The 2015 melting season

[Neven]

Thanks, epiphyte and diablo.

[magnamentis]

I've decided I want to say something. 

...

I think what is happening, is that the melt ponds in the Central Arctic are freezing over now that temperatures are dropping below zero.

Seeing is believing...

yep, thanks, just thought about doing (posting) the same, all very logical and obvious for those who bother to have a close look at things. :-) kudos

[Lord M Vader]

It looks like our cyclone is a "MAC" - "Moderate Arctic Cyclone". The most recent run from GFS take the cyclone to about 985 hPa at lowest.

The cyclone should also do damage as it push warm water at CAA coast further north including warmer air. In addition it should stir up warmer water from depth which should do some damage. Another thing is that the "Arm" should be slashed apart. How many km² of ice loss would that yield?

Another thing to watch is the possibility of another small but rather intensive cyclone at 990 hPa that GFS is foreseen to track up at Svalbard in accordance with a center of 1020-1025 hPa equalling a rather strong pressure gradient. The ice should be compacted but also take a good deal of damage given how thin it's there. SST are very high in this area, especially north of Novaya Zemlya. Looks like DMI is classifying the water at 5-8^oC If winds are pushing that water north....

It finally seems like the ice in Laptev and Baffin Bay is deteriorating. What's surprising me most is HOW that little plot of ice in the Northern Hudson Bay STILL is alive and looks so healthy!!! Any suggestions? I know the winter was very cold there but still...

What do you think guys?

[seaicesailor]

The high ( AO down to -2) has brought an interesting race between compaction by refreezing and compaction by winds. From Wipneus plots, refreezing is mostly at CAB, compaction by winds mostly at peripheral seas. Another question: is melting per se still happening? Apart from CAA, Baffin and the little Laptev bite bite.
I would say yes but it is not apparent.

[seaicesailor]

It looks like our cyclone is a "MAC" - "Moderate Arctic Cyclone". The most recent run from GFS take the cyclone to about 985 hPa at lowest.

The cyclone should also do damage as it push warm water at CAA coast further north including warmer air. In addition it should stir up warmer water from depth which should do some damage. Another thing is that the "Arm" should be slashed apart. How many km² of ice loss would that yield?

Four years ago Aug 22 this other MAC caused the sharp drop seen in most 2011 area/extent curves. Neven called it flash melting, and was not clear if it was a sensor problem...., only that most sensors registered it.

Anybody remembers the strenght of this storm? Cant find archived data.

The most plausible explanations of flash melting were dispersal of loose floes, waves wetting out the surface, and enhanced bottom melt. Later on, some of the ice showed up again. A "peek a boo" but for real

Edit. Got the GFS Archive Aug 22 2011, max strength 985 hpa. Didnt get stronger. To compare apples to apples:

[slow wing]

Thanks for the knowledgeable comments on the recently observed loss of lower concentration regions in the ice pack, as well as the terrific photos from the Healy and the buoy: likely to be refreezing of melt ponds.

The U. Bremen update shows a bit more of that today on the Pacific side. (Maybe heading in the other direction on the Atlantic side.)

But the update also shows the continuing rapid retreat of ice pack edge, whether by compression or erosion, on both the Russian and Pacific sides.

Click on gif to crossfade between yesterday's and today's maps...

[solartim27]

Well,...does anyone know where the Shell Oil drilling rigs are at?  The high winds go through Sunday in the current forecast, and Fram is getting hammered as well.

[stackmaster]

Something is giving the ESS Arm a real beating, lots of fracturing happening over the last 48 hours.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c04.2015237.terra.1km

[BornFromTheVoid]

ADS extent now just 38k off the 2014 minimum, while losing extent at an average of 65k/day over the last 5 days. If we maintain this loss rate, we'll be below the 2013, 2010 and 2009 minima within 5 days

[jdallen]

I have to agree, lower temperatures does seem to be taking the edge off of surface melt.  However, I think before we declare things done, we really need to take into account the fact that SST's and the Anomalies are *huge*.  There are 8C+ anomalies on either side of Svalbard and in the Amundson gulf.  That's just the start; the whole Arctic is superheated, energy wise, and we're about to stir it up thoroughly with a couple of moderately intense Cyclones combined with a high pressure system to give us a dipole.

It's *always* been told to me that the actual air temperatures over the Arctic are not a factor until such time as they permit large scale direct re-radiation from the surface out of the atmosphere.  That's not going to happen until the humidity drops generally (as H2O is a major GH gas), and temperatures drop consistently below minus 5-10C.  Until then, I don't think we've got the energy sink to offset bottom melt.

And to that end, I think the numbers we see for water temperatures are pretty definitive.  There's a huge amount of energy there, and we're about to shake things up such that it can be applied more easily to the ice. (note that one CC of air is about 1.2 *milligrams* of mass, as compared to 1000 milligrams for a cubic CC of water.  That's water having about 1000 times the energy density of the air at STP.  It will take a few weeks for zero insolation actually having an impact on temperatures in any serious fashion.

The Grind will continue.

(edit: I almost forgot to add my screen shots...)

[BornFromTheVoid]

Using the NSIDC daily extent, the loss since the start of July to the 23rd of August, at 4.71 million km2, is the 3rd largest on record, after 2012 (4.96) and 2007 (4.76). It's also over a million more than 2014 (3.67) and 2010 (3.51).

[JayW]

25/0z ECMWF ENS prog the storm at 985mb. Edit, and with 24 hour intervals, it's likely lower at some point
http://www.tropicaltidbits.com/analysis/models/?model=ecmwf-ens&region=ak&pkg=T850_mslp&runtime=2015082500&fh=48&xpos=0&ypos=204

[Neven]

985 hPa, that's more like it.

Environment Canada has it at 991 hPa at the moment, coming in through Bering Strait:

[iceman]

25/0z ECMWF ENS prog the storm at 985mb. Edit, and with 24 hour intervals, it's likely lower at some point

Some of the strongest winds will be near the Chukchi end of the ice arm.  We might see an increase in concentration from snow in that locale, followed by a drop as bottom melt from the stirred-up water column takes hold.

[BornFromTheVoid]

If you look through the GFS ensembles here, even at just 2 days away there are important differences with where the center of the low ends up.

Several runs keep it close to the Chukchi sea, some bring it into the Beaufort and others into the Pacific section of the CAB. When it comes to the melt potential, a storm in the Chuckhi isn't going to do a whole lot, while quite a bit of damage could be done in the Beaufort or CAB.

The latest operational (and thus highest resolution) run has the storm sitting roughly on the boundary between the CAB, Chukchi and Beaufort. It could do quite a bit of damage there.

[F.Tnioli]

I've decided I want to say something. 

I think what is happening, is that the melt ponds in the Central Arctic are freezing over now that temperatures are dropping below zero. This effect will show up in the area data, and not in the extent data, as those melt ponds never were counted as open water. Another reason could be that there is little compaction going on, and thus no compensation there.

Second, if you want to know what happens with the CT SIA data two days in advance you need to go to the 2015 sea ice extent and area data topic, where Wipneus pre-calculates the numbers. There you will see yet another uptick of 47K, bringing the series to +224K, which is pretty exceptional.

Still, I think CT SIA will start to go down in a couple of days. How low it will go below the previous dip, depends on the weather, to be more precise winds, to be even more precise compaction.

Thank you. For both deciding and confirming. Also, yes, i know about Wipneus' thread, but i still stick to the "official" interactive thing most of the time. Personal quirk, if you will.

Pretty exceptional it was even without extra 47K, being faster gain per day than even similar refreeze of 2005. And today Arctic is quite warmer than in 2005 in general, me thinks. With extra 47K, it becomes... Pretty strange. To me.

Note how late summer area graph behaves unusually since 2013. Long nearly no-decline periods for it in 2013 and 2014 late summer, and now this thing. You might remember my hypothesis about it, the controversial one. I won't repeat it now. If it's correct, then it well might be we've seen the minimum area already - provided that area went below both 2013 and 2014 minimums already, and unless something GAC'ish would come in; as supposed by someone else in Wipneus' topic. If this will materialize, i would probably see to articulate my hypothesis in a proper form in a proper location; two years of unusual late summer ice behaviour could indeed be a coincedence, but three years in a row? Hardly.

Next few weeks will show.

[seaicesailor]

If you look through the GFS ensembles here, even at just 2 days away there are important differences with where the center of the low ends up.

Several runs keep it close to the Chukchi sea, some bring it into the Beaufort and others into the Pacific section of the CAB. When it comes to the melt potential, a storm in the Chuckhi isn't going to do a whole lot, while quite a bit of damage could be done in the Beaufort or CAB.

The latest operational (and thus highest resolution) run has the storm sitting roughly on the boundary between the CAB, Chukchi and Beaufort. It could do quite a bit of damage there.

Centered in Chukchi or Beaufort, the winds at the north side of the storm should force the loose ice to drift toward the main pack and get compacted. The arm would also be affected.

Inside the CAB, however, the storm might cause the opposite effect (divergent drift, and so extent stall or even increase). At this time of the year, whatever effect in the main pack would be healed soon afterwards by refreezing. Altogether, this might actually lead to a higher minimum extent.

I read that this storm pulls warm air first, but then a very cold snap follows.

[Frivolousz21]

The 00z euro is pretty freaking epic.

The western CAB, CAA and Beaufort totally devastated

The laptev region is getting pounded by a long fetch of 20kt winds coming off the warm pool.

Over the next 24 hours two wind Maxima's will be smoking parts of the ice.

As I write this a long fetch of winds 300 miles wide at roughly 20kts is running from the Russian coast to the NATL

 On the pacific side explosive winds of up to 33-34kts sustained will be sliding south over the arm and over the pacific main pack rubble by tomorrow am.

By 12z tomorrow sustained winds of 25--35kts run 00 miles long centered along 78N from the western cab to eastern ESS.

Laptev region getting smoked.

We might see a couple century's the next 3 days.

If the 00z euro is right extent will see near record or record drops the next 10 days

[Frivolousz21]

[quote name="The_Global_Warmer" post="3663417" timestamp="1440513180"]

It was at the start of August that there was talk of "if" 2015 on nsidc would seperatw from 13-14.

And talk of a 5.0 mil min+. 

2015 has plummeted past the last two summers and will almost certainly have a Sept min below 5 mil km2.

And this is with good weather for all of August.

Considering snow cover matched and passed 2012 in July for lowest on record on the ice imagine if we had a dipole June.

2015 would have likely lost the most volume in one season.

Extent and area easily would have been 2nd lowest.

Winds have overall been easterly in the Western cab region.

The ice being messed up like it is says THE SNOW ALBEDO FEEDBACK IS HUGE!!!

Bottom melt started in June all the way to 82N with vigorous BIM South of 75N.

This is a month early historically.  Bottom ice melt per 2000s didn't even reach 82N in the CAB at all most years.






If we end up with a weird winter where the Western CAB ends up with say 10-20CM of snow at most all the way to 82N with an average of 5-10CM.

And we get a major ridge the last week of April through May the damage would certainly be historic by June 1st.

Imagine the land over NW Canada and Alaska along the Arctic Ocean and Mackenzie delta being snow free by the first week of May.

To get a melt out the CAA/Western CAB will need to be snow free by mid May.  And the rest of the CAB by early June.

Solar insolation is so strong by mid May that melt would be vigorous by June 1st with clearly historically early melt ponds.

Under this scenario A major CAA/GIS/CAB Ridge in June would cause widespread surface melt at historic levels through the cab by July 1st.  Bit straight epic early bottom ice melt.

From there new record lows would easily come from just average weather.

A 2015 like July would have the entire CAB in shambles by Aug 1st.

The CAA ice free almost.

A continued dipole or a couple major cyclones would clean today up and we would be left with ice only North of GIS.

What I am I am most interested in is the potential ssts over the Western CAB/Beaufort/NWP.

We could easily see 5-10C to 80N on aug 1st under the 2 weeks earlier scenario.

With 10-20C South of that to the Beaufort.

Would such warmth competently destabilize the surface cold layer?

And become well mixed with the Psaciic warm layer around 50M?

Would this impact the refreeze?

The two week early scenario would cause unprecedented warming of the 0-1500M near surface air mass as well.

Allowing for a potential feedback of warm air masses penetrating the arctic a week or two earlier than current historical records.

This would be during the 400w/m2+ period. As well.

It's really a perfect storm of positive feedbacks.



As for the next 3 days.

The biggest wild card is those huge winds mixing this heat and ice together.

Also there is 2-3 days coming of surface temps above 0C over the Western CAB.  That is also a huge booster to melt versus say a vortex with -3 to -6C surface temps and snow.

There will be a period of light rain/drizzle falling through a very warm airmass as well.





The ESS ice arm is also shattering right now.

With warm water on 3 sides of it.

And bottom melt in that region potentially lasting into mid September while being moderate to strong even severe another 10-14 days under ideal conditions it will be very interesting to watch unfold.

The laptev bite is emerging.

Amsr2 channel 89ghz shows the Laptev/Nansen basin starting to get down in the sub .5M range over a decent area.

A 00Z euro outcome would likely cause a pretty huge area over there to compact/melt a lot between now and the min.[/quote]

[sedziobs]

Winds seem to favor some Fram export from day 4 onwards, with a high over Greenland and lows scattered around the Norwegian Sea and Greenland Sea in the 4-7 day period.

[Lord M Vader]

Something that REALLY should scare the heck of most people here is the latest ECMWF 12z run!!

IF, and there should be a BIG IF considering that it's far out in the forecast period!

Look at the movements of the foreseen three tropical cyclones steering west by RRR!! One doesn't need a wide imagination to have a fantasy idea that they sometimes in September should have a good chance to be steered north into Arctic dragging very warm and moist air into the loose ice pack...

Will be very interesting so see upcoming runs!!

OTOH, the odds for a significant drop on the Atlantic side has fallen as the weather pattern seems to be lacking southerlies northward.

Friv, do you concur with me? Good to see you back btw Neven, what's your opinions? One final melt blast to come before we say good night to the Arctic and turn our eyes to Antarctica where the SIE have more or less stalled the last couple of weeks...

//LMV

[Rick Aster]

Considering snow cover matched and passed 2012 in July for lowest on record on the ice imagine if we had a dipole June.

I think this is basically right. We no longer need to look for freak weather to create a melt-out. An unlikely combination of weather patterns will do it, a bad luck streak for the ice. And if we're counting on luck to hold the ice together, it's just a matter of time before that luck runs out.

[Neven]

Friv, do you concur with me? Good to see you back btw Neven, what's your opinions? One final melt blast to come before we say good night to the Arctic and turn our eyes to Antarctica where the SIE have more or less stalled the last couple of weeks...

//LMV

I think melting because of air temps or solar radiation is becoming more insignificant by the day. It's all up to bottom melting (depending on ice thickness) and compaction now. There still is a lot of loose ice on the Pacific side of the Arctic and storms will probably on the whole speed up the melting process, but I don't know how much damage can still be done to all that relatively homogeneous looking ice on the Atlantic and Siberian sides of the Arctic.

As for the Antarctic: If Arctic SIA hadn't stalled so spectacularly in the last couple of days, we'd probably have a new and totally unexpected lowest global sea ice anomaly on record by now (as recorded by Cryosphere Today, the only global measure of sea ice area we have I believe). It might still happen if Antarctic sea ice stays like this for a week or so, as I think Arctic SIA decrease may pick up again in days to come.

It would be funny, because it would make the climate risk deniers' argument look so stupid, but other than that, global sea ice area doesn't really mean that much as a measure.

[seaicesailor]

Expected drift (GLB CICE model). To get an idea.
It might be even more intense for the thickest ice floes.
It is not clear that extent will plummet immediately, since the storm may spread part of the loose ice, but the final outcome does not seem good for the ice. Area should drop quickly.

[jdallen]

Expected drift (GLB CICE model). To get an idea.
It might be even more intense for the thickest ice floes.
It is not clear that extent will plummet immediately, since the storm may spread part of the loose ice, but the final outcome does not seem good for the ice. Area should drop quickly.

Boy, the drift speed prediction for the 28th looks really ugly.  The Beaufort looks like it gets turned into a blender.

[stackmaster]

Good to see you here Friv, thanks for posting.

[Nick_Naylor]

Expected drift (GLB CICE model). To get an idea.

In case anyone wonders, the ARC drift predictions are essentially identical.

[technophile50]

"Did you read about the heating sensors having at least a 1.7F bias being discovered at Reagan International Airport in DC?"
Nope. Don't care. Doesn't matter - http://www.woodfortrees.org/plot/rss/plot/rss/offset:1.7/plot/rss/trend/plot/rss/offset:1.7/trend If your eyecrometer tells you that the rate of warming is different between the original ("real") RSS temperature and the offset ("Reagan Airport adjusted to hide the decline") RSS, it needs adjusting.

 #Data from Remote Sensing Systems
#http://www.ssmi.com/msu/msu_data_description.html
#----------------------------------------------------
#
#File: RSS_Monthly_MSU_AMSU_Channel_TLT_Anomalies_Land_and_Ocean_v03_3.txt
#
#Time series (rss) from 1979 to 2015.58
#Least squares trend line; slope = 0.0120869 per year <==================
1979   -0.117062
2015.58   0.325117
#Data ends
#Number of samples: 2
#Mean: 0.104028
#
#Time series (rss) from 1979 to 2015.58
#Offset by 1.7
#Least squares trend line; slope = 0.0120869 per year <===================
1979   1.58294
2015.58   2.02512
#Data ends
#Number of samples: 2
#Mean: 1.80403
e

If you STILL think that the bias at Reagan (or of any other Republican) makes any difference in global warming AT ALL, to however many decimal places you can calculate, you need to further your math education.

And you might want to consider this from Dr Carl Mears http://www.remss.com/blog/recent-slowing-rise-global-temperatures-

The Recent Slowing in the Rise of Global Temperatures
"Measurement Errors:

......  A similar, but stronger case can be made using surface temperature datasets, which I consider to be more reliable than satellite datasets (they certainly agree with each other better than the various satellite datasets do!).

"Conclusion:

My view is that the subduction of heat into the ocean is very likely a significant part of the explanation for the model/observation discrepancies.  What is less clear is whether or not this subduction is due to random fluctuations in the climate, or some sort of response to anthropogenic forcing."

Mears is a smart guy; see "Recent hiatus caused by decadal shift in Indo-Pacific heating"; Veronica Nieves et al; http://www.sciencemag.org/content/349/6247/532.full

".... We find that cooling in the top 100-meter layer of the Pacific Ocean was mainly compensated for by warming in the 100- to 300-meter layer of the Indian and Pacific Oceans in the past decade since 2003. "

A little more on topic - I've been considering that cyclones are heat engines driven by the temperature difference between warm surface waters and the atmosphere above/around the core of the storm. Eckmann transport driven by an Arctic cyclone over open (melted out) ocean would continuously provide warm(ish) water from lower in the ocean column; the temperature difference in the summer & early fall wouldn't be all that great, but as the surface temperatures fell with the changing season, could a late cyclone develop into a permanent feature like Jupiter's "Red Spot"?? Upwelling 3 degree  salty water driven by Eckmann pumping being churned to release latent heat into a rising column of (relatively) warm moist air in the core, spiraling out in bands with precipitation falling as a "snow hurricane". in a subzero environment?

[slow wing]

Yet another day of the continuing retreat of the ice edge from the Laptev Sea (fast!), ESS (the 'forearm') and the Atlantic side.

Now almost no ice pack protruding beyond 10 degrees from the Pole on the Atlantic and Laptev Sea sides.


Waiting for the forecast storm to hit the ice on the Pacific side and seeing what emerges! 


Click on gif to crossfade between yesterday's and today's U.Bremen ice concentration maps...

[Lord M Vader]

Latest GFS 00z run hints a possible nightmare for the Arctic sea ice! IF it would fall out we'll have a another "MAC" -  "Moderate Arctic Cyclone" in about 6-7 days or so...

What does the EURO say?

Geesh, things are really getting exciting now when we are at the end of the melting season!

//LMV

[greatdying2]

Cross-posted from the Polarstern thread:

Personally, I will be particularly interested to see how well various thickness/volume models will agree (or disagree) with these in situ observations.

Polarstern at 84.3N   31.0E 15-08-26 06:00:

Air temperature dropped to -5.1°C, water decreased to -1.7°C.

Observed ice thickness category increased

• Predominantly medium first-year ice (70-120 cm thick) and thick first-year ice (>120 cm thick) and some thinner (younger) first-year ice

This seems to be in general agreement with Copernicus Marine Service formerly known as MyOcean TOPAZ model, see below

If this thickness model is correct, there may be little to slow the advance of the Laptev bite.

[seaicesailor]

Cross-posted from the Polarstern thread:

Personally, I will be particularly interested to see how well various thickness/volume models will agree (or disagree) with these in situ observations.

...
This seems to be in general agreement with Copernicus Marine Service formerly known as MyOcean TOPAZ model ...

If this thickness model is correct, there may be little to slow the advance of the Laptev bite.

PIOMAS estimate was about 1m in the region of Laptev bite, but going down fast July 31. See Wipneus animation:

http://forum.arctic-sea-ice.net/index.php/topic,119.msg60637.html#msg60637

I believe all models predict about the thinnest FYI there,  which grew below average during Winter.

[seaicesailor]

Latest GFS 00z run hints a possible nightmare for the Arctic sea ice! IF it would fall out we'll have a another "MAC" -  "Moderate Arctic Cyclone" in about 6-7 days or so...

What does the EURO say?

Geesh, things are really getting exciting now when we are at the end of the melting season!

//LMV

I saw something in the EURO too but more knowledgeable people will tell you. It is not so far away in time . . .

[Jim Hunt]

Surf's up at approximately 77.5 N, 165 W:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/summer-2015-images/#OBuoy12

[stackmaster]

Lots of green ice north of there on Bremen!

[weatherdude88]

DMI arctic sea ice volume is showing big gains.

[Nick_Naylor]

Surf's up at approximately 77.5 N, 165 W:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/summer-2015-images/#OBuoy12

Can you interpret this data for a surf-illiterate like myself?

[F.Tnioli]

Yep, DMI volume merrily hopping up and up. I was checking it continuosly last few weeks. It is one of... uncertainties which fueled my assumption above (about possibility that we are already past minimum 2015 ASI area figure). It is hard to imagine area to plunge while volume grows, isn't it. For thin edges to disappear while thicker inner areas freeze much faster than volume loss at the edges - would take quite unusual (rather "perfect" for such scenario) weather, me thinks.

Under "uncertainty" term, in this case, i mean widespread (here) opinion about questionable reliability of DMI volume graph. We'll see what PIOMASS will tell us in ~1 week, though.

[Buddy]

Here is a link to take a peek at.  Look at the 6th and 7th graphics on the page.  They show the DMI volume from 8 days ago...and now.

Volume is being LOST on the periphery of the ice sheet and in the Canadian Archipelago....and there must be MORE VOLUME GAINED in the central Arctic to outweigh the loss of ice volume on the outside portions of the ice sheet.

But clearly...the outside portion of the ice sheet is still losing extent and volume.

http://climatechangegraphs.blogspot.com/2012/08/arctic-sea-ice-volume-extent-charts_30.html

[greatdying2]

DMI arctic sea ice volume is showing big gains.

Are you sure you like this model? It also shows 2015 reaching the 3rd and nearly the 2nd lowest volume on record, almost 1 SD lower than the 2004-2013 period, and far lower then 2013 or 2014.

Also, if you think this model reflects reality, what physical mechanism do you propose might have caused this quick uptick over the past week?

 

[Jim Hunt]

Can you interpret this data for a surf-illiterate like myself?

This was a reference back to stackmaster's Surf's up swells up?.

O-Buoy 12 is now obviously bobbing up and down on a "swell" of some sort north of the Chukchi Sea, presumably the effect of the "cyclone" in the vicinity. Quantifying it further from the webcam image is a bit tricky though! Here's the "significant wave height" and "peak wave period" forecast for round about the same time. Quite a large swell for the Arctic Basin, but pretty insignificant compared to what's going on in the North Pacific!

[crandles]

Are you sure you like this model? It also shows 2015 reaching the 3rd and nearly the 2nd lowest volume on record, almost 1 SD lower than the 2004-2013 period, and far lower then 2013 or 2014.

Also, if you think this model reflects reality, what physical mechanism do you propose might have caused this quick uptick over the past week?

 

It doesn't show 2010 so I don't think you can be sure it isn't 4th lowest or even higher according to that measure.

PIOMAS reckons volume is above 2011 and area increases in the last few days are a couple of possibilities though I agree that that much of a volume gain doesn't seem likely this early. Different models having small differences in dates at which minimum occurs shouldn't be too surprising, but.... I would expect area minimum to occur before volume minimum but I doubt this is certain: Could thin ice in centre of pack start gaining thickness before open water further south starts to freeze over?

[plinius]

I am not sure one should put so much theory and speculation into the DMI stuff. The answer will more likely be: Since the area got corrected upwards due to disappearance of melt ponds, DMI simply filled the gaps with the surrounding thickness, correcting its volume. It is practically impossible that volume is on the rise due to widespread bottom melt, which will last far into September. If a model can't deal with that it is faulty and not "indicating something".

[jdallen]

Can you interpret this data for a surf-illiterate like myself?

This was a reference back to stackmaster's Surf's up swells up?.

O-Buoy 12 is now obviously bobbing up and down on a "swell" of some sort north of the Chukchi Sea, presumably the effect of the "cyclone" in the vicinity. Quantifying it further from the webcam image is a bit tricky though! Here's the "significant wave height" and "peak wave period" forecast for round about the same time. Quite a large swell for the Arctic Basin, but pretty insignificant compared to what's going on in the North Pacific!

And we are glad it is.  3 meter swells are bad enough, and if they get to the ice, they will shatter it.  Was it Wadhams who observed swells about that size tearing up 15KM/day of the ice margin on the Atlantic side?  Regardless, across a wide front, it will both cause more ice to be exposed to heat in the water, and bring more heat to it.

If we saw swells the size of those showing up in the North Pacific... well, actually, I'd rather not contemplate that too deeply right now.

[Nick_Naylor]

Can you interpret this data for a surf-illiterate like myself?

Here's the "significant wave height" and "peak wave period" for round about the same time. Quite a large swell for the Arctic Basin, but pretty insignificant compared to what's going on in the North Pacific!

Thanks Jim. Quite a lot of action in the 2-5 meter range, which ought to stir things up detectably.

[seaicesailor]

Can you interpret this data for a surf-illiterate like myself?

This was a reference back to stackmaster's Surf's up swells up?.

O-Buoy 12 is now obviously bobbing up and down on a "swell" of some sort north of the Chukchi Sea, presumably the effect of the "cyclone" in the vicinity. Quantifying it further from the webcam image is a bit tricky though! Here's the "significant wave height" and "peak wave period" forecast for round about the same time. Quite a large swell for the Arctic Basin, but pretty insignificant compared to what's going on in the North Pacific!

And we are glad it is.  3 meter swells are bad enough, and if they get to the ice, they will shatter it.  Was it Wadhams who observed swells about that size tearing up 15KM/day of the ice margin on the Atlantic side?  Regardless, across a wide front, it will both cause more ice to be exposed to heat in the water, and bring more heat to it.

If we saw swells the size of those showing up in the North Pacific... well, actually, I'd rather not contemplate that too deeply right now.

Actually there is an area there of 4 meter+ and almost 10 seconds of period. From Wikipedia:

56 km/h (~30 kts) of wind blowing 24 h (needing a fetch of 322 mi, which is available in Chukchi sea open water right now), creates 4.1 m (13 ft) waves with 8.6 s of period.

This is the swell of an average Atlantic storm, a swell that is strong for the Arctic (not much open water available usually).

NSIDC extent up +35k, area just in the other direction, down -34k.

[Neven]

Cyclone has now reached 989 hPa, still not hugely low, but should do some damage:

[greatdying2]

I am not sure one should put so much theory and speculation into the DMI stuff. The answer will more likely be: Since the area got corrected upwards due to disappearance of melt ponds, DMI simply filled the gaps with the surrounding thickness, correcting its volume. It is practically impossible that volume is on the rise due to widespread bottom melt, which will last far into September. If a model can't deal with that it is faulty and not "indicating something".

Totally agree.

[TerryM]

A little more on topic - I've been considering that cyclones are heat engines driven by the temperature difference between warm surface waters and the atmosphere above/around the core of the storm. Eckmann transport driven by an Arctic cyclone over open (melted out) ocean would continuously provide warm(ish) water from lower in the ocean column; the temperature difference in the summer & early fall wouldn't be all that great, but as the surface temperatures fell with the changing season, could a late cyclone develop into a permanent feature like Jupiter's "Red Spot"?? Upwelling 3 degree  salty water driven by Eckmann pumping being churned to release latent heat into a rising column of (relatively) warm moist air in the core, spiraling out in bands with precipitation falling as a "snow hurricane". in a subzero environment?

It's an interesting idea, but I question why latent heat, as opposed to sensible heat would prolong the life of the system? I'm probably just missing some part of your argument, but an explanation would help (me).
As warmer, deeper waters are pumped to the surface, thereby increasing the temperature delta at that point, wouldn't this sensible heat as it is transferred to the local atmosphere be sufficient to extend the life of the system? Any latent heat from evaporation, in the center, followed by precipitation spiraling out would tend to lower the delta, at least as I see it.
Terry

[jdallen]

A little more on topic - I've been considering that cyclones are heat engines driven by the temperature difference between warm surface waters and the atmosphere above/around the core of the storm. Eckmann transport driven by an Arctic cyclone over open (melted out) ocean would continuously provide warm(ish) water from lower in the ocean column; the temperature difference in the summer & early fall wouldn't be all that great, but as the surface temperatures fell with the changing season, could a late cyclone develop into a permanent feature like Jupiter's "Red Spot"?? Upwelling 3 degree  salty water driven by Eckmann pumping being churned to release latent heat into a rising column of (relatively) warm moist air in the core, spiraling out in bands with precipitation falling as a "snow hurricane". in a subzero environment?

It's an interesting idea, but I question why latent heat, as opposed to sensible heat would prolong the life of the system? I'm probably just missing some part of your argument, but an explanation would help (me).
As warmer, deeper waters are pumped to the surface, thereby increasing the temperature delta at that point, wouldn't this sensible heat as it is transferred to the local atmosphere be sufficient to extend the life of the system? Any latent heat from evaporation, in the center, followed by precipitation spiraling out would tend to lower the delta, at least as I see it.
Terry

Concur with Terry.  Latent heat wouldn't shift the temperature difference such that you'd see thermal expansion of atmosphere or increased humidity - both of which would be needed to support a cyclone.  Best Eckmann pumping could do, and does do, is hold back ice formation by replacing heat loss required to thicken ice.