly obviously the case - the rise and fall of the oceans due to the gravitational pull of the Moon and the Sun is caused by an expansion and contraction of the watercolumn in the deep ocean.

The surface of the ocean moves up and down due to pressure. This is well established and a rule of thumb is that every 1hPa corresponds to 1cm over deep ocean. So a single point in mid ocean may rise or fall by several feet over the course of a few days. And similarly, the sea level under a rapidly moving cyclone is significantly higher than in surrounding areas.

This pressure-induced movement is almost exclusively vertical. A rapidly moving low pressure area does not pull several km3 of sea water along (half a meter times 100km square is 5 km3 or 5000 million tons). The underlying watercolumn expands and contracts due to changes in the density of water. The mass does not change, but the volume does. See here for the relationship between pressure and density of water.

Pressure is a direct result of gravity, as is "slope" or "up" and "down". A ship sailing north from the equator is not going "down" even if, due to the shape of our planet, it is moving closer to the center of the Earth the further north it goes. The surface of the ocean follows a surface of equal gravitational pull, where the gravity of Earth and other plantes in competition with the centrifugal forces of the spin of the planet, creates a shape that contains the total mass of our planet.

The diurnal tidal fluctuation of the center of gravity creates the tides. When the center is closer to the Pacific, to take an example, it has the same effect as a fall in pressure - both water and air expands. The atmosphere is at more or less the same thickness around the globe and thus experiences an even up-and-down tidal movement in an eastward propagating wave.

But the oceans are vastly different, going from an average deep-sea depth of some 4000 meters down to nothing over the continents. The bulge of expansion wants to move towards the east, but the continents are in the way. This leads a much more complicated distribution of the tidal effect than would otherwise be the case, but the basic tenet still holds: Tidal movement is vertical expansion of water.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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uniquorn

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Re: Tides
« Reply #139 on: August 10, 2020, 07:52:17 PM »
surely there is a paper on this somewhere

Some insignificant lateral movement 280km from the nearest coast  ;)
more details here
« Last Edit: August 10, 2020, 08:00:14 PM by uniquorn »

uniquorn

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Re: Tides
« Reply #140 on: August 10, 2020, 08:09:14 PM »
mosaic buoys in the fram strait. Are people really suggesting that continuous rotational movement doesn't affect melt? Please read upthread for further examples.

oren

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Re: Tides
« Reply #141 on: August 11, 2020, 02:33:45 PM »
this is actually fairly obviously the case - the rise and fall of the oceans due to the gravitational pull of the Moon and the Sun is caused by an expansion and contraction of the watercolumn in the deep ocean.

The diurnal tidal fluctuation of the center of gravity creates the tides. When the center is closer to the Pacific, to take an example, it has the same effect as a fall in pressure - both water and air expands. The atmosphere is at more or less the same thickness around the globe and thus experiences an even up-and-down tidal movement in an eastward propagating wave.

the basic tenet still holds: Tidal movement is vertical expansion of water.
I am sorry binntho, but all sources I have read point to these statements being fully in the wrong. The solid Earth and the water and air column do expand and contract slightly due the gravitational effects of the moon (and/or sun), but these do not cause the main effect of the tides. It is rather the lateral movement of water - due to the tangential forces - that causes the main effect of the tides.
These are not necessarily strong currents, and need quantification to support various claims on the effects of tides. But the qualitative explanation you provide is simply wrong.

I found this text to be more comprehensive than most.
https://www.lockhaven.edu/~dsimanek/scenario/tides.htm
Quote
The moon's gravitational force acts in two ways on the earth:
* It stretches solid objects—an effect proportional to the inverse cube of the distance from the moon. This effect is simply too small to account for the tidal bulges in ocean water.
* The tangential components (tangent to earth's surface) exert tractive forces on large bodies of water directed toward the tidal bulges. These are also proportional to the inverse cube of distance from the moon. This is the dominant reason for tides in large bodies of water.

There are other sources which say the same things but less clearly.
Wikipedia says the same by the way.
Quote
Equilibrium
The equilibrium tide is the idealized tide assuming a landless Earth. It would produce a tidal bulge in the ocean, with the shape of an ellipsoid elongated towards the attracting body (Moon or Sun). It is not caused by the vertical pull nearest or farthest from the body, which is very weak; rather, it is caused by the tangent or "tractive" tidal force, which is strongest at about 45 degrees from the body, resulting in a horizontal tidal current.

But if you want to go on with the claim of vertical expansion only (which I am 100% convinced is wrong), please provide solid and clear supporting sources.

johnm33

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Re: Tides
« Reply #142 on: August 11, 2020, 09:34:29 PM »
Great find Oren, the best single read on tides i've seen, the only two things he didn't address that came up for me in my thinking on the subject was that the moon doesn't really orbit the Earth but they circle one another in a kind of flattened helix, and although the oceans tides cannot circle the planet i wondered, if there was a solid core surrounded by liquid heavy metals whether they were free to 'slosh around' contiually and if so which would remain nearer the moon? but that's ot here.
I'll have to re-read the centrifugal/centripetal section because i had come to the veiw that these were intrinsic, if you will, to the gyroscopic motion of the atoms, and in this way the force acting on a molecule sprang from within in reaction to changing circumstance/position.

binntho

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Re: Tides
« Reply #143 on: August 12, 2020, 07:03:00 AM »
Oren, the document you linked to above seems very good and perhaps I have to reconsider. First i was interested in what he means by tractive so I'll include the definition from the article:

Quote
Tidal forces have radial components and tractive (tangent to the earth's surface) components. The radial components stretch or compress solid materials radially. The tractive components stress solid materials laterally, and, in the case of liquid materials, can physicaly move them significanty.

He then goes on to claim that

Quote
Water is very nearly incompressible and is clearly not rigid. So the tidal bulges in water arise because some water has moved toward the bulges from elsewhere, that is, from other regions of the ocean.

It is the claim that water is nearly incompressible that is obviously inconsistant with what I am saying. And it seems I have to retreat from my position - one of those scenarios where what you are absolutely certain you think is right turns out to be wrong. Which is why I'm an atheist!

To further hammer the point home, I found a peer-reviewed paper that explains the tides in much the same way as the author of the article you linked to, Tides and Water Levels

So it turns out that it is the lateral force that causes the tidal bulge, and in my enthusiasm in battling against the pseudoscience of Johnm and others I have myself gone down the wrong path.

So let's backtrack a bit: The main misconception of tides that I have been arguing against is that the tides somehow move vast amounts of water OTHER THAN the daily back-and-forth fluctuation.

Perhaps it is important to seperate this into two phenomena: The pulling of waters into a tidal bulge on the one hand, which I'll concede is what happens, and the tidal bulge pulling waters with it as it moves.

The first point, i.e. the pull and release of waters into the bulge, is simply a back-and- forth movement that doesn't really do anything. The second point is an absolute precondition for the claims of Johnm and others.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

binntho

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Re: Tides
« Reply #144 on: August 12, 2020, 07:21:05 AM »
To clarify my position (which does not really change all that much even if my understanding of the basic forces behind the tides was wrong):

1. Tides do cause a back-and-forth movement. I think I've said this so often, so very many times, but it is important: It is a back AND forth movement. First one way, then the other. If it goes one way, it has to go the other way.

2. Tidal currents only exist where coasts or bathymetry interfere with the movement of the "bulge". And importantly, these currents go back and forth - if it moves water one way, it also moves water the other way.

3. The lateral movement of the tidal bulge does not pull water with it. The bulge rises and falls, it propagates as a wave and like all waves, it does not move water along with it.

A global estimate of the amount of water that gets pulled into the tidal bulge is some 150.000 km3, based on the areas of the oceans excluding the Arctic and the Mediterranean (where the tidal effect is minimal) and assuming an average of 50cm between high and low tide.

So every day, the tides move 150.000 km3 of water into each of the two tidal bulges. In comparison, the Gulf stream moves 13.000 km3 of water daily past Newfoundland. These numbers should demonstrate to anyone that even if the tides are moving large amounts of water back and forth, the water, on average and from day to day, STAYS IN PLACE.

If further evidence is needed, just look at the global ocean currents. They do not follow the movement of the tidal bulge. It may appear that they do in the North Atlantic, but if you look at the Pacific then it becomes obvious that ocean currents are not affected by the tides.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

binntho

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Re: Tides
« Reply #145 on: August 12, 2020, 07:37:18 AM »
So why do I keep hammering at this? My first posting was as a response to someone claiming that there was a "tidal surge" into the Arctic.

This second batch of postings was in a response to postings from Johnm which blamed tides on everything, but specifically the claim that the tides were somehow forcing large amounts of Atlantic waters all around the Arctic (including the ESS and Beufort), pushing large amounts of Atlantic waters into and through all parts of the Arctic, forcing turbulence and what not everywhere he looked.

All of these claims are based on thinking that the movement of the tidal bulge equates lateral movement of vast amonuts of waters. Which is where I started - by saying that the tides are an up-and-down movement, not a lateral movement.

And the actual lateral movement is back-and-forth, not the one-way forcings that Johnm sees. And perhaps he is realising that he cannot use the tides to support his claims - I guess we are all learning something from this!

I refer specifically to the following posting from yesterday:

Looking at Mercator salinity 30m it seems the Atl. waters are short circuiting and returning along Lomonosov from Laptev, they appear to be mixing with returns from ESS creating turbulence immediately beneath the openings in the ice north of Greenland.  I also suspect overflow from the Canadian side, by Belov trough, is forcing internal waves and actual movement in the basal layers towards Fram.
Strange that it [Atl.] doesn't get mixed maybe there's a wall of inert water holding station along the American side?

Are Atlantic waters "returning" from the Laptev, along the Lomonosov ridge, all the way to the north of Greenland along with "returns" from the ESS? What mysterious forces are at work here, cutting accross the entire Arctic ocean, with no regard for the halocline, thermocline or the currents that actually do exist? At least it's no longer the tides that are causing these vast currents that Johnm thinks he is seeing everywhere.

But his abuse of the tides, and the general lack of understanding of the tides that has lead to the amazing acquiescence of many members towards Johnm's postings seem to lead to others thinking that the tides somehow are a major force that can be used to explain all sorts of things. For example this from a poster from yesterday:

Quote
Wonder if it's due to ice thickness, perhaps due to the higher tide cycle,

The main point here is that the tides do not have any significant effect on anything. Which is not to say that they do not have some effect. They do, they exist and they cause some slight lateral movement, and some localized turbulence. But in the larger scale of things, they are simply not important.

Anybody with experience of sailing on the open oceans knows this: The tides are simply not important, they have no real effect on anything, unless in coastal waters.
« Last Edit: August 12, 2020, 07:46:08 AM by binntho »
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Re: Tides
« Reply #146 on: August 12, 2020, 09:11:03 AM »
I think many times people assume that when someone stops arguing a point they are conceding the point. I don't think anyone should make that assumption. Especially with the number of trolls we seem to get on this site. (I don't have much experience on other forums so I have no real basis for comparison). There are many reasons not to respond.  I am beginning to realize life is too short to respond to those who are more interested in arguing than getting to the truth. I enjoy learning through discussion. In most circles consensus is often reached when those who know better stop arguing with  those who won't listen. That is why IMO group think tends to be so ridiculous.  Thankfully in science experiments lead to winners and losers in the long term and not stubbornness.  Unfortunately I get the impression that on this forum as on most of the Internet stubbornness reigns supreme.

oren

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Re: Tides
« Reply #147 on: August 12, 2020, 10:54:58 AM »
Quote
To clarify my position (which does not really change all that much even if my understanding of the basic forces behind the tides was wrong)
Binntho, it appears that at first you concede that the solid basis of your claims was wrong all along, and then you return to the same claims along with the accusation of pseudoscience. Just like the tides, the concepts moved back and forth and stayed in the same place.

However, now that you finally concede the main point - that tides do move large amounts of water laterally - I believe in your zeal you have not stopped to consider the implications.
It's true that tides move water back and forth, as the bulge does not stay in the same place. It's also true that it's not the same water that orbits the Earth along with the bulge, so it has some similarities to a wave. However for 6 hours water does move laterally, and a large amount of it. Now ask yourself:
A. What happens when the transported water has different properties than the water in the location it arrives to? E.g. Temperature, salinity, chemical signature.
B. What happens when that water gets deflected to the side by land or shallow bathymetry?
C. What happens when the water is transported north or south?
(All of these are various conceptual examples of ratcheting, converting a cyclical phenomenon into a unidirectional phenomenon).

The answer in all cases is that the incoming water gets mixed with the resident water, and 6 hours later when the reverse transport occurs it is slightly different water that comes back.
In case B a current or gyre may develop. The tide moves the water onto a diagonal feature, and the water is shifted sideways. When the reverse tide happens, the water transported back could be different water.
In case C the water being transported north is shifted east by the Coriolis effect. When the reverse tide occurs, the water being transported south is shifted west.
Now imagine you are in the Arctic, the coldest and freshest water in the NH. Any incoming water will almost by definition be warmer and more saline than the resident water. In addition incoming water will by definition be moving north and thus be pushed east, inducing a current inside the Arctic basin. Recall that the Arctic Ocean does not have many openings to the south, so a narrow opening will emit an eastbound tidal current that cannot be pulled back completely during outflow, as the water was already deflected beyond the opening. Bottom line, the tides do bring energy into the Arctic. How much? No clue. Negligible? I doubt it.

Lest we forget, tides may also cause fast ice to break - they lift it physically, thus possibly inducing its detachment from its anchoring points, and in addition may twist it laterally, if different tide heights are induced in sufficiently close locations. Of course all this applies only to coastal regions, but that is where fast ice is to be found. Fast ice is much more resilient to melting and export than mobile ice, thus higher tides may be somewhat detrimental to ice survival.

Of course these are just intuitive ramblings. I am no expert on tides. Neither are you, is what I finally realized.

While reading a bit more on tides, I asked myself whether tides have a significant north-south component. Had the moon been orbiting the Equator, no such component would have occurred. It turns out the moon's orbit is inclined by 18-28 degrees from the plane of the Equator, with an 18 year cycle. 2015 saw the minimal inclination, and 2024 will see the maximal inclination. Thus a north-south component does exist. I am sure people who know something about tides know all this.
And here's a little diagram that shows tidal amplitudes in the Arctic Basin, from an interesting paper about "Tidal currents in the western Svalbard Fjords". (Yes, they do exist).
Remember tidal range is double the tidal amplitude.
https://www.sciencedirect.com/science/article/pii/S0078323415000883


binntho

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Re: Tides
« Reply #148 on: August 12, 2020, 11:50:50 AM »
Oren, yes I do continue because the main point I have been trying to make doesn't seem to get accross.

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What happens when the transported water has different properties than the water in the location it arrives to?
...
What happens when the water is transported north or south?

There is no "transported water" in the open ocean. That's the whole point. The "bulge" attracts water to itself laterally (as I have conceded). But the bulge does not move any water as it itself moves, as you have yourself just agreed.

And as I have repeatedly said, from the very beginning, bathymetry and coastal contours are different from the open ocean. There is transport of water in the Nares strait - first one way, then the other. It's tiny compared to the whole oft he Arctic and has no large-scale effect. There is turbulence in some specific bathymetric settings and this has some mixing effect, but not really quantified and unlikely to matter at all in the larger context.

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The answer in all cases is that the incoming water gets mixed with the resident water, and 6 hours later when the reverse transport occurs it is slightly different water that comes back.

Only in the extremely tiny and dispersed cases of coastal tidal currents - of which the Nares current and it's extension to the north-east along the coast of Greenland is the only one!

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Of course these are just intuitive ramblings. I am no expert on tides. Neither are you, is what I finally realized.

I never claimed to be an expert on tides, and you never thought I was (or you would never have argued with me!). On the contrary, I find them complicated and confusing, but I do know that they are not important in the large scale of things, and they do not really have any effect in the open ocean.

You see, if tides were that important, the scientific literature would be full of it. But it isn't. It's really extremely difficult to find any scientific papers about the Arctic that have anything to say about tides, and I've previously linked to scientific papers that would have mentioned tides if they were important, but they didn't, so they aren't.

And the main point all the time has been that some people seem to think that the tides move, or "transport", vast amounts of water laterally and can force them into the Arctic. Which is wrong.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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JayW

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Re: Tides
« Reply #149 on: August 12, 2020, 12:06:56 PM »
Regarding the Yermak plateau
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Turbulent mixing near the Yermak Plateau during the Coordinated Eastern Arctic Experiment
Abstract
Recent current measurements obtained from drifting platforms over the Yermak Plateau in the eastern Arctic Ocean confirm that the plateau is a region of greatly enhanced diurnal tidal currents. Modulation of the diurnal currents is clearly related to the plateau topography, as has been previously proposed. We show, however, that temporal variability due to spring‐neap modulation must also be considered in interpreting records from drifting platforms. We review simple models of tidal current amplification in this region and find that the previous assumption of near‐resonant, barotropic shelf waves propagating around the plateau's entire perimeter is inconsistent with the true topography. Instead, we propose that the diurnal variability is due to topographic shelf waves at the K 1 and O 1 tidal frequencies that are generated at points on the plateau's perimeter where the waves' group velocities are near zero. Observed cross‐slope variations in ellipticity, orientation, and magnitude of tidal oscillations are consistent with the presence of topographic waves generated in this manner. The topographic enhancement of the diurnal tide near the Yermak Plateau has important consequences for the sea ice cover, hydrography, and general circulation of this region. For example, the stress divergence applied by the tidal currents at the ice base greatly exceeds the typical divergence of the surface wind stress, and tides may therefore be important to local ice deformation. The strong cross‐slope tidal currents also appear to be responsible for the production of high‐frequency internal wave packets, which are associated with energetic diapycnal mixing in the pycnocline. We also consider the possibility that tidal rectification is responsible for a mean current transporting Atlantic Water clockwise around the plateau.
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/92JC01097

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Effects of tides on the quasi-steady upwelling-downwelling regimes and water mass exchange between the Arctic and Atlantic Oceans.
Abstract
Astronomical tides are strong in the regions of the Arctic shelf and GIN Seas, with amplitudes reaching up to 4.4m in the Hudson Strait, 2-3m in the White Sea and greater than 1m in the Canadian Archipelago. If nonlinear friction is present, at the sea bed or within a stratification water column, periodical motions transfer energy to shear stresses with a substantial non-periodic component. Over bottom topography, anomalous bottom shear stress generates vorticity and vertical motions, resulting in either an ageostrophic circulation or geostrophic upwelling/downwelling of isopycnals. Using a pan-Arctic and a North Atlantic ocean-ice model, both of which explicitly resolve tides, we examine the effects of tides on the vertical motions generated by Ekman pumping near the sea bed and at the ice-ocean interface, and the stretching and tilting of vorticity. We found that tides significantly increase the intensity of vertical upwellings and downwelling regimes near the shelf break. We extend the semi-geostrophic two dimensional Eliassen -Sawyer equation and three-dimensional omega-equation to take into account the effects of tides. We also discuss the application of the equations for the analysis of watermass transformations and dense water overflow in the main gateways between the Atlantic and Arctic Oceans : Fram Strait, Yermak Plateau, Barents Sea shelf break, Denmark Strait and Faroe Channel.

https://ui.adsabs.harvard.edu/abs/2016EGUGA..18.6301L/abstract
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