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Andreas T

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The 2016/2017 freezing season
« on: July 20, 2016, 02:07:49 PM »
prompted  by a discussion on the melting season thread I have started this a more than a month earlier than last year.
I hope nobody thinks this is to signify an early start to the refreeze, I don't believe in spells, jinxes and that sort of "magical" thinking.
It is interesting by the way to have a look at the start of last years thread with the benefit of hindsight. We are trying to learn from our observations and wish to derive an understanding which lets us detect signs of what the future will bring. I have learned that there is huge complexity in the melting and freezing of arctic sea ice and that makes me cautious with predictions. But we are all amateurs here (despite the expertise some people bring here from related areas or by doing a lot of research as a leisure activity) and that give us the benefit of not having to worry too much about making a guess and seeing something it turn out very differently. Trying to make that guess can make us work harder at understanding and being critical of ourselves as of others. So lets see how much what we have learned so far can help us in our guessing and where we need to learn more.

jplotinus

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Re: The 2016/2017 freezing season
« Reply #1 on: July 20, 2016, 03:58:42 PM »
I imagine there might well be responses that it is far too soon to have started this thread. You may even be accused of unfairly seeking to achieve "pinned" status. I for one do not begrudge you that status at all.

In fact, based on the 'stall' that persisted throughout June and the ongoing 4 day lull in melt momentum, I would say thinking ahead toward the freezing season is perfectly proper.

I also think the extent lull (jaxa/IJIS) occurring over last 4 days may end up serving as the definite indicator that 2016 will not surpass the 2012 minimum. But, then again, the Arctic is unpredictable.

Michael Hauber

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Re: The 2016/2017 freezing season
« Reply #2 on: July 20, 2016, 11:12:10 PM »

I see your point about what extent may mean for the melting season, but what about the freezing season?  What does a higher extent of more broken up and widely dispersed ice portend for the freezing season?  As a chemist we know that crystals form more rapidly when there are already seed crystals present.  Supercooled water can remain liquid well below freezing until it is exposed to a tiny ice crystal.  And then bam!! (to quote or paraphrase Frivolous), ice will immediately form throughout the entirety of the water.  Isn't it possible that a wide extent of broken up ice chunks dispersed more evenly throughout the Arctic than usual might act like a bunch of seed crystals that will cause more rapid and extensive re-freezing of ice in October through December compared to the type and speed of freezing that occurs with open waters?  I can see that this summer the broken up ice might suddenly turn into a huge expanse of ice-free open water, as happened in 2012.  If so, then my vote of a higher than the polled average of ice extent will be way off and I will eat crow-shaped ice chunks.  But if minimum ice extent turns out to be 4,500,000+ km2 and the ice at this time is more widely dispersed than it normally is, it might very well result in more rapid, extensive, and complete freezing once the Arctic turns to freezing. 

Wherever ice is dispersed the water in between cannot warm far above freezing without the heat being used to melt ice.  Wherever there is large amounts of open water the water can absorb lots of sunlight energy without the heat being used to melt ice.  Then when air temps drop low enough for freezing the water in between the ice can melt straight away, whereas the large areas of open water have to lose their heat first before freezing can start.

I am confident that a widely dispersed ice pack would result in faster freezing than a compact ice pack, given the same total area of ice.

rapid refreezes are definitely bad for the ice/improve the chances of a bigger melt the following year. no 'maybe' about it

Why would that be so?
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seaicesailor

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Re: The 2016/2017 freezing season
« Reply #3 on: July 21, 2016, 01:21:22 AM »
I understand that gaps within dispersed ice, especially in the CAB, will refreeze quickly for what Michael has explained, this has been observed in other seasons. There is an inertia due to bottom melting but if gaps were relatively small compared to the extent of ice around, the accumulated heat should be much less than at the edges. And it tends to be colder for obvious reasons (little warmth from periphery, no warm currents in general). So I agree with some of what FTB implies with his chemistry analogy, but for these different reasons.
However the ice can get compacted before Sep.
About the "the rapid refreeze is good for the ice" somebody may have a really solid explanation in one direction or the other.

Michael Hauber

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Re: The 2016/2017 freezing season
« Reply #4 on: July 21, 2016, 02:01:21 AM »
One thing I can think of is that windy conditions could create more mixing, pulling more heat out of the deeper ocean and delaying ice formation.  Still conditions could form ice faster on the surface leaving more heat underneath.  Thicker ice means insulation holding the heat in, and potentially restricting the further growth of ice later in the freeze season. 

But faster freeze due to colder conditions with similar wind?  I'd expect thicker ice, with no downside.  Colder conditions more likely to be still?
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jdallen

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Re: The 2016/2017 freezing season
« Reply #5 on: July 21, 2016, 02:43:28 AM »

rapid refreezes are definitely bad for the ice/improve the chances of a bigger melt the following year. no 'maybe' about it

Why would that be so?
Decreased rate of heat transfer through the ice.  Loss of heat from open water is far higher than areas covered even with fairly thin ice.   Paradoxically, if we have more open water dumping heat (and melting slush that forms), the better off we are for the next melt season. 

Eventually of course, we want the balance to tip over to ice formation, but before then we want as much heat vented out of the atmosphere as possible.
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Andreas T

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Re: The 2016/2017 freezing season
« Reply #6 on: July 21, 2016, 09:04:36 AM »
I agree with jd that it comes down to heat loss at the water surface. The difficulty is to see how a larger heat loss does not produce lower temperatures at the surface and the water temperature does not go below freezing point (I don't think supercooling is a feature in the arctic ocean where water isn't entirely clear and snow can easily provide "seed crystals")
The key here is that sea water has its density maximum at its freezing point, but then the ice that forms has lower density because salt is rejected from the ice crystal. If I would cool  sea water slowly it would stay liquid until it all has reached freezing point. In the ocean water is slightly above freezing point when ice starts to form at the surface and strong cooling of the ice/ air surface allows that ice to float on water which would melt it if it would simply be dropped into a large container of that stuff.
As long as the surface of sea water is colder than the bulk of it there will be convection moving cold water from the surface down and replacing it with warmer water. Because the temperature at the water surface (water/air or water/ice) can not be lower than freezing temp. the way that heat transfer out of the bulk of the water can change is by changing the rate of convection, i.e. speeding up or slowing down movement.
With open water and wind we can expect movement of water in the vertical direction which helps that transfer of heat to the surface. With an ice cover that additional movement is absent. Since water can not move up and down in the exactly the same place at the same time the convection which continues to cool the sea below the ice also has a horizontal component which is impeded by the solid ice surface. All in all convection is slower under ice than at the open water surface.
This is how thickening of sea ice reaches a limit: when the ice is 3 meter thick (to give a rough figure) even very cold temperatures at the top will only carry as much heat through the ice (by conduction) as is taken from the cooling ocean below. Of course the ocean would eventually get so cold it would start to freeze regardless of how slowly heat is removed but then summer comes along before that and there are such other heat inputs as deeper, warmer but saltier water which does not take part in the convection described earlier.

In that simplified situation heat loss is undoubtedly reduced. But how much would in that (at this moment hypothetical) dispersed older ice at the start of the freezing season move and compact the thin younger ice, opening leads which freeze thereby producing a not much less thick ice cover than is found usually?

Feeltheburn

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Re: The 2016/2017 freezing season
« Reply #7 on: July 24, 2016, 09:21:28 AM »
Thanks Andreas, for providing a forming for discussing dynamics of refreezing.  I was just musing the other day and of course made some comments questioning the data record in addition to the ice as seed crystal hypothesis.  That made my post seem far more skeptical than in reality it was meant to be. I have a certain mindset based the bizarre fact that (1) I was sort of a pyro as a kid and became interested in chemistry that way, (2) studied chemistry in college though I originally declared as political science major, (3) went to law school and am practicing lawyer, and (4) formed a company that does R&D and owns patents relating to "green cement" technology to reduce CO2 footprint of cement and concrete.  Points (3) and (4) have jaded me and make me overly critical of certain points of view. But believe me I'm self-critical and self-correct as much as possible and quite pleasant and ingratiating in person notwithstanding my acerbic writing style.http://forum.arctic-sea-ice.net/Smileys/default/grin.gif

I appreciated everyone's passion and dedication to this endeavor and hope to not step on toes but wish to learn.
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SCYetti

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Re: The 2016/2017 freezing season
« Reply #8 on: July 24, 2016, 03:58:59 PM »
Thanks AndreasT for your post. The mechanics of freezing is something I've given a lot of thought. I agree with everything you posted except for the super-cooling. Wouldn't super cooling have to occur in the Arctic Ocean at depth. Each 10 meters of water equals about 1 atmosphere pressure?

Andreas T

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Re: The 2016/2017 freezing season
« Reply #9 on: July 24, 2016, 07:32:57 PM »
But what would be cooling water at that depth, i.e. where would the heat go to cool the water down there?
The coldest water at depth is cold because it has cooled at the surface (under the antarctic sea ice afaik) so while it could be colder than -2oC without freezing because it is at high pressure it can't get colder with a warm Earth beneath it and warmer surface water above it.

Or am I misunderstanding your question?

SCYetti

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Re: The 2016/2017 freezing season
« Reply #10 on: July 24, 2016, 08:26:14 PM »
Andreas - you understood my question despite a misplaced question mark. I'll give it some more thought and do some research and maybe get back to you if I find anything.

Feeltheburn

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Re: The 2016/2017 freezing season
« Reply #11 on: August 13, 2016, 07:35:36 AM »
From a post on 2016 melting season:

"However, every observer must remember that the more pulverized the sea ice becomes, the harder it is to estimate melting because the melt is increasingly driven by mixing of pulverised ice with sea water. (Water-sitting 3-dimensional ice surface area grows towards infinity the more pulverized and smaller the pieces of sea ice become - this facilitates ever greater heat transfers between water and ice. Strong winds mix sea water more efficiently in these circumstances."

It seems to me that in a reversible process factors that are favorable for producing an equilibrium effect in one direction should do the same when driven in the opposite direction.  Therefore, if highly dispersed ice promotes faster melting in the summer because of increased surface area around the edges, it should promote faster refreezing in the winter for the exact same reason.  Ice likes to form on ice like any crystal.  More solid surface area and wider distribution of ice when conditions favor refreezing should hasten refreezing.  If that were not so, then it shouldn't hasten melting either.  Given the dogged tendency of the highly dispersed ice to hang around this melt season notwithstanding warmer water temperatures means the quoted matter above may be error.  If so, then so would be my hypothesis of faster refreezing.  I'm happy to be wrong.  I just want there to be consistency in observation and prediction.
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anthropocene

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Re: The 2016/2017 freezing season
« Reply #12 on: August 13, 2016, 08:45:51 AM »
It is interesting by the way to have a look at the start of last years thread with the benefit of hindsight. We are trying to learn from our observations and wish to derive an understanding which lets us detect signs of what the future will bring. I have learned that there is huge complexity in the melting and freezing of arctic sea ice and that makes me cautious with predictions. But we are all amateurs here

So what do you think are the lessons that could be learned from last year's freezing thread? Is it possible to draw up a hypothesis from those lessons? What measurements and tests could support or disprove that hypothesis? One of the great features of science is the scientific method and that it is quite simple and anybody can follow it. Also the scientific method stands apart and is independent of whoever is applying it. I dislike too much emphasis being made on the distinction of "professional" and "amateur". Two points to back that up:
1) Until maybe 100 years ago the vast majority of scientists would have been classed as "amateur". That didn't stop great advances in science being made.
2) The Olympics is on at the moment - many of the athletes will be classed as professional. Some athletes at the games will be amateur and there are many more amateur athletes in the world competing in the sports for fun. Do amateurs - because they are amateurs - get an opt out of doing the sport properly because they are amateurs? Do amateur marathon runners run part of the distance get in a car and drive several miles because they "are only amateurs"?

icy voyeur

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Re: The 2016/2017 freezing season
« Reply #13 on: August 13, 2016, 12:56:56 PM »

It seems to me that in a reversible process factors that are favorable for producing an equilibrium effect in one direction should ...

It's not an equilibrium process. Not even close. There's layerings of different salinity and thermal layers. The question is, how much mixing occurs and by what mechanisms. During summer melting you get light, low salinity cold water on top which is metastable.  During winter freezing you get high salinity water on top which is unstable because it's heavy. Larger ice sheets dampen swells which dampens one mode of mixing.  Freshman chemistry is a poor starting point to address dynamic systems.

Andreas T

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Re: The 2016/2017 freezing season
« Reply #14 on: August 14, 2016, 02:10:52 AM »
Feel the burn, you say you are critical of what you are told, but you should also be critical of the very poor reasoning with which you draw analogies between processes at very different scales. You repeat the idea of dispersed ice forming nuclei for crystalization. This is nonsense at the scale of the arctic ocean and you simply ignore any opportunity to learn more about this.
Ice will form more easily and quickly between dispersed ice floes than on a large expanse of open water. The question which matters is: what does that mean for heat loss from the ocean. I have adressed that above but you seem to pay no notice to it. You would not be the first chemist with a poor ability to think scientifically I have come across, but you should at least be aware of your limitations and not mistake vague analogy for science.
Ice yoyeur is right in pointing to the asymmetry in the processes of melting and freezing: the process of solidifying water is happening in a situation where transfer of heat into the water is different from transfer of heat out of the water, salt is concentrated in sea water during freezing which produces buoyant ice, the convection currents for melting and freezing are not reversible.

anthropocene: the main lesson I draw from looking back is that prediction on the basis of little understanding, mistaken analogy and preconceived opinion is futile. I find the arctic capable of behaving in many different ways, a changing arctic will keep surprising us. With the comment about amateurs I meant that we can be more uninhibited to make guesses than the people who have professional reputation at stake. Many people writing on this forum are showing little self scrutiny, professionals are worried about making statements which can be shown to have been poorly evaluated. Amateurs rarely have spent the amount of time developing knowledge of the field which I would expect of a professional. We also lack access to information and the contact with knowledgeable people which have an interest in us gaining knowledge such as an academic supervisor might have.



RoxTheGeologist

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Re: The 2016/2017 freezing season
« Reply #15 on: August 14, 2016, 04:39:47 AM »

The more I read about the Arctic, the more complicated I anticipate any predictive model would be.   One thing seems certain, there is more thermal energy in the Arctic than in the past few years, more heat from the atmosphere, and (though hard to prove) more heat in the water forming the Atlantic Water layer. How these interact, how it affects the weather, how that effects the regions exposed to sunlight and snow cover all seem to have a huge impact on what we consider defining metrics of the state of the Arctic sea ice extent. It is hard to model; it's complicated.

What we can be sure of is the first statement. The world is hotter, there is more energy in the Arctic. The world's climate changing at an unprecedented rate, and, I fear, It's going to be a huge challenge to my children's generation.


Michael Hauber

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Re: The 2016/2017 freezing season
« Reply #16 on: August 15, 2016, 03:24:28 AM »
It seems to me that more pulverized ice would add sea ice extent faster than an equal area of solid ice.  The reason being that pulverized ice has a large area of open water close to the ice edge, which must be nearly at freezing point, and will therefore freeze over more or less instantly.  In contrast with one solid area there is only likely to be a small area of water near the ice boundary that is close to freezing point, and most of the rest of the water will be above freezing point requiring significant cooling before it can freeze.

I can't see why the salinity or stability of the water underneath would do anything to change this.  Is this about bottom freezing?  I would naively expect that bottom freezing is determined by the thickness of the ice (thicker ice insulates better and freezes slower) and the air temperature below.  Does proximity to open water change this in some way?
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Tor Bejnar

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Re: The 2016/2017 freezing season
« Reply #17 on: August 15, 2016, 03:55:06 AM »
Michael,
I think what you wrote might be true for ice in fresh water, but in sea water, the water has to get much colder in order to extract the salt.  "Old" ice in sea water will be stable in temperatures no new ice can form in.   (All this is true if I've learned what others have taught in these threads correctly.)
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Feeltheburn

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Re: The 2016/2017 freezing season
« Reply #18 on: August 15, 2016, 05:35:39 AM »

You repeat the idea of dispersed ice forming nuclei for crystalization. This is nonsense at the scale of the arctic ocean and you simply ignore any opportunity to learn more about this.
Ice will form more easily and quickly between dispersed ice floes than on a large expanse of open water. The question which matters is: what does that mean for heat loss from the ocean. I have adressed that above but you seem to pay no notice to it. You would not be the first chemist with a poor ability to think scientifically I have come across, but you should at least be aware of your limitations and not mistake vague analogy for science.

Ice yoyeur is right in pointing to the asymmetry in the processes of melting and freezing: the process of solidifying water is happening in a situation where transfer of heat into the water is different from transfer of heat out of the water, salt is concentrated in sea water during freezing which produces buoyant ice, the convection currents for melting and freezing are not reversible.


Thanks for the lessons Andreas.  I didn't ignore what you said.  I just didn't understand it as being a direct or even indirect response to something I had said previously. 

I have no doubt I don't understand all the variables in this complex multi-variable system like you do.  But I don't think it's far-fetched to assume that if highly dispersed ice promotes melting because of higher surface area of the ice-water interface, the same ought to be true for refreezing. 

And sorry to refer to this process as "reversible" and at "equilibrium".  I do recognize that sea ice usually melts at about 0 degrees C, while ice forms when ocean water is cooled to about -1.8 degrees C.  So yes, it's not a perfect mirror image.

I feel it a major consolation that you agreed with me that more dispersed ice should hasten refreeze albeit for reasons much more nuanced and well-thought out.  Thanks for tossing me a bone.

My point, however, was not to repeat the "seed crystal" analogy but rather to respond to a point made by someone else that dispersed ice should hasten melting.  In fact, your point seems to show that dispersed ice per se would not have this effect in this complex system and that other factors are at work.  If so, fine.  I don't pretend to know that much.  I'm taking baby steps and thought that if the statement that dispersed ice promotes melting did not cause any notice or criticism it must have been generally accepted as true.  My comment was simply one of perceived symmetry of the effects of the surface area of the ice-water interface.  If true, and perhaps it's not, that the increased surface area of the sea ice-ocean water interface can promote faster melting when conditions are favorable for melting, the reverse should be true - the same increased surface area of the sea ice-ocean water interface should promote refreezing when conditions are favorable for refreezing.
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Andreas T

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Re: The 2016/2017 freezing season
« Reply #19 on: August 15, 2016, 09:25:50 AM »
This is where the details matter. Yes increased surface area increases the heat transfer from water to ice. And if water receives heat from elsewhere it will melt the ice, if ice transfers more heat away than the water recieves, it will freeze the water. That is plain thermodynamics.
The thing is that we are looking at that process in an ocean of salt water which recieves heat by shortwavelengths of EM radiation and emits it by longwavelength, where meltwater is cold and buoyant, where salt water melts ice at -1.5o. Where water absorbs heat when it isn't covered by ice but doesn't when a thin layer of ice reflects that shortwave radiation so only a small fraction of it reaches that water.
Then the logic you apply to the question is not valid. I don't have more time right now but may come back to this later.

jdallen

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Re: The 2016/2017 freezing season
« Reply #20 on: August 15, 2016, 06:15:03 PM »
My point, however, was not to repeat the "seed crystal" analogy but rather to respond to a point made by someone else that dispersed ice should hasten melting.  In fact, your point seems to show that dispersed ice per se would not have this effect in this complex system and that other factors are at work. 

Completely contrary both to fact and what's been presented.  Very simply - dispersed ice means greater surface area exposed to heat, both directly through side melt and indirectly via increased uptake of heat from insolation, or, heat retrieved from depth via increased circulation caused by movement (Ekman pumping).  There is more to it, but just these facts break your hypothesis.

If so, fine.  I don't pretend to know that much.  I'm taking baby steps and thought that if the statement that dispersed ice promotes melting did not cause any notice or criticism it must have been generally accepted as true.  My comment was simply one of perceived symmetry of the effects of the surface area of the ice-water interface. If true, and perhaps it's not, that the increased surface area of the sea ice-ocean water interface can promote faster melting when conditions are favorable for melting, the reverse should be true - the same increased surface area of the sea ice-ocean water interface should promote refreezing when conditions are favorable for refreezing.

Two words:  Hysteresis and Enthalpy.  Systemically , how conditions change over time in the arctic - including the mechanics of re-growing the Arctic pack suffer from Hysteresis - the way the system changes lags behind those supported by current forces in play.

Secondly we have enthalpy - the total heat in the system - which has increased monstrously over the last 3 decades and that increase is accelerating, due to increased input of heat into it from multiple sources which are catching up with changing conditions; and Further, is not being reduced in the refreeze season at a rate which offsets the new inputs.  The heat we had last winter with the absurdly low ice maxima and 30C+ positive temperature anomalies is testimony to that.  I actually found that far more terrifying than the collapse of the pack in 2012, and I think it may be just as significant, if not more.

Dispersed ice will have virtually no effect one way or another on the refreeze.  It will be governed entirely by two things - the current enthalpy of the system, and how fast the system can transport that heat out of the top of the atmosphere.  In this, the formation ice is a net hindrance, as it reduces circulation, convective transfer and evaporative transfer of heat.  Conduction through ice is a poor replacement.  I'd say hope for cold temperatures and open water as long as possible.  It's how the ice will be preserved.
« Last Edit: August 15, 2016, 07:06:45 PM by jdallen »
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Andreas T

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Re: The 2016/2017 freezing season
« Reply #21 on: August 16, 2016, 01:50:55 AM »
My comment this morning was written in a hurry and in retrospect isn't very informative. One thing to mention is that breaking ice into smaller floes and spreading them over a larger area of water is not actually increasing the surface area of the ice by much because floes are so thin relative to their size: breaking a 1m thick 10kmx10km floe into 100 1kmx1km floes increases surface area from  100.04km2 to 100.22km2 if I don't count the top surface. To have a significant increase the pieces must be much smaller because the ice is relatively thin and therefore has an already large surface area per volume. This has already been discussed on the forum and is not in dispute.
Because ice cover reduces the absorption of solar radiation by water by reflection a coherent area of ice cover means the majority of heating of water takes place further away from the ice. Some of that heat is likely to be lost to the atmosphere rather than get to the ice before the melt season ends.
Another effect, mentioned by JD, which differentiates between contigeous and dispersed ice cover is mixing: the melting ice freshens the upper water layer, under an ice cover this can protect the ice from saltier water which melts ice at lower temperature. Increased relative movement of water and ice which I expect to occur with more dispersed ice will increase the convection which increases the rate of melting.
So unless the dispersed ice cover has effects on fog and cloud which reduces heating, I do expect more volume to melt if ice is dispersed.

Now to the freezing. I have attached a still from Obuoy12 last year. What I think this shows (although in mid August it was still too warm to last) is how the ice provides calm water where snow can float on the surface and would in colder weather freeze into an ice layer which eventually covers the gap between the floes. Again it is not the surface area of the ice which is significant but the way the presence of ice affects the movement of water.
Again radiation plays a role: both water and ice loose heat by thermal IR, but the ice surface reaches lower temperature because convection in the water brings warmer water to the surface. That cold ice cools air which helps to cool the water surface. As is often stated, air temperatures have to be well below freezing to form ice on water which in its bulk is actually not yet at its freezing point. As JD writes, a quickly formed ice layer can actually reduce heat loss from the bulk of the water. Again it is reduced movement under the ice which slows the inevitable heat transfer from warmer water to colder ice. So faster freeze counterintuitively does not mean increased heat loss, it means heat is lost from a relatively small volume of surface water which turns to ice and then impedes cooling of the rest of the water column.

This is how I think understanding of the mechanisms involved provides insights where analogies and generalizations can mislead.


Juan C. García

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Re: The 2016/2017 freezing season
« Reply #22 on: August 16, 2016, 02:40:06 AM »
My comment this morning was written in a hurry and in retrospect isn't very informative. One thing to mention is that breaking ice into smaller floes and spreading them over a larger area of water is not actually increasing the surface area of the ice by much because floes are so thin relative to their size: breaking a 1m thick 10kmx10km floe into 100 1kmx1km floes increases surface area from  100.04km2 to 100.22km2 if I don't count the top surface.

I made this calculations:
__________________

On a floe 1m thick 10kmx10km:
One side: 10km long x 1 meter thick = 10 km2
Because there are four similar sides: 10 km2 x 4 = 40 km2
Because it is only one floe: Total: 40 x 1 = 40 km2

__________________
On the other hand, on 100 floes, 1m thick 1kmx1km:
One side: 1km long x 1 meter thick = 1 km2
Because there are four similar sides: 1 km2 x 4 = 4 km2
Because there are 100 floes: Total: 4 x 100 = 400 km2

__________________
Edit: This is not counting the top and bottom faces, that have the same area (total 100 km2 top and 100 km2 bottom).

Sorry. My mistake. I will correct my comment!
« Last Edit: August 16, 2016, 03:00:53 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

Juan C. García

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Re: The 2016/2017 freezing season
« Reply #23 on: August 16, 2016, 03:09:45 AM »
I made this calculations:
__________________

On a floe 1m thick 10kmx10km:
One side: 10km long x 1 meter thick (0.001 km) = 0.01 km2
Because there are four similar sides: 0.01 km2 x 4 = 0.04 km2
Because it is only one floe: Total: 0.04 x 1 = 0.04 km2

Including the bottom face: 100.04 km2, if 100% of the side faces are in contact with the water.

__________________
On the other hand, on 100 floes, 1m thick 1kmx1km:
One side: 1km long x 0.001 km thick = 0.001 km2
Because there are four similar sides: 0.001 km2 x 4 = 0.004 km2
Because there are 100 floes: Total: 0.004 x 100 = 0.4 km2

Including the bottom face: 100.4 km2, if 100% the side faces are in contact with the water.

__________________
This is not counting the top face.
Sorry for my first comment.   :-X
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

Andreas T

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Re: The 2016/2017 freezing season
« Reply #24 on: August 16, 2016, 01:49:30 PM »
Thank you Juan, you are right of course, I should have doubled the "break" lines because they create new surfaces on both sides of the break!  :-[  Thats the danger of posting past bedtime, and the benefit of critical readers putting it right when mistakes are made!

Juan C. García

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Re: The 2016/2017 freezing season
« Reply #25 on: August 17, 2016, 01:12:40 AM »
Thank you Juan, you are right of course, I should have doubled the "break" lines because they create new surfaces on both sides of the break!  :-[  Thats the danger of posting past bedtime, and the benefit of critical readers putting it right when mistakes are made!

You are welcome, Andreas T. The true is that I could not believe that the difference was so little, so I checked it. As you, should not post on the Forum late at night (I live at Mexico). But it is a routine to check Bremen, ADS and Neven's Forum before I go to bed. So I also made a mistake (huge in my case), thinking that the difference was bigger.
The true is that 100.22 or 100.4 km2 is the same (it is not relevant), so you are right.
« Last Edit: August 17, 2016, 01:22:58 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

Juan C. García

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Re: The 2016/2017 freezing season
« Reply #26 on: August 17, 2016, 01:50:19 AM »
I still believe that one hundred floes of 1x1 km are more vulnerable than 1 floe of 10x10 km. I would say that the difference is important if there are long waves or swell in the Arctic Ocean and we take into account the top surface.
Assuming strong waves (5 meters high, by example) that are able to wash 100 meters of one side of a floe:
___________________
On the 10x10 km floe:
The washed area on the top surface will be: 10 km x 0.1 km = 1 km2
Because it is just one floe, the total area wet or washed will be 1 km2.
___________________
In the other hand, with 100 floes, 1km x 1 km each:
The washed area on the top surface on one floe will be: 1 km x 0.1 km = 0.1 km2
Because there are 100 hundred floes: 0.1 km2 x 100 = 10 km2
___________________
So the washed area on 100 (1x1km) floes is 10 times bigger than the washed area of the one (10x10 km) floe. Of course, that should induce more melting on the ice, if the waves are coming periodically.
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

abbottisgone

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Re: The 2016/2017 freezing season
« Reply #27 on: August 21, 2016, 09:21:40 AM »
I still believe that one hundred floes of 1x1 km are more vulnerable than 1 floe of 10x10 km. I would say that the difference is important if there are long waves or swell in the Arctic Ocean and we take into account the top surface.
Assuming strong waves (5 meters high, by example) that are able to wash 100 meters of one side of a floe:
___________________
On the 10x10 km floe:
The washed area on the top surface will be: 10 km x 0.1 km = 1 km2
Because it is just one floe, the total area wet or washed will be 1 km2.
___________________
In the other hand, with 100 floes, 1km x 1 km each:
The washed area on the top surface on one floe will be: 1 km x 0.1 km = 0.1 km2
Because there are 100 hundred floes: 0.1 km2 x 100 = 10 km2
___________________
So the washed area on 100 (1x1km) floes is 10 times bigger than the washed area of the one (10x10 km) floe. Of course, that should induce more melting on the ice, if the waves are coming periodically.
It's a surface area argument essentially...

Is this correct: if hot goes to cold- as the first law of thermodynamics says- then the heat from the spark plug is trying to find the relative cold surface of the fuel. All the shaping of the chamber and engineering of a misted fuel load injection and so forth is simply to maximise this basic physical need of all object?

Assuming I am half correct then heat content from the ocean will enjoy as much surface contact with sea ice as possible! (??)

DID I GET IT RIGHT?
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2phil4u

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Re: The 2016/2017 freezing season
« Reply #28 on: August 21, 2016, 07:59:24 PM »
I was also thinking about some effects of the storm, for example more saltheavy water from depth was going up and of course it will later refreeze but in absolute, there is coming heat from the ocean and is going into space.
And today wipneus data shows an uptick.
MAybe all the heat went to the ice has also a big positive effect total also because of low temperatures at 945er level.
So like the poster before, if water with higher temps come over ice, then this water will cool down and in winter maybe this effect didnt matter at all for the next season.
Also saw that thaw daying is not that difference between 80s and now but winter temperatures was much higher.
But we have El Nina, maybe the cliff is not there the next few years.

Juan C. García

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Re: The 2016/2017 freezing season
« Reply #29 on: August 22, 2016, 06:49:05 AM »
It's a surface area argument essentially...
DID I GET IT RIGHT?

Yes. it's a surface argument essentially.

My comment didn't get into thermodynamics, it is just about the perimeter of the floes:

       One floe of 10 x 10 km: Perimeter = 10 x 4 = 40 km2.
       One hundred floes of 1 x 1 km: Perimeter = 100 x 1 x 4 = 400 km2.

So, the perimeter of the 100 1x1 floes is 10 times the perimeter of the one 10x10 floe.
If there is some activity related to the perimeter (or like waves making an area related to the perimeter), the 100 smaller floes will be more vulnerable than the bigger floe.

Edit: Maybe in the freezing season, the effect will be the contrary: If the perimeter promotes the freezing, then the freezing will be stronger with the 100 smaller floes.  :)
« Last Edit: August 22, 2016, 07:08:20 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

icy voyeur

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Re: The 2016/2017 freezing season
« Reply #30 on: August 22, 2016, 09:55:09 AM »

Is this correct: if hot goes to cold- as the first law of thermodynamics says- then the heat from the spark plug is trying to find the relative cold surface of the fuel. All the shaping of the chamber and engineering of a misted fuel load injection and so forth is simply to maximise this basic physical need of all object?

No. Yuck. Please don't do that again. It's obscene.
A spark isn't trying to do anything. It just is. The spark is disconnected from later consequence, how well fuel is mixed with oxygen, shape of a cylinder or your need for speed. The spark depends on the potential and the dielectric with various 2nd and 3rd order effects which are mostly corrects to the dielectric. 

Beyond that, and this relates to ice melting and freezing, other dynamics are in play than just thermodynamics. Kinetics, convection, diffusion and more. Equilibrium style thermodynamics sets some limits, informs on how the kinetics of various processes changes with T but it's really very complex.

Consider the dual gradients of T and salinity in the water column. Model it as the consequence of what are differential equations involving the rates of diffusion, convection, turbulence, radiation, heat of fusion at the ice/water interface, salt exclusion and on. Simplify it to competing rates. Water pours into a jug at a fixed rate. As the jug fills, increasing the water column, a hole in the bottom of the jug leaks more and more water. Except that can be modeled by a simple differential equation and for freezing/thawing we have so many more variable.

Now it's perfectly reasonable to attempt to consider a single effect, to model a simplified system, or otherwise speculate but please, don't begin with completely bogus physics. Systems don't "want" to do things, or "try" to reach equilibrium or move heat. But I've ranted enough. Bad thermo does that to me.

bbr2314

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Re: The 2016/2017 freezing season
« Reply #31 on: August 22, 2016, 11:07:51 AM »

Is this correct: if hot goes to cold- as the first law of thermodynamics says- then the heat from the spark plug is trying to find the relative cold surface of the fuel. All the shaping of the chamber and engineering of a misted fuel load injection and so forth is simply to maximise this basic physical need of all object?

No. Yuck. Please don't do that again. It's obscene.
A spark isn't trying to do anything. It just is. The spark is disconnected from later consequence, how well fuel is mixed with oxygen, shape of a cylinder or your need for speed. The spark depends on the potential and the dielectric with various 2nd and 3rd order effects which are mostly corrects to the dielectric. 

Beyond that, and this relates to ice melting and freezing, other dynamics are in play than just thermodynamics. Kinetics, convection, diffusion and more. Equilibrium style thermodynamics sets some limits, informs on how the kinetics of various processes changes with T but it's really very complex.

Consider the dual gradients of T and salinity in the water column. Model it as the consequence of what are differential equations involving the rates of diffusion, convection, turbulence, radiation, heat of fusion at the ice/water interface, salt exclusion and on. Simplify it to competing rates. Water pours into a jug at a fixed rate. As the jug fills, increasing the water column, a hole in the bottom of the jug leaks more and more water. Except that can be modeled by a simple differential equation and for freezing/thawing we have so many more variable.

Now it's perfectly reasonable to attempt to consider a single effect, to model a simplified system, or otherwise speculate but please, don't begin with completely bogus physics. Systems don't "want" to do things, or "try" to reach equilibrium or move heat. But I've ranted enough. Bad thermo does that to me.

I would disagree with ^ assertion.

This is slightly off-topic but I would use the below as evidence that there is intention behind systems and that they do not merely exist in a vacuum, they behave with *some* sort of intent.

https://en.wikipedia.org/wiki/Fermat%27s_principle

If light can have intention (i.e., the moment it originates, it already knows its eventual end-point which is how it can take the shortest path possible), then why wouldn't other physical systems express similarly?

RoxTheGeologist

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Re: The 2016/2017 freezing season
« Reply #32 on: August 22, 2016, 05:52:04 PM »
Wow... No please. There is no "intent' in the universe. Particles might have a defined path from there initial characteristics but do not confuse that with design. We often explain concepts with 'want' or 'need', because it allows easier comprehension, but that's for high school. A photon does not have a consciousness that is implied by 'intent'

icy voyeur

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Re: The 2016/2017 freezing season
« Reply #33 on: August 22, 2016, 07:56:53 PM »
I would disagree with ^ assertion.

This is slightly off-topic but I would use the below as evidence that there is intention behind systems and that they do not merely exist in a vacuum, they behave with *some* sort of intent.

https://en.wikipedia.org/wiki/Fermat%27s_principle

If light can have intention (i.e., the moment it originates, it already knows its eventual end-point which is how it can take the shortest path possible), then why wouldn't other physical systems express similarly?

Wrong forum to continue to discuss Fermat's principle, Schrödinger's cat, tunneling, or Maxwell's Demon, but your interpretation of Fermat is wrong.  Frankly, I can't even guess how you came to that interpretation. Almost wish I did.

Iceismylife

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Re: The 2016/2017 freezing season
« Reply #34 on: August 22, 2016, 08:37:58 PM »
I would disagree with ^ assertion.

This is slightly off-topic but I would use the below as evidence that there is intention behind systems and that they do not merely exist in a vacuum, they behave with *some* sort of intent.

https://en.wikipedia.org/wiki/Fermat%27s_principle

If light can have intention (i.e., the moment it originates, it already knows its eventual end-point which is how it can take the shortest path possible), then why wouldn't other physical systems express similarly?

Wrong forum to continue to discuss Fermat's principle, Schrödinger's cat, tunneling, or Maxwell's Demon, but your interpretation of Fermat is wrong.  Frankly, I can't even guess how you came to that interpretation. Almost wish I did.
https://forum.arctic-sea-ice.net/index.php/topic,1655.0.html

I'd like to talk more about this so I started a thread in the off topic section.

TerryM

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Re: The 2016/2017 freezing season
« Reply #35 on: August 26, 2016, 08:27:01 PM »
Any thoughts on whether these late storms, by mixing the upper strata of the water column, then exposing this mixed column to the atmosphere in the following months, contributes to very high ice numbers in the following melt season?
2012 had a fairly late, very strong and longlasting arctic storm which helped produce the record melt numbers of that year. Did the storm also contribute to the rebound experienced in 2013?
It seems as though. by mixing the upper, fresh strata with the lower warmer/saltier layers, that during winter months the convection required before ice can grow would extend to a much deeper level than what would have been the case if no storm had occurred.
This thicker 'mixed' strata would be cooler and less able contributing to bottom melt during the next melt season.
A storm occurring early in the melt season, while more ice cover was in place, would contribute much less mixing either by wave action or Ekman pumping, and therefore would have less effect on the following seasons.
Based on this I'm now expecting 2017 to be a 'rebound' year, similar to 2013.
Terry

2phil4u

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Re: The 2016/2017 freezing season
« Reply #36 on: August 28, 2016, 06:36:59 PM »
I also think about this, freshwater on the surface freezing over can not export that much heat then saltier water in winter, so ohc should go down (if you only consider this).
I also feel that open water at n80 now with storms, esp in late september can have good effects.
But there is also stuff in internet, sorry for my bad englisch, that if water is warmer and startet melting earlyer it can give more heat and grow later but much faster in winter because it has time to mix with lower layers and so of course overall give more energy to space, but of course early openwater in summer also will reduce albedo, so this is the other factor.
But i think if storms are late and we dont count something like fraimtransport or multiyear ice it should have positive effects, not sure if this compensate or even overcompensate the damage, but if end august or early september it surely will end up to give more heat to space, but if this heat is from south and south isnt important it might be not this good as it seems from this standpoint of view.

abbottisgone

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Re: The 2016/2017 freezing season
« Reply #37 on: August 30, 2016, 10:45:18 AM »
I appreciate the information I've just received.

No, but seriously, I will try and speak a little more correctly.

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iceman

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Re: The 2016/2017 freezing season
« Reply #38 on: September 02, 2016, 12:10:15 PM »
for your October viewing pleasure: the Wrangel Stump regrows and seeks out its phantom lower limb, which is reconstituting itself from the seawater and a few scattered bones

oren

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Re: The 2016/2017 freezing season
« Reply #39 on: September 02, 2016, 03:57:16 PM »
Any thoughts on whether these late storms, by mixing the upper strata of the water column, then exposing this mixed column to the atmosphere in the following months, contributes to very high ice numbers in the following melt season?
2012 had a fairly late, very strong and longlasting arctic storm which helped produce the record melt numbers of that year. Did the storm also contribute to the rebound experienced in 2013?
It seems as though. by mixing the upper, fresh strata with the lower warmer/saltier layers, that during winter months the convection required before ice can grow would extend to a much deeper level than what would have been the case if no storm had occurred.
This thicker 'mixed' strata would be cooler and less able contributing to bottom melt during the next melt season.
A storm occurring early in the melt season, while more ice cover was in place, would contribute much less mixing either by wave action or Ekman pumping, and therefore would have less effect on the following seasons.
Based on this I'm now expecting 2017 to be a 'rebound' year, similar to 2013.
Terry
I came to this thread with these same thoughts. The GAC or PAC-MAN or whatever it's called is sucking heat out of the ocean, potentially setting up a rebound year. It's far from certain as AGW is more advanced than in 2013, the Atlantic is making inroads into the Arctic, and the state of the remaining ice at season's end is terrible. But still, raiding the heat piggy bank this year might leave less for next year.

mmghosh

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Re: The 2016/2017 freezing season
« Reply #40 on: September 02, 2016, 05:02:06 PM »
Lets not forget the thermal inertia of water.  It is very possible that 2017 could be a record low.  2016 July still came in as the hottest ever, in spite of a fading el Nino.

https://www.ncdc.noaa.gov/sotc/global/201607

Lord M Vader

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Re: The 2016/2017 freezing season
« Reply #41 on: September 02, 2016, 05:59:20 PM »
About the idea that late season storms affects next seasons melt season I must ask if there wasn't a intensive cyclone roaring over the Arctic in august 1995? If so, it's worth to mention that 1996 was one of the lousiest and coldest melting seasons we have seen in modern times, perhaps THE coldest one wrt 925 hpa temps from A. Slaters page.

RoxTheGeologist

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Re: The 2016/2017 freezing season
« Reply #42 on: September 02, 2016, 08:04:23 PM »

I found this paper on the effects of freezing on the Arctic/Atlantic and heat and freshwater budgets

http://onlinelibrary.wiley.com/doi/10.1002/2015JC011045/full

There is a really good introduction on the history of analysis on the Arctic/Atlantic interaction.

Dundee

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Re: The 2016/2017 freezing season
« Reply #43 on: September 03, 2016, 01:24:45 AM »

I found this paper on the effects of freezing on the Arctic/Atlantic and heat and freshwater budgets

http://onlinelibrary.wiley.com/doi/10.1002/2015JC011045/full

There is a really good introduction on the history of analysis on the Arctic/Atlantic interaction.


Not light reading, but should perhaps be required reading. I suspect this is about as simple a description as can be made of the role of ice in the interaction of the atmosphere, the deeper ocean proper, and the surface low-salinity lens.

If, before exclaiming "well, that must mean . . . " or "this observation means that this result must surely follow", one does not have a basic understanding of the one dimensional models presented in this paper as well as the underlying assumptions and simplifications included in them (as well as how, where, and why they would no longer be valid and the resulting implications), then it would be fair to state the exclaimer needs to do more homework.

In the forum we tend to speak more of the latent heat of fusion than of evaporation, but I suspect water entering and leaving the atmosphere has a lot to do with some things that happen in the Arctic that are otherwise inexplicable. One specific case is the nearly complete decoupling of ice conditions before roughly the equinox on the subsequent peak - changes in evaporation/ precipitation are more than influential enough (so far) to rein things back in.

I also note the paper succinctly discounts the impact that obstructing water flow though the Bering Strait would have on the overall Arctic heat balance.

RoxTheGeologist

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Re: The 2016/2017 freezing season
« Reply #44 on: September 03, 2016, 03:52:15 AM »

Not light reading, but should perhaps be required reading....

I agree, I read it once through, drew some conclusions, debunked those conclusions on a second read. It is not light, but it's also extremely well written, and I think very relevant to what we are going to see over the next few months in the Laptev, Kara and in the Barents; particularly in light of the current storms and the energy budget that they attribute to water in the atmosphere.


seaicesailor

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Re: The 2016/2017 freezing season
« Reply #45 on: September 06, 2016, 07:37:06 PM »
From the melting season thread I repost on an interesting remark by A-Team
...
It's not clear whether BB will melt out this season or remain as a few raisins in the re-freeze pudding. The Beaufort appears to be very close to melt equilibrium.

The same analysis could be done for the Wrangel arm and Chukchi. There too the trend is off and on but perhaps still slightly down, again suggesting early September conditions close to a phase boundary.
...


Either this map is completely wrong or the Pacific half of the Arctic is far from being in "melt equilibrium". If for melt equilibrium is meant freezing point.  Very curious to see the evolution of SSTs as the temperatures gradually drop.

Now I wonder what could be understood by "melt equilibrium" in the Arctic if it is not melting point. Perhaps there is a definition out there.
It may happen that surviving floes cool down surrounding water enough to create first ice structures out from the water surface, but bottom melting continues and lateral melting too in the smallest floes. Perhaps the equilibrium occurs when the propagation of this new ice is fast enough. Then the new ice area grows at the same rate as the area decrease of the small floes still melting out. This can happen only once the water is cold enough. The SST far from the ice can still be greater than melting temperature so long as the heat flux from the warmer water by mixing does not overwhelm the heat released by the cooling water around the bigger floes and to the atmosphere.
Any comment appreciated. It is going to be interesting in the next weeks, I guess.


JimboOmega

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Re: The 2016/2017 freezing season
« Reply #46 on: September 08, 2016, 08:15:20 PM »
Any thoughts on whether these late storms, by mixing the upper strata of the water column, then exposing this mixed column to the atmosphere in the following months, contributes to very high ice numbers in the following melt season?
2012 had a fairly late, very strong and longlasting arctic storm which helped produce the record melt numbers of that year. Did the storm also contribute to the rebound experienced in 2013?
It seems as though. by mixing the upper, fresh strata with the lower warmer/saltier layers, that during winter months the convection required before ice can grow would extend to a much deeper level than what would have been the case if no storm had occurred.
This thicker 'mixed' strata would be cooler and less able contributing to bottom melt during the next melt season.
A storm occurring early in the melt season, while more ice cover was in place, would contribute much less mixing either by wave action or Ekman pumping, and therefore would have less effect on the following seasons.
Based on this I'm now expecting 2017 to be a 'rebound' year, similar to 2013.
Terry
I came to this thread with these same thoughts. The GAC or PAC-MAN or whatever it's called is sucking heat out of the ocean, potentially setting up a rebound year. It's far from certain as AGW is more advanced than in 2013, the Atlantic is making inroads into the Arctic, and the state of the remaining ice at season's end is terrible. But still, raiding the heat piggy bank this year might leave less for next year.

Do we think there's less overall heat than there was in 2012... or 2015?  Will the waters be slower to freeze.

Andreas T

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Re: The 2016/2017 freezing season
« Reply #47 on: September 09, 2016, 11:12:01 PM »
As an illustration of the effect that the presence of ice has on heat loss from the ocean as input from sun and atmosphere diminishes, here are some IR images from wordview band 31  http://go.nasa.gov/2crFbvP
Ice surface cools quickly and strongly, water, which was almost indistinguishable from ice in the summer, shows up as warmer leads, and floes show different surface temperatures presumably due to different thickness.
This is also seen among the more dispersed ice, the colder ice surface reduces heat loss from water beneath it compared to open water, yet air which moves from cold ice to warmer water can support freeze up of adjoining water surfaces as described in earlier comments.

Nightvid Cole

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Re: The 2016/2017 freezing season
« Reply #48 on: September 10, 2016, 04:28:22 AM »
New ice is forming around the "shoulder" area, filling in some of the holes.

seaicesailor

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Re: The 2016/2017 freezing season
« Reply #49 on: September 15, 2016, 12:48:39 AM »
Euro forecast, next four days. Cold storm; 30 kt, near gale-force winds on wide open peripheral seas.
Poll: should we place this gif at the melting season thread instead? 8)
« Last Edit: September 15, 2016, 01:03:25 AM by seaicesailor »