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Rob Dekker

Neven, thank you. Great overview.
As for your remark about the Bering and the Chukchi :

Yes, all that ice that was used to mislead a couple of extra people here and there in some quarters, is now gone.

Indeed, I was one of these people.
I thought that the harshest Alaskan winter on satellite record would at least slow down the melting rate in the Western Arctic.

But it seems that none of that mattered much. The 2012 situation in the Bering and Chukchi now is most resemblant to 2007, and we all know where that led to..

I am still wondering what this means. Why did a harsh winter not restore pre-2000 conditions in the West-Arctic ? How come this area (which melts out completely in summer) seems to be little affected by the harsh winter conditions ?

With the Western side seemingly without memory of it's winter conditions, and the Eastern side being in a deplorable state (all through winter and increasingly so now), I now once again have become an 'alarmist'.

Misfratz.wordpress.com

Hopefully I'm not boring people by linking to the OSTIA SSTs again, but it's very interesting that the cold SSTs are still there in the Bering Sea/North Pacific, but there are now warmer SSTs to the north.

That cold SST anomaly looks to have been entirely irrelevant, and I certainly find that surprising. I've been surprised by a lot of things so far this melting season, and it's only just the middle of June.

Neven

I was also expecting more of a buffer from that extra ice in the Bering Sea, Rob. Also in the form of warmer SSTs, but as Misfratz shows, this doesn't seem to hold up either. I had already noticed some red and orange spots around Bering Strait on the DMI SST anomaly map:

Rob Dekker

Thanks Misfratz, for that OSTIA link.
The anomaly plot confirms your finding and is most amazing :
http://ghrsst-pp.metoffice.com/pages/latest_analysis/sst_monitor/ostia/anom_plot.html?i=17&j=1
Where did that heat North of the Bering come from ?

Rob Dekker

Thanks, Neven,
Your plot, and Misfratz, seem to suggest that albedo-effect is at least a major factor in that area right now : heat accumulates in open water (mostly in that hole in the Beaufort), due to brutal solar irradiance at this time, and that affects large areas by ocean current and atmospheric transport. Anyone have any other explanations at this time ?

Misfratz.wordpress.com
Where did that heat North of the Bering come from ?
The obvious place to look for it is in the ocean deeps, but I've not been able to find deep ocean temperature analyses far enough north.

The Australian Bureau of Meteorology do have a "global" analysis of ocean temperatures at 150m and 400m, but here "global" = "between 60N and 60S", which isn't far enough north for our purposes.

The other possibility is that a relative lack of snow cover in that area would allow the land to heat up quickly, and then subsequently warm the ocean surface.

Peter Ellis

We go through this every year. The surface heat anomaly is a consequence of the ice loss, not vice versa. This is because the surface of melting ice is held at zero degrees C, while water surfaces can rise above that.

Positive anomalies near the ice edge very simply reflect pixels that are open water this year (above zero) but that are ice-covered in an "average" year (exactly zero). The SST anomaly map gives you no additional information beyond what you can see by looking at the ice concentrations.

To see the real heat input anomalies, you have to look at the water temperatures a little way under the surface, and/or the atmospheric temperatures a little way above the surface, away from the inversion layer that holds everything at zero.

Further away from the ice edge, SST anomalies become more meaningful since you're comparing like with like (water with water).

Mike

Great post Neven, my opinion is that warm currents from the atlantic are flowing under the icepack to the Bering Sea and on the siberian side also. I think the Lomonsov Ridge divides the flow into the two basins and warms the side areas from underneath. I don't know much about the currents in the Arctic and I am merely surmising this as the cause of the melt pattern from looking at the charts. I'm looking forward to further posts on this!

Glacierchange.wordpress.com

I hope you will take a look at Hudson Bay in two or three weeks. Even if we know it will all go, the ice seems poised for rapid reductions. I discussed snowpack around Chruchill Manitoba with researchers from Waterloo University and Sherbrooke Unviersity who noted how thin snowpack was thin this winter. That can both aid is sea ice development and reduces the snow overburden that becomes incorporated in the ice. For Svalbard I notice that the glacier snowlines are not yet rising, Svalbard glaciers

idunno

Hi Neven,

Great post.

I think there is an important difference between some of the "fringe" seas.

In a point much belaboured in some denialist circles, a decline of the ice in the Hudson Bay, say, does not directly affect the Central Arctic.

But in these really marginal seas what do we find this year...

Gulf of St Lawrence anomaly +30
Hudson -150
Okotsch 0
Bering +20

There is then a second category of fringe seas, which are clearly the outskirts of the central citadel of ice in the Arctic Basin and Canadian Archipelago:

Barents anomaly -300
Kara -400
Laptev -180
East Siberian -150
Chukski -100
Beaufort -180

In a third category, I would put the Greenland sea, which is an entirely special case, as the presence of more ice in the Greenland sea is probably bad news for the Central area, as it has probably originated there and been blown South:

Greenland anomaly +50

Lastly, the two areas where we all expect the ice to last longest:

Arctic Basin anomaly -100
Canadian Archipelago -50

All figures taken from eyeballing CT regional graphs.

My point finally being that of the current total area anomaly of 1.6M missing ice, about 1.5M is missing from areas where it leaves the AB/CA central pack in harm's way.

Harvey Puca

The Canadian archipelago was +3 C above average last year... not good for the sea ice up there

http://www.ec.gc.ca/adsc-cmda/default.asp?lang=En&n=77842065-1

Harvey Puca

However 2010 was a real scorcher in the Canadian Arctic

http://www.ec.gc.ca/adsc-cmda/default.asp?lang=en&n=B49D9F0B-1

Wayne Kernochan

@Neven I'm a bit puzzled by your take on the Bering Sea. Eyeballing it in a naive way, it seems to me that the ice above Alaska is much thinner than in previous years (lots of non-purple). Am I missing something?

FrankD

Peter, I agree, and its worth also considering the flip side of that coin - seas with freshly melted ice are actually a little below 0. I think (and its just a think) that areas that are ice covered are weighted to zero (not given a value, but not "null" either. So an area that is on average ice covered will have an average temperature of zero. Where such an area is open water with ice melting in it, it will be measured at below zero, and thus be a negative anomaly, such as in the lower Greenland Sea at the moment).

This is the complementary situation to yours (where the melt zone is displaced a little, water that is at or below zero on average suddenly appears to be quite warm,).

I really like DMI's chart, but you have to be careful with what you read into it. I find Environment Canada's more expansive maps much more useful for interpreting what is going on (although they only have absolute temps, not anomalies). Current days map at: http://www.weatheroffice.gc.ca/data/analysis/351_50.gif

Neven

Nice eyeballing, idunno!

it seems to me that the ice above Alaska is much thinner than in previous years (lots of non-purple). Am I missing something?

Wayne, first of all, UB has switched from AMSR-E to SSMIS, so that may have something to do with it. Second, the sensor could be fooled by melt ponds, and judging by the CAPIE graph (lowest percentage in the 2005-2012 period) there is a lot of melt ponding, probably right in that area where all the clear skies have been lately. Third, the colours don't say everything on SIC maps (whether from UB or CT). They change a lot from one day to the next.

Rlkittiwake

I'm intrigued by the appearance of this ice:

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c03.2012165.terra.250m

This image shows the Chukchi Sea with the north coast of Alaska heading over to Wrangell Island. The area on the far left might technically be the Beaufort Sea; I'm not sure where the boundary is.

Towards the bottom of the left hand side, there's a huge amount of the now-traditional slurry of large floes floating freely in the frigid water.

About a third of the way down, though, it looks like the ice is still in one piece but the weaker areas are vanishing in place. This is counter to how I would have assumed the ice behaved during break up. I would have assumed that in general, the ice became mechanically fractured due to wave swell and the action of the currents, and that the water was not cold enough for the ice to re-consolidate.

From this, however, it looks like the sea itself is warm enough to melt the briny "glue" out from in between purer (older?) areas of ice.

One of the things that I can't get my head around is that the solid-looking area is closer to the coast than the broken area. Maybe it's ice that was transported from north of the Canadian archipelago into warmer waters? But still, why would the area towards the north look worse?

While I'm enjoying the aerial imagery, are these algal blooms, areas of sediment, or both coming out of the MacKenzie River?

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2012165.terra

I know that the areas north of Scandinavia and Eastern Russia can have some staggering blooms in the summer, but I wasn't aware of that happening on the Canadian/American side.


Artful Dodger

Well...

I for one am not convinced by the whole Canadian Archipelago 'Last-of-the-Mohicans' thesis... until/unless somebody provides a theory that simultaneously explains how ALL 4 ocean-terminating ice sheets have melted out, AND the < 5m thick broken and salty sea sea ice survives in place.

That is, explain how this last bastion of rotten ice resists being flushed into either the Beaufort or the N. Greenland Sea to die? Then I'll be convinced.

c.f. Sharp et.al (2011) "Extreme melt on Canada’s Arctic ice caps in the 21st century"

If 100+ vertical metres of rock-hard pure-water ice can't take the heat, why would the sea ice?

Cheers,
Lodger

Evilreductionist.blogspot.com

I know that the current rate of ice melt is exciting, but as of yet it does not seem to me that we have too much clear evidence that this year will break the record. After all, this time last year ice was at a record low and it did not break the record. Weather still has a huge role to play in all this. I think that all we can say at this stage is that the thin late season ice is melting very rapidly, which is something that we expected in any case.

Twemoran

Rikittiwake

'While I'm enjoying the aerial imagery, are these algal blooms, areas of sediment, or both coming out of the MacKenzie River?'

Wonder it the fires around Yellowknife last May/June might have had an effect on water quality. Great Slave Lake can be seen glowing with a rather ghastly green sheen from day 154 forward, and it did look much better in past years.

Terry

Account Deleted

While I agree weather, etc. will have the ultimate say in whether the record fall this year or not. This year is a further 200+ K km^2 ahead of last year in terms of seaice loss from the core arctic area, than the total SIA/SIE figure suggests. We also appear to still be losing sea ice out thru the Fram Strait.

Bfraser

@Frank D.

Artful Dodger recently addressed the issue of the reported temperature of ice:

http://neven1.typepad.com/blog/2012/04/20112012-winter-analysis.html?cid=6a0133f03a1e37970b01630581c6a2970d#comment-6a0133f03a1e37970b01630581c6a2970d

Basically, the temperature assigned to ice is the freezing point of water of the same salinity. So it should never get colder as it melts.

But it could be warmer than usual if the ice is fresher than usual.

Werther

Today The Economist had this on it's site:
http://www.economist.com/node/21556921

Looks like the season is raising some attention. In the last line the author holds on to optimism: 'In the end, the world is likely to get a grip on global warming'.

Account Deleted

The depressing bit are the comments following the article.

Rob Dekker

Peter Ellis said :

We go through this every year. The surface heat anomaly is a consequence of the ice loss, not vice versa. This is because the surface of melting ice is held at zero degrees C, while water surfaces can rise above that.

Thanks Peter, that is certainly correct. However, in this (2012) case the question was where that heat came from that melted that ice in the first placed, considering that the Chukchi went through the harshest winter in satellite-recorded history.

We talked about this previously, and I think you suggested that it was heat imported through the Bering. But Misfratz' OSTIA link clearly shows a strongly negative anomaly for Northern Pacific waters (and has been like that for the past 6 months) so there is less heat coming through the Bering than in 'average' years.

Another suggestion was that the heat that melted (and is melting) the Chukchi is ocean heat flux caused by solar irradiance through the ice, from areas (like the Beaufort) where ice may be anomalously thin, or experience albedo-effects where it is already melted out. I pointed at the under-ice heat flux from flux-buoy25 :
http://www.oc.nps.edu/~stanton/fluxbuoy/deploy/buoy25_deltaT.html

which is located in the ice between the Chukchi and the Beaufort open ocean areas, which shows that there is for sure significant heat running under the ice for the past few months (current running towards the Chukchi).

One could still argue that IF the heat came from ocean heat flux from the Beaufort, that the ice in between should have melted out first, or if it did not, that at least much of that heat should be lost before it reaches the Chukchi.

So I still find it somewhat of a mistery as to why the Chukchi is melting out as fast as other years, even though the winter was the harshest on record.

Could atmospheric heat be the cause ? Have atmospheric temperatures been significantly above freezing over the past month ?

Peter Ellis

Ah, I see. My comment about heat import through the Bering was in the context of looking for explanations for the flux buoy data (more ocean heat flux after it moved from the deep basin into the shallow shelf). As such it's related to general ocean topography rather than the details of any specific year - I have no idea whether any ocean currents will be stronger/weaker/warmer/cooler this year than any other. I am, after all, a random idiot on the Internet :-)

As well as oceanic / atmospheric fluxes as you suggest, a further factor could be snow. A harsher winter may have led to more snowfall around that region, which paradoxically means the ice doesn't thicken up as much as normal due to the insulating effects of the snow, and also leads to increased early melt ponding (decreased albedo) as the snow thaws.

For atmospheric heat in particular, you can find the 850 hPa temperatures here:
http://www.wetterzentrale.de/topkarten/fsavnnh.html

(In the top bar, select "GFS" on the left, then "N-Hemisph." in the middle panel, then "850hPa Temperatur" in the third panel)

This is the temperature at an altitude of ~1.5km, above the boundary layer that gets clamped to zero. You can see that these temperatures are above zero over the Chukchi, and have been for some time.

Rob Dekker

Another point of data as to what is happening on the boundary of the Chukchi and the Beaufort is this Ice Thethered Profile report from ITP53 buoy :
http://www.whoi.edu/itp/images/itp53dat3.jpg

This one is at 74.873° N, 158.1084° W right now, not too far away from from flux-buoy25, and it shows that down to 75 meters, water is warming up significantly over the past few months. Why ? Solar irradiance through the ice ?

Or is it the disruptions in the stratification layer, brings up heat from some 500 meters down occasionally ? That layer also seems a bit 'unstable' lately, which significant saline and heat movements at great depth...

Rob Dekker

Thanks Peter,
Does wetterzentrale also do 'anomaly' plots ?

Kris

Evilreductionist wrote:

After all, this time last year ice was at a record low and it did not break the record.

Depends on your point of view. According to UNI-Bremen and it's method of calculation 2011 is hitherto the minimum extension record year.

UNI-Bremen counted in 2007 the minimum at about 4,4 milions km², whereas NSIDC at about 4,1 millions km².
Thus according UNI-BREMEN the SIE dropped in 2011 under 4,4 millions km² to a minimum record.

And imho UNI-BREMEN methods are as good as those from NSIDC, maybe even better as they are a bit more cautious and reluctant.


Mike Constable

Rlkittiwake

Re: your ice picture http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r05c03.2012165.terra.250m :-

The floes at the bottom left tend to be large and white whereas those a third down are bluer (thinner?) and smaller so may be crushed together at the moment (What later?).

What is amazing to me is that the shore-fast ice at Barrow (top left with isolated ice floe pointing at it) tends to be protected by grounded pressure ridges at the 20m isobath - 60 foot thickness of ice built up and removed most years!

Mike

Phil263

@Colin Maycock

About the article from the Economist :

The depressing bit are the comments following the article.

The scariest part is the "geo-engineering" bit. This utopia seems to be raising its ugly head every time we are confronted with a "too hard to tackle" problem!

Kris

More about Bremen versus NSIDC in the NSIDC september 2011 report. Look under 13 september, fifth paragraph (Other sea ice data ecc ...)

Harvey Puca

I was wondering what effect the earlier and warmer influx of fresh water from the rivers flowing into the Arctic may be causing

Misfratz.wordpress.com

Harvey Puca

I was wondering what effect the earlier and warmer influx of fresh water from the rivers flowing into the Arctic may be causing
Interesting question!

I found this NOAA webpage on Arctic rivers, which states:

The Arctic Ocean receives a large amount of fresh water from river runoff relative to its area, compared to other oceans. There are five major rivers that flow into the Arctic, the Mackenzie and Yukon in North America, and the three largest in Asia, the Ob, Yenisey and Lena Rivers. The Ob and Yenisey Rivers show an increase since the 1980s.
So it's possible that the greater influx of river water is having an influence - let's play with some numbers!

The increase in the annual Yenisey River flow is somewhere between 2,000 and 4,000 (m^3/s), while the increase in the Ob river is smaller than this. I'm going to estimate the combined increase at 4,000 m^3/s.

This is an extra 1.3e11 m^3 of river flow per year, or 1.3e14 kg.

Britannica give peak river temperatures of 14-19C, so it is perhaps reasonable to conservatively estimate a mean temperature for the increased flow of 5C.

The heat capacity of water at this temperature is ~ 4.2 J/(gK), so the heat released by cooling this extra river flow to 0C would be 1.3e14 * 5 * 4.2 * 1000 = 2.7e18 J

The specific enthalpy of fusion of water is 334,000 J/kg, so the amount of ice this heat would melt is 2.7e18 / 3.34e5 = 8.1e12 kg which is roughly 8.9e9 m^3 of ice melted.

At an average thickness of 2m, that is around 4,500 square km of sea-ice melted, every year, by increased river flow, or 90,000 km^2 over the last two decades.

Assuming all my arithmetic has been accurate, that's quite a small (3%), if not infinitesimal, contribution to the overall decline of roughly 3 million km^2 in the September minimum extent over the satellite period.

Climate Changes

The depressing bit are the comments following the article.

...and to find out in WUWT page a copycat of the graphs linked here by Neven. Not sure whether to discredit or else...

http://wattsupwiththat.com/reference-pages/sea-ice-page/


Kevin McKinney

Peter Ellis, I don't know how "random" you may be, but an "idiot" you certainly are not! ;-)

But I'm skeptical of this bit:

A harsher winter may have led to more snowfall around that region, which paradoxically means the ice doesn't thicken up as much as normal due to the insulating effects of the snow, and also leads to increased early melt ponding (decreased albedo) as the snow thaws.

"Harsher" here means "colder," I think, and snow doesn't scale linearly with cold. My belief--I think fairly well-founded--is that snowfall tends to be greatest in temp regimes that are *just* sub-freezing, since really cold air tends to be really dry air, too. In truly "Arctic" winter temps, my guess would be that snowfall is pretty insensitive to temperature variation.

Actual specific, detailed information on this question heartily welcomed...

Pete Williamson

It is intriguing to think about the difference between the Bering Sea and the Barentz Sea beyond just this year.

This is maybe not the best way to display long term trends, there may be seasonal trend and so on, but these two satellite era records from CT of the two seas illustrate the striking difference.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/region.all.anom.region.2.jpg

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/region.all.anom.region.6.jpg

Nevens description of positive feedback loops that go on and on don't really get to the heart of it. Sure you could have annual variability that put a stop to this in the Bering Sea but it appears to be stalled for the whole 30 years.

My bet is like Mike with the avection of heat in Atlantic waters into the Arctic as being the signficant driver here. This eventually makes it all the way to the Chukchi Sea through currents in the Arctic but the Bering Sea is cut off from this process. But I'm below novice on the physical processes of the arctic, I'm ready to be educated.

Matthew Opitz

And meanwhile, the CT SIA massacre continues. Anomaly now at -1.692 million sq km. Area at 8.410 million sq. km.

Otto Lehikoinen

Re:currents in Arctic, this might be of interest, i can't read them well, but probably here are people who can: http://bulletin.mercator-ocean.fr/html/produits/psy3v3/ocean/regions/bull_ocean_arc_en.jsp?nom=psy3v3_20120613_22809

Rlkittiwake

I suppose rain could cause the ice to fall apart in situ. This seems like a more reasonable explanation than freakishly warm water somehow going from the Kara Sea to the Chukchi Sea without passing Go and without collecting $200.

A few days ago there were droplets on NOAA's North Pole Webcams. Maybe it was moisture that fell or blew on the lens and then melted due to internal heat from the mechanism, or maybe it was actual rain at the north pole.

Kris

Rikittiwake wrote:

I suppose rain could cause the ice to fall apart in situ.

No, you (= we all, everybody) can be absolutely sure about it.
Just look at the 26 August - 2 September 2007 report from the Polarstern.

Rob Dekker

Another explanation for the rapid decline in the Chukchi despite a hash winter may be the ice movement :
The Beaufort Gyre is churning nicely clockwise over the past couple of weeks, moving ice away from the Alaskan/Canadian coasts and into the Arctic basin. Not sure if that movement is anomalous in the satellite record, but it surely explains a lot.

My gut feeling is that there are many factors involved, from inceased ocean heat flux in winter keeping ice thinner than during the 'good-old' average years, to increased atmospheric influx (spring temperatures higher than average blowing warm air over the ice margin earlier in the season), increased ice movement due to thinning and reduced volume overall in the Arctic, reduced snow cover increasing atmospheric temperatures over the land, Beaufort gyre spinning earlier and harder than normal, etc etc...

Seke Rob

Saw a report flashing by about the speedup of the Thermohalines in the past 50 years [did not bookmark]. No trouble in thinking that climate change, more heat in, more vapor, more salinity building at surface substantially upsets the balance and stratification [though it's said that the surface heating actually helps to block the colder [CO2 richer] layers to stay down and mitigate CO2 reentry in the atmospheric cycle. The greater power with which the DWF is seemingly now running off Greenland, may though overpower that mechanism. It's a bloody big pump running there... action / reaction. And that by itself if vacuuming in warmer waters from the south dragging it into the Arctic Basin.

Artful Dodger

Rob Decker asked:

"Why did a harsh winter not restore pre-2000 conditions in the West-Arctic?"

I suggest that one factor why the Chukchi sea ice did not thicken as expected was the "Arctic Hurricane" of November 2011. This storm created wave action strong enough to mix the surface layer down to 50 m, thus breaking up the fresh water lens at the surface. Anytime salinity is greater than 30 psu, surface water sinks as it cools, bringing up warmer deep water. Viola, heat source and thin sea ice.

If we ever get a strong depression over an open Arctic Central Basin, one that is strong enough to mix the surface water with the salty layer underneath, well that's game over for future Arctic sea ice. The Arctic will be a new lobe of the Atlantic, and will no more freeze in Winter than the North Atlantic does now.

Rob Dekker

Thanks Lodger,
That storm in Nov 2011 surely stirred up things a bit at that time. I think the estimate was that the immediate effect caused a 2.5 cm ice melt across a wide margin. However, I doubt that it caused much long-tem effects.
Here is ITP bouy 55 again :
http://www.whoi.edu/itp/images/itp55dat3.jpg
The storm occurred around day 316. The bouy data shows that indeed waters got stirred up down to some 75 meters, and it seems that a lot of salt made it to the surface, which did not really 'freshen up' after that.
But I don't see much evidence that the storm had a significant long-term effect, especially noting that this buoy got into the continental shelf area shortly after that, where stratification is less of an issue, and ITP data gets a bit messed up and less trustworthy.

That all said, you are very right that a thorough mixing of deeper ocean waters would mean the end of Arctic sea ice. There have been some papers published on that (threshold, non-linear) effect, and we may wish that we won't get there any time soon. Although that stratification layer is a serious timebomb lurking around to finish off whatever we had left over of thoughts of 'resilient' climate or 'negative' feedbacks and such.

Rob Dekker

Sorry, I forgot to mention the core of my argument : The really significant heat hangs around much deeper, at around 700 meters, and ITP data suggests that the Nov 2011 storm affected these deep ocean layers much at all. Yet.

Artful Dodger

Quite right Rob, it's that 30 psu salinity threshold I'm on about. The storm track of the "Arctic Hurricane" also took it right through the area in question, at a time when summer/fall fresh water run-off is at a low level.

Do you have a link for the track of ITP55? It'd be great to see how close it was to the storm track.

Returning to the OP's question, a couple of other factors spring to mind. CO2 in the Arctic peaked at 400 ppm, and CH4 (methane) at 1950 ppb, possibly much more locally. The equivalent forcing is at least 630 ppm CO2e... that's gonna leave a mark!

Cheers,
Lodger

Rob Dekker

According to the location file from ITP 55's main page :
http://www.whoi.edu/page.do?pid=70997
on day 316 of 2011, ITP 55 was at 153.3793 W 74.2730 N.

Neven's animation of the storm impact :
http://neven1.typepad.com/blog/2011/11/storm-impacts.html#tp
suggests that this location was a few hundred km away from the edge 'flash melt' zone that the storm caused. Which makes the salinity anomaly in the ITP 55 record ever more impressive. But note that the storm was mostly over the continental shelf, not over the deep Arctic. This may explain why deep-water (500 m etc) stratification was not significantly affected.

Incidentally, ITP 53 has since moved into this same area, and shows this profile :
http://www.whoi.edu/itp/images/itp53dat3.jpg

Seems that recent cloud-free conditions cause a lot of heat to build-up in the upper 75 meters under the ice. Can't be good...

Regarding CO2e forcing, the 630ppm you quote would be responsible for some 8 W/m^2 year-around atmospheric forcing. That is very significant, and if you are right, will surely leave a big dent in Arctic sea ice thickness over the long run. For starters, it would explain 2 C of the 2-4 C higher winter temperatures during the Arctic winter that have been observed...

dominik lenné

One humble remark:
I think one of the most important factors concerning melting is solar irradiation. So any reasoning on happening or not happening melting in a certain region should be based on irradiation history of the weeks passed. Unfortunately I dont have one.

Dominik

Artful Dodger

Hi Dominik,

Since the OP's question was regarding Winter sea ice thickening, we can assign a near zero value to insolation during that time. The main source of heat is outgoing long-wave radiation (OLR) from the surface, which consists of a mixture of sea ice and flaws or leads, and some open water early in the season.

However, the main take-away from this discussion is that if the Nov 9-10, 2011 "Arctic Hurricane" provided enough turbulence to thoroughly mix the top 75 m surface layer over large parts of the Chukchi sea, then vastly more heat is available at the surface before freeze-up compared to a stratified surface layer, where salinity remains below the critical value of about 30 psu.

Let's watch how fast it melts!

Kevin McKinney

630 Ce--rather amazing; that's more or less double the pre-Industrial. It's well-known that the best estimate for equilibrium sensitivity to a CO2 doubling is around 3 C, but what I don't recall OTOMH is the transient sensitivity estimates? (They apply globally, not regionally, I presume, but still.)

Evilreductionist.blogspot.com

Transient sensitivity has a central value of 2 degrees.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-6-4-2.html

And according to UAH, the temperature above the Arctic ocean has been increasing by 0.53 degrees per decade for the last 33 years, which translates into an increase of around 1.7 degrees.

http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt

Kevin McKinney

Thanks, ER. That is an interesting tid-bit, to be sure!

Rob Dekker

ER,
That's a great table you got there.
And from UAH (Dr.Spencer) of all sources !
Is that data plotted in any graph form ?
And what is the exact source of the data ?

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