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ChrisReynolds

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Re: The 2014 Melting Season
« Reply #2350 on: July 23, 2014, 09:14:49 AM »
What I do like to know, is what is going to happen volume-wise, especially with all that thicker ice in the core of the ice pack. If things continue like that, we won't be nearing ice-free conditions any time soon.

Neven,

I was going to reply here, but thought that as I've already largely made up my mind it was worth a blog post. The result is here:
http://dosbat.blogspot.co.uk/2014/07/the-slow-transition.html

Basically I think winter ice growth will oppose the factors that have led to strong ice volume loss over past decades. That volume loss is now at an end. We face a relatively slow transition to a seasonally sea ice free state some time late next decade to the 2030s.

F.Tnioli

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Re: The 2014 Melting Season
« Reply #2351 on: July 23, 2014, 11:51:27 AM »
Quote: "To get to a state of near ice free conditions in late summer we will need to see significant thinning of the winter peak thickness, which needs far greater winter warming.".

You forgot the word "soon" after the word "summer"? Because in some ~20 years tops, we'll see ice free Arctic even if April maximums will remain at present levels, i think. Here's why.

Sir, if i am not mistaken, http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAprSepCurrent.png insists that for last 4 years, maximum volume was some 22...23k km^3, while minimum volume was 3,7...5,5 km ^3. From this, i conclude that nowadays, some ~18k km^3 of sea ica melts to water every melt season. Your hypothesis is that max volume won't be dropping any much in the observable future (being FYU and all) - sound one (alas i'm not so sure thermodynamic equilibrium during winter would stay much like it is now - methane clathrates are bubbling, you know). Even if it would, - the quote above does not account for possible changes during melting season, which is the reason i am posting this. The difference is not astronomical: with the same ~22,5k maximums, all it takes to see an ice free Arctic ocean - is melt of extra ~4,5k km^3 of sea ice, which is 25% more ice melt per melt season. Since 1980, melt seasons have strengthened their melting power: an average melt season around 1980 was melting some 15,5k km^3 of sea ice, nowadays some average melt season melts some ~18k km^3 of sea ice, as mentioned above. Important part is, almost all of this increase of 2,5k km^3 - has happened not gradually "since 1980", but after ~2002, i.e. during last 12 years. And with the exception of 2013, this trend was accelerating, too.
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crandles

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Re: The 2014 Melting Season
« Reply #2352 on: July 23, 2014, 12:32:01 PM »
Quote
"To get to a state of near ice free conditions in late summer we will need to see significant thinning of the winter peak thickness, which needs far greater winter warming."
.

You forgot the word "soon" after the word "summer"? Because in some ~20 years tops, we'll see ice free Arctic even if April maximums will remain at present levels, i think. Here's why.

Sir, if i am not mistaken, http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAprSepCurrent.png insists that for last 4 years, maximum volume was some 22...23k km^3, while minimum volume was 3,7...5,5 km ^3. From this, i conclude that nowadays, some ~18k km^3 of sea ica melts to water every melt season. Your hypothesis is that max volume won't be dropping any much in the observable future (being FYU and all) - sound one (alas i'm not so sure thermodynamic equilibrium during winter would stay much like it is now - methane clathrates are bubbling, you know). Even if it would, - the quote above does not account for possible changes during melting season, which is the reason i am posting this. The difference is not astronomical: with the same ~22,5k maximums, all it takes to see an ice free Arctic ocean - is melt of extra ~4,5k km^3 of sea ice, which is 25% more ice melt per melt season. Since 1980, melt seasons have strengthened their melting power: an average melt season around 1980 was melting some 15,5k km^3 of sea ice, nowadays some average melt season melts some ~18k km^3 of sea ice, as mentioned above. Important part is, almost all of this increase of 2,5k km^3 - has happened not gradually "since 1980", but after ~2002, i.e. during last 12 years. And with the exception of 2013, this trend was accelerating, too.

Yes strongly agree with this. Perhaps also mention that if the ice is thinner at maximum then more ice is able to melt due to lower albedo. Therefore the peak volume doesn't have to decline by the full 4.5k Km^3.

The words I would disagree with would be 'significantly' and 'far greater'. A 4k km^3 reduction from 22k km^3 might seem significant but if it has already fallen from 30k km^3 to 22k km^3 perhaps it is more like 'noticeable more' than 'significant' or 'far greater'.

I would say the 'far greater' is particularly bad because there might be other ways of getting the thinning eg more mobility meaning more FYI and less MYI and slower rate of heat loss without necessarily requiring higher temperatures.


(Actually I can't find where quote came from and maybe I should see it in context before commenting.)
« Last Edit: July 23, 2014, 12:40:58 PM by crandles »

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Re: The 2014 Melting Season
« Reply #2353 on: July 23, 2014, 12:42:24 PM »
Just a question Chris.

Did you factor in a smaller winter window for the creation of the FYI?  The trend is clear, melt starts earlier, goes on longer and the re-growth is later.

If the window for FYI is, say, 4 months, instead of 5 or 6, what does this do to the thickness of the FYI?  Would it be more like 1M instead of 2M.  Or somewhere in between?

Just a thought and something you did not mention, that I saw, in your article.
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ChrisReynolds

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Re: The 2014 Melting Season
« Reply #2354 on: July 23, 2014, 01:03:39 PM »
F.Tnioli,

From this post in April:
http://dosbat.blogspot.co.uk/2014/04/what-is-future-of-arctic-sea-ice-part-2.html
Where I look specifically at the Central Arctic, because it is the central Arctic that must melt out to give ice free conditions. By definition ice free at the end of the melt season is when April Volume = Melt Season Loss.

Melt season losses and April volume converge around 2020 assuming that April volume continues to drop.


If I hold April volume level from recent years then the two lines converge in the late 2020s


If I add in the estimated thinning of FYI of 1.5cm/year to the April volume then the projected sea ice free is in the mid 2020s.


However all of that relies on continually increasing melt season losses. This is not guaranteed, nor is it likely in my opinion. A large element of the increased losses is not due to a long term increase in volume loss during the melt season, but is due to step jumps after 2007 and 2010, both years of large volume loss.

Using PIOMAS volume for the Arctic Ocean. The linear fit to 1978 to 2006 volume loss from Aprilm to September has a slope 0.036 (+/-0.21)km^3/yr, so it suggests the trend is postive, i.e. over that period there has been an increase in melt season losses. However the y axis intercept is 11.88k km^3 (where the trend line starts), by 2006 the trend line is at 12.94k km^3. Taking the recent periods and averages of summer losses:

Period_______ Average summer loss
1978 to 1982, 12.54
2003 to 2006, 13.01
2007 to 2009, 14.02
2010 to 2013, 15.16

So while there has been a gradual increase of summer loss over the period 1989 to 2006, the (admitedly short) periods thereafter show step increases of summer loss. I've singled out 2007 and 2010 because they were years of substantial volume loss. This volume loss has led to a thinning of the ice which has aided more rapid melt in the melt season.

Critical is understanding what is leading to the increased loss of volume during melt seasons. It is increased amounts of ice in thinner categories leading to greater open water formation and greater ice albedo feedback. If thickness merely tends to a nominal 2m in April then further gains through April thinning will not happen. The process will instead be more gradual.

Therefore I doubt that seasonal losses will continue to increase as they have done in recent years.
« Last Edit: July 23, 2014, 01:29:46 PM by ChrisReynolds »

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Re: The 2014 Melting Season
« Reply #2355 on: July 23, 2014, 01:12:32 PM »
What I do like to know, is what is going to happen volume-wise, especially with all that thicker ice in the core of the ice pack. If things continue like that, we won't be nearing ice-free conditions any time soon.

Me too!  Take a look at the new (not yet "operational") global HYCOM/CICE/NAVGEM version of Arctic sea ice thickness. Would anyone care to play "spot the difference" with ACNFS? I've asked the obvious question on the HYCOM forum but it has yet to be approved, let alone answered!

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ChrisReynolds

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Re: The 2014 Melting Season
« Reply #2356 on: July 23, 2014, 01:26:55 PM »
Just a question Chris.

Did you factor in a smaller winter window for the creation of the FYI?  The trend is clear, melt starts earlier, goes on longer and the re-growth is later.

If the window for FYI is, say, 4 months, instead of 5 or 6, what does this do to the thickness of the FYI?  Would it be more like 1M instead of 2M.  Or somewhere in between?

Just a thought and something you did not mention, that I saw, in your article.

2007 and 2012 saw massive gains in volume despite delays to the onset of melt. This is because the rate of growth of ice for open water and thin ice is extremely fast. The following graphic is from Thorndike 1975.



It shows how the rate of growth (cm/day) on the vertical axis varies with the ice thickness (horizontal axis). Say you increased the length of the freeze season, you'd get only small increase in thermodynamic thickening because by 1.5m and above the rate of ice growth is small. This is because as the ice thickens it better insulates ocean (warmer) from the colder atmosphere. So for anything over 1.5m thickness, shorten the freeze season even by as much as a month and you get very little impact on thermodynamic thickness, because growth to well over 1m thick is so extremely vigorous, once the sun has set and temperatures plummet.

To get a freeze season as short as 4 months requires us to work back from the peak of volume in April, this is set by the rising of the sun. But we could move it back to March to be on the side of your suggestion. That would need freeze to start at the end of November, at which time in recent years the Arctic Ocean is already ice covered.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=11&fd=21&fy=2007&sm=11&sd=21&sy=2012
In 2007 and 2012 the ocean wasn't ice covered until the end of November.

As GHG levels increase and with further warming an even shorter, warmer freeze season is possible. But much of the warming we have already seen over winter is surface hugging and probably due to thinner ice. We will need a substantial increase in CO2/CH4 to counter the cold of winter, or a sudden appearance of strong cloud radiative feedback, I don't expect either to suddenly increase as much as needed in the next twenty years (e.g. CO2 levels when the Arctic was last winter ice free were at least double pre-industrial IIRC - 160ppm to go before we hit such levels).

crandles

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Re: The 2014 Melting Season
« Reply #2357 on: July 23, 2014, 01:27:46 PM »
Just a question Chris.

Did you factor in a smaller winter window for the creation of the FYI?  The trend is clear, melt starts earlier, goes on longer and the re-growth is later.

If the window for FYI is, say, 4 months, instead of 5 or 6, what does this do to the thickness of the FYI?  Would it be more like 1M instead of 2M.  Or somewhere in between?

Just a thought and something you did not mention, that I saw, in your article.

Probably not directed at me, but:

The nearer the ice gets to its thermal equilibrium thickness the slower it grows so perhaps still close to the equilibrium thickness. Chris Reynolds graphs are certainly showing slight declines in the most frequent thickness peaks eg


I would like to see people discuss what they think are the main causes. I am inclined to think upward heat flux, GHG levels, and winter temperatures rather than size of time window for thickening.

I think it is interesting that there is very little if any thinning of ice less than 1.5m thick. If the ice edge was moving north at all locations, retreat northwards could be suggested as explaining this. However there is only really retreat of the edge at maximum in Barents, land defines the edge preventing retreat northwards in places like Laptev, ESS, Beaufort, Kara ...

If the length of time window was at all important we would presumably see thinning in the thin ice as well as the most frequently occurring thickness.

Having said this I am still a little puzzled by the lack of thinning in the thin ice.



Above looks like there is more thinning than thickening but looking at the data Chris Reynolds provided the change in volume for ice thinner than 1.5m is negligable.

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Re: The 2014 Melting Season
« Reply #2358 on: July 23, 2014, 04:27:59 PM »
Crandles,
The thickness distribution in the thin ice is entirely  a product  of the weather pattern over winter. In the last  three years all the ice up to  2 m on Chris's April graph has melted. So  everthing below that  is simply winter growth.
I'd suggest that the growth of thick ice is a function of the ice's ability to  move away from the Ellesmere/Greenland coast.  This land area protects the ice from warmer water that  effects all the rest  of the ice, it  allows the ice to regrow, ie Winter Freeze is greater than summer melt.  However as the rest of the icepack loses multi-year ice the MYI  of the Ellesmere/ Greenland coast is increasingly  exposed to warmer waters and winds that lead to its collapse.

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Re: The 2014 Melting Season
« Reply #2359 on: July 23, 2014, 04:52:08 PM »
Chris, I don't see any reason for the rate of summer melt increase to flatline, slow down, or even be linear. As the ice thins, the surface/volume ratio increases, which should increase the rate of melt. The thick MYI held off major assaults in 2017 and 2012, but that ice is nearly gone. What we have now is this "mesh ice" that spreads out as the edges melt (which, though it is a negative feedback (because it keeps more of the ocean covered with ice), is a short-lived one). That spreading increases the surface (both top and bottom) that can melt.

ChrisReynolds

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Re: The 2014 Melting Season
« Reply #2360 on: July 23, 2014, 05:20:53 PM »
Bruce,

"As the ice thins, the surface/volume ratio increases, which should increase the rate of melt."

But that's my key point; the ice will not continue to thin as fast as it has done. We've lost all of the MYI that can be lost given that the ice doesn't melt away totally in the summer, now we have a residual MYI in a mainly first year ice pack. The thickness of the FYI is set by thermodynamic thickening over the winter.

See the agreement between the loss of thick ice (>2m) and reduction in CT Area as ice >2m thick has increased.


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Re: The 2014 Melting Season
« Reply #2361 on: July 23, 2014, 05:21:53 PM »
The melt cannot flatline.  Look at the weather in Alert, and it was like this yesterday too:

July 23, 2014 weather report for
ALERT, NUNAVUT, CANADA

    Weather report as of 20 minutes ago (15:00 UTC):
    The wind was blowing at a speed of 11.8 meters per second (26.5 miles per hour) from South in Alert, Canada. The temperature was 12 degrees Celsius (54 degrees Fahrenheit). Air pressure was 998 hPa (29.47 inHg). Relative humidity was 58.0%.

Towns on the North coast of Canada have been even warmer.
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crandles

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Re: The 2014 Melting Season
« Reply #2362 on: July 23, 2014, 05:22:46 PM »
Crandles,
The thickness distribution in the thin ice is entirely  a product  of the weather pattern over winter. In the last  three years all the ice up to  2 m on Chris's April graph has melted. So  everthing below that  is simply winter growth.

Yes agree with that, it is all FYI. But if winter temperatures are warmer since 2007 than before, and GHG levels are higher and upward heat flux is higher, why isn't thin ice in Laptev and ESS getting thinner? Certainly weather can push MYI to different location one year compared to next. Certainly year to year winter weather plays an enormous role and will dominate for a single year change. However, when you average over serveral years in this case (per axis labels) 1986 to 1995 is compared to 2009-2013, why isn't thin ice in Laptev and ESS getting thinner? Maybe 5 years of the latter period isn't long enough of a period to average over? (Seems unlikely with 14 year gap between 10 year period and 5 year period?)


Quote
I'd suggest that the growth of thick ice is a function of the ice's ability to  move away from the Ellesmere/Greenland coast.  This land area protects the ice from warmer water that  effects all the rest  of the ice, it  allows the ice to regrow, ie Winter Freeze is greater than summer melt.  However as the rest of the icepack loses multi-year ice the MYI  of the Ellesmere/ Greenland coast is increasingly  exposed to warmer waters and winds that lead to its collapse.

I wouldn't. I talked of thermal equilibrium thickness before. Thickening above thermal equilibrium thickness is mainly dynamics. I.e. compression causing the ice to get thicker or slabbing. That happens as the general movement is towards CAA/Ellesmere/North Greenland coast not away from it. Growth then is a function of time available in that area to get crushed and thickened and the ice strength/ability to resist crushing. As the ice becomes more mobile it will spend less time there so less time to thicken. However as the equilibrium thickness declines so the strength and ability to resist crushing also declines. That doesn't make it easy to see what will happen in the future. What we have seen so far is a reduction in thickness of the ice (presumably as age of ice declines) but also a reduction in how wide the band of thick ice is along CAA/Ellesmere/North Greenland coast. I suspect this area of thick ice will continue to decline with the width continuing to decline.

I think the maximum volume will continue to decline a little longer and at a very slow rate for a lot longer. This is subject to change - another year with max volume like 2013 or 2014 might persuade me that Chris Reynolds is right.

crandles

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Re: The 2014 Melting Season
« Reply #2363 on: July 23, 2014, 05:37:07 PM »
Chris, I don't see any reason for the rate of summer melt increase to flatline, slow down, or even be linear. As the ice thins, the surface/volume ratio increases, which should increase the rate of melt.

If the winter volume flatlines, why would summer melt increase?

You can't now argue 'as the ice thins' because it will be same thickness with winter volume flatlining.

Surface/volume ratio is useful for speed of ice cubes melting in your drink. However in this case heat is plentiful and it is a matter of how quickly it melts. The Arctic could well be a different situation where there is plenty of time for things to happen but heat availability is limited by the length of the summer.

OK so maybe maybe the effective length of summer increases as snow cover on land melts out earlier. That is not affected by volume of ice at maximum so that can continue.

Note that I don't expect winter volume to flatline - there are still GHG increases, temperature increases, and probably ocean upward heat flux increases.

Because I don't expect winter volume to flatline, I expect summer melt to continue to increase. However I do see lots of potential for the rates of these to slow down.


Nick_Naylor

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Re: The 2014 Melting Season
« Reply #2364 on: July 23, 2014, 06:02:56 PM »
The availability of heat for melting is also very dependent on atmospheric and oceanic currents, which are not so easy to predict. There is already plenty of heat at depth in the Arctic to melt the ice.

It seems certain that as the melting of the thin ice happens earlier in the season, this will lead to more warming in open waters. Is there a critical temperature at which this warm surface water surrounding the ice upsets the existing balance and exposes the remaining ice to a steady flow of warmer water - whether from below or from the periphery?

Similar questions arise related to increased flow and temperature of fresh water from Canadian and Siberian rivers, as the land warms and precipitation becomes stronger.


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Re: The 2014 Melting Season
« Reply #2365 on: July 23, 2014, 06:11:32 PM »
The melt cannot flatline.  Look at the weather in Alert, and it was like this yesterday too:

July 23, 2014 weather report for
ALERT, NUNAVUT, CANADA

    Weather report as of 20 minutes ago (15:00 UTC):
    The wind was blowing at a speed of 11.8 meters per second (26.5 miles per hour) from South in Alert, Canada. The temperature was 12 degrees Celsius (54 degrees Fahrenheit). Air pressure was 998 hPa (29.47 inHg). Relative humidity was 58.0%.

Towns on the North coast of Canada have been even warmer.
And it's likely get much warmer for at least the next few days, especially on Friday. E.g.,

Arctic Bay:
http://weather.gc.ca/city/pages/nu-10_metric_e.html



Normals: min 2, max 8.


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Bruce

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Re: The 2014 Melting Season
« Reply #2366 on: July 23, 2014, 06:21:50 PM »
But that's my key point; the ice will not continue to thin as fast as it has done. We've lost all of the MYI that can be lost given that the ice doesn't melt away totally in the summer, now we have a residual MYI in a mainly first year ice pack. The thickness of the FYI is set by thermodynamic thickening over the winter.
I guess I don't get your point, then. If all the ice is first year ice then, by definition, the ice has completely melted out the previous summer. If the ice isn't all first year, then there remains some MYI, and the volume decrease can continue.

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Re: The 2014 Melting Season
« Reply #2367 on: July 23, 2014, 06:26:43 PM »
Crandles,

"Note that I don't expect winter volume to flatline - there are still GHG increases, temperature increases, and probably ocean upward heat flux increases."

Nor do I expect a flatline, but post 2010 I think we're in a period after an inflection of winter peak volume. 2013 and this year's late start have messed up the pattern somewhat, so I need more years to be 100% sure.

By the way, we now have four years of very similar peak April monthly average PIOMAS volume, that's what's been bugging me since I saw April's data and worked out how similar it was to 2m of ice. All figures below April volume in thousand km cubed.

2000   23.550
2001   24.008
2002   23.700
2003   23.686
2004   22.532
2005   22.657
2006   21.681
2007   20.289
2008   21.141
2009   21.241
2010   20.803
2011   19.323
2012   19.387
2013   19.556
2014   19.287

ChrisReynolds

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Re: The 2014 Melting Season
« Reply #2368 on: July 23, 2014, 06:31:09 PM »
But that's my key point; the ice will not continue to thin as fast as it has done. We've lost all of the MYI that can be lost given that the ice doesn't melt away totally in the summer, now we have a residual MYI in a mainly first year ice pack. The thickness of the FYI is set by thermodynamic thickening over the winter.
I guess I don't get your point, then. If all the ice is first year ice then, by definition, the ice has completely melted out the previous summer. If the ice isn't all first year, then there remains some MYI, and the volume decrease can continue.

No they can't. By definition any year with surviving ice will make multi year ice. But whereas the maximum lifetimes of such ice was of the order of a decade in the past, now the lifetimes are mainly under four years, and it keeps getting replenished. So until we hit zero ice at the end of the summer we will always have a residual of MYI, we are at that stage now. EDIT in italics.

Check out the graph plot on this image:
http://nsidc.org/arcticseaicenews/files/2014/04/Figure5.png
« Last Edit: July 23, 2014, 06:39:07 PM by ChrisReynolds »

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Re: The 2014 Melting Season
« Reply #2369 on: July 23, 2014, 07:22:49 PM »
MYI might actually end up thinner than FYI the year the arctic melts out.

See the Canadian basin last winter the MYI left over from 20143 was mostly 1-1.5 Meters thick and it only grew .3 to .4 meters more.

while new FYI West of their in the Chukchi region grew 2-2.5M.

That MYI being ravished was probably not much different than the FYI at that point but becuase of it being an insulator the ice couldn't out grow the FYI.

So volume wise it's a way to lower volume even further then an entire sheet of FYI.
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Re: The 2014 Melting Season
« Reply #2370 on: July 23, 2014, 07:27:03 PM »
Look at the weather in Alert, and it was like this yesterday too:

It's a bit cloudy today. However yesterday was nice and clear when Landsat 8 passed overhead. Following a brisk stroll from Alert a bracing dip in the Lincoln Sea is there for the taking!
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Re: The 2014 Melting Season
« Reply #2371 on: July 23, 2014, 07:27:48 PM »
The melt cannot flatline.  Look at the weather in Alert, and it was like this yesterday too:

July 23, 2014 weather report for
ALERT, NUNAVUT, CANADA

    Weather report as of 20 minutes ago (15:00 UTC):
    The wind was blowing at a speed of 11.8 meters per second (26.5 miles per hour) from South in Alert, Canada. The temperature was 12 degrees Celsius (54 degrees Fahrenheit). Air pressure was 998 hPa (29.47 inHg). Relative humidity was 58.0%.

Towns on the North coast of Canada have been even warmer.

12C at Alert!?  Yah, no flatline here, and cause no doubt of the ubiquitous melt ponds in the region I see in Worldview.

I saw this in Climate Reanalyzer last weekend. It appears the heat will be entirely as bad as predicted.
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Re: The 2014 Melting Season
« Reply #2372 on: July 23, 2014, 07:44:33 PM »
The 12sz GFS is just flat nasty and delivers a crushing blow to the Pacific side.

This is progged to be by far the warmest air mass of the season this is very similar to the set up 2013 had in the July 7th-18th period when it plummeted.





Stay tuned folks because if this happens like this which the model are in high agreement on things are about to "dramatically" change.

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BornFromTheVoid

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Re: The 2014 Melting Season
« Reply #2373 on: July 23, 2014, 09:34:50 PM »
The forecast strong melt conditions are beginning to inch into the reliable time frame.
One of the important differences between the forecast high pressure and previous high pressure systems we've had in the Arctic this year is that the forecast one has support from mid latitude ridging, which can sustain a feed of warm air into the Arctic.

The strong mid/high latitude ridging doesn't come from central Russia, in fact, it comes up though Pacific. This strong ridge can be seen from the beginning of the ECM run, in the black box on the image below. It has upper level support too (meaning it's more likely to be strong, and last longer), as can be seen with the orange/red colours.



The smaller ridge, moving up from central Russia can also be seen, but it's the Pacific one that has the potential to cause sustained strong melting.

Anyway, as we move forward, we see the Pacific ridge moving toward the Bering Sea, while the weaker Russian ridge moves into the Laptev sea, carrying the first wave of warm air into the Arctic ocean.

ECM t72


Both ridges carry substantial warmth, which can be seen by viewing the temperature at the 850hPa level. The weaker Russian ridge has a smaller pocket of warm air than the Pacific ridge, and so is likely to run out of steam quite early.



As the Russian ridge weakens, it drifts westward and combines with the Pacific ridge, reinforcing it and helping to pull a new wave of warm air into the Arctic, in a very 2007-esque pattern.






It's this feed of warm air, courtesy of the strong ridge toward the Bering strait, that has the potential to start a period of very strong melt. This was one element of the pattern that caused so much damage in July 2007, the other element being a coincident Greenland ridge/-ve NAO which helped to pull the warm air further into the Arctic, while pushing the ice toward the Fram strait (which we're very much lacking this time around).
Still, with the ice as thin and weak as it is thesedays, if the forecast pattern comes off and the Pacific ridge lasts a while, we could well start challenging the bottom 3 years once more.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

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Re: The 2014 Melting Season
« Reply #2374 on: July 23, 2014, 09:38:59 PM »
Check out the graph plot on this image:
http://nsidc.org/arcticseaicenews/files/2014/04/Figure5.png
Unless one takes the last two years as the new trend, an extrapolation of those curves says that the 4-years ice is basically done (i.e., down to a couple percent, which is likely less than the uncertainty in the measurements), the 3-4 and 2-3 year ice is pretty much the same plus or minus a year or two. That really only leaves 1-2 year "MYI" in any quantity and that's maybe 10% to 20%, which could easily get taken out in a warm year -- heck, it could all just float out through the Fram if the wind blows hard enough.

It seems to me that your argument is that since the MYI is mostly gone, we've basically shifted gears into a new quasi-stable equilibrium, and are now approaching "ice free" asymptotically rather than exponentially. Is that a fair characterization?

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Re: The 2014 Melting Season
« Reply #2375 on: July 23, 2014, 09:56:37 PM »
Check out the graph plot on this image:
http://nsidc.org/arcticseaicenews/files/2014/04/Figure5.png
Unless one takes the last two years as the new trend, an extrapolation of those curves says that the 4-years ice is basically done (i.e., down to a couple percent, which is likely less than the uncertainty in the measurements), the 3-4 and 2-3 year ice is pretty much the same plus or minus a year or two. That really only leaves 1-2 year "MYI" in any quantity and that's maybe 10% to 20%, which could easily get taken out in a warm year -- heck, it could all just float out through the Fram if the wind blows hard enough.

It seems to me that your argument is that since the MYI is mostly gone, we've basically shifted gears into a new quasi-stable equilibrium, and are now approaching "ice free" asymptotically rather than exponentially. Is that a fair characterization?

Possibly.  I think it should be noted, we do not need to reach "ice free" before the reduction in ice generally screws up the climate in the northern hemisphere. We already are getting a taste of that.
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Re: The 2014 Melting Season
« Reply #2376 on: July 23, 2014, 10:08:26 PM »
It seems to me that your argument is that since the MYI is mostly gone, we've basically shifted gears into a new quasi-stable equilibrium, and are now approaching "ice free" asymptotically rather than exponentially. Is that a fair characterization?

Broadly speaking, yes.

Got some niggles about the use of asymptotic, but I get why you use the term.

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Re: The 2014 Melting Season
« Reply #2377 on: July 23, 2014, 10:13:01 PM »
Check out the graph plot on this image:
http://nsidc.org/arcticseaicenews/files/2014/04/Figure5.png
Unless one takes the last two years as the new trend, an extrapolation of those curves says that the 4-years ice is basically done (i.e., down to a couple percent, which is likely less than the uncertainty in the measurements), the 3-4 and 2-3 year ice is pretty much the same plus or minus a year or two. That really only leaves 1-2 year "MYI" in any quantity and that's maybe 10% to 20%, which could easily get taken out in a warm year -- heck, it could all just float out through the Fram if the wind blows hard enough.

It seems to me that your argument is that since the MYI is mostly gone, we've basically shifted gears into a new quasi-stable equilibrium, and are now approaching "ice free" asymptotically rather than exponentially. Is that a fair characterization?

Possibly.  I think it should be noted, we do not need to reach "ice free" before the reduction in ice generally screws up the climate in the northern hemisphere. We already are getting a taste of that.

Agreed, nor is ice-free a pre-requisite for large emissions of methane from the East Siberian Shelf. I'm not convinced that is a serious risk (I'm with Archer and others on that subject), but I understand Shakhova & Semiletov, and what they are concerned about does not need ice free conditions. In fact the East Siberian and Laptev seas are already very close to being seasonally ice free, what the rest of the Arctic does is not so important in respect of localised ocean warming over the ESS sediments.

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Re: The 2014 Melting Season
« Reply #2378 on: July 23, 2014, 10:24:02 PM »
Great analysis Bornfromthevoid.


Another factor is the Canadian Basin is already in terrible shape.

This is skewed a bit by clouds but we can see the ESS region is where the work needs to be done.

The ice inside that black box is in a world of hurt already.  We can easily expect 1M of bottom melt over much of that area the next 50 days.







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Re: The 2014 Melting Season
« Reply #2379 on: July 23, 2014, 11:23:58 PM »
Hiya, is there a note of where those three clusters are in the Arctic?  Are they with the O-Buoys, and if so which ones?

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Re: The 2014 Melting Season
« Reply #2380 on: July 23, 2014, 11:26:15 PM »
I've got a reply to my HYCOM/ACNFS questions, courtesy of AlanW on the HYCOM forum:

Quote
The ocean (HYCOM) component of what will be GOFS 3.1 once it is operational has been improved over ACNFS, but the CICE version is the same.  The sea ice differences are 1) the GOFS hindcast started from more realistic initial conditions (primarily a better ice thickness) than ACNFS, 2) GOFS assimilates ice concentration data across the full Arctic domain (not just along the ice edge as in ACNFS).  Neither one assimilates sea ice thickness.

The Global system's Arctic total sea ice volume is closer than ACNFS's to that from PIOMAS.


Here's the (non operational!) GOFS 3.1 version of current Arctic sea ice thickness:



which makes a lot more sense to me than the ACNFS version.
« Last Edit: July 23, 2014, 11:40:30 PM by Jim Hunt »
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Re: The 2014 Melting Season
« Reply #2381 on: July 23, 2014, 11:38:26 PM »
Hiya, is there a note of where those three clusters are in the Arctic?  Are they with the O-Buoys, and if so which ones?

No, they're not with the O-Buoys. For (currently somewhat out of date) locations see:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/#MIZ

If you're really keen you can click through to the MIZ site and check out the current KML file. I keep pestering them for the promised IMB buoy data, but no joy as yet. There are a lot of buoys in the Beaufort at the moment! Those 3 charts show just a small fraction of the data that's being acquired.



« Last Edit: July 23, 2014, 11:46:05 PM by Jim Hunt »
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Re: The 2014 Melting Season
« Reply #2382 on: July 24, 2014, 12:42:16 AM »
If that GOFS thickness map is accurate and we get the forecast conditions we could be on our way to an ice free north pole.  Not only will we see some significant heat, we'll see strong winds blowing right through the hear of the Laptev bite, and with plenty of open water to set up some wave action as well.
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Re: The 2014 Melting Season
« Reply #2383 on: July 24, 2014, 01:04:34 AM »
Thanks for that Chris.

I guess my mind was wondering what happens when the summer/autumn heat budget is so great that the winter freeze over only locks in the heat in the ocean.  At which point a sea that is above -2 is going to melt the ice from below all winter long.  With only the severe cold and accumulated snow keeping the ice above.  In fact more snow will drive the ice further into the warm water creating more melt, rather than growth.

Yes I know it won't happen any time soon and that we see pretty much all the ocean dropping below -2 in the winter; allowing the ice creation to reach 1.5M or 2M pretty early in the season.

I could be wrong, but that heat has to go somewhere.  Yes it can cycle out or dive deep but, at some time, it's going to remain close to the surface.  I'm guessing that point comes when we start to see coastal water temps hitting 12C - 14C for extended periods of time (months).

Maybe I'm jumping ahead a decade or two.  I don't know.  The only thing I can know for sure is that the Arctic is going to surprise the hell out of us every year until it does whatever it does.
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Jim Hunt

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Re: The 2014 Melting Season
« Reply #2384 on: July 24, 2014, 01:35:19 AM »
Yes I know it won't happen any time soon and that we see pretty much all the ocean dropping below -2 in the winter; allowing the ice creation to reach 1.5M or 2M pretty early in the season.

Perhaps I've misunderstood what you're getting at Neil, but the water beneath the ice in the Arctic ocean doesn't "drop below -2 (Celsius) in the winter": http://nsidc.org/cryosphere/seaice/characteristics/brine_salinity.html

"Sea that is above -2"  doesn't "melt the ice from below all winter long" either.  When the air above the ice is -20 and the water underneath it is -1.7 or so the ice just keeps on getting thicker!

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/#2013I
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Re: The 2014 Melting Season
« Reply #2385 on: July 24, 2014, 02:17:07 AM »
Get your tickets to the pain train.  The models keep upping the ridging.

If that happens the ESS is in a wee bit of trouble in a hurry.

The fast ice will go POOF.



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Re: The 2014 Melting Season
« Reply #2386 on: July 24, 2014, 02:21:15 AM »
The models clear the skies over the Pacific side and have about 8-10 days left of 400w/m2.

Still above tropics daily insolation until the end of the first week of August.

Good insolation until the last week of August between 70-80N.

The clock is ticking it will be a race.

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Re: The 2014 Melting Season
« Reply #2387 on: July 24, 2014, 02:25:24 AM »
Hiya, is there a note of where those three clusters are in the Arctic?  Are they with the O-Buoys, and if so which ones?

No, they're not with the O-Buoys. For (currently somewhat out of date) locations see:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/#MIZ

If you're really keen you can click through to the MIZ site and check out the current KML file. I keep pestering them for the promised IMB buoy data, but no joy as yet. There are a lot of buoys in the Beaufort at the moment! Those 3 charts show just a small fraction of the data that's being acquired.
Doesn't the following give their locations?

(from http://www.apl.washington.edu/project/project.php?id=miz).
The Permian–Triassic extinction event, a.k.a. the Great Dying, occurred about 250 million years ago and is the most severe known extinction event. Up to 96% of all marine species and 70% of terrestrial vertebrate species became extinct; it is also the only known mass extinction of insects.

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Re: The 2014 Melting Season
« Reply #2388 on: July 24, 2014, 02:45:49 AM »
If that happens the ESS is in a wee bit of trouble in a hurry.

The fast ice will go POOF.
The ESS fast ice is pretty much going POOF already. If that projected heat hits, the whole ESS is going to go POOF.

On the bright side, if your and BFTV's high pressure materializes, we might get the first good, cloud free, view of the Pacific side that we've had in weeks. If you can call that a bright side.

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Re: The 2014 Melting Season
« Reply #2389 on: July 24, 2014, 03:02:35 AM »
It seems to me that your argument is that since the MYI is mostly gone, we've basically shifted gears into a new quasi-stable equilibrium, and are now approaching "ice free" asymptotically rather than exponentially. Is that a fair characterization?

Broadly speaking, yes.

Got some niggles about the use of asymptotic, but I get why you use the term.
I don't particularly agree with your assessment, but I can see why you would come to that conclusion. I guess time will tell. We should probably agree on what "ice free" means, beforehand, though. I mean, it's going to be hard to get to 100% ice free waterways with Greenland sitting there dumping gigatons of thick ice into the ocean all year every year. But when do you stick a fork in it? At 95% extent reduction from, say, the 1980's average? Or maybe 98% volume reduction? I'm not really sure myself -- but I've been thinking along the 95% or 98% lines. At that point it's unmistakably a new world (not that it isn't already, but you get my point -- nobody could look at it and claim "natural variation").

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Re: The 2014 Melting Season
« Reply #2390 on: July 24, 2014, 03:45:48 AM »
If that happens the ESS is in a wee bit of trouble in a hurry.

The fast ice will go POOF.
The ESS fast ice is pretty much going POOF already. If that projected heat hits, the whole ESS is going to go POOF.

On the bright side, if your and BFTV's high pressure materializes, we might get the first good, cloud free, view of the Pacific side that we've had in weeks. If you can call that a bright side.

I find it exciting.  No reason to fret over it.  It's way out of my control.

18z GFS ensemble mean is brutal.



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Re: The 2014 Melting Season
« Reply #2391 on: July 24, 2014, 03:55:57 AM »
This melt season is so very interesting to me.  I know it's never going to be in 2012 territory, but the more images of the ice I see, in conjunction with compaction and dispersion in other areas, the more I wonder about the current area stats.  Not that I doubt them to be incorrect, but rather not as telling about the condition of the ice.  It just seems so frail this year.  I remember Top Gear did a race to the pole (magnetic) not that long ago. I feel as though that would be near impossible at the moment given the fragmented state of the ice.  Moreover, I'm extremely interested to see how the models play out, as the heat looks to build substantially from this rather mild summer.  Lastly, It's also interesting seeing how ice has again flowed into Barrow...I feel as though that ice is going to melt out before the refreeze begins.
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Re: The 2014 Melting Season
« Reply #2392 on: July 24, 2014, 07:21:36 AM »

"Sea that is above -2"  doesn't "melt the ice from below all winter long" either.  When the air above the ice is -20 and the water underneath it is -1.7 or so the ice just keeps on getting thicker!


From a number of old research articles, the rule of thumb I worked out was that you'll get approximately 10CM of ice per degree C below the freezing point of seawater (about -2C).


So NeilT, -20C would produce ice about 180CM thick.  The insulative qualities of ice impede heat flow such that ice can't thicken much past that - heat flow from the ocean prevents the phase change at the bottom of the ice.  Ice much thicker than 3M requires ridging in any event; the ice places such a cap on heat flow there's just too much energy available.

Now, without heat input from somewhere, you'll not get anything but the most trivial bottom melt if the temperature rises. No continuous bottom melt in the middle of winter.

My sense of things watching events in the past is, you don't really get a lot of bottom melt until the ice reaches thermal equilibrium with the water it is sitting on - namely, reaches about -1.8C.

Once that happens, more of the energy input into the system can get directed towards causing a phase change rather than raising temperature.
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F.Tnioli

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Re: The 2014 Melting Season
« Reply #2393 on: July 24, 2014, 08:59:23 AM »
...
(Actually I can't find where quote came from and maybe I should see it in context before commenting.)
It came from the link provided by the author of the post directly prior to mine, i.e. from http://dosbat.blogspot.co.uk/2014/07/the-slow-transition.html . I believe i did not miss any important context when quoting the part i quoted, too.
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Re: The 2014 Melting Season
« Reply #2394 on: July 24, 2014, 10:27:56 AM »
F.Tnioli,

...
However all of that relies on continually increasing melt season losses. This is not guaranteed, nor is it likely in my opinion. A large element of the increased losses is not due to a long term increase in volume loss during the melt season, but is due to step jumps after 2007 and 2010, both years of large volume loss.
...
Critical is understanding what is leading to the increased loss of volume during melt seasons. It is increased amounts of ice in thinner categories leading to greater open water formation and greater ice albedo feedback. If thickness merely tends to a nominal 2m in April then further gains through April thinning will not happen. The process will instead be more gradual.

Therefore I doubt that seasonal losses will continue to increase as they have done in recent years.
I doubt it too, but not in a way you do. My doubt is related to the lack of complete knowledge of all possible major factors which influence Arctic melt mode. There is, if small, possibility that anthropogenic (man-made) change may be a major factor - few years ago, i've seen a part of a very serious discussion of a few very serious scientists which i (nor any member of general public) was not supposed to be able to see, and it mentioned that "we have to start it in 2013, otherwise it'd be too late" - they were talking about cooling the Arctic artificially. I do not exclude the possibility that they actually started to do it, exactly in 2013 indeed.

But other than that, i think you are missing some important factors which accelerate summer melt even when practically all ice is FYI:
 - the change of average chemical composition of FYI in recent years. Generally, afaik, average salt content of the ice is increasing, and i believe this leads to easier melt (ice melts at lower temperature);
 - naturally fluctuating SSTs for most of world ocean, and influence of this fluctuation upon Arctic. Most simplifying, one can relate to El-Nino / La-Nina events, http://ggweather.com/enso/oni.htm . As you see, 2007 and 2010 volume drops relate very nicely to distinct peaks of SSTs worldwide. There is some time lag and variability - the fraction of warmer near-surface water energy which ends up in Arctic is different every time, and paths are not the same - sometimes it takes longer for much El-Nino heat to arrive to Arctic than other times. Yet, general correlation is definitely present. Well, last ~1,5 years were rather calm, and luckily, possibility for a strong El-nino starting early this summer did not materialize, but current reports ( http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf , etc) indicate some 80% probability of El-nino this fall. If it happens, - even moderate-strength El-nino may result in yet another massive drop of minimum annual volume some time in 2015 or 2016. You shouldn't exclude such drops - these are a very part of average trend; if you exclude such years, then also at least exclude same number of years which had most freeze up - and then calculate;
 - vast areas of shallow Arctic continental shelf are now open to sunlight for a large part of high insolation months. Those will release methane in rapidly increasing amounts. Some already do, since ~2010. We talk ~hundred million of tons of the gas - annually. For now. In some 10...20 years, it may get to Gt-scale. I hope you do know GHG properties of methane. If you do not, you should. What's not usually mentioned, though, is the local effect. See, methane GHG potential is multiplied by high insolation during Arctic June/July, - i mean that the more energy comes in per day, the more energy (in absolute numbers) end up being trapped by the same amount of GHGs. Plus, local concentrations are, of course, much higher than worldwide averaged methane content, - this is also sometimes forgotten. Last but not least, local warming above/at Arctic shallow continental shelves which contain much methane clathrate not far from seabed, - will of course create self-reinforcing feedback: the more methane ends up in the air in the region (for a substantial time) -> the more energy is trapped by this methane's GHG effect -> the faster warming goes -> the faster methane gets released. In a sense, now-nearly-complete loss of MYI was one big thing shaping the mode of Arctic melt, yes, - but methane release in Arctic is likely to become the "next big thing", you see. If you are not familiar with dr. Shakhova and dr. Semiletov papers and interviews - perhaps you'd like to seek them: those are scientists who are working there, in the field, in Arctic, and their work is much about methane clathrates (among other things). Findings are not exactly... encouraging.
 - Thermal inertia and recent massive warming of Arctic. See, Arctic surface temperatures rised up much higher than world average during late 20th century and 2000s ( http://appinsys.com/globalwarming/RS_Arctic_files/image026.gif ). Estimates vary, somewhat; personally, i estimate Arctic is now some ~3,5C above pre-industrial, if not more. And most of this change happened after 1990. Thing is, thermal inertia is a huge thing in all large things oceanic. Arctic is not an exception. Again, estimates vary, but general agreement is some 30...40 years - is the time which is required for any deep ocean to get saturated with heat enough to approach the new equilibrium. During this time frame, ocean absorbs much of the energy which otherwise would go towards increasing surface temperatures. But obviously, as it does so, - it loses its potential to do so (granted that forcing would become stabilized - which is, of course, not the case; i am just trying to illustrate physics of it). End result is: what melt we've seen so far - is mostly the result of things done some 25+ years ago; things done since then - in 1990s, in 2000s, and last few years, - are mostly not yet reflected by the state of Arctic ocean (and thus, its ice). Yet, we know what were the things done during last ~25 years - namely, mankind emitted about as much carbon dioxide as it did during all of its previous industrial history (yep, just in 25 years or so!); massive increase in forest fires average strength and amount, resulting in more CO2 into the air; methane content has rised, too; industrial and transport activities in Arctic more than doubled.

How exactly you can expect any sort of stability in such conditions - is beyond me. Sure, it's possible theoretically - if humans would indeed geoengineer in the Arctic powerfully enough, and/or if the Sun suddenly would get cool enough, or, say, if good aliens would arrive to Earth and lend us a hand of knowledge and galactic friendship, for a funny example. Because if things go "on their own" - Arctic already has more than needed to see it ice-free in about some 5...10 years, the only thing preventing it from being ice free right now (by the end of the summer, of course, - not year-round) - is thermal inertia mentioned above...
« Last Edit: July 24, 2014, 11:02:31 AM by F.Tnioli »
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crandles

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Re: The 2014 Melting Season
« Reply #2395 on: July 24, 2014, 11:29:50 AM »
- Thermal inertia and recent massive warming of Arctic. See, Arctic surface temperatures rised up much higher than world average during late 20th century and 2000s ( http://appinsys.com/globalwarming/RS_Arctic_files/image026.gif ). Estimates vary, somewhat; personally, i estimate Arctic is now some ~3,5C above pre-industrial, if not more. And most of this change happened after 1990. Thing is, thermal inertia is a huge thing in all large things oceanic. Arctic is not an exception.


Again, estimates vary, but general agreement is some 30...40 years - is the time which is required for any deep ocean to get saturated with heat enough to approach the new equilibrium
(my bold)

Probably not a perfect exception but

Ice at surface holds the temperature to freezing. Before freezing recommences in the winter, most of the heat has to be lost. I am not entirely sure how deep a column this applies to. Likely some heat is accumulating below this depth, but with water generally sinking rather than rising, I suspect any effect at surface is pretty weak. Certainly I don't expect some bombshell hitting the Arctic after 30-40 years of GW.

Could we get a moderator to split off all the posts about Chris Reynolds 'Slow Transition' blog entry? It all relates to later years than 2014 in this thread.

F.Tnioli

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Re: The 2014 Melting Season
« Reply #2396 on: July 24, 2014, 11:32:08 AM »
...
As GHG levels increase and with further warming an even shorter, warmer freeze season is possible. But much of the warming we have already seen over winter is surface hugging and probably due to thinner ice. We will need a substantial increase in CO2/CH4 to counter the cold of winter, or a sudden appearance of strong cloud radiative feedback, I don't expect either to suddenly increase as much as needed in the next twenty years (e.g. CO2 levels when the Arctic was last winter ice free were at least double pre-industrial IIRC - 160ppm to go before we hit such levels).
I do - with a caveat that it won't be CO2 per se, but CO2e (CO2 equivalent, which includes CO2 itself, methane, N2O and (insubstantial so far) other GGHs). In 1998, world athmosphere was at 412 ppmv CO2e (source: IPCC). In 2012, world athmosphere was at 509 ppmv CO2e (source: Blasing, T.J., Current Greenhouse Gas Concentrations). By 2020, it may well reach 600 ppmv CO2e, given the shape of the trend. Plus there is the local amplification above major GHG emissions sources, as mentioned in my previous post.

Pre-industrial athmosphere was some ~320 ppmv CO2e or so, i believe.
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F.Tnioli

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Re: The 2014 Melting Season
« Reply #2397 on: July 24, 2014, 11:35:24 AM »
...
Could we get a moderator to split off all the posts about Chris Reynolds 'Slow Transition' blog entry? It all relates to later years than 2014 in this thread.
I disagree. It all relates to this melt season as well as to future and past ones. Without understanding wider picture, one can't be competent about the present events. Mathematician would say: without knowing the function, one can not calculate a value.

Mighty grateful to Chris for bringing those issues in - no matter i disagree with him on some detail. He's done a great thing for this thread, imho. He should be thanked, not separated.
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F.Tnioli

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Re: The 2014 Melting Season
« Reply #2398 on: July 24, 2014, 12:16:51 PM »
- Thermal inertia and recent massive warming of Arctic. See, Arctic surface temperatures rised up much higher than world average during late 20th century and 2000s ( http://appinsys.com/globalwarming/RS_Arctic_files/image026.gif ). Estimates vary, somewhat; personally, i estimate Arctic is now some ~3,5C above pre-industrial, if not more. And most of this change happened after 1990. Thing is, thermal inertia is a huge thing in all large things oceanic. Arctic is not an exception.


Again, estimates vary, but general agreement is some 30...40 years - is the time which is required for any deep ocean to get saturated with heat enough to approach the new equilibrium
(my bold)

Probably not a perfect exception but

Ice at surface holds the temperature to freezing. Before freezing recommences in the winter, most of the heat has to be lost. I am not entirely sure how deep a column this applies to. Likely some heat is accumulating below this depth, but with water generally sinking rather than rising, I suspect any effect at surface is pretty weak. Certainly I don't expect some bombshell hitting the Arctic after 30-40 years of GW. ...
Sure, ice-covered areas/times are different, insulating is a major factor, yes. Still not an exception though, since we talk warming - i.e., increase of open water areas/times. In such areas and at such times, it is open water - much like any other ocean. There are important details to it, of course - http://en.wikipedia.org/wiki/Brine_rejection is one, and high albedo during spring is another. The former reduces thermal inertia, the latter increases it, in terms of the whole Arctic ocean. In general, it's still about few decades, i believe - heat capacity of the 0...100m water layer of the Arctic ocean is tremendous: it is ~1,4 millions cubic kilometers of water, specific heat capacity of water near 0...10C is some 4,2 J/g*K, which means that in order to increase the temperature of this near-surface 0...100m layer of Arctic ocean by just 1 degree celcius (annual average, of course), one would need to spend 4,2* 1,4 * 10^6 //"millions"// * 10^9 //cubic kilometers to tons// * 10^6 //tons to grams// = 5,9 * 10^21 joules of energy. And this value is completely independant from means of delivery of said amount of energy: it does not matter how you put the energy into that layer of water, in practice, it is a combination of direct solar input, secondary solar input (such as re-radiated by seabed of shallow continental shelves absorbing some direct sunlight which penetrated shallow waters), ocean currents from sub-polar and other for any reason warm regions, precipitation, air currents, geothermal, volcanic and, of course, secondary radiation of GHGs. Some of these "delivery methods" even work despite the ice cover, to some or even full extent.

The calculated amount of energy is, again, for just 1C average annual increase of said 0...100m layer of water in the Arctic ocean. Perspective: it is equivalent to nearly 12 times higher amount of energy than the whole mankind energy consumption as of 2010 - and yet in the same time, it is "only" 0,59% of the total Sun's energy hitting Earth each year.

Of course, annual losses of near-surface energy (ultimately radiated back into space) nearly even out the input. And, obviously, Arctic is not "whole Earth", and there is high albedo of snow and ice for much of high-insolation months, too. That's why and that's how Arctic ocean, much like any other ocean, serves as a "heat absorber" for several decades after any substantial energy balance change towards warming. But with every passing year, as it gets saturated (relative to initial condition, whatever starting point you set), - its ability to absorb more heat decreases gradually, resulting in more heat ending up warming the surface (which is what we are most interested in, of course).

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crandles

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Re: The 2014 Melting Season
« Reply #2399 on: July 24, 2014, 12:42:56 PM »
Separate into a new thread was not meant to imply a downgrade. I agree Chris Reynolds should be thanked for his carefully researched and thoughtful contributions.

I thought a separate thread would allow fuller discussion without getting in the way of talk of what is happening imminently and prevent this getting lost in a few months time in amongst all the discussion of the latest happenings. It is because it is important enough that I don't want it to get lost which it surely will when this thread is already up to page 49.