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jdallen

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Re: The 2015 melting season
« Reply #3200 on: August 09, 2015, 05:29:50 AM »
<snippage>

... But, for the first time this season if I recall correctly, the Atlantic side is showing a drop in concentration over a wide front and that extends all the way in to around 5 degrees from the Pole.

Still only yellows and oranges but who knows if it is the start of something? Others have posted evidence of warm water encroaching under the Atlantic side of the ice pack.

The uncertainty of it all is illustrated for me by this melt season's history in the Beaufort Sea as just posted by Jim Hunt:

There the ice concentration collapses region by region and without any evident warning.

Is it too late for something similar on the Atlantic side?

Let's put it in context with some SST's.

I wish I'd been keeping better track, but my sense is, there's been a steady march of higher temperatures out of the Barents and Kara towards the central pack.

Recall a couple of things; most measures suggest to a greater degree that a lot of that ice close to the Atlantic side is 1M or less in thickness.

Recall also, that you get past -1.5C, you'll be adding about ~1.75CM/day of bottom melt per 0.5C increase in temperature (4.5 CM/day at 0C).  Anecdotal  support only, but I'm convinced that's the reason for the very sharp demarcation of the ice front on the Atlantic side.  As the surface temperatures advance, the front has retreated; more rapidly over the last week or so.

It suggests to me that intrusion from warmer water which *is* being driven in that direction at depth from the Gulf Stream and its descendants is beginning to have a visible effect on the marginal ice.  I think we saw some of this, at about the same time in both 2013 and 2014.

If the flow is more diffuse, it might have an effect on the concentration metrics similar to what you see in the DMI graphic.  It may be we are seeing the result of persistent, low level delivery of heat under the ice, which hasn't previously made itself known.
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Pmt111500

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Re: The 2015 melting season
« Reply #3201 on: August 09, 2015, 06:37:07 AM »
The last time EOSDIS Worldview had a clearish image from around NP was on 20150804. False color from contrast enhanced photo. Never mind that big red blotch over the western hemisphere, that's some shadows of the clouds. NP looks to be in a bit better shape than in 2012.

ChrisReynolds

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Re: The 2015 melting season
« Reply #3202 on: August 09, 2015, 07:55:41 AM »
Paul Beckwith,  I had a couple posts # 2408+2410 upthread re. North Pacific warm water putting lots of heat into the Arctic. I make the argument that it is not directly sending that heat past the Bering Strait via water currents.

  Steele et al 2010 ( not me )showed that 80% of the ocean heating in the Pacific Arctic north of Alaska is from ocean heat flux, and only 20% due to ocean lateral heat flux( e.g. Bering Sea inflow), which mostly occurs within a few hundred kilometers from the coast. Moreover, the movement of Pacific Water from the Aleutian Passes to BeringStrait takes more than one year.  So pacific water is exposed to winter sea ice during it's voyage and loses it's heat.

This July supports this argument. It is hard to say exactly when the Dipole Anomaly started as it appears in the early July 1 to 10 July average, but isn't strong in daily plots, However it was in late June / Early July that it started, and the response of the ice was pretty simultaneous (within ten days), i.e. far to quick to be ocean driven.

DavidR

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Re: The 2015 melting season
« Reply #3203 on: August 09, 2015, 10:17:45 AM »

I wish I'd been keeping better track, but my sense is, there's been a steady march of higher temperatures out of the Barents and Kara towards the central pack.

{snip}  Anecdotal  support only, but I'm convinced that's the reason for the very sharp demarcation of the ice front on the Atlantic side.  As the surface temperatures advance, the front has retreated; more rapidly over the last week or so.

It suggests to me that intrusion from warmer water which *is* being driven in that direction at depth from the Gulf Stream and its descendants is beginning to have a visible effect on the marginal ice.  I think we saw some of this, at about the same time in both 2013 and 2014.

Practically the whole of the Kara and North Atlantic regions had a week of very clear weather at the start of the month. This must  have put a lot of extra heat into those oceans that will translate into melt  over the next few weeks.

It would not be at all surprising to see significant breakup of the pack there over the remainder of this month.  It is already open water to 83 deg nth which is near to the northern most extremity of the Laptev bite last year.
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Frivolousz21

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Re: The 2015 melting season
« Reply #3204 on: August 09, 2015, 11:41:19 AM »
Based on current ssts, modis, 00z models, amsr2 channel 89 scans, and historical reference.











My final predictions:

The next 10-12 days will probably see jaxa lose around 1 million in extent.

Putting it around 4.9 mil km2 on August 20th IMO.

CT area I see dropping down to about 3.3 mil km by the 20th.


Finals:

Jaxa: 4.15-4.50(4.31)
CT: 3.0-3.2(3.1)
Piomas: 5100-5500

I will say I bet cryosat for October shows bigger losses than piomas will show for the CAB.

Now if we end up ice free all the way up to 78N+ along the CAA coast into the CAB then piomas will lose some of that ridiculously over done 3M+ ice on the July update.






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JayW

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Re: The 2015 melting season
« Reply #3205 on: August 09, 2015, 11:43:13 AM »
First attachment is the CFSv2 sea ice anomaly forecast from July, 12 , second attachment is the CFSv2 from this morning.  Looks like it had a change of heart following July, what a difference a month makes.  ;D.  Seems like it has a cold/thick ice bias at least during boreal summer months.  With a forecast nearing -2 million km2 in November, I'm wondering if that cold bias carries into fall as well, if at least the beginning of the "refreeze" season might be a bit slow. ;D

By the way, I'm not really a huge fan of the CFSv2, more posing for shits and giggles.

http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/
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iceman

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Re: The 2015 melting season
« Reply #3206 on: August 09, 2015, 01:10:53 PM »
  ....
But first we want to know what will happen in and around the Beaufort holes, of course. That's more interesting than the numbers right now. I think I'm going to post about those holes on the ASIB over the weekend. They're spectacular.
  ....

Climate Reanalyzer shows mixed conditions over the coming week, but it looks as though the holes will expand somewhat around the ends nearest Banks and Wrangel islands, and close up a bit in between.
    Net, the "arm" of ice nearer the coast (loosely visualized) will appear slightly closer to detaching from the main pack.

seaicesailor

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Re: The 2015 melting season
« Reply #3207 on: August 09, 2015, 02:05:23 PM »
At the risk of looking as if I am brown-nosing, I can't but recommend the following links to dosbat blog early posts (summer 2011) about arctic dipole and summer ice drift due to storms, of extreme relevance to the current state of the season:

http://dosbat.blogspot.com.es/2011/08/arctic-dipole-sea-ice-loss.html?m=0

http://dosbat.blogspot.com.es/2011/08/sea-ice-drift-speeds-in-arctic.html?m=0

Chris explains what they consist of in a very easy manner to understand for people as noob as me, but digging into research papers. I found this while looking for refs about effect of storms on loose-ice drift as in the Pacific right now. Might it be that 2011 had a post-dipole state affected later by storms just as 2015?


seaicesailor

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Re: The 2015 melting season
« Reply #3208 on: August 09, 2015, 02:47:31 PM »

A thing or two I have learned from one of the references of the dedicated thread to divergence (Arctic Background) is that free-ice drift, as in Beaufort right now, can be considerably strong for relatively weak wind speed, since a free floe is not constrained by lateral stress forces as in a cohesive pack. Furthermore, divergence angles of MYI (presumably the thickest) floes can be greater than for thinner ice, since Coriolis force is proportional to floe mass, that is, to its thickness.

This effect may explain why holes opened so fast in Beaufort past days with such a weak storm. Relatively weak winds of 10 - 20 KT were causing 30 cm/s plus of divergent drift. Thin ice may break up easily but perhaps not open up so fast?

However, Ekman pumping should not be expected in great quantity, since direct wind drag over the open water is weaker than over ice (which then drags the water), unless we are speaking of a very strong storm (2012). Ekman pumping is optimal over thin, deformable but cohesive pack as in June Laptev or Fall new ice.

PS. A-team is helping understand the references. Recommended going to the thread

https://forum.arctic-sea-ice.net/index.php/topic,1344.0.html
« Last Edit: August 09, 2015, 03:05:26 PM by seaicesailor »

Gonzo

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Re: The 2015 melting season
« Reply #3209 on: August 09, 2015, 03:48:46 PM »
Quote
jdallen
It suggests to me the current dynamics are in line with what was going on in 2012.

Quote
Rubikscube
I think the resemblance between 2012 and 2015 is striking

Are you sure? Most of those weaknesses I pointed at show up in the satellite photos as well.
The first image is from yesterday NE Greenland. The second is from Aug 16 2012 (nearest clear day, and it is skewed around a bit because of different sat angles, but it's the same area). This is just an example, and not the best example, but anywhere you look and compare the satellite images, there appears to be more break-up of the ice this year. Remember, the 2012 image is more than a week from now, and it looks less fractured than yesterday. If we could see Aug 8 2012 as a cloudless day, I think it would look very uniform.
And I think the melt season will be longer this year, by almost a week.
Also, has anyone compared current SSTs with the same day of 2012?
Thanks.
« Last Edit: August 09, 2015, 03:56:45 PM by Gonzo »

Gonzo

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Re: The 2015 melting season
« Reply #3210 on: August 09, 2015, 03:55:20 PM »
Quote
Pmt111500
The last time EOSDIS Worldview had a clearish image from around NP was on 20150804. False color from contrast enhanced photo... NP looks to be in a bit better shape than in 2012.
Do you have the NP for the same time in 2012 to compare? When I try to find a clear day for this date in 2012, the nearest one is later in August, and looks pretty uniform compared to this, but it may not have as good resolution as today.
« Last Edit: August 09, 2015, 10:17:43 PM by Gonzo »

Neven

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Re: The 2015 melting season
« Reply #3211 on: August 09, 2015, 04:15:22 PM »
And I think the melt season will be longer this year, by almost a week.
Also, has anyone compared current SSTs with the same day of 2012?

Here you go, 2 day difference:
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Gonzo

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Re: The 2015 melting season
« Reply #3212 on: August 09, 2015, 04:25:10 PM »
Quote
Neven
Here you go, 2 day difference:

Thanks.
Interesting, with 2012 still attached to Siberia. Looks like it is surrounded this year, on all sides. This can't be good.
Where is that SST page for current conditions, by the way? Thanks
« Last Edit: August 09, 2015, 04:45:47 PM by Gonzo »

ChrisReynolds

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Re: The 2015 melting season
« Reply #3213 on: August 09, 2015, 05:43:12 PM »
First attachment is the CFSv2 sea ice anomaly forecast from July, 12 , second attachment is the CFSv2 from this morning.  Looks like it had a change of heart following July, what a difference a month makes.  ;D.  Seems like it has a cold/thick ice bias at least during boreal summer months.  With a forecast nearing -2 million km2 in November, I'm wondering if that cold bias carries into fall as well, if at least the beginning of the "refreeze" season might be a bit slow. ;D

By the way, I'm not really a huge fan of the CFSv2, more posing for shits and giggles.

http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/


The PIOMAS data released so far is not complete, and I can't wait for the next set. Basically what is missing is the daily data and daily gice. July was such an extraordinary month that the monthly average gridded ice thickness from PIOMAS doesn't tell the whole story. I need to see the daily gridded data.

If Zhang updates his August SIPN prediction with ice state at the end of July it will be different from that of July (initial conditions for June/early July).

ChrisReynolds

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Re: The 2015 melting season
« Reply #3214 on: August 09, 2015, 07:18:27 PM »
Global Weather Logistics, via Crysophere Today...
http://globalweatherlogistics.com/seaiceforecasting/gfs.850mb.vectors.arctic.html

The cyclone that is due to cover the entire Arctic Ocean on 13 to 15 August (Thursday Friday Saturday) is interesting, I'm not sure what effect it will have. But what is interesting is what happens in the Pacific.

Tropical Storm Molave is shown on this 96 hr (4 day ahead - 12 August) with a heading arrow.
http://www.opc.ncep.noaa.gov/shtml/P_96hrsfc.gif

Going back to the first link, this is seen as the strong cyclone that proceeds from Japan, and the seems to get entrained by the Cyclone in the Arctic Ocean and drawn in to Bering as the Arctic Ocean cyclone declines.

seaicesailor

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Re: The 2015 melting season
« Reply #3215 on: August 09, 2015, 07:37:41 PM »
Global Weather Logistics, via Crysophere Today...
http://globalweatherlogistics.com/seaiceforecasting/gfs.850mb.vectors.arctic.html

The cyclone that is due to cover the entire Arctic Ocean on 13 to 15 August (Thursday Friday Saturday) is interesting, I'm not sure what effect it will have. But what is interesting is what happens in the Pacific.

Tropical Storm Molave is shown on this 96 hr (4 day ahead - 12 August) with a heading arrow.
http://www.opc.ncep.noaa.gov/shtml/P_96hrsfc.gif

Going back to the first link, this is seen as the strong cyclone that proceeds from Japan, and the seems to get entrained by the Cyclone in the Arctic Ocean and drawn in to Bering as the Arctic Ocean cyclone declines.

If that center cyclone ended up a bit more toward Siberian side (that is south of the Pole :P ) it would be even more interesting

cesium62

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Re: The 2015 melting season
« Reply #3216 on: August 09, 2015, 08:12:50 PM »
Global Weather Logistics, via Crysophere Today...
http://globalweatherlogistics.com/seaiceforecasting/gfs.850mb.vectors.arctic.html

The cyclone that is due to cover the entire Arctic Ocean on 13 to 15 August (Thursday Friday Saturday) is interesting, I'm not sure what effect it will have. But what is interesting is what happens in the Pacific.

Tropical Storm Molave is shown on this 96 hr (4 day ahead - 12 August) with a heading arrow.
http://www.opc.ncep.noaa.gov/shtml/P_96hrsfc.gif

Going back to the first link, this is seen as the strong cyclone that proceeds from Japan, and the seems to get entrained by the Cyclone in the Arctic Ocean and drawn in to Bering as the Arctic Ocean cyclone declines.

The other part I find interesting is the small cyclone now in the Chukchi that moves out over The Arm.  Followed a couple days later by another small cyclone in the Chukchi that follows about the same path.  And meanwhile, over on the Atlantic side, it looks like one of the storms there finally barely breaks through into the Arctic Basin.

ChrisReynolds

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Re: The 2015 melting season
« Reply #3217 on: August 09, 2015, 08:29:57 PM »
Cesium,

Initally it is the genesis of the basin wide cyclonic system that interest me, out of the low pressure mass over Eurasia comes a minor cyclonic system, this intensifies right as it hits Beaufort and then goes into a bumbell tango with the first system you mention before the two mass into the single system.

It is what happens next, the incoming TS Molave is 'fed upon' by the pre-existing basin wide cyclone at the end of the sequence. IF the forecast is right and Molave turns up on time then the two cyclones could prove to be very interesting. I don't want to get too excited right now, it's a very long term forecast, but the interaction of the former TS and the existing cyclonic system could cause a weather bomb.
https://en.wikipedia.org/wiki/Explosive_cyclogenesis

Here in the UK, despite former hurricanes and TSs coming across the Atlantic, having dissipated some power on the US Eastern Seaboard, they can still be some of the most violent autumn storms we get.

This might end up being as important this year as the GAC was to 2012.


Sea Ice Sailor,

See the above.  ;)

jdallen

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Re: The 2015 melting season
« Reply #3218 on: August 09, 2015, 08:43:14 PM »
Quote
jdallen
It suggests to me the current dynamics are in line with what was going on in 2012.

Quote
Rubikscube
I think the resemblance between 2012 and 2015 is striking

Are you sure? Most of those weaknesses I pointed at show up in the satellite photos as well.
The first image is from yesterday NE Greenland. The second is from Aug 16 2012 (nearest clear day, and it is skewed around a bit because of different sat angles, but it's the same area). This is just an example, and not the best example, but anywhere you look and compare the satellite images, there appears to be more break-up of the ice this year. Remember, the 2012 image is more than a week from now, and it looks less fractured than yesterday. If we could see Aug 8 2012 as a cloudless day, I think it would look very uniform.
And I think the melt season will be longer this year, by almost a week.
Also, has anyone compared current SSTs with the same day of 2012?
Thanks.
I'll have to check SST's, but I absolutely agree the ice in 2015 is far more broken up than in 2012.  It is definitely far more vulnerable than the 2012 ice was.

I also agree that the melt season will probably run a week longer; I'd actually hazard it may be two to three, and that we may not see a minimum until after 1 October.  It depends on two things I think; continued high SST's along the periphery of the pack, and import of heat from further south via the remains of east Pacific cyclones.  The first will provide the necessary heat for continued melt; the second will offset radiative losses which normally would reduce the effect of the first.
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jdallen

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Re: The 2015 melting season
« Reply #3219 on: August 09, 2015, 09:01:23 PM »
<snippage>

It is what happens next, the incoming TS Molave is 'fed upon' by the pre-existing basin wide cyclone at the end of the sequence. IF the forecast is right and Molave turns up on time then the two cyclones could prove to be very interesting. I don't want to get too excited right now, it's a very long term forecast, but the interaction of the former TS and the existing cyclonic system could cause a weather bomb.

This might end up being as important this year as the GAC was to 2012.

<snippage>

I hadn't thought about the input of energy from the TS when looking at that arctic cyclone forming a week out, but as you note, the input of heat and moisture seems to be timed to arrive in just the nick of time.   The 850MB winds  pick up momentum and speed just as they cross the Bering to rush in at what looks like 100-150KPH.
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Shared Humanity

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Re: The 2015 melting season
« Reply #3220 on: August 09, 2015, 09:04:46 PM »
CAB is under assault. What effect will these storms have?

Bruce Steele

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Re: The 2015 melting season
« Reply #3221 on: August 09, 2015, 10:16:18 PM »
Chris, " 1 Bergeron " at the poles would be a drop in pressure of 28 mb/ in 24 hours . If in a week to ten days the , as yet unnamed , basin wide cyclone has a one day pressure drop of 28 mb we will have an Arctic " cyclone bomb ".

Rubikscube

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Re: The 2015 melting season
« Reply #3222 on: August 09, 2015, 10:33:24 PM »
I also agree that the melt season will probably run a week longer; I'd actually hazard it may be two to three, and that we may not see a minimum until after 1 October.  It depends on two things I think; continued high SST's along the periphery of the pack, and import of heat from further south via the remains of east Pacific cyclones.  The first will provide the necessary heat for continued melt; the second will offset radiative losses which normally would reduce the effect of the first.

I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

Gonzo

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Re: The 2015 melting season
« Reply #3223 on: August 09, 2015, 10:45:44 PM »
Slow Wing
Quote
Not sure how much of the difference from yesterday is just peek-a-boo ice and fluctuations. But, for the first time this season if I recall correctly, the Atlantic side is showing a drop in concentration over a wide front and that extends all the way in to around 5 degrees from the Pole.
Looking at a close up of what Slow Wing pointed out, this looks like either a big drop in concentration in 24 hours, or a correction in the model. I think the latter is more likely, and they couldn't get accurate readings for that area in the last week or so, and this is more accurate. That lowering of concentration in reds and yellows is also close to the thinner ice on other maps. Unless this concentration from Aug 8 is a glitch (which I doubt) the whole area on that side of the pole could disintegrate, and in time will join up with that lower concentration in the Lincoln Sea. After that the warmth could eat through the middle there towards Beaufort.
Aug 7 on top
Aug 8 on bottom.
Then, sea ice thickness of Aug 8.
« Last Edit: August 09, 2015, 10:51:18 PM by Gonzo »

ChrisReynolds

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Re: The 2015 melting season
« Reply #3224 on: August 09, 2015, 11:06:37 PM »
Chris, " 1 Bergeron " at the poles would be a drop in pressure of 28 mb/ in 24 hours . If in a week to ten days the , as yet unnamed , basin wide cyclone has a one day pressure drop of 28 mb we will have an Arctic " cyclone bomb ".

Thanks Bruce.

seaicesailor

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Re: The 2015 melting season
« Reply #3225 on: August 09, 2015, 11:29:28 PM »
I also agree that the melt season will probably run a week longer; I'd actually hazard it may be two to three, and that we may not see a minimum until after 1 October.  It depends on two things I think; continued high SST's along the periphery of the pack, and import of heat from further south via the remains of east Pacific cyclones.  The first will provide the necessary heat for continued melt; the second will offset radiative losses which normally would reduce the effect of the first.

I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

I only can think on one reason similar to jdallen's, which is excessive heat from a record warm NH transferred to the Arctic within next 30 days or so. That obviously depends on the weather to come.

Edit. Modified in view of the May-June NH temp average time series from NOAA
« Last Edit: August 09, 2015, 11:52:11 PM by seaicesailor »

Neven

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Re: The 2015 melting season
« Reply #3226 on: August 09, 2015, 11:58:59 PM »
I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

Exactly. If all that dispersed ice on the Pacific side of the Arctic doesn't disappear by the end of this month (no more peek-a-booing), it will be perfect refreezing material. That's what cut the 2010 melting season short.
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jdallen

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Re: The 2015 melting season
« Reply #3227 on: August 10, 2015, 12:00:24 AM »
I also agree that the melt season will probably run a week longer; I'd actually hazard it may be two to three, and that we may not see a minimum until after 1 October.  It depends on two things I think; continued high SST's along the periphery of the pack, and import of heat from further south via the remains of east Pacific cyclones.  The first will provide the necessary heat for continued melt; the second will offset radiative losses which normally would reduce the effect of the first.

I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

I only can think on one reason similar to jdallen's, which is excessive heat from a record warm NH transferred to the Arctic within next 30 days or so. That obviously depends on the weather to come.

Edit. Modified in view of the May-June NH temp average time series from NOAA
Bingo.

You speak directly to my point.  It's not heat applied to the Arctic; it's heat replacing that *lost* by the Arctic, which permits bottom melt to continue.

That said, Rubik and Neven both have a valid point.

To that end, if the slush does permit a quick refreeze, that actually isn't helpful, long term.  It would tend to put a lid on the heat already present, and constrain the build up of thicker ice over winter.

So many competing feedbacks....
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seaicesailor

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Re: The 2015 melting season
« Reply #3228 on: August 10, 2015, 12:01:16 AM »
I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

Exactly. If all that dispersed ice on the Pacific side of the Arctic doesn't disappear by the end of this month (no more peek-a-booing), it will be perfect refreezing material. That's what cut the 2010 melting season short.

And didn't this on 2010 depend on August weather and heat transfer from lower latitudes (just asking, I don't know)?

seaicesailor

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Re: The 2015 melting season
« Reply #3229 on: August 10, 2015, 12:14:24 AM »

Bingo.

You speak directly to my point.  It's not heat applied to the Arctic; it's heat replacing that *lost* by the Arctic, which permits bottom melt to continue.

Yes. Storms is what comes to my mind, followed by warm airs as shown by you and CR; in that case, a lot of melting/compaction may happen before refreezing, if temperatures are risen in Pacific side.

This is all speculation. Who knows how it will play, so thrilling as a classic
Time for bed  :-X

DavidR

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Re: The 2015 melting season
« Reply #3230 on: August 10, 2015, 05:02:44 AM »
I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

Exactly. If all that dispersed ice on the Pacific side of the Arctic doesn't disappear by the end of this month (no more peek-a-booing), it will be perfect refreezing material. That's what cut the 2010 melting season short.

And didn't this on 2010 depend on August weather and heat transfer from lower latitudes (just asking, I don't know)?

In 2010 SST's above 80N June(19th) and July (46th) were ranked very low according to NOAA.  In comparison June 2015 was 36th and July 4th warmest; warmer than every year since 2003. This suggests a lot more melting in the 80N region, and warmer seas going into August.

This should  translate into a stronger and probably longer melt season for the remainder.
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slow wing

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Re: The 2015 melting season
« Reply #3231 on: August 10, 2015, 07:24:34 AM »
The U. Bremen update confirms some weakness in the Arctic ice pack that is near the Atlantic edge, as was first seen yesterday.

As expected, large changes in the peripheral seas on the Pacific and Siberian sides, where the wind is and where the ice is already fragmented. We can see the wind direction from the edges. Presumably the rest of it is mostly fluctuations from local variations crossing the colour thresholds in one direction or the other.

Trying again for the cross-fade effect. (It doesn't seem to even load all the colours correctly for me! Do you all see the black background on the plot dated 9 August? Where did that come from? It wasn't in the original image from U. Bremen.) Click on gif, hopefully for cross-fade flashing to and from yesterday's map:




JayW

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Re: The 2015 melting season
« Reply #3232 on: August 10, 2015, 12:26:31 PM »
I think this is the greatest probabilities of above average temps across the arctic regions that I have seen depicted on the 8-14 day NAEFS ask boreal summer.  I know looking at weather models a week out is fraught with peril, but I'm certainly in the crowd that feels this last month (or so) of the melting season could be exciting.  :)  (in this case exciting= more melting)   :P

The NAEFS are just probabilities of above/below average temps, not anomalies, don't want any confusion.

http://weather.gc.ca/ensemble/naefs/semaine2_combinee_e.html
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JayW

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Re: The 2015 melting season
« Reply #3233 on: August 10, 2015, 12:53:30 PM »
Global Weather Logistics, via Crysophere Today...
http://globalweatherlogistics.com/seaiceforecasting/gfs.850mb.vectors.arctic.html

The cyclone that is due to cover the entire Arctic Ocean on 13 to 15 August (Thursday Friday Saturday) is interesting, I'm not sure what effect it will have. But what is interesting is what happens in the Pacific.

Tropical Storm Molave is shown on this 96 hr (4 day ahead - 12 August) with a heading arrow.
http://www.opc.ncep.noaa.gov/shtml/P_96hrsfc.gif

Going back to the first link, this is seen as the strong cyclone that proceeds from Japan, and the seems to get entrained by the Cyclone in the Arctic Ocean and drawn in to Bering as the Arctic Ocean cyclone declines.

Hope people don't mind this here.

He's a few tropical cyclone tracking resources that might be of interest in light of Molave.  Or for anyone who enjoys tracking the tropics. 


First attachment ECMWF ensemble tracks.
Not everything is freely available on this site, but it's free ECMWF ensembles.  :)  (Molave is WP15)
http://www.emc.ncep.noaa.gov/gmb/jpeng/TC_ens_V1.html

Second attachment is the 8/12z UKMO ensemble tracks (many other ensembles available here)
http://ruc.noaa.gov/tracks/

Third attachment is the NCEP ensembles (red is the control run)
http://www.emc.ncep.noaa.gov/mmb/gplou/emchurr/glblgen/index_old.html

Lastly, a link to the HWRF site
http://www.emc.ncep.noaa.gov/gc_wmb/vxt/HWRF/index.php
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iceman

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Re: The 2015 melting season
« Reply #3234 on: August 10, 2015, 01:03:19 PM »
I don't see any reason to believe there will be a late minimum this year. CT area numbers show no trending toward later minimums and I don't think you will find much correlation between low and late minimums either. If anything, I would say the high presence of low concentration areas filled with slush and ruble favors a slightly early refreeze this year.

Exactly. If all that dispersed ice on the Pacific side of the Arctic doesn't disappear by the end of this month (no more peek-a-booing), it will be perfect refreezing material. That's what cut the 2010 melting season short.

And didn't this on 2010 depend on August weather and heat transfer from lower latitudes (just asking, I don't know)?

In 2010 SST's above 80N June(19th) and July (46th) were ranked very low according to NOAA.  In comparison June 2015 was 36th and July 4th warmest; warmer than every year since 2003. This suggests a lot more melting in the 80N region, and warmer seas going into August.

This should  translate into a stronger and probably longer melt season for the remainder.

I can see Rubikscube's and Neven's reasoning about remnants of dispersed ice nucleating a refreeze - though in 2010 the effect appears to be more a quick start to the freeze season than an early minimum.
    It seems likely there will still be mid-Sept melting forces acting on the ice in more southerly latitudes (not just Beaufort but also southern CAA and maybe even remnant ice in southern Laptev) which offsets refreeze in the CAB.  However, the effect may be more pronounced on volume - a late decline in anomaly - than on area/extent.

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Re: The 2015 melting season
« Reply #3235 on: August 10, 2015, 02:54:55 PM »
Trying again for the cross-fade effect. (It doesn't seem to even load all the colours correctly for me! Do you all see the black background on the plot dated 9 August? Where did that come from? It wasn't in the original image from U. Bremen.) Click on gif, hopefully for cross-fade flashing to and from yesterday's map:
Cross fade is working (and yes I do see a colour shift). Thanks!
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Gonzo

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Re: The 2015 melting season
« Reply #3236 on: August 10, 2015, 03:09:33 PM »
Quote
Slow Wing: Do you all see the black background on the plot dated 9 August? Where did that come from? It wasn't in the original image from U. Bremen.)
Not sure what you are aiming for, and how you are building these? If it's a png file, it has built-in transparency (a mask that can make pixels see-through if needed), so if you are fading, then it has to fade to a color behind it, usually a neutral gray, but depending on how you are making these, maybe it is fading to black, or it is multiplying - adding up the pixel darkness values - in layers. (The fading or multiplying may not affect the other highly saturated and bright colors).  Try changing your original png file, that you downloaded from U Bremen, to a jpeg first. jpegs do not have transparency and will fade to white only. If there is a multiplying effect going on, then it is in the software or coding, and jpeg won't help that.
« Last Edit: August 10, 2015, 03:21:20 PM by Gonzo »

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Re: The 2015 melting season
« Reply #3237 on: August 10, 2015, 07:58:03 PM »
GFS has backed off on the idea of a large cyclone near the pole in the short run, but still bring some terrifically bad weather up into the Bering Sea and Alaska in the longer run.  We'll see.

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Re: The 2015 melting season
« Reply #3238 on: August 10, 2015, 08:44:24 PM »
GFS has backed off on the idea of a large cyclone near the pole in the short run, but still bring some terrifically bad weather up into the Bering Sea and Alaska in the longer run.  We'll see.


The danger for the ice may be actually that bad weather in Bering, people showed yesterday being an extratropical cyclone. Each time I look at GFS new forecast, the predicted cyclone hits America or Bering but changing the location a lot. Indeed we'll see.

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Re: The 2015 melting season
« Reply #3239 on: August 10, 2015, 09:05:58 PM »
Latest ECMWF also has some bad weather in Alaska in the same time frame, but not seemingly indicating as much impact on the Arctic. Notice also the two huge typhoons in the Western Pacific! Lots of heat energy being transferred around the atmosphere and oceans (if they verify, I should say)!

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Re: The 2015 melting season
« Reply #3240 on: August 10, 2015, 10:21:00 PM »
Sea Ice Sailor pointed out that JD Allen first spotted the potential Molave issue, thanks both of you.

It doesn't look like it's going to be much of a player now, weather within the Arctic is now looking rather uneventful for the rest of the week. But Molave does seem to feed a preceding low, and Alaska might be in for a storm.

Anyway, both extent and area in the peripheral seas continues to show level anomalies (extent), or climbing anomalies (area).

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Re: The 2015 melting season
« Reply #3241 on: August 10, 2015, 11:44:24 PM »
Sea Ice Sailor pointed out that JD Allen first spotted the potential Molave issue, thanks both of you.

It doesn't look like it's going to be much of a player now, weather within the Arctic is now looking rather uneventful for the rest of the week. But Molave does seem to feed a preceding low, and Alaska might be in for a storm.

Anyway, both extent and area in the peripheral seas continues to show level anomalies (extent), or climbing anomalies (area).

My sense as well.  It looks like the NE Pacific high pressure ridge broke down some, which is permitting the moisture to shift to the east and slightly south.  If it firms up, or even if it doesn't, the flow from the high may still pin-ball the moisture north - more towards the eastern Beaufort and the CAA.

But right now, not as worrying as it might have been.
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Neven

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Re: The 2015 melting season
« Reply #3242 on: August 11, 2015, 12:06:35 AM »
Chris Reynolds, looks like you're about to talk your old friend again, because the (classic) Dipole forecast is becoming more and more pronounced:
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seaicesailor

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Re: The 2015 melting season
« Reply #3243 on: August 11, 2015, 12:21:14 AM »
Sea Ice Sailor pointed out that JD Allen first spotted the potential Molave issue, thanks both of you.

Did I? I don't think so but you welcome.

Quote

It doesn't look like it's going to be much of a player now, weather within the Arctic is now looking rather uneventful for the rest of the week. But Molave does seem to feed a preceding low, and Alaska might be in for a storm.


Come on, that wind forecast simulation was thilling! If such a warmth strikes down upon the Artic with great vengeance and furious anger. It is still far in the forecasts.

In your blog you say there is nothing surprising, but not uneventful. Weak storms and some warm flow are on schedule. Beaufort SSTs seem warmer already. CAA is being fried as always this season.

Weak storms have proved to disperse, and damage MYI much more than expected.

And what is going on in the Atlantic side? That is even surprising for me, but I lack experience.

Enough for today  :-X

Greenbelt

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Re: The 2015 melting season
« Reply #3244 on: August 11, 2015, 02:14:46 AM »
Chris Reynolds, looks like you're about to talk your old friend again, because the (classic) Dipole forecast is becoming more and more pronounced:

Also very interesting the nearly stationary large and strong low south of Iceland sending warm air northward in front of it.

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Re: The 2015 melting season
« Reply #3245 on: August 11, 2015, 02:39:02 AM »
Anyway, both extent and area in the peripheral seas continues to show level anomalies (extent), or climbing anomalies (area).

So...  If the peripheral seas had completely melted out today, we would still see rising anomalies while we waited for the historic average to catch up.  I'm not sure I like using this anomaly approach.  It leads to you saying stuff which sounds like its devastating to certain points of views, but which doesn't mean anything if we take it out of context.  And in order to supply the context, we pretty much ignore the sentence and study the graph for awhile to see how 2015 compares to 2012, 2011, and 2007.

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Re: The 2015 melting season
« Reply #3246 on: August 11, 2015, 03:49:31 AM »
Sad to say, but it is coming apart. This is nothing like as robust as it was the same time in 2012.
Not even close. It's coming apart.
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slow wing

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Re: The 2015 melting season
« Reply #3247 on: August 11, 2015, 04:13:27 AM »
Yep. progress in the melt seen in today's U. Bremen update, showing ice pack disintegration in several regions that have gone beyond the day-to-day fluctuations and are more advanced than on any previous day this season:
  • the Beaufort arm is more separated, by a larger hole, than previously. There are almost gaps in the arm at around 135 degrees West, showing large individual floes or else rafts of floes.  Parts of the other end of the arm, in the Chukchi Sea, are showing only patterns of light blue dots (~25% concentration) on the dark blue background. The arm looks like it might separate completely soon, while disintegrating further;
  • The 'forearm' in the ESS that sticks out between 150 and 165 degrees East is shortening. The middle finger is no longer straight and defiant; and
  • Over on the Atlantic side, the small appendage between 75 and 90 degrees East looks to be dissolving.

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


Adam Ash

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Re: The 2015 melting season
« Reply #3248 on: August 11, 2015, 04:53:04 AM »
Its interesting looking at the Cryosphere charts for all the peripheral seas - all ice pretty well gone - and their charts showing either zero or below normal anomalies for this date.

Now the chart for the central Arctic Basin is starting it's nose-dive too - currently showing an anomaly of about -750,000 sq km.  The race is on! (That is: the race is on to the end of weather as we know it!!!)  Oh dear...

NeilT

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Re: The 2015 melting season
« Reply #3249 on: August 11, 2015, 08:42:41 AM »
And on the Barrow Webcam, in the distance, we can see lines of ice being pushed into the warmer coastal waters. Where, of course they will vanish.

That ice must be MYI, FYI simply could not have survived that long or that far now.

Next, looking at the Bremen concentration maps, must be a massive crash in extent as those arms finally melt out, either suddenly or over a week or so.

However it's clear that the actual melt out is either slowing or moving into a different phase.  Not that the weather can't kick it off again.

CT area records look like it will either hit 3rd or 4th in the record set but might just hit second if the weather obliges.

The NW passage looks like it will finally be clear for easy navigation in the shallow channel in a week or two.

For me the more dramatic thing is the CAA breaking up and the ice heading North instead of South.

Certainly a year to watch.  The main thing, for me, this year, is that it is clear the Arctic is moving to a different state and how it will respond to heat inputs and weather, is going to change the way in which we anticipate (model), the future changes in the Arctic.
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