The 2020 melting season

[Butterflyy]

https://climate.rutgers.edu/snowcover/table_area.php?ui_set=0&ui_sort=0

By the way, it is funny that the area of snow in North America (without Greenland) (the last column) for the last week of May (22nd) is now the maximum after 2004... Maximum over the past 16 years. And someone else does not believe in the cooling effect from aerosols of bitumen oil extracted in Canada. 

Believe it or not, I still believe it is more linked to a shift of the Arctic ice volume center of mass location toward Groenloand that affects air masses patern accordingly. But I guess it will need more data to demonstrate this. If it makes little sense, arctic ice melt should be slowed closer to Canadian archipelagio.
Perhaps both factor are to be accounted for..  more aerosols creates further precipitation, cooler temperature helps preserve the snow.

[Steerpike]

I think 2012 can teach us a lot and perhaps we need to investigate more what happened that year. From a very high maximum extent to a remarkably low record minimum (a record still held). Up to now I've assumed it was the GAC in late summer, but something extraordinary happened between 4th and 13th June as well. As Juan C Garcia pointed out in the Extent thread, there was an average daily loss of 126K km2 over those 9 days.

Looking for clues I came across this in the NSIDC report from July 2012. Melt ponds started around the average date, ice at start of the period was thicker than normal, then boom. The report seems to put it down to sunshine, high temperatures (presumably WAA) and foggy nights (high humidity?).

Thoughts?

[uniquorn]

ascat day70-154. Warmer, possibly more humid, weather is likely to 'whitewash' familiar ascat features soon. As it does every year.

[oren]

ascat day70-154. Warmer, possibly more humid, weather is likely to 'whitewash' familiar ascat features soon. As it does every year.

As usual thank you for these animations.
The whitewashing has already started. It occurs to me that this correlates with regions of widespread snowmelt and albedo preconditioning. I wonder if "whitewashing date" can be an interesting indicator for comparison across years.

Edit: Having looked at 2019 Ascat animations (finally located in the test space thread) determining such a date is very difficult.

[Juan C. García]

I think 2012 can teach us a lot and perhaps we need to investigate more what happened that year. From a very high maximum extent to a remarkably low record minimum (a record still held). Up to now I've assumed it was the GAC in late summer, but something extraordinary happened between 4th and 13th June as well. As Juan C Garcia pointed out in the Extent thread, there was an average daily loss of 126K km2 over those 9 days.

Looking for clues I came across this in the NSIDC report from July 2012. Melt ponds started around the average date, ice at start of the period was thicker than normal, then boom. The report seems to put it down to sunshine, high temperatures (presumably WAA) and foggy nights (high humidity?).

Thoughts?

I am going to bed now, but thinking about it, there was not ASIF that year, but Neven was writing continuously in his ASI Blog. Excellent place to look for information:

https://neven1.typepad.com/blog/2012/06/index.html

[Back to topic]

[binntho]

Good to wake up to some interesting discussions! I'm thinking that this start-of-melting season has ssen a better class of commentators than many a previuos year (except of course we don't have A-Team anymore).

One thing I was thinking while reading was that we tend to forget bottom melt, and focus on top melt from all sorts of different causes, insolation and WAA, stormy weather, rain and condensation.

But I seem to remember reading a paper saying that top- and bottom melt follow each other in magnitude, so that e.g. 2012 saw both rapid top melt and unusually strong bottom melt and that the same pattern is repeated in other years - sluggish top melt coinciding with slow bottom melt and vice versa.

I can't remember where i saw this, perhaps it rings a bell with somebody else, but I don't really see where the variation in bottom melt should come from. Is there a causal link between the two, i.e. does increased top melt cause increased bottom melt? Or is there a shared external cause?

I'm sure there are lots of people here who knows a lot more than I do about this, it surely would tickle my knowledgebone to hear from some of them!

[Phoenix]

2012 in a nutshell.

1. Begin with then record low volume in Sept. 2011.
2. Many spikes in temp (relative to long term average) from Dec 2011 to March 2012
3. Elongated melting season as evidenced by DMI 80N temps. Hit 0C about 7-10 days earlier than usual and stayed there 7-10 days longer. Perhaps the season with most days >=0C per DMI 80.
4. GAC of sustained duration and record low August pressure.
5. Mackenzie delayed release which was apparently much more consequential than GAC.
6. Winds / ice transport concentrating the remaining ice in a smaller area making 2D picture look worse than 3D.

Other than April and May 2012, this was a season almost perfect on fundamentals and then aided by unusual GAC and rare Mackenzie situation.

2020 began with a slightly lower volume base in Sept. 2019 and advantage with higher GHG levels, but squandered the advantage with a cool-ish winter and is now 6th in volume. The path to a record now relies on an unprecedented finish. Some very adverse conditions will have to develop AND become very sticky. Mid-May extremes offered a chance to move up, but the sticky part didn't seem to come through.

[nanning]

Perhaps it is not what you are looking for but I've found these:

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2000GL012088
H. J. Trodahl, S. O. F. Wilkinson, M. J. McGuinness, T. G. Haskell
"Thermal conductivity of sea ice; dependence on temperature and depth" (2001)

From the abstract:

In particular, we find that experimental results are lower than predicted, due to disorder in the crystalline structure of the ice. The reduction is nearly a factor of two near the top surface of the ice. Deeper in the ice, in contrast, heat flow is enhanced by a contribution from brine convection.

(bolding by me)

This surface heatflow reduction has been found to be an artifact:

https://seaice.alaska.edu/gi/publications/pringle/06PTH.pdf
D.J.Pringle, H. J. Trodahl and T. G. Haskell
"Direct measurement of sea ice thermal conductivity: No surface reduction" (2006)

From the abstract:

We have reexamined the analysis of these previous array measurements and have identified analytical effects that rendered this analysis unreliable in the presence of high-frequency surface temperature variations and pronounced surface warming and cooling events. We conclude that this apparent near-surface conductivity reduction was an artefact.

(bolding by me)

[binntho]

Perhaps it is not what you are looking for but I've found these:

Close but no cigar. Thanks anyway!

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2000GL012088
H. J. Trodahl, S. O. F. Wilkinson, M. J. McGuinness, T. G. Haskell
"Thermal conductivity of sea ice; dependence on temperature and depth" (2001)

From the abstract:

In particular, we find that experimental results are lower than predicted, due to disorder in the crystalline structure of the ice. The reduction is nearly a factor of two near the top surface of the ice. Deeper in the ice, in contrast, heat flow is enhanced by a contribution from brine convection.

(bolding by me)

So they are saying that brine is flowing inside the ice and enabling heat transfer by convection. That is very interesting, I never even realized that was a possibility.

[Steerpike]

Re June 2012, thanks everyone for the feedback.

Much of this reinforces a feeling I've had for years of following this forum that humidity is the key factor. A dew point above zero at surface level coupled with at least a light wind really kills the ice (leading, significantly at this time of year, to widespread melt ponding).

Other factors play a part too of course - early land based snow melt raises the temperature of air reaching the Arctic, insolation warms blue sea (more significant later in the year, but more significantly just now in raising temp & humidity on nearby land). Wacky jet stream leads to higher air temp & moisture reaching the ice. Storms mix it all up and river outflows add more heat and mixing.

Finding info on surface level dew point seems tricky though - the best I can find is on Windy (I attach a couple of images identifying one spot I think would be more susceptible to melt due to this).

S.

[Frivolousz21]

Its really foggy.

Albedo is in the tank tho and it's not repairing under the fog. 

However solar matters a lot right now.

Should see some clearing with surface pressure differential increasing.

The models keep a quasi-dipole going but unless there is clearing the melt will be driven by the warm air in place or winds.

There has been sun on the Pacific side but the CAB and CAA are well protected.

[oren]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

[binntho]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

So the reason why "bottom melt" this season is not a topic for the melting season thread is that we have no ideas what causes it or how to quantify it?

[Frivolousz21]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

So the reason why "bottom melt" this season is not a topic for the melting season thread is that we have no ideas what causes it or how to quantify it?

I think he means the mechanics of bottom melt are not for this thread.

Bottom melt itself is definitely a legit topic.

However it's way to early for any substantial measurable bottom melt in the Arctic Basin

[Phoenix]

The May PIOMAS data is insightful. 2020 is 6th all-time overall and 8th in the CAB which is a much more useful indicator of end of season outlook. Given the relative historical consistency of CAB volume losses from mid June to end July, 2020 is likely to be ~ 8th place in CAB volume on Aug 1.

The volume story is telling us that we're in a recovery year.

2012 was able to differentiate after 8/1 in a big way so a late season boost in CAB losses (as compared to prior years) before the minimum is possible.

I think the place where we are easily misled is the constant messenging about Arctic amplification which does not highlight an important exception. AGW is not materially increasing average surface temperatures N of 80N during peak melting season. What's happening outside the core is interesting, but largely irrelevant to projecting the season minimum.

Correction: 2014 was a peak season outlier in terms of slower CAB loss during peak season so perhaps a bit less consistency than originally implied. But no outliers noted on the high side, so the inference remains largely the same.

[Phoenix]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

The following research paper attributes some of the 2007 extreme melt season to increased bottom melt caused by more open water.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL034007

There was an extraordinarily large amount of ice bottom melting in the Beaufort Sea region in the summer of 2007. Solar radiation absorbed in the upper ocean provided more than adequate heat for this melting. An increase in the open water fraction resulted in a 500% positive anomaly in solar heat input to the upper ocean, triggering an ice–albedo feedback and contributing to the accelerating ice retreat.

[pleun]

I think the place where we are easily misled is the constant messenging about Arctic amplification which does not highlight an important exception. AGW is not materially increasing average surface temperatures N of 80N during peak melting season. What's happening outside the core is interesting, but largely irrelevant to projecting the season minimum.

the fact that temperature doesn't go up does not mean that there's no energy exchange

[binntho]

I agree that the mechanics of bottom melt are better discussed elsewhere. So I am thinking that there must be a thread for that, but dang me if I can think of a way to find it (if it exists, that is).

As for the paper you link to Phoenix, it makes me wonder how the solar heating of open ocean can cause bottom melt of ice. The authors themselves say: "Earlier work has established the importance of solar heating of open water on bottom melting of the ice [Maykut and McPhee , 1995; Perovich , 2005]. " but looking at the two linked papers (i.e. their abstracst) seems to indicated that they are not saying anything about the impact of insolation on open water, but rather, that bottom melt is caused primarily by solar energy reaching through the ice into the uppermost layer of ocea, as opposed to coming from warmer reaches further down.

[Phoenix]

As for the paper you link to Phoenix, it makes me wonder how the solar heating of open ocean can cause bottom melt of ice.

I don't represent expertise that would enable me to critique the conclusions of the authors. What I can offer from the limits of observing last season is the ice within the Beaufort Gyre disintegrating into many small floes with lots of open water between the floes. In such a configuration, the ice might be more subject to wind forces and moving around a lot. When the wind moves the ice into a region of previously warmed water, you might get bottom melt.

The high mobility of the ice in the region addressed in the paper could be a factor making this phenomena less applicable to other regions where the ice does not separate into so many smaller isolated pieces.

This explanation is just an initial guess though.

[Phoenix]

I think the place where we are easily misled is the constant messenging about Arctic amplification which does not highlight an important exception. AGW is not materially increasing average surface temperatures N of 80N during peak melting season. What's happening outside the core is interesting, but largely irrelevant to projecting the season minimum.

the fact that temperature doesn't go up does not mean that there's no energy exchange

I agree, which is why I have been sitting on this observation for a while and not being in a rush to leap to any conclusions about it. But today, Oren posted the historical CAB volume charts and I see a connection. The CAB volume losses per PIOMAS during the peak melting season are unusually consistent as well. The combination of consistent volume losses and consistent temperature during peak season is worth something more than just consistent temperature on its own.

I encourage folks to go to the PIOMAS thread and look at the CAB volume chart and look for annual variations from day 165 to day 210. 2017 was slow from days 165 to 180, but other than that
not much variation. Relative position entering day 165 was extremely highly correlated to position on day 210. The year to year variation is coming from other parts of the year when AGW is more influential at the CAB surface.

This pattern suggests very high probability that 2020 will not advance materially in CAB volume relative to other years before August and makes it a high probability that this will be a recovery year with respect to total Arctic volume at the minimum.

[Freegrass]

Latest Five Day Forecast
Wind + Temp @ Surface

[oren]

I agree that the mechanics of bottom melt are better discussed elsewhere. So I am thinking that there must be a thread for that, but dang me if I can think of a way to find it (if it exists, that is).

"Basic questions about melting physics" in the ASI section, changed to "Basic questions and discussions about melting physics" to enable a slightly wider scope.

[jdallen]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

So the reason why "bottom melt" this season is not a topic for the melting season thread is that we have no ideas what causes it or how to quantify it?

I think he means the mechanics of bottom melt are not for this thread.

Bottom melt itself is definitely a legit topic.

However it's way to early for any substantial measurable bottom melt in the Arctic Basin

Generally agree.

Bottom melt over all is difficult to measure other than abstractly without buoys in place equipped with thermistors to measure water temperature at depth.

As it is, bottom melt is actually fairly straight forward as it is roughly governed by an equation based on sea water temperature.  I've posted the formula before at various times, guess I'll need to find it again.

Find that temperature, and based on how much it is above -1.8C, you can guess the melt rate with reasonable accuracy. 

[Frivolousz21]

Regarding bottom melt, this is not really a discussion for this thread, but in short bottom melt is affected by:
* Core ice temperatures, which go up in partial correlation with top melt. AFAIK significant bottom melt can happen before significant top melt.
* Insolation transmitted through the ice, which goes up in correlation with top melt
* Movement of the ice, due to various processes at the ice-water interface.

So the reason why "bottom melt" this season is not a topic for the melting season thread is that we have no ideas what causes it or how to quantify it?

I think he means the mechanics of bottom melt are not for this thread.

Bottom melt itself is definitely a legit topic.

However it's way to early for any substantial measurable bottom melt in the Arctic Basin

Generally agree.

Bottom melt over all is difficult to measure other than abstractly without buoys in place equipped with thermistors to measure water temperature at depth.

As it is, bottom melt is actually fairly straight forward as it is roughly governed by an equation based on sea water temperature.  I've posted the formula before at various times, guess I'll need to find it again.

Find that temperature, and based on how much it is above -1.8C, you can guess the melt rate with reasonable accuracy.

I think for every 0.5C in wash m warnth you lose an extra CM a day of ice

[VeganPeaceForAll]

Interesting article
https://www.scientificamerican.com/article/high-temperatures-set-off-major-greenland-ice-melt-again/?fbclid=IwAR2O4JGSxMdonPQApjs5Xly2Z5REfi_uOMZMQTlaTDyTugxOM0zxoSuj_Kw

[pearscot]

I don't understand this season. AT ALL!

For a while, and up until about 2 weeks ago, I was convinced the arctic was melting at a fairly robust rate given the generally high number of clear days. Moreover, the lack of snow cover and warmth coming in on the Russian/Siberian side seemed to indicate sustained warmth in those regions bleeding onto the ice.

Rivers are melting and pouring into the arctic now and Barrow looks like July; yet when comparing the entire ice pack to last year, 2020 now appears to have WAY more ice, especially on the entire North American side from Alaska to east Canada. The temperatures on windy also suggest that decently sized areas are at or around 32f as well. Nothing makes sense...I had expected to see the cliff continue, but now everything is stalled out and the landfast ice is still attached to the coast at Barrow.

I'm out of guesses as to what's going on in the system at large... :/

[bbr2315]

I don't understand this season. AT ALL!

For a while, and up until about 2 weeks ago, I was convinced the arctic was melting at a fairly robust rate given the generally high number of clear days. Moreover, the lack of snow cover and warmth coming in on the Russian/Siberian side seemed to indicate sustained warmth in those regions bleeding onto the ice.

Rivers are melting and pouring into the arctic now and Barrow looks like July; yet when comparing the entire ice pack to last year, 2020 now appears to have WAY more ice, especially on the entire North American side from Alaska to east Canada. The temperatures on windy also suggest that decently sized areas are at or around 32f as well. Nothing makes sense...I had expected to see the cliff continue, but now everything is stalled out and the landfast ice is still attached to the coast at Barrow.

I'm out of guesses as to what's going on in the system at large... :/

The snowpack in North America is very high outside of Alaska. Alaska and parts of the Yukon melted early but Nunavut is whiter than any year in the satellite record since 2000. The other years in the analogs for melt-out of Lake Winnipeg all featured lackluster melt seasons but I believe they were especially lackluster in the CAA.

While I would not hedge on 2020 being a slow melt season overall I think this is a decent indicator that the CAA is going to hold up very well this year which may also offer some benefit to Beaufort and adjacent CAB.

Mid-winter weather may not be ongoing at Igloolik, but it certainly is not summertime. And the end of this forecast is 10 days from solstice!

[igs]

I don't understand this season. AT ALL!

For a while, and up until about 2 weeks ago, I was convinced the arctic was melting at a fairly robust rate given the generally high number of clear days. Moreover, the lack of snow cover and warmth coming in on the Russian/Siberian side seemed to indicate sustained warmth in those regions bleeding onto the ice.

Rivers are melting and pouring into the arctic now and Barrow looks like July; yet when comparing the entire ice pack to last year, 2020 now appears to have WAY more ice, especially on the entire North American side from Alaska to east Canada. The temperatures on windy also suggest that decently sized areas are at or around 32f as well. Nothing makes sense...I had expected to see the cliff continue, but now everything is stalled out and the landfast ice is still attached to the coast at Barrow.

I'm out of guesses as to what's going on in the system at large... :/

Just wait, it will, 2012 for example was not only much higher but had a small plateau around these dates and somehow it happens every year several times just not at the same time.


Further the "easy to melt" ice is mostly gone and now the "Beaver" has started to eat through the large and hard Oak Trunk" so to say. Once a good way through the next cliff is waiting for sure.


All this provided the weather does not change towards Ice-Retention in a significant way.

[Phoenix]

I'm out of guesses as to what's going on in the system at large... :/

I'm not a weather expert, but I can try a big picture observation that might be helpful.

The most important I think is regarding the location of the prevailing circumpolar wind field and jet stream. We know that Arctic amplification is weakening the gradient which powers these winds and air masses are more likely to shift into and out of the Arctic.

During the winter, the polar air stayed close to the pole like the old days and we built some thicker ice in many places than we have in recent years. Now we see a lot of the polar air has shifted south toward N. America. This has resulted in a colder CAA and a warmer Siberia.

In a old world in which the polar air mass stays more centered around 90N, then we see more consistent results. In a world where the polar air mass is moving around, we need to take this into consideration. The outcome this year speaks to a polar air mass which has moved its weighted center slightly toward NA and the Pacific. In this proposed configuration, places like Beaufort and CAA have a higher effective latitude and Siberia has a lower effective latitude and the results follow.

The other big difference vs last year is the influence of the Pacific. Much warmer in the N. Pacific last year and earlier presence of warm SST's in the Arctic.

It's going to be an interesting looking ice map at the minimum.

[ajouis]

I'm out of guesses as to what's going on in the system at large... :/

I'm not a weather expert, but I can try a big picture observation that might be helpful.

The most important I think is regarding the location of the prevailing circumpolar wind field and jet stream. We know that Arctic amplification is weakening the gradient which powers these winds and air masses are more likely to shift into and out of the Arctic.

During the winter, the polar air stayed close to the pole like the old days and we built some thicker ice in many places than we have in recent years. Now we see a lot of the polar air has shifted south toward N. America. This has resulted in a colder CAA and a warmer Siberia.

In a old world in which the polar air mass stays more centered around 90N, then we see more consistent results. In a world where the polar air mass is moving around, we need to take this into consideration. The outcome this year speaks to a polar air mass which has moved its weighted center slightly toward NA and the Pacific. In this proposed configuration, places like Beaufort and CAA have a higher effective latitude and Siberia has a lower effective latitude and the results follow.

The other big difference vs last year is the influence of the Pacific. Much warmer in the N. Pacific last year and earlier presence of warm SST's in the Arctic.

It's going to be an interesting looking ice map at the minimum.

How can it go closer to the North Atlantic and the pacific at the same time ?! Not the first time it is mentioned either but I can't make sense of it

[Frivolousz21]

The wind flow is forecasted to stay predominantly in a Pacific to Atlantic flow.

It's not always perfect but this will start to show over the next 2 weeks with water opening up in different spots from the Beaufort to the laptev.

In the long range the GFS keeps going to a major blow torch dipole  for mid June on.


That is the required catalyst to push 2020 into a position for near record or record lows.

If that doesn't happen then record lows are off the table.

[Frivolousz21]

The weather pattern is very convoluted it's like two different patterns are trying to establish themselves that contradict each other and they're jockeying for position in the atmosphere.

And the result is this weak off placed dipole attempt.

While Greenland is essentially stuck in +AO hell.  Even tho the AO isn't that positive.

How this pattern evolves will straight up decide the season.

A powerful sunny ridge by the 20th at the latest is required if we're going to try to break record lows but we really need that ridge to establish itself by like the 13th to the 15th.

[Phoenix]

How can it go closer to the North Atlantic and the pacific at the same time ?! Not the first time it is mentioned either but I can't make sense of it

Read the post more carefully. I wrote N. America, not N. Atlantic.

[johnm33]

Thick ice is rotating into Beaufort, so Amundsen may clear but my guess is the CAA coast needs to clear before Beaufort will. IF that means that Pacific waters are moving east into ESS then the ice there will weaken and cause losses as it moves north.

ice thickness and sssalinity courtesy of Hycom.

[Phoenix]

The weather pattern is very convoluted it's like two different patterns are trying to establish themselves that contradict each other and they're jockeying for position in the atmosphere.

And the result is this weak off placed dipole attempt.

While Greenland is essentially stuck in +AO hell.  Even tho the AO isn't that positive.

How this pattern evolves will straight up decide the season.

A powerful sunny ridge by the 20th at the latest is required if we're going to try to break record lows but we really need that ridge to establish itself by like the 13th to the 15th.

Is there a place on the forum where we can read up on the influence of AO on the Arctic sea ice so we can begin to guess what "+AO hell" means in context?

Also, when you are referring to "this pattern" as the one which determine the outcome of the season, are you referring to AO?

[Aluminium]

May 31 - June 4.

2019.

[Phoenix]

Big oil spill in the Arctic. Didn't know which thread.

<Not here. And already reported in another thread. O>

[Phoenix]

May 31 - June 4.

2019.

We can begin planning the sailing trip from amundsen gulf to the pacific and a freely spinning gyre. Throw in an active nares strait which is sucking ice from northern ellesmere and a strong southerly wind through the CAA and we could see the return of the megacrack.

[Niall Dollard]

Throw in an active nares strait which is sucking ice from northern ellesmere

Is sucking ? Why use the present tense ?

[ajouis]

How can it go closer to the North Atlantic and the pacific at the same time ?! Not the first time it is mentioned either but I can't make sense of it

Read the post more carefully. I wrote N. America, not N. Atlantic.

You should add it to the glossary then

[Phoenix]

Throw in an active nares strait which is sucking ice from northern ellesmere

Is sucking ? Why use the present tense ?

I hope it's clear that I'm describing the future scenario which gives rise to a megacrack. Since the megacrack does not exist today, it's implied that that the conditions which give rise to it are also not present. 'will be sucking" is a way to use the term while still referring to future tense.

Just to be clear, none of the condition which were noted are in existence today. There is still a connection between the pack ice and the AK which inhibits the rotation of the gyre, there is no southerly wind through the CAA and Nares is still closed (but projected to open soon).

Apologies for any confusion.

[Freegrass]

Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water

Big change in the forecast for Fram export. It's suddenly looking a lot better for the ice.

[gandul]

A warm June for polar regions
https://twitter.com/judah47/status/1268916522451439616?s=20

[Jim Hunt]

A fairly clear view of the Lena Delta and thereabouts today:

https://GreatWhiteCon.info/resources/arctic-sea-ice-images/summer-2020-images/#Laptev

[Paul]

In the short to medium term, it's probably fair to say conditions look fairly favourable for the sea ice(in theory) with a fairly large but slack low pressure system dominating the CAB and towards the Laptev region. It looks like some warmth may head into parts of the ESS and perhaps the Chukchi sea although how much warmth and how long that lasts is unclear although early indication seems to be it will be a brief 1 day affair but impacts on the ice willl be interesting too see.

Also it looks like the Beaufort high will break down and more troughing will arrive therefore slowing down the Beaufort Gyre movement, that is quite a few days away though and subject to change.

Going to be interesting too see what the models will do with this low pressure system and whether it will deepen or not, most runs I seen don't deepen it much at all and remain fairly shallow.

Of course large drops may still happen because of continuous melting in the Kara, Baffin and Hudson Bay, we are getting to that time of year where larger drops are to be expected.

[igs]

In the short to medium term, it's probably fair to say conditions look fairly favourable for the sea ice(in theory) with a fairly large but slack low pressure system dominating the CAB and towards the Laptev region. It looks like some warmth may head into parts of the ESS and perhaps the Chukchi sea although how much warmth and how long that lasts is unclear although early indication seems to be it will be a brief 1 day affair but impacts on the ice willl be interesting too see.

Also it looks like the Beaufort high will break down and more troughing will arrive therefore slowing down the Beaufort Gyre movement, that is quite a few days away though and subject to change.

Going to be interesting too see what the models will do with this low pressure system and whether it will deepen or not, most runs I seen don't deepen it much at all and remain fairly shallow.


I see only heat adjacent to the entire cost on the russian side and a lot of warmt in other places as well hence we must be looking at totally different sources though.

I mostly use Climate Reanalizer to get the bigger picture, knowing that when it comes to exact temps it's often on the higher than on the accurate end but still.


Please elaborate your findigs and/or sources that support it.

Of course large drops may still happen because of continuous melting in the Kara, Baffin and Hudson Bay, we are getting to that time of year where larger drops are to be expected.

[Paul]

I use Meteociel(French website) too look at the Northern hemisphere weather charts and they clearly show a fairly large but largely shallow cyclone. The heat I can see is on the adjacent ESS coastline and some of this via a ridge of high pressure will hit the ESS and Chukchi regions. The Laptev and the CAB looks largely chilly too my eyes and the Beaufort high breaks down by a more slacker set up.

How it all develops after that remains to be seen but largely imo, there is very little in the forecast which should suggest the ice might be in trouble but the ESS and Laptev don't look in a great shape in anycase so it may not matter what the weather does.

How do you see the current output?

[Freegrass]

The warming of the Alaskan Coastal Current is becoming visible along the beaufort coast.

I wonder if those temperature anomalies on the ice are caused by surface melting. Nullschool is using a different dataset this year, so does anyone know how to read this? If you take the Sea Surface Temperature setting, the ocean is -1.8°C all over the place. So could the anomalies be a reading on top of the ice, aka melt pond temperature? Or ice temperature?

[gandul]

Not so sure the centered low will cool down things apart from the central CAB immediately, it seems will be pulling heat from the continents. Anyway, if it persists, then this thread is gonna lose many visitors.

[Paul]

Not so sure the centered low will cool down things apart from the central CAB immediately, it seems will be pulling heat from the continents. Anyway, if it persists, then this thread is gonna lose many visitors.

The low itself does not pull in the heat, its an Arctic low hence its own cold air blob and low thicknesses. The warmth comes in via a ridge over the ESS and Chukchi but there's uncertainty just how much heat comes in and how long it lasts for. E.g on the GFS it looks brief but some signs on the ECM it may last longer.