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BornFromTheVoid

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Arctic Refreeze Discussion: 2014/2015
« on: September 22, 2014, 07:59:57 PM »
Looks like it's time for a new thread. Seems most measures have hit their minimum and are now on the way up.
The ECM shows colder than average uppers over the next 5 days, so an opportunity for some above average ice growth.

T0


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As the ocean releases its heat, we will likely see above average surface temps persisting for a while though, as has been the case in most recent autumns.

Based off the NSIDC extent (using a 5 day running average), below is a graph of the largest 7 day extent increases recorded for each year since 1979



It will be interesting to see where 2014 ends up!

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #1 on: September 22, 2014, 09:51:49 PM »
Void, my gut feeling tells me people are reluctant to comment because they'd rather have Summer linger on for a few more weeks :)

The 7 day increases you graph, are they from September/October, or any time of the year? I thought November was the best month for refreeze, but that is perhaps only for volume?
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Neven

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #2 on: September 23, 2014, 02:05:11 AM »
This is now the official freezing season thread. Thanks for opening, BFTV.
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Neven

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #3 on: September 23, 2014, 02:19:00 AM »
Lord M Vader had already posted a freezing season thread a month ago, but he was so early that I forgot.  :-[ ::)

To make it up I post his latest comment here:

So, now when we have reached the minima we can put our attention to the Arctic weather winter 2014/2015.. The last couple of years the SIE per JAXA have been more than 8 Mn km2 at October 31 (except for 2012).

Given the rather high sea ice extension in Barents Sea I won't be too surprised if the SIE may be close to 9 Mn km2 by October 31. Last time that happened was 2008.
« Last Edit: September 23, 2014, 12:11:52 PM by Neven »
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #4 on: September 23, 2014, 07:56:37 AM »
Void, my gut feeling tells me people are reluctant to comment because they'd rather have Summer linger on for a few more weeks :)

The 7 day increases you graph, are they from September/October, or any time of the year? I thought November was the best month for refreeze, but that is perhaps only for volume?

Yes it is. Early freeze season extent gains are very rapid as thin ice spreads very fast.

BornFromTheVoid

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #5 on: September 23, 2014, 11:20:57 AM »
Void, my gut feeling tells me people are reluctant to comment because they'd rather have Summer linger on for a few more weeks :)

The 7 day increases you graph, are they from September/October, or any time of the year? I thought November was the best month for refreeze, but that is perhaps only for volume?

Unfortunately, my laptop is on the way out. So I've lost all the data that went into that graph!
As far as I can remember, the date range of fastest gains went from something like the week up to October 6th for the earliest, and to December 8th for the latest. The majority of them occur in mid to late October.

Neven

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #6 on: September 23, 2014, 12:14:13 PM »
Unfortunately, my laptop is on the way out. So I've lost all the data that went into that graph!

Tell me about it, my second HD died a couple of days ago. It was more or less my back-up HD, but there was some stuff I hadn't copied to my laptop (my double back-up), like my Arctic Archives! All those animations, graphs, etc, lost.

I'm so stupid...  >:( :'(

But that was the first and last time this happens to me.
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iceman

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #7 on: September 23, 2014, 03:00:35 PM »
That's quite a setback, Neven.  Fortunately the ASIF community has a collective memory that will offset the loss of data to some extent.

BornFromTheVoid

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #8 on: September 23, 2014, 05:09:02 PM »
Unfortunately, my laptop is on the way out. So I've lost all the data that went into that graph!

Tell me about it, my second HD died a couple of days ago. It was more or less my back-up HD, but there was some stuff I hadn't copied to my laptop (my double back-up), like my Arctic Archives! All those animations, graphs, etc, lost.

I'm so stupid...  >:( :'(

But that was the first and last time this happens to me.

Makes my 40 minutes of lost work seem like so little now! I think you always have to lose something big before backing up data consistently becomes a priority.

Anywho, I re-did the stuff from yesterday. Below is a graph showing the day of the year that the fastest 7 day extent increase finished on. There's a slight trend toward an earlier maximum date, which is to be expected. The range is from October 7th to December 8th, so my memory wasn't too far off yesterday.


viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #9 on: September 23, 2014, 06:01:09 PM »
My macbook served itself to some red wine a week ago, while I was sleeping innocently. Luckily, only the Return key stopped working, and I finally found a (software) fix for that. Use memory sticks for backup, guys. The cheapest (bytes/cost) sticks store 128 GB these days. (Note to self: Employ daily or at least weekly backups from now on!)
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #10 on: September 24, 2014, 07:00:26 AM »
This IJIS Yearly Mean Extent graph may look a bit messy, but there is a pattern here — a 5–year cycle — if you look closely: In both 2007 and 2012 you have steep descents down to record Autumn minima. Then in 2008 and 2013 follow steep ascents, packing a lot of ice to the yearly mean. The 3rd year of the cycle, 2009 and 2014, are fairly uneventful years with only a slight descent in mean extent.

The 4th year of the cycle is 2010 and 2015, where a major descent is starting. The descent continues with year 5 of the cycle, 2011 and 2016, perhaps. And by now you've had 1 record extent minimum (2007) and 3 record volume minima (2007, 2010, 2011) in the first cycle, and 1 record extent and volume minimum (2012) in the second cycle. But 3rd year 2014 is .303 million km² below 2009 for September 23rd, so if the 4th and 5th year — 2015 and 2016 — resemble 2010 and 2011 in any way, we may see huge drops in average extent and volume that go beyond even 2010 and 2011, and also impressive new minimum records for PIOMAS ice volume, before 2017, the first — and possibly record — year of yet another 5–year cycle.

If correct, the Yearly Mean Extent graph will likely start a descent as early as October 2014 and continue all the way through a 'Perfect Storm' 2015 until we have a new record minimum volume in September. This means that the Arctic Refreeze of 2014 will be very exciting indeed. Though maybe a bit confusing: The sea ice extent will of course increase, but the speed and size of the refreeze will determine whether this Yearly Mean Extent graph will sport an October descent or not.
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jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #11 on: September 24, 2014, 11:02:02 AM »
I for one will start tracking 2 meter temps more closely; temperatures bottom to top in fact.  Perhaps it can give us a sense of the heat leaving the system, and by inference, an idea of how volume is rising.

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Rubikscube

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #12 on: September 24, 2014, 08:07:44 PM »
2014 was a year which appeared at first to become the ultimate comeback, but then everything went wrong. In fact in March, at the very beginning of melt, I thought chances of record where vast. Not only because volume has caught up with 2012, but because there was so much volume stacked up along CAA and so little was left in more crucial places such as Laptev and ESS.

In March though, the polar vortex came back together, and ice started flowing into Barents once more. Without this export taking place throughout the spring I think extent could have been at least 0,5M lower at minimum. Then in late April, May things started to go wrong when snow cover deficits failed to keep up with other post-2007 years and lack of heat import brought 80N temps below normal, and despite indications of the opposite, propper melt conditions never materialized in early June. HP-systems did appear, but no propper heat nor any winds to speak of, only crisp sunshine on what seems to have been too much snow. Super bad melting conditions for June it appears, so bad that volume couldn't even keep up with 2013.

July weather this year was boring and uneventful, LP-dominated and too cold, it kind of resembled that of July 2012 I would claim, but the difference was that in 2012 there were more ponds, more heat lingering around and in general more weak ice to melt, nevertheless July was no good month in 2012 either.

I would also maintain that if the weather in August had occurred 2 months earlier, then 2014 would have rivaled 2012 almost regardless of what would happen next, but as "August weather", and with such limited amounts of ponds and slush to work with, massive HP-systems without a proper dipole setup seems to do the ice more good than harm, hence the historic bad volume melt.

Looking back with hindsight, I can hardly imagine that it could have become any worse than this, taking into account conditions in March. And as a result of all this, I would argue that the virtually ice free date may have been postponed with 2 years, perhaps more. Before 2017 seems less plausible every day. Though, I'm really looking forward to see whether we can see yet another "volume catch up" this winter, and I will be left speechless if 2012 is caught at maximum like it was this year.

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #13 on: September 24, 2014, 09:19:55 PM »
It will mean more when the September data is used. But looking at August PIOMAS volume.



Note that the only region with unusually high volume for recent years is the Central Arctic, CAA not shown also has a high volume in comparison to recent years. I've not yet formed a firm opinion about what this means for peak volume, but my suspicion is peak volume may be around 24.5k km^3, that's the average for April 2011 to 2014 with an extra 2k km^3 added on (the current excess over recent years).

I'll be watching what happens to the extra mass in the Central Arctic.

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iceman

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #14 on: September 25, 2014, 03:18:14 PM »
The peak volume question merits some thought.  I suppose the actual peak (freeze season maximum) mainly reflects ice dynamics, while the "high minimum" during recent and upcoming years (near end of melt season) says more about spring and summer weather.  Given that atmospheric conditions were mixed during this past melt season, I wouldn't necessarily expect that 2014 marks the "high minimum" for, say, 2008-2017.  But any weather-related variability in ice volume loss will be against a gradually dropping trendline, as Chris R has shown on Dosbat.
      If I find any good articles or data that bear on this question, I will find a suitable PIOMAS thread to post to.
     
Side note, I'm sticking with my earlier guess of a net volume loss for this September.  We'll see what PIOMAS says in a couple weeks.

BornFromTheVoid

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #15 on: September 27, 2014, 09:09:32 PM »
It seems the Arctic is about to switch from mainly negative upper air temperature anomalies to positive over the weekend, which may slow the rate of increase.

Tomorrow


4 days ahead


EDIT: stats were wrong...
« Last Edit: September 28, 2014, 04:29:42 PM by BornFromTheVoid »

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #16 on: September 28, 2014, 05:34:27 AM »
Extent 5th lowest by Sunday September 28th?
« Last Edit: September 28, 2014, 06:05:54 AM by viddaloo »
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #17 on: September 29, 2014, 07:26:06 AM »
2% of 2014 max extent refrozen. 5th lowest as of September 28th, but with a Sunday margin of just 41k km² back to 2010.

Next target is 2008, 350k km² below 2014. 4th lowest by Thursday October 30th?
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Comradez

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #18 on: September 29, 2014, 05:14:03 PM »
I just wanted to point out that the Northern Hemisphere snowcover is way above normal right now on Rutgers Global Snow Lab.  Negative albedo feedback much?  Does this foreshadow the start of a cold winter season?

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #19 on: September 29, 2014, 06:40:44 PM »
I just wanted to point out that the Northern Hemisphere snowcover is way above normal right now on Rutgers Global Snow Lab.  Negative albedo feedback much?  Does this foreshadow the start of a cold winter season?

The departure looks similar to this time last year and way different than 2012. However by Jan 2014 the anomaly was negative while Jan 08-13 had positive anomalies. 2014 was a warm winter.

So I suggest we would need the positive anomaly to last quite a bit longer before we should expect a cold winter

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #20 on: September 29, 2014, 07:35:08 PM »
I just wanted to point out that the Northern Hemisphere snowcover is way above normal right now on Rutgers Global Snow Lab.  Negative albedo feedback much?  Does this foreshadow the start of a cold winter season?

The departure looks similar to this time last year and way different than 2012. However by Jan 2014 the anomaly was negative while Jan 08-13 had positive anomalies. 2014 was a warm winter.

So I suggest we would need the positive anomaly to last quite a bit longer before we should expect a cold winter

Also relevant is the location of that snow cover.

 If it is at high enough latitude, it in fact will decrease rather than increase heat loss.  If on the ice, it will actually retard thickening of the ice.

High albedo in areas with low incident insolation and short days doesn't strike me as likely to make weather particularly cooler.
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jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #21 on: September 29, 2014, 10:20:43 PM »
More food for thought regarding snow cover.

Snow has approximately 1/4 the insulative value of fiberglass insulation; by extension,  40CM of snow reduces heat flow to the same degree ~10CM of fiberglass would.

Further, the elimination of prompt transfer of heat from ice directly to air via convection will be reduced considerably.  Reduced convective flow should decrease the rate at which heat is *physically* transported to where it can be lost.

QED, snow on the pack  ice acts like an "inverse melt pond", considerably reducing the rate at which new ice can form. Early season positive snow cover anomalies are not good for the ice.

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #22 on: September 30, 2014, 12:42:00 AM »
The area of high-concentration ice I was following has not done much, and my guess is this could be the last day it remains a recognizable feature on the Bremen map. It has drifted slightly west, possibly moving it toward warmer water — though really, movement in any direction but north would be into an area of open water. If this is thicker ice it must still be affected by bottom melt even though surface refreezing is occurring around it.

Comradez

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #23 on: September 30, 2014, 05:51:10 PM »
It is true that snow on top of ice will reduce melt.  However, that's not what we are seeing right now.  At least, that's not what Rutgers Global Snow Lab shows.  Granted, they don't show snow cover on top of the ice.  Is there any product on the Internet that actually shows that?

Rutgers Global Snow Lab shows snow over land.  Aside from insulating the permafrost from the cold somewhat over the winter, snowcover over the lower latitude land areas can only make the winter colder - partly by reducing albedo, and partly by causing more release of heat to the open sky at night. http://www.theweatherprediction.com/habyhints/207/

crandles

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #24 on: September 30, 2014, 07:30:46 PM »
Is there any product on the Internet that actually shows that?

PIOMAS is a model rather than a measurement but Chris Reynolds mentioned there was snow on ice data up to Aug 2014. I assume that is a monthly average that is available for each grid point within a week of the month end rather than daily figures for each grid point.

As PIOMAS is driven in part by atmospheric reanalysis data, it might not be too bad?

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #25 on: September 30, 2014, 11:09:36 PM »
It is true that snow on top of ice will reduce melt.  However, that's not what we are seeing right now.  At least, that's not what Rutgers Global Snow Lab shows.  Granted, they don't show snow cover on top of the ice.  Is there any product on the Internet that actually shows that?

Rutgers Global Snow Lab shows snow over land.  Aside from insulating the permafrost from the cold somewhat over the winter, snowcover over the lower latitude land areas can only make the winter colder - partly by reducing albedo, and partly by causing more release of heat to the open sky at night. http://www.theweatherprediction.com/habyhints/207/

Quibble - snow will increase albedo, not reduce it.  Second,  it doesn't cause more heat loss, it reduces it by reducing additional thermal transfer from earth or ocean.  The rate of radiative loss doesn't increase.

What changes is the source of the heat - the atmosphere -  which is a much smaller reservoir of heat.  It declines faster and reaches equilibrium - a balance between outgoing radiation and incoming heat sources - at a lower temperature.

Loss from the 500lb gorilla - earth and ocean - is actually slowed down.
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crandles

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #26 on: October 01, 2014, 01:08:37 AM »
Quibble - snow will increase albedo, not reduce it.  Second,  it doesn't cause more heat loss, it reduces it by reducing additional thermal transfer from earth or ocean.  The rate of radiative loss doesn't increase.

What changes is the source of the heat - the atmosphere -  which is a much smaller reservoir of heat.  It declines faster and reaches equilibrium - a balance between outgoing radiation and incoming heat sources - at a lower temperature.

Loss from the 500lb gorilla - earth and ocean - is actually slowed down.

I'll quibble your quibble.

>snow will increase albedo, not reduce it.

Note that Comradez preceded the reducing albedo comment by "Rutgers Global Snow Lab shows snow over land. Aside from insulating the permafrost..."

Therefore we are talking albedo/emissivity of Long-wave radiation from Earth not ocean or sea ice. Snow has quite low albedo and therefore high emissivity for long-wave radiation.

Snow has high albedo to short (solar) wavelengths but not for infra red wavelengths.

.

"Aside from insulating the permafrost" seems to indicate we are all agreed there in an insulating effect of snow. Not sure we are recognising all the effect though:

Atmosphere radiates to ground effeciently, causing some melt and the water trickles though the snow where the permafrost freezes the water to form part of the active layer freezing. This will warm the permafrost. While snow insulates reducing the permafrost sensible heat loss, the heat flow is increased by such latent heat transfer.

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #27 on: October 01, 2014, 07:26:02 AM »
<snippage of redundancy>

I'll quibble your quibble.

Fair enough ;)


>snow will increase albedo, not reduce it.

Note that Comradez preceded the reducing albedo comment by "Rutgers Global Snow Lab shows snow over land. Aside from insulating the permafrost..."

Therefore we are talking albedo/emissivity of Long-wave radiation from Earth not ocean or sea ice. Snow has quite low albedo and therefore high emissivity for long-wave radiation.

Snow has high albedo to short (solar) wavelengths but not for infra red wavelengths.

Excellent education and correction.

Can we quantify the distribution?  Would the difference in albedo render the snow more effective at capturing IR emitted by atmosphere directly rather than just via sunlight?  What sort of heat content do you think we are looking at, fractionally, by way of the sunlight on the snow?  You can just point me at references, or suggest a direction.


"Aside from insulating the permafrost" seems to indicate we are all agreed there in an insulating effect of snow. Not sure we are recognising all the effect though:

Atmosphere radiates to ground effeciently, causing some melt and the water trickles though the snow where the permafrost freezes the water to form part of the active layer freezing. This will warm the permafrost. While snow insulates reducing the permafrost sensible heat loss, the heat flow is increased by such latent heat transfer.

Permafrost can still be a net reservior of heat, if the atmosphere is cold enough ;)

I'm not sure the scenario you describe isn't zero sum.  I'm also somewhat skeptical of the scale of transfer. 

Heat taken up in the snow will remain there longer than heat radiated or convectively transferred from ground directly to atmosphere. The direction of movement is stochastic, and all in the gradient.  The snow tends to fight the movement of heat regardless of direction.

I'd be less skeptical of the effect of IR through snow if we were on the "hot" side of the equinoxes.  At this point, I'm not sure the incident sunlight would produce significant enough heating to cause the kind of melt/refreeze transfer you are talking about.
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #28 on: October 01, 2014, 08:24:14 AM »
This week, we see the Yearly Mean Extent descent increasing in daily drops — down 507 km²/d — and weekly we're now down 1116/w. For the past 30 days the net change is still up 5882 km²/m.

The Five Year Cycle hypothesis is now strengthened 27.9% since Sep 24 — and the Big Descent is 32 days ahead of schedule. Even with 0% and 0 days the prognosis would be dramatic for the ice; the added strength just makes the descent even steeper than what the Five Year Cycle hypothesis expects, statistically. Next week we'll probably go below the 10.3 mill line, plus we'll see whether this dramatic strengthening actually continues or was just beginner's luck.

PS: Note also that the prognosis is sharpened slightly for each day of new data, so that the forecast for October 2016 is now for 9.3 mill — which would be a million km² gone from the average extent in just 2 years — whilst October 2016 was set for 9.5 mill just 2 days ago.



2014 has gone purple since last week, automatically getting that colour from Google after overtaking 2013 (light green) on the 27th of September and 2010 on the 28th, so that 2014 is now 5th lowest extent-wise. At the same time, and because of this, purple is now descending at a rate of about 3000 km² per week since the start of the descent, and the strength of the 5-year cycle hypothesis is up almost 30%.

This also means that the chance of a new record minimum in 2015 is up 30% since September 24th, or maybe rather that the coming minimum will be 30% more extreme? The figure anyway measures the delta of 2013 and 2014 compared to that of 2008 and 2009. This graph gives a little more detail to 2014, while losing some of the context and easyness of the first graph:



Finally, a prediction that 2008 will be overtaken by next Friday:

3% of 2014 max extent refrozen. 5th lowest as of September 28th, but with a Tuesday margin of just 69k km² back to 2010.
Next target is 2008, 239k km² below 2014. 4th lowest by Friday October 10th?
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crandles

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #29 on: October 01, 2014, 10:40:22 AM »
Permafrost can still be a net reservior of heat, if the atmosphere is cold enough ;)

Sure I was trying to say we all appeared to agree on this.

Quote
I'm not sure the scenario you describe isn't zero sum.  I'm also somewhat skeptical of the scale of transfer. 
...
At this point, I'm not sure the incident sunlight would produce significant enough heating to cause the kind of melt/refreeze transfer you are talking about.

I meant to leave it vague as to scale of these transfers as I don't know. Sorry if I gave the impression that latent transfer was outweighing or balancing the slow down of sensible heat flow

Quote
Can we quantify the distribution?  Would the difference in albedo render the snow more effective at capturing IR emitted by atmosphere directly rather than just via sunlight?  What sort of heat content do you think we are looking at, fractionally, by way of the sunlight on the snow?  You can just point me at references, or suggest a direction.



Back radiation from atmosphere (333 in image) is larger than solar radiation absorbed (161) already and that is just on average. When you look at high latitudes during winter when there is few hours of sunlight at a low angle, the back radiation from atmosphere is going to be much larger than incoming solar absorbed.

The above is before mentioning the difference in albedo for snow for short wavelength and long wavelengths.

For a more quantitative answer you would presumably want formulas that deal with latitude, time of year, typical atmospheric temperature profile for time of year for a snow covered location. Sorry I am struggling to find a reference or link that would cover that sort of detailed information. Maybe someone else knows one? A public source climate model might have it but it is a bit large to go through and pick out the required information.

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #30 on: October 01, 2014, 06:56:58 PM »
Great graphic, Crandles.  I'm a visual thinker, so the images give my imagination something to chew on.  There's a lot there I can extrapolate on.  It ( and your commentary) give me ideas as to what to hunt for.

I apologize if I come off as abrasive.  No value judgement is intended.
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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #31 on: October 01, 2014, 11:06:00 PM »
Comparison maps with 2007, 2012, 2013 and 2010 (29th Sep) show that the situation is a little bit different from a couple of weeks ago. There is for example less ice than 2013 all the way from Beaufort to Kara, while CAA seems to be filling up very fast. Barents still has more ice than any other year, but the gap appears to be shrinking.

Rubikscube

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #32 on: October 05, 2014, 12:31:15 PM »
From a statistical point of view, there seems to be little or no correlation between autumn snow cover extent in the high (or lower) latitudes and snow (or ice) melt during the following spring and summer. Of the two recent years that saw the snow cover in Siberia settle down latest (2008 and 2009), one saw a slow melt in this area the following spring, while the other saw a very rapid one. This also seems to be the case for most other years, resulting in the overall picture being rather inconclusive.

If one looks very hard, one can possibly draw the conclusion that late snow gives a marginally higher chance of an early melt, something I would attribute to the simple fact that more snow is harder to melt than less snow. Apart from that, no feedbacks from autumn snow seem have any effect on the following summer, and probably not in the longer term either. To me, October snow is more a "symptom" than a cause.

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #33 on: October 08, 2014, 10:43:16 AM »
Have a look at the jet stream over the arctic right now:

http://earth.nullschool.net/#current/wind/isobaric/250hPa/orthographic=-59.77,80.92,257

Weird looking flow.

SST temp bands in the North Pacific are 3-500 KM further north than average - 2c or more above average.
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #34 on: October 08, 2014, 01:42:16 PM »
Last week I predicted that 2014 IJIS extent would be lower than 2008 by Friday 10th October. It was lower Tuesday 7th (but 2009 has now come back even lower than 2014 so we're still 5th lowest).

Yearly Mean Extent is down 985 km²/day, down 4677 km²/week and down 1954 km²/month.
« Last Edit: October 08, 2014, 05:30:05 PM by viddaloo »
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BornFromTheVoid

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #35 on: October 08, 2014, 04:05:53 PM »
Quite a slow start to the refreeze this year. In fact, the -ve anomaly compared to the 81-10 average is current the largest it's been all year, at -1.42 million km2 for the NSIDC extent (with 5 day average).

Rubikscube

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #36 on: October 14, 2014, 07:33:03 PM »
There is still way more ice on the Atlantic side than during all the other years of particular interest (12. Oct 2007, 2012 and 2013), although compared to the very low years, the Pacific still makes up most of the difference. The additional year this week is 2009 which is tracing very close to 2014 on SIE, and one can perhaps see why. Notice that I have taken extra care to remove the false ice this week, so the smaller patches along the coasts should largely be counted as real.
« Last Edit: October 14, 2014, 07:39:04 PM by Rubikscube »

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #37 on: October 15, 2014, 09:52:24 AM »
This week we see the Yearly Mean Extent descent stabilizing at about 1100 km²/day — and weekly we're now down 7438. For the past 30 days the net change is now down 11 970 km².

The Five Year Cycle hypothesis is now strengthened 67% since Sep 24 — and the Big Descent is 47 days ahead of schedule. (Even with 0% and 0 days the prognosis would be dramatic for the ice; the added strength just makes the descent even steeper and the gap even bigger than what the Five Year Cycle hypothesis expects, statistically.) The Yearly Mean Extent is now very close to the 10.3 mill line, and also very close to the July 14th yearly low–point of 10.2978. Today we will most likely cross and go lower than 2013 for the same day (Oct 15th). For 5YC reference, 2009 yearly extent went lower than 2008 on December 3rd, meaning the descent will be 49 days ahead of the corresponding descent 5 years ago.

Note also that the prognosis is sharpened slightly for each day of new data, so that the forecast for October 2016 is now for 9.28 mill (yearly average extent) — which would be a million km² gone from the average extent in just 2 years — whilst October 2016 was set for 9.5 mill just 16 days ago.

As per September 30th in Piomas' data, no Yearly Mean descent has yet started in (modeled) sea ice volume.

The second graph below gives more detail to the 2014 descent in Yearly Mean Extent, while losing the overview of the first 5–Year Cycle graph:
« Last Edit: October 15, 2014, 10:01:30 AM by viddaloo »
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Pmt111500

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #38 on: October 16, 2014, 05:41:21 AM »
Quite a slow start to the refreeze this year. In fact, the -ve anomaly compared to the 81-10 average is current the largest it's been all year, at -1.42 million km2 for the NSIDC extent (with 5 day average).

Salts from Bardarbunga (or rather, the new shield volcano forming in Iceland, the high intensity fissure eruption that's been going on now for 1,5 months) are possibly having an effect, as these have been keeping at low altitudes and depositing most of sulfates to arctic ocean and not going to stratosphere. It'll be interesting to see the analysis of this. Are springtime eruptions much different in this respect as there's plenty of light as opposed to now? When, during a year, should a phreatic-phreatomagmatic eruption happen for it to have a maximum effect on arctic sea ice?
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #39 on: October 16, 2014, 12:17:11 PM »
13% refreeze now. Notice how gaps to esp. 2012 and 2008 are narrowing and widening, respectively.
« Last Edit: October 16, 2014, 03:01:46 PM by viddaloo »
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Michael Hauber

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #40 on: October 20, 2014, 12:43:29 PM »
Comparing to previous years there has been very little formation of ice along the coasts of Alaska and Siberia.  In contrast there has been more ice forming in the Kara sea area than most recent years, and the Barents sea remains much higher than other recent years.

Will we see another low ice amount in the Bering sea this winter?  Is there any connection between the high sea ice amounts in the Bering sea from 07 to 12 and the low summer ice minimums over that period?
Climate change:  Prepare for the worst, hope for the best, expect the middle.

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #41 on: October 20, 2014, 08:03:59 PM »
Michael,

I've attached a plot of Bering Sea March Extent. Not sure it looks like a good predictor of summer sea ice. 2011 was a tie with 2007, yet had a low March extent. However it is striking that post 2007 years have high extent, I'd not noticed it until now.

In some work a couple of years ago I noticed that the Aleutian low was unusually low in recent years (if I recall correctly). But all that year's stuff has been archived and I can't put my hands on the drive right now.

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #42 on: October 20, 2014, 08:05:51 PM »
ASCAT is starting to reveal the large central white mass of thicker ice from this year.
http://manati.star.nesdis.noaa.gov/ascat_images/ice_image/msfa-NHe-a-2014292.sir.gif

More here:
http://manati.star.nesdis.noaa.gov/ascat_images/ice_image/

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #43 on: October 22, 2014, 05:47:33 AM »
This week we see the Yearly Average Extent drop falling all the way to just 208 km²/day — and weekly we're now down 5447. For the past 30 days the net change is down 18 455 km². We're also finally below 10.3 mill km² — exactly 8 months after we fell below 10.4 on February 21st. Only 4 previous years have ever been this low, and 2014 will be the 4th year with a calendar year YAE below 10.3, but the first of those to not set an Autumn all–time low. This means the general level is now extremely low, when even a slow non–record year is stumbling around in 10.2 territory.

The current Big Descent that began on January 5th 2014 has already removed 120 283 km² from yearly averages. During the week we will probably pass the July 14th yearly low–point of 10.2978. Today's YAE is 27 828 km² lower than 2013 for the same day (Oct 21st), and it will be another 53 days before 2009 is that low compared to 2008.

The forecast has settled on October 24th 2016 as the low–point of this descent, and a current estimate for this date of 9.35 m km² — a loss of 1.07 m km² of Arctic sea ice since the beginning of the descent, on January 5th of this year. If correct, this will be the biggest descent in IJIS history.

First graph below shows 2014 + 2009 detail. The second presents the general overview.

QUESTION: If the 2 first years after 2007 and 2012 are in some sort of 'after–shock' after the record lows, what could be the physical cause of this?
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Rubikscube

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #44 on: October 22, 2014, 04:09:31 PM »
Since the snow cover extent has been soaring lately, I made a snow cover comparison similar to those I made earlier this spring. Though, I'm not sure how informative they are since I personally find them a little bit messy and chaotic this time.

The pics are 2014, 2013 and 2012 respectively, I believe the date is October 19th, but since CT labels the maps in its compare tool with different dates than those in its archive, it is hard to be sure (the CT archive appears in general quite flimsy, as random dates and entire section are missing everywhere). Reds are decrease, blues are increase.

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #45 on: October 22, 2014, 05:32:35 PM »
QUESTION: If the 2 first years after 2007 and 2012 are in some sort of 'after–shock' after the record lows, what could be the physical cause of this?
I'm thinking maybe something to do with the freshwater in the Gyre, or upwelling of warmer water from the deep. To quote Wikipedia on the Gyre:

Quote
The Beauford Gyre is a clockwise rotating system, flowing the same direction as the high pressure area over the Arctic which in turn is caused by falling dense air spreading southward with Coriolis turning the south flowing wind to the West. Lighter surface water piles up in the centre of the gyre due to Coriolis which sends surface water to the centre of the system. In so far as counter clockwise atmospheric systems such as the hurricane of Aug6, 2012 cause the rotation of surface water to reverse, this surface water will be "flung" outward and replaced by upwelling of the deep, saltier, warmer Atlantic water which underlies the fresher colder Arctic water. This mixing would be expected to lead to accelerated melting.

Maybe a Gyre reversal as that of August 6th 2012 did 2 things: 1) cause hot upwelling and further Aug/Sep melt in 2012, and 2) fling so much freshwater south that the refreeze goes into hyperdrive? In any case, the Yearly Average Extent for 2013 and 2014 is way up compared to that of 2012.

And from mtkass.blogspot.com:
Quote
The Beaufort Gyre Exploration Project reports that the amount of fresh water stored on the surface of the Arctic Ocean is equal to a number of years flow of rivers emptying into the Arctic ocean.  However, the Beauford Gyre can reverse direction.  As reported by the BGEP, the cycle is from 4 to 8 years in each direction.
« Last Edit: October 22, 2014, 07:50:00 PM by viddaloo »
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Shared Humanity

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #46 on: October 24, 2014, 07:31:57 PM »
Could the snow cover over Asia be due to the large expanse of open water on the northern coast, certainly the Laptev but the ESS and Chukchi as well. The cold coming from the pole over Asia should be picking up a lot of moisture off this open water.

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #47 on: October 24, 2014, 09:50:18 PM »
Could the snow cover over Asia be due to the large expanse of open water on the northern coast, certainly the Laptev but the ESS and Chukchi as well. The cold coming from the pole over Asia should be picking up a lot of moisture off this open water.

http://earth.nullschool.net/#current/wind/isobaric/850hPa/orthographic=-332.96,91.40,483

At 850mb this suggests there is entrainment of air from the open Arctic Ocean over Asia. Research indicates a role for open water in recent year's large snow advances over Eurasia.

Rutgers data has stopped as of 20 Oct due to the NCEP/NCAR data outage, which is still not resolved. However as of 19 Oct there is a substantial positive snow area anomaly over Eurasia.
http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2014&ui_day=292&ui_set=2

On that page use the single '<' for YEAR to step back to see snow cover anomalies for that date on different years. Currently the anomaly is large.

Nightvid Cole

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #48 on: October 24, 2014, 10:12:21 PM »
DMI seems to be showing that the North of 80 temperatures are one of the hottest autumns on record, I'm expecting to see volume anomaly drop significantly on the next PIOMAS update but time will tell...

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #49 on: October 25, 2014, 12:13:13 AM »
DMI seems to be showing that the North of 80 temperatures are one of the hottest autumns on record, I'm expecting to see volume anomaly drop significantly on the next PIOMAS update but time will tell...
It would certainly make things more normal compared to extent. Average volume has been up all year, while average extent has been down.

Edit: 9% volume refreeze versus 21% extent refreeze, if my estimates are correct. Seems normal, as these figures were 10% and 22% for 2013.
« Last Edit: October 25, 2014, 01:23:03 AM by viddaloo »
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