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RoxTheGeologist

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Re: The 2020/2021 freezing season
« Reply #300 on: October 14, 2020, 06:19:10 PM »

.....

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

....


... And air with increased humidity to reduce emissions to space.

Général de GuerreLasse

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Re: The 2020/2021 freezing season
« Reply #301 on: October 14, 2020, 09:18:46 PM »
Quote
No idea, I’d say it’s too cold
I would say it's far too warm between the ice pack and the entire Siberian side to even be considering refreezing inroads by Nov 1st. The southern limit of ice has hardly budged since Oct 1st (magenta line) so still has 1200 km to go. The sea surface temperature anomalies are remarkable today and even out nine days to Oct 22nd, per Mercator Ocean.

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

A delayed freeze has significant consequences in terms of thinner, brine pockety ice by spring like it did last year in the wake of the extreme TransPolar Drift

The Chukchi is even slated to get warmer towards the end of the month from incoming advection of yet warmer waters from the Bering Sea. At this rate, the southern Chukchi will remain open water into early or even mid January.

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to >10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback."

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean
IV Polyakov et al
Science  21 Apr 2017
https://science.sciencemag.org/content/356/6335/285.full  free full

Arctic sea ice is being increasingly melted from below by warming Atlantic water
Tom Rippeth  Prof Physical Oceanography, Bangor ME
September 18, 2020  popularization by co-author of two papers above
https://theconversation.com/arctic-sea-ice-is-being-increasingly-melted-from-below-by-warming-atlantic-water-144106

"What’s causing this decline in minimum sea ice extent? The short answer is our changing climate. But the more specific answer is that Arctic sea ice is increasingly being thinned not just by warm air from above but by ever-warmer waters from below.

In fact, in a recently published scientific study my colleagues and I looked at why sea ice was melting in the eastern Arctic Ocean and showed that the influence of heat from the interior of the ocean has now overtaken the influence of the atmosphere.

While atmospheric heat is the dominant reason for melting in the summer, it has little influence during the cold dark polar winter. However, the ocean warms the ice from below year-round. Our new research shows that this influence has more than doubled over the past decade or so and is now equivalent to the melting of nearly a meter thickness of sea ice each year.

Further to the east, this warm water has been isolated from the sea surface and so sea ice by a layer of colder, fresher water. However, as the heat blob is getting warmer and moving closer to the surface its influence is now spreading eastwards through the Arctic.

In a second scientific paper we showed that currents in the upper Arctic ocean were increasing, which when combined with declining sea ice and the weakening of the boundaries between layers of warm and cold water, was potentially stirring more warm water from the heat blob towards the surface. The combined impact is a new back and forth relationship between sea ice and ocean heat which could lead to a new ocean climate state in the eastern Arctic Ocean."

Hi A-Team, I have two questions.

Concerning the first image, the temperature anomalies are compared to what average?

I also have the impression to see through the pack ice areas of warmer sea water below the geographical North Pole, illusion of my old eyes or reality?

Thank you for your precious posts.
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Re: The 2020/2021 freezing season
« Reply #302 on: October 15, 2020, 08:31:42 AM »
A large red field of wind is forecasted in the Arctic.

aslan

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Re: The 2020/2021 freezing season
« Reply #303 on: October 15, 2020, 09:09:55 AM »
On top of all the retroaction already described, there is also the fact that an open ocean generate less friction, and the lack of an inversion increase even more the wind speed at surface. This is visible for the storm of Friday and Saturday. The low level jet brings stronger winds at surface over open ocean than sea ice. The cross section is from south to north, trough the low level jet for Saturday at 12Z. Higher wind speed reached the surface open ocean.

P.S. ; One important point... For the map, it is wind speed at 500m, not surface. There is two LLJs, one over sea ice and one over open ocean, but strong winds at 10m are only found over open ocean.
« Last Edit: October 15, 2020, 12:11:42 PM by aslan »

El Cid

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Re: The 2020/2021 freezing season
« Reply #304 on: October 15, 2020, 09:49:06 AM »
But wouldn't stronger winds vent more heat out of the Arctic and therefore speed up refreeze? I mean, with stronger winds, heat exchange should be faster, the water should cool down faster and ice should appear faster as well. So isn't it a positive feedback, meaning that big open seas lead to faster refreeze due to stronger winds?

aslan

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Re: The 2020/2021 freezing season
« Reply #305 on: October 15, 2020, 09:57:15 AM »
This means a stronger broclinic zone, with more clouds and moisture keeping the Arctic warm, and it means a weaker halocline with more mixing and shoaling of the Atlantic waters. By the way, even though the anomalies of temperatures are less extreme, the islands of the russian arctic are still running for the hottest month of October in record from the Barents to the East Siberian sea :

http://www.pogodaiklimat.ru/monitor.php?id=20069

http://www.pogodaiklimat.ru/monitor.php?id=21432
« Last Edit: October 15, 2020, 12:12:31 PM by aslan »

binntho

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Re: The 2020/2021 freezing season
« Reply #306 on: October 15, 2020, 10:07:24 AM »
This is the second mentioning of "shoaling" in recent days, see also A-Teams post above:

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed ...

I understand shoaling to mean what happens to waves as the approach shallower water (shoals) . According to Wikipedia shoaling happens when depth is less than half the wavelength.

Other meanings are "becoming shallower" and also when aquatic organisms group together (e.g. a shoal of herring).

So how does that fint into the bigger picture of an open ocean as Aslan seems to talk about, and what is meant by a phrase like "shoaling of the Atlantic Waters" as in the paper quoted by A-Team?
because a thing is eloquently expressed it should not be taken to be as necessarily true
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aslan

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Re: The 2020/2021 freezing season
« Reply #307 on: October 15, 2020, 10:50:59 AM »
This is the second mentioning of "shoaling" in recent days, see also A-Teams post above:

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed ...

I understand shoaling to mean what happens to waves as the approach shallower water (shoals) . According to Wikipedia shoaling happens when depth is less than half the wavelength.

Other meanings are "becoming shallower" and also when aquatic organisms group together (e.g. a shoal of herring).

So how does that fint into the bigger picture of an open ocean as Aslan seems to talk about, and what is meant by a phrase like "shoaling of the Atlantic Waters" as in the paper quoted by A-Team?

Err I am not really good at speaking english. AW are below the halocline. With waves, mixing weakens the halocline and allow heat transfer from the AW. For me shoaling means that AW are "less deep" and nearer to surface, with increased heat flux.

For the baroclinicity, I have added the vorticity (blue, positive, and red negative) and T'w in black. We can see that near the surface, the strong inversion is associated with the gradient in wind speed. This also creates shear and then vorticity. We have, as usual, shear zone and vorticity to the left and right to the LLJ, but near the surface there is also vorticity associated with the shear zone at the interface between sea ice and open ocean. But the max of vorticity over sea ice in the lowest 500 meters is really linked to the interface between sea ice and open ocean, it is not linked to the shear due to the deceleration of wind speed.

binntho

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Re: The 2020/2021 freezing season
« Reply #308 on: October 15, 2020, 11:06:17 AM »
[ AW are below the halocline. With waves, mixing weakens the halocline and allow heat transfer from the AW. For me shoaling means that AW are "less deep" and nearer to surface, with increased heat flux.

I think you are right, and this is probably what they meant in the article that A-Team linked to as well. And as such it is a proper if perhaps not common use of the word "shoaling".

Other than that I enjoy your postings, they are verey educational and gives a different view of the strangeness that is the modern Arctic.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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A-Team

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Re: The 2020/2021 freezing season
« Reply #309 on: October 15, 2020, 12:51:57 PM »
Quote
sea surface anomalies relative to what baseline years? How is SST measured under the ice pack?
There are a lot of mysteries associated with polar data displayed on the flashy Mercator Ocean portal. Sparse and infrequent observational input from moorings might constrain the model but satellite data is limited to surface parameters such as waves, currents, wind, salinity and temperature. It's not clear that these (and Archimedean considerations) suffice to model conditions at depth or under the ice pack.

The impossible underwater detail shown say for Bering Strait inflows -- can it be more than an ensemble run for illustrative purposes? Here it must be said that oceanography is a whole lot slower moving than weather. Thus salinity at 3000m in the Makorov Basin might change but on a century or even millennial basis, not daily like air pressure. Once known though, it constrains the rest of the model.

The baseline years for SST aren't provided but are presumably conventional (though who and how was it measured daily?). In terms of the relative anomaly of Oct 2020 SST, Mercator only offers Oct 2019 which was a lot less: http://bulletin.mercator-ocean.fr/en/PSY4#3/65.95/-72.51

Other quantities go back a few years farther and are provided at various depths. The SST anomaly is only provided for the surface. The Leaflet tool does not couple palette to image colors (like AMSR2_AWI) making it difficult to do more than estimate anomaly values.

There's a very elaborate new GIS layer tool called CMEMS that's only received scant attention on the forums. It has quite a few SST products and better descriptions. The layers are still supplied by Mercator Ocean though the Lobelia Earth viewer is an amazing development.

"Arctic Sea and Ice surface temperature product based upon observations from the Metop_A AVHRR instrument. The product is a daily interpolated field with a 0.05 degrees resolution, and covers surface temperatures in the ocean, the sea ice and the marginal ice zone. Temporal extent… 7 July 2018 to now."

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408
Quote
shoaling?
Shoaling is a old nautical term; shoals like those off NE Greenland are shallows where a ship could run aground; thus a shoaling course (rapidly decreasing depth to the bottom) is concerning. In oceanography, it just means a water mass of interest is getting closer to the surface. 

The Gulf Stream core depth in the Fram off Svalbard is about 300m, too deep to affect the ice above given the density stratification keeping AW in its place until the Yermak. Various mixing processes described in Polyakov 2020 are now causing Atlantic Water heat to rise closer to the surface, not just north of the SV-FJL-SZ line but progressing beyond to the Laptev shelf during the 15 years of the shelf transect mooring data.

There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts. As with Pine Island and Thwaites ice sheets in Antarctica and marine terminating glaciers in west Greenland, once change is marine-driven, it's much harder to affect outcome.
« Last Edit: October 15, 2020, 11:54:50 PM by A-Team »

BornFromTheVoid

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Re: The 2020/2021 freezing season
« Reply #310 on: October 15, 2020, 01:59:43 PM »
The pressure gradients this weekend looks like producing some significant waves from the Chukchi through to the Laptev sea, often over 5 m. The effect this has on the halocline and newly formed ice should be interesting.
Data from the ECMWF

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

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Re: The 2020/2021 freezing season
« Reply #311 on: October 15, 2020, 02:20:40 PM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!

I don't understand why only 11 people looked at the precipitable water video from yesterday...  ???

Yes, it's windy, and the ocean will get a big stir, with more harm to the halocline I presume? But I understand now that moisture is the most potent greenhouse gas on earth, that besides bringing in heat from southern latitudes, it's also preventing the Arctic ocean from releasing heat...

It's like a pre-heated blanket covering an Arctic fever, and nobody is looking at it?  :o

When a High Pressure System can't cool down the Arctic after equinox, that's messed up, isn't it?
« Last Edit: October 15, 2020, 02:30:52 PM by Freegrass »
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gandul

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Re: The 2020/2021 freezing season
« Reply #312 on: October 15, 2020, 02:21:54 PM »
...
There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts.

Not sure how that works.

Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space. It is not going to lead to more sea ice decline, since in the following days darkness is an almost infinite sink of heat excess until next Spring. So this weekend is going to lead to less heat stored beneath.

Where in the preceding paragraph am I wrong?

binntho

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Re: The 2020/2021 freezing season
« Reply #313 on: October 15, 2020, 02:49:56 PM »
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
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Freegrass

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Re: The 2020/2021 freezing season
« Reply #314 on: October 15, 2020, 02:59:09 PM »
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?
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Re: The 2020/2021 freezing season
« Reply #315 on: October 15, 2020, 03:36:44 PM »
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?

Id go as far as to suggest its inevitable that Siberia will have anomalously high snow-mass-balance this Autumn/Winter given that large amounts of open Arctic water will increase precipitation. The prevailing wind pattern this week is toward the continent. You can see the Siberian Islands already have positive anomalies of +100cm snow depth.

There are some forum members who would argue that once a certain depth is reached, this snowfall would be protective in the following summer and would help to prevent a blowtorch in June. Personally, im not convinced we will ever see this effect.
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aslan

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Re: The 2020/2021 freezing season
« Reply #316 on: October 15, 2020, 03:41:17 PM »
...
There's always been enough incoming heat to melt all the ice, the issue has been meager re-distribution by double diffusion staircases prior to export back out the Fram. However the downward trend in sea ice has brought a change-over from atmospheric to marine dominance of the energy balance.

As the buoyancy gradient (thermohalocline) begins dissipating from more shear and turbulence attributable to more open water resulting from sea ice decline, the heat brought nearer to the surface just leads to more sea ice decline, a runaway positive feedback that the authors see as immune to climate change mitigation efforts.

Not sure how that works.

Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space. It is not going to lead to more sea ice decline, since in the following days darkness is an almost infinite sink of heat excess until next Spring. So this weekend is going to lead to less heat stored beneath.

Where in the preceding paragraph am I wrong?

The Arctic in winter is not an infinite heat sink. Definitively NOT. There is a thing names moisture and another names cloud which is in play,

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2020&mes=10&day=15&hora=12

and there is also the fact that heat builds up in summmer in Arctic, and the heat transported from the tropics - a region where the bilan is strongly positive - etc. Arctic in winter is not an infinite heat sink. And never was one by the way. It is not a proof, but just look at the correlation between Nh and T at Ostrov Vize here for example :

http://ogimet.com/cgi-bin/gsynres?ind=20069&decoded=yes&ndays=50&ano=2012&mes=1&day=15&hora=12

Freegrass

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Re: The 2020/2021 freezing season
« Reply #317 on: October 15, 2020, 03:54:39 PM »
Let's take this weekend as example. Strong winds are going to pull some (or a lot) of heat excess to the open ocean surface, which is continuously going to be released to the atmosphere (much colder than the ocean surface) and to the space.

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?
I guess a huge part of that heat will rain back down on earth? And if not rain, snow, which will insulate?

Id go as far as to suggest its inevitable that Siberia will have anomalously high snow-mass-balance this Autumn/Winter given that large amounts of open Arctic water will increase precipitation. The prevailing wind pattern this week is toward the continent. You can see the Siberian Islands already have positive anomalies of +100cm snow depth.

There are some forum members who would argue that once a certain depth is reached, this snowfall would be protective in the following summer and would help to prevent a blowtorch in June. Personally, im not convinced we will ever see this effect.
My guess is that snow is easier to melt than ice? And wet snow - covered in "industrial and natural dirt" - decreases albedo?
And snow will prevent the giant Siberian ice cube (permafrost) from cooling down significantly?
« Last Edit: October 15, 2020, 04:45:27 PM by Freegrass »
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Sublime_Rime

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Re: The 2020/2021 freezing season
« Reply #318 on: October 15, 2020, 04:13:23 PM »

Isn't this exactly what Arctic Amplification is about? The heat is transferred from the ocean to the atmosphere, raising air temperatures and delaying refreeze. The atmosphere nearest the surface rapidly warms while the surface cools. But if heat is constantly being brought up from below, and the air is constantly pulling this heat out and distributing it in the atmosphere, then atmospheric temperatures will rise.

This will delay refreeze significantly I should think. The only question is how long this excess heat stays in the atmosphere before radiating out to space. That is perhaps the most important part of the equation: The heat that is released from the ocean this weekend, will some of it still be lingering next week or next month or will it all disappear out into space within a few hours?

I think you allude to the crux of this question for me. which is how the massive amount of heat contained in the oceans is distributed. I think there are negative and positive feedback components of increased open water, but the overall effect is positive feedback...based on how the increased heat solar energy is distributed. One could argue there is a negative feedback from increased heat release from open water, and thereby less heat available for bottom melt. So the question seems to be: Is the heat and moisture release from open water more efficient at distributing heat to melt ice than if that heat remained in the sea water and contributed to bottom melt.

I think, considering that open water by definition is not interfacing efficiently with ice until it freezes, that the answer is yes. Also since open water increases potential for vertical mixing, the articles posted by A-team two days ago offer another means by which a positive feedback may exist (open water allowing deep Atlantic warmth to mix further up into contact with ice).
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A-Team

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Re: The 2020/2021 freezing season
« Reply #319 on: October 15, 2020, 05:25:40 PM »
The 04 Aug 2020 article by Polyakov, Rippeth, Fer ... is an easy read, just skip over the data and methods sections; the first 3 authors have over 60 years of combined research experience on this very topic. It's not productive to speculate ab initio on your own without consideration of observational data and reviewed publications -- those are the point of departure.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089469 free full 2020
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001GL011111 free full 2002

The Copernicus CMEMS viewer by Lobelia Earth is really something. There's a learning curve but it's fast and stable. The pop-up even graphs the whole history of all the variable layers chosen! Hopefully more people here will look into this tool.

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408

Below, the lobelia-earth graphic looks at an ice thickness cut-out over sea surface temperatures. Colors and contrast have been tweaked to bring out the main talking points namely (1) freeze-up, like melt, is largely a peripheral growth story (bright orange), (2) the Chukchi and north Svalbard are quite a bit warmer than the already too-warm Laptev and will be the last to freeze and (3) another 'Wrangel arm' is developing (faint orange) from the current lobe at 160-180º that will approach the ESS as the next major freezing season development.
« Last Edit: October 15, 2020, 05:34:07 PM by A-Team »

aslan

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Re: The 2020/2021 freezing season
« Reply #320 on: October 15, 2020, 05:41:55 PM »
I think it is worth remembering we are living on Earth not Mars... We have a layer of gas above ours heads which is not transparent to IR. Even in the old, dark, dry Arctic of the past it was impossible to radiate an infinite amount of heat to space. There is always an upper limit. A temperature inversion in the low layer, even in Siberia in the 1880s could not have been greater to ~ -25°C. At some point, even in an absolutely dark and dry Arctic a point of equilibrium will be reached. And on top of that amount of heat lost to space is not primarily a function of the temperature at surface, it is not the case, definitively. The temperature at surface is not totally decorrelated from the heat lost to space of course. But there is an atmosphere above surface, in the end. It is Earth here, not Mars... Heat has to go trough the atmosphere before, and there is on the road CO2, CH4, H2O in every states possible, etc... And now that Arctic is providing a lot of heat and moisture, we are seeing a new state where there is a layer of clouds and moisture in the low layers which is isolating the surface, with temperature between 0 and -5°C at 2 meters versus -20°C to -30°C at 2 meters in the case there is no clouds.
Holy mother of Einstein, it is Earth here, not Mars !
The picture which follows is the forecast for Saturday for a given model. It is the minimum for the temperature of brilliance in infrared (10.8 microns) for the all day. Scale is from blue for the warmest (~0°C) to white (~ -40°C) going trough the brown / beige / I don't know which color (-10°C to -20°C). There is also the isolign for the surface temperature of -2°C to roughly approximate the edge of sea ice (more or less, we all see what the shape of sea ice currently). Over Beaufort, yes we are radiating at 0°C (blue color) and we are losing heat to space. But over Chukchi, ESS, Laptev, Kara, Barents, we have a layer of clouds as thick as the troposphere. And the temperature of brilliance is -20°C to -40°C. The temperature of brilliance is more directly correlated to heat lost to space than surface temperature. This really means, this really means, that during the storm, we are not going to radiate heat toward space at ~0°C from the ocean. We are going to radiate heat at -20°C or -30°C or -40°C. And there is a factor 1.5 to 2 between the radiation from a black body at 0°C and a black body at -30°C or something. The heat stirred by the storm is heat at ~0°C, the heat lost to space is heat at -30°C, and there is a ratio of 1.5 to 2 between the two... I made the same map but with the mean of the IR temperature from Friday to Thurday. The ice sheet is high and dry, radiating at -30°C and isolating the ocean at 0°C below. The Beaufort is, yes, a good heat sink fully radiating toward space. But for the siberian side, the clouds are here as the ice sheet, isolating the surface below. Even with a mean over 5 days, almost all the siberian side is forecasted to be isolated.
« Last Edit: October 15, 2020, 06:00:22 PM by aslan »

Comradez

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Re: The 2020/2021 freezing season
« Reply #321 on: October 15, 2020, 07:24:37 PM »
Thank you Aslan!  That is a very revealing graphic, and something worth keeping an eye on during the winter season.  It shows that the important thing, when judging whether open ocean in the winter is a positive or negative feedback, is the heat vented to space from the top of the atmospheric column, not the heat vented from the surface to slightly above the surface.  If the layer slightly above the surface is almost as opaque to IR as sea ice is, then that near-surface atmospheric layer basically functions like replacement sea ice—except it is "sea ice" that also lets the water column below it mix up warmer, saltier water to the surface, so double no-bueno there. 

A-Team

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Re: The 2020/2021 freezing season
« Reply #322 on: October 15, 2020, 11:13:06 PM »
Quote
Thank you Aslan!
Indeed Aslan has putting out some excellent corrective posts on net exchanges of energy via blackbody radiation (for ice: graybody emissivity) which goes on 24/7/365 ice cover or not.

Emissions are strictly proportional to the body's kelvin temperature to the fourth power (wiki: Stefan-Boltzmann) with the wavelength of maximal energy fading out inversely with temperature towards far infrared (wiki: Wien's displacement law). This era was the dawn of quantum mechanics with Planck having to invoke emission packet quantization in 1900 to resolve cavity unboundedness (wiki: ultraviolet catastrophe).

The amount of blackbody radiation emitted at 0ºC hardly differs from that at -1.8ºC being only 0.68% greater. The spectrum is very flattened but peaks at 2898 μm/kelvin temperature. A nice online tool for drawing the spectrum for any temperature and emissivity, along with energy per steradian, is at:

https://www.spectraplot.com/blackbody

Textbooks usually just show the sun's spectrum, a blackbody at 5778 K peaking at 0.501 μm in the green rather than say a mammal's blackbody emissions at 310K (wavelength in far infrared, 9.3 microns) or freezing sea water at 10.7 μm or freezing freshwater at 10.6.

The classical greenhouse effect arises from conversion of solar radiation, half of whose TOA energy lies below 0.710 μm, to heat that raises surface temperature and thus subsequent emissions at blackbody-appropriate longer wavelengths which are then adsorbed by greenhouse gases such as water vapor and CO2 that wouldn't have absorbed reflected visible so that solar is partially retained as atmospheric heat.

Arrhenius was already going on about this in 1896, with Fourier and Tyndall even earlier. Boltzmann equipartitioning had been established but not the molecular rotational and vibrational quanta accounting for (or missing in the crystalline state) the specifics of favored adsorptive/emissive wavelengths.

Blackbody radiation is by no means the only mechanism for cooling of Arctic open water and is not specific to it in the manner of evaporation, conduction and convection which are severely impeded by dry snow over thickening ice (wiki: heat equation). The overall energy flux has been studied for many decades at year-round ice camps and most recently by Mosaic.

The Arctic, one of the cloudiest places on earth, mainly has a low stratocumulus cloud cover which can be mixed phase (vapor, water droplets, snow crystals) adsorbing radiation from below and re-emitting it isotropically (ie sending 50% back down). [[Fixed typo noted by nanning below: means no preferred direction, all directions equally, so half up half down.]]

In fall and winter, this amounts to a seasonally delayed greenhouse effect with the Arctic often supplying its own self-limiting water vapor though moist intrusions from lower latitudes are also important. Microwave products such as Ascat can be adversely affected by this into even November and even later by major advective events.
« Last Edit: October 16, 2020, 01:55:39 PM by A-Team »

Cook

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Re: The 2020/2021 freezing season
« Reply #323 on: October 15, 2020, 11:17:00 PM »
But wouldn't stronger winds vent more heat out of the Arctic and therefore speed up refreeze? I mean, with stronger winds, heat exchange should be faster, the water should cool down faster and ice should appear faster as well. So isn't it a positive feedback, meaning that big open seas lead to faster refreeze due to stronger winds?

How times change. I don't think anyone in the recent past would have imagined such a statement for the Arctic in October. An Arctic where there is heat to be vented out from. An Arctic where more wind and air transported from warmer regions is supposed to make it "cool down faster". An Arctic where big open seas are going to make things colder rather than warmer. I find these statements quite remarkable.

This time of year, due to lack of solar heating the Arctic is cooling as it loses heat outer space. Any winds/mixing from other regions will tend to warm it.

Just for the record, the Arctic is currently about +5C warmer than average, and that, folks is NOT a feedback that is somehow going to make things cool down and freeze "faster".


josh-j

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Re: The 2020/2021 freezing season
« Reply #324 on: October 15, 2020, 11:25:15 PM »
If the arctic is warm, of course it will radiate more heat than if it was cold and icy. But that isn't a good thing at all, its just physics  ;)

I'm not sure that observing more heat "venting to space" is as much of a feedback as it is just an observation of how hot the arctic is.

You don't look at a red hot pan you put on the stove without water inside and say, well at least there is a feedback in that it being hot means it is radiating heat away more. It certainly is doing so, but that doesn't mean it will reach room temperature faster than if you didn't heat it up in the first place.

Edit: removed broken household heating analogy :)
« Last Edit: October 15, 2020, 11:32:11 PM by josh-j »

Aluminium

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Re: The 2020/2021 freezing season
« Reply #325 on: October 16, 2020, 07:40:14 AM »
October 11-15.

2019.

nanning

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Re: The 2020/2021 freezing season
« Reply #326 on: October 16, 2020, 07:41:37 AM »
Thanks for your high quality and informative posts!

A-Team wrote: "re-emitting it anisotropically" with text coloured blue.
I'm sorry, I try to understand these posts and this maybe a stupid question, but shouldn't that be "re-emitting it isotropically"?
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jdallen

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Re: The 2020/2021 freezing season
« Reply #327 on: October 16, 2020, 07:50:35 AM »
<snip>
The Copernicus CMEMS viewer by Lobelia Earth is really something. There's a learning curve but it's fast and stable. The pop-up even graphs the whole history of all the variable layers chosen! Hopefully more people here will look into this tool.

https://cmems.lobelia.earth/data?view=viewer&crs=epsg%3A3408
<snip>
I agree... just started playing with it and already impressed.
This space for Rent.

El Cid

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Re: The 2020/2021 freezing season
« Reply #328 on: October 16, 2020, 07:53:41 AM »
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

binntho

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Re: The 2020/2021 freezing season
« Reply #329 on: October 16, 2020, 07:58:08 AM »
It's not productive to speculate ab initio on your own without consideration of observational data and reviewed publications -- those are the point of departure.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089469 free full 2020
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2001GL011111 free full 2002

Being properly chastened, I hastened to read the two publications. The first one is very good, and totally on topic for our discussion. The second one left me scratching my head in amazement.

To begin with, the article is 20 years old and thus out of date given the subject matter. But the purpose of the arcticle is to show that there is no polar amplification. It does that by using a fairly common denier trope of claiming that multidecadal oscillations are confusing the signal, and once these are taken into account, the authors seem to be claiming to show that the arctic air temperatures have not incrased faster than global temperatures. Hence no "global warming arctic amplification"!

My conclusion (which may of course be totally wrong) is that this is an outdated article with erroneus conclusions, and I fail to see what it has to do with our discussions or the ongoing changes in the Arctic.
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: The 2020/2021 freezing season
« Reply #330 on: October 16, 2020, 08:00:19 AM »
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

grixm

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Re: The 2020/2021 freezing season
« Reply #331 on: October 16, 2020, 08:43:26 AM »
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.

But the cup does. And the cup here is the ocean where the ice can form.

El Cid

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Re: The 2020/2021 freezing season
« Reply #332 on: October 16, 2020, 08:58:41 AM »
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

Your room does not cool down when you blow across a cup of tea.

I asked about the tea (ice forming) not the room (global temps) not even the cup

Never mind

binntho

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Re: The 2020/2021 freezing season
« Reply #333 on: October 16, 2020, 09:28:12 AM »
You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.

The cup comparison repeats the same fallacy - the air that flows over the surface of the cup is a lot hotter than the surrounding air, and if we take the cup to be the open waters of the Arctic, then the surroundings of the cup are the rest of the Arctic. And blowing across the surface of the cup is going to warm up the surroundings faster than not blowing across the surface of the cup.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Oyvind Johnsen

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Re: The 2020/2021 freezing season
« Reply #334 on: October 16, 2020, 09:49:46 AM »
Ok, just for the record, there was some talk upthread about stronger than usual winds in the Arctic. I asked about whether these winds should cool down the Arctic faster. It may be a stupid question, but when I have a hot cup of tea and blow it continuously, it cools down faster than if it stays calm.
But maybe the Arctic ain't my cup of tea...

The air you blow out is colder than the air just above the tea. Blowing the tea will increase the temperature difference between the tea surface and the air above it, and thereby increase heat loss. Whereas winds blowing into the Arctic in general will be warmer than the air above the sea, causing the opposite effect.

El Cid

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Re: The 2020/2021 freezing season
« Reply #335 on: October 16, 2020, 10:38:41 AM »
OK, so asking whether current strong winds will lead to faster or slower ice formation (=freezing) in the Arctic is a fallacy. Yeah, whatever.
Though this was the freezing season thread last time I checked.

There could have been many possible answers, like:

- wind speed does not have a major effect on ice formation or
- wind speed has this and this effect on ice formation or
- it depends, in this case this happens in that that happens or
- we do not know

I mean, I don't understand the hostility. It is a highly relevant question for this freezing season and noone has yet written anything relevant other than bugger off.

But oren will stop me now I know, so end of rant

binntho

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Re: The 2020/2021 freezing season
« Reply #336 on: October 16, 2020, 11:06:26 AM »
It seems to me that lots of people have been trying to answer this or similar questions. And the general consensus seems to be "no", or "perhaps", or "not sure". But not "yes" as far as I can see.

The wind is part of the Arctic, and when the wind blows faster over warm waters, the wind warms up faster and the waters cool down faster. Does that speed up or slow down refreeze?

The process of freezing sea water requires very cold air, and any process that warms up the air is going to slow down refreeze. Strong winds over open waters warms the air, quicker, hence slows down refreeze even more ... or mabye not?

The fallacy was when you compared strong winds in the Arctic with blowing air over a cup of tea. The winds are part of the Arctic, but the air over the cup is not part of the cup. It is thus a false comparison.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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SimonF92

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Re: The 2020/2021 freezing season
« Reply #337 on: October 16, 2020, 11:09:08 AM »
One could argue that the wind over the ESS right now is not part of the Arctic
Bunch of small python Arctic Apps:
https://github.com/SimonF92/Arctic

binntho

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Re: The 2020/2021 freezing season
« Reply #338 on: October 16, 2020, 11:17:27 AM »
And the ocean is of course not part of the Arctic eather, with the waters constantly flowing from one part of the world to another.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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SimonF92

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Re: The 2020/2021 freezing season
« Reply #339 on: October 16, 2020, 11:24:43 AM »
And the ocean is of course not part of the Arctic eather, with the waters constantly flowing from one part of the world to another.

I agree with your point binntho- about the cup being a part of the room
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oren

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Re: The 2020/2021 freezing season
« Reply #340 on: October 16, 2020, 11:28:17 AM »
Folks, please don't get tied up in knots.
El Cid, I thought yours was a good question. However, it seems the analogy doesn't work so well because the ocean is not much warmer than the wind, and because the ocean is deep. OTOH yes, the wind will help mix and cool the deeper layers and eventually achieve refreeze. But when the wind is warmer than the ocean, well I guess the opposite is true. Of course, all this would not have happened if the ocean was not abmormally warm, so nothing here to be happy about.
Other folks, please treat questions nicely and please make your answers to the point, especially avoiding sarcasm.
In general I find it best to avoid analogies from everyday life as they often don't fit what goes on in the Arctic.

so_whats_happening

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Re: The 2020/2021 freezing season
« Reply #341 on: October 16, 2020, 02:06:12 PM »
Hey folks first time poster in any refreezing thread just figured I would try to better understand what is going on in the arctic, not my strong suit but trying to branch out and understand the different components in the Earth System.

So first and foremost these will all be arbitrary numbers no factual numbers.

Starting off we have open waters with a temperature of 5C in the surface layer of the ocean. We have a wind system coming in causing mixing to decent depths as one would expect in an open ocean. With this, say 20-30mph, wind across open waters that are warmer one would think on a normal basis that this would cause cooling, which it does for the ocean waters in this case. So now we have cooled the ocean waters from 5 to 3C that heat just doesn't escape as many have noted it goes into the surrounding environment. The heat from the ocean also plays its role even though some of that heat is loss it still warms the environment so it acts sort of like a double whammy in that sense. So now instead of having an atmosphere that was fairly close to freezing say around -5C the combined heat bring this closer to 0C if not potentially warmer. Now if the winds persist the idea is that this released heat from not only the ocean but from the winds cooling the ocean wont just sit over one area it spreads throughout the arctic and even potentially onto land depending on distance and location of the event.

Is it the leftover moisture in the atmosphere causing the issue and concern for the lack of refreezing because in order to remove that moisture it must precipitate which in turn causes clouds and further warming the surrounding atmosphere? I know snow insulates so the blanket then potentially doesn't allow proper refreezing to occur which in turn doesn't allow for cooler temps to form?

Maybe I need a little guidance better into that understanding, but I also believed removal of heat from the ocean was a good thing especially if wind patterns kept up to advect this from just staying in the same place. Moisture is a blessing and curse at the same time.

Please don't scrutinize me to harshly

psymmo7

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Re: The 2020/2021 freezing season
« Reply #342 on: October 16, 2020, 02:06:40 PM »
Well moderated Oren!

oren

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Re: The 2020/2021 freezing season
« Reply #343 on: October 16, 2020, 02:28:06 PM »
Welcome, s_w_h. The first post is the hardest.

Shared Humanity

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Re: The 2020/2021 freezing season
« Reply #344 on: October 16, 2020, 02:49:23 PM »


I mean, I don't understand the hostility. It is a highly relevant question for this freezing season and noone has yet written anything relevant other than bugger off.


You asked a relevant question but I see very little hostility in the responses, simply persons disagreeing with you.

The Walrus

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Re: The 2020/2021 freezing season
« Reply #345 on: October 16, 2020, 03:29:36 PM »
You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.

The cup comparison repeats the same fallacy - the air that flows over the surface of the cup is a lot hotter than the surrounding air, and if we take the cup to be the open waters of the Arctic, then the surroundings of the cup are the rest of the Arctic. And blowing across the surface of the cup is going to warm up the surroundings faster than not blowing across the surface of the cup.

I think you are looking at the issue from the wrong side.  The water will freeze when the water surface temperature falls below freezing, regardless of the air temperature. 

Your tea cup analogy is good, in that air flowing across the cup will warm the surrounding air.  However, the more important point is that it cools the tea.  Wind is a good transport of heat, moving heat from hotter to colder surfaces.  Higher wind speed will facilitate heat loss from a warmer surface, cooling the surface faster than slower winds.  As winter approaches, the water will be warmer than the air as water retains heat (the reverse occurs in summer).  As the air cools, higher wind speeds will facilitate heat loss from the oceans.  Hence, the surface will freeze faster with higher wind speeds.

One final note.  High wind speeds create surface turbulence, which inhibits freezing initially.  Once the winds diminish, the surface will freeze.  This happens routinely in inland lakes, where cold winds cool the water surface, but freezing does not occur until the winds die down.  Then the entire lake freezes very quickly.

Tor Bejnar

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Re: The 2020/2021 freezing season
« Reply #346 on: October 16, 2020, 03:46:47 PM »
There is enough heat in the Arctic Ocean to keep the surface functionally or literally ice-free, we are told, but much of this heat is stored beneath the halocline.  With an ice-free surface, winds will cause the upper part of the Arctic Ocean to mix, making more of this heat available to the lower atmosphere (and beyond).  Stronger winds will remove heat from the surface of the water faster, but these stronger winds will also mix more of the water column.  At some point, with continuous-enough and strong-enough winds, the halocline will disappear and 'all' of the ocean heat becomes available to be transferred to the air.  And if what we're told is true, the Arctic Ocean will cease to freeze over.  With climate change, the "-enoughs" become more and more achievable, as the speed of heat removal from the lower atmosphere to outer space slows due to the thickening CO2e blanket.

If the autumn winds are really just breezes that minimally mix the water, then the water column below the halocline remains out of the picture [the hot plate, with 200 mm of insulation on top of it, on which the tea cup sits has 'no' influence on the blown-on cup of tea].  Here, the surface water cools faster with the breeze - faster than if there is no breeze - with time that heat transfers to space, or is replaced with an 'endless' supply of cold dry air from 'elsewhere'.  So with cooled water and the heat removed from the air above the water, ice can now form.  I'm pretty sure a breeze coming off the continents in October will speed up the surface cooling, thus hastening the surface freezing.
Arctic ice is healthy for children and other living things.

gerontocrat

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Re: The 2020/2021 freezing season
« Reply #347 on: October 16, 2020, 04:25:50 PM »
In the years 2007, 2012 and 2019, after the very low minimum sea ice extent in those years, extent sharply rebounded in the second half of October and the first few days in November. After that, for the remainder of the freezing season, extent gains were much more average in those years.

This was NOT the case in 2016. There was no massive increase in extent gains at that time or during the entire freezing season. As a result the March 2017 maximum was a record low. What was the difference? I'm not sure.

Perhaps even though 2019 had a higher AWP (i.e. potential) than 2016, clouds and inclement weather reduced the amount that AWP became real ocean heating, while in 2016 there was plenty of sunshine. If that is the case, then 2020 is similar to 2016. The GACC ensured that much of the AWP became real ocean heating, even though AWP was marginally below 2019. This suggests that large sea ice extent gains might not occur this year from now to early November (and beyond?)

The test will come in the next two to three weeks
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RoxTheGeologist

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Re: The 2020/2021 freezing season
« Reply #348 on: October 16, 2020, 07:39:47 PM »

You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.



Correct me if I misunderstand - the ocean and air both lose heat through emission of LWIR. Low air temperature doesn't cause the ocean to freeze; rather it is indicative of the physical conditions that cause freezing. If the ocean is warm, then the air above it will be warm as the ocean is so much more massive.

pearscot

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Re: The 2020/2021 freezing season
« Reply #349 on: October 16, 2020, 07:40:39 PM »
One thing I would like to remark on is the substantial wave action as of late on the Siberian side of the Arctic. To me, it is extremely important and I think it will have some profound effects. I realize the below image is created with models and is not 100% accurate, however current winds in that region are substantial and I think there are some significant waves.

Completely still water only needs to cool the very surface to the sea water freezing point, however during such wind events, mixing ensures that the ENTIRE column of water must reach that temperature in order to freeze during extremely strong winds. Moreover, I believe the effects of the winds will be twofold.

First, my understanding (and is shown in the animation of the stagnation and/or slight advancement of the Laptev Bite recently), that the current weather is affecting the ice edge and either stalling the melt or causing bottom melt. I would have to imagine 19ft waves crashing into the ice edge is going to cause some significant damage.

Second, and I think more importantly, (as Tor stated), the substantial waves are promoting mixing during a time in which the sea is SUPPOSED to be covered with ice. That cool surface layer is now being agitated and is in no way helping the ever-diminishing halocline layer. I don't know the long term implications of wave action in terms of how it affects the refreeze, but for me the most concerning aspect is the constant mixing during the transition period going into winter.

I think both of these are important components and will continue to define the Arctic in the modern era. Granted I cannot prove this as fact, but it is evident how streams can continue to flow well below freezing due to the water's movement.
pls!