The 2015 melting season

[Killian]

Killian, 6roucho,

Critical slowing is a decreasing recovery from perturbations...

Forgot to attach this look at possible bifurcations in the Arctic over time, perhaps giving you some periodicity to play with.

[Gonzo]

greatdying2

2015 is getting very close to both 2011 and 2007 on this NSIDC chart.

That's a serious attempt at correction on their part, combined with a fast collapse over the last month. None of these models are all that good until the cloud clears and they get to double-check them visually. Most places have had some clear skies in the last week or so, and they are making corrections. It will continue, as the cloud clears. Then they will continue to follow the downward march moving fast towards 2012.
 3-4 weeks melting season left, due to warmest year on record globally, warmest waters, etc.

[jdallen]

Every run of GFS looks very different so far out, and hence I have very little confidence in this 12:00 version, but....

Wuf!

GAC 2.oh.  A bit late, so the impact on extent and area is less certain.

But as you say, the runs have been inconsistent.

Now, I suggest we keep track of the 3 (!!!!) cat 4 Cyclones active in the Pacific.  They may have an influence on Arctic weather in a few days.

[OldLeatherneck]

******************SNIP*************
 3-4 weeks melting season left, due to warmest year on record globally, warmest waters, etc.

I wouldn't count on there being 4 weeks left to the melt season. The date that ADS (IJIS) Extent has reached annual minimum during the last twelve years has varied between September 9th and September 21st.  I understand that AGW is going to eventually lead to longer melting seasons, but I see no reason to believe that there will be a full week of additional melting in 2015. My gut feeling is that extent will not hit it's minimum before the 15th and might even be a day or two later that the 21st, but I would be shocked if the minimum occurred after 24th or 25th.

However, this is the Arctic and we've all been surprised before.

[Gonzo]

Not sure what the MS Bremen passengers are all looking at.
Up in the Laptev Sea, Siberian islands today.
Webcam
http://www.hl-cruises.com/nc/ships/ms-hanseatic-ms-bremen/expedition-ships/ms-bremen/webcam-ships-position

[plinius]

Well, if you look into the programme of such a cruise, I suppose that even a couple of scattered ice floes will be a relief. At least I would do hard with the "entertainment" on these things and probably spend all my time looking at the waves... So, would think they are looking just at ice floes.

[slow wing]

U. Bremen's update shows most of the action on the Pacific side. The Beaufort Arm and shoulder continue to dissolve away. Quite a bit of ice has disappeared from near the CAA, although much of that was peek-a-boo ice that had re-appeared yesterday.

The main channel of the Northwest Passage is looking quite open as well, although there is a whole thread on that topic and e.g. Worldview would give a more accurate picture.

Click on gif to crossfade between the concentration maps for the past 3 days...

[Adam Ash]

Not sure what the MS Bremen passengers are all looking at.

...or Mr Putin's flag bobbing on a foaming lump of calthrate?   

[diablobanquisa]

New ice at the Laptev Sea?

08/29:


08/31:

[Glenn Tamblyn]

Latest from Climate Reanalyser has this



Sure its a few days out, but the leadup to it is interesting. Spins up in the Kara then moves across above the Laptev & ESS. Perfect for some flash-melting in the remaining holdout regions.

[F.Tnioli]

Not sure what the MS Bremen passengers are all looking at.

...or Mr Putin's flag bobbing on a foaming lump of calthrate? 

Speaking of calpthrats (hehe), any idea whether and where data from those two points would be available to the public?

[seaicesailor]

Really, it's a very long list. There is no one mechanism, there is just all kinds of bad stuff going on moving in and out of phase. Had we had 2007 weather this summer, new lows in area and volume, guaranteed. But we didn't. We had the third in a string of cool summers with relatively little transport via Fram - itself perhaps a developing hysteresis on melt rate.

The ice is preconditioned (from the bottom up, imo): It's popcorn throughout, with some exception in the upper center opposite Greenland/Canada. Thicker floes sitting in mush. I've talked about this and the bottom melt and thinning a lot, but not here. I think the volume models are way off.

Cheers

This Summer was very warm for the Northern Hemisphere and for the Arctic in particular. Google "global temperatures NOAA" if you wish. As for the Arctic, see the current SSTs, for instance (I don't mind cherry-picking this time)

BTW, right now this map shows an interesting fact: the area of ocean heat excess that is contributing most to direct melting right now is that yellowish area in Beaufort/Chukchi, because even when there is just 1 C of above average temperature, this will keep bottom and lateral melt of dispersed and broken ice for a good while (google "ITP buoy arctic" and "mil buoy arctic" and "greatwhitecon").

Nice image Diablobanquisa. See in the map green/blueish area around the Laptev's bite's bite.

[Jim Hunt]

Latest from Climate Reanalyser has this

Currently Metociel GFS looks like this next Monday:



whereas ECMWF looks like this:



Not exactly 100% agreement just yet!

[Glenn Tamblyn]

Jim

The interesting possibility isn't just the outcome at the end of the prediction period but the trajectory getting there. Bashing the CAB above Laptev and CAB above ESS is probably the biggest remaining wild-card this season.

[Pi26]

Really, it's a very long list. There is no one mechanism, there is just all kinds of bad stuff going on moving in and out of phase. Had we had 2007 weather this summer, new lows in area and volume,

This Summer was very warm for the Northern Hemisphere and for the Arctic in particular. Google "global temperatures NOAA" if you wish. As for the Arctic, see the current SSTs, for instance (I don't mind cherry-picking this time)

BTW, right now this map shows an interesting fact: the area of ocean heat excess that is contributing most to direct melting right now is that yellowish area in Beaufort/Chukchi, because even when there is just 1 C of above average temperature, this will keep bottom and lateral melt of dispersed and broken ice for a good while (google "ITP buoy arctic" and "mil buoy arctic" and "greatwhitecon").

Nice image Diablobanquisa. See in the map green/blueish area around the Laptev's bite's bite.

For the rest of the world the Arctic Airconditioner always seems completly melted, as soon it requires its ice mostly to cool its local waters and air. Seems currently already from beginning of August?

[Gonzo]

diablobanquisa

New ice at the Laptev Sea?

It looks like it just blew in there during the week.

[meddoc]

Really, it's a very long list. There is no one mechanism, there is just all kinds of bad stuff going on moving in and out of phase. Had we had 2007 weather this summer, new lows in area and volume,

This Summer was very warm for the Northern Hemisphere and for the Arctic in particular. Google "global temperatures NOAA" if you wish. As for the Arctic, see the current SSTs, for instance (I don't mind cherry-picking this time)

BTW, right now this map shows an interesting fact: the area of ocean heat excess that is contributing most to direct melting right now is that yellowish area in Beaufort/Chukchi, because even when there is just 1 C of above average temperature, this will keep bottom and lateral melt of dispersed and broken ice for a good while (google "ITP buoy arctic" and "mil buoy arctic" and "greatwhitecon").

Nice image Diablobanquisa. See in the map green/blueish area around the Laptev's bite's bite.

For the rest of the world the Arctic Airconditioner always seems completly melted, as soon it requires its ice mostly to cool its local waters and air. Seems currently already from beginning of August?

Yes, that may be true for the ice itself. But the cold air being held by it in one place it's another story. The jetstream anomalies are expected to ramp up exponentially as soon as the ice is gone.
Making weather chaos in the NH permanent.
And we haven't touched on the issue of clathrates.

[Bruce Steele]

Seaicesailor, For some buoy data specifics on those Beaufort surface anomalies we have ITP buoy# 82 at 77.9 N with surface temperatures in range of  - 1 to -1.2 and for ITP buoy # 85 at 74.8 N there has been a heat spike for surface temps at above 0 to -.2 at 6 meters. This buoy continues to set records exceeding anything in the entire record of water temperatures recorded in the Beaufort Sea for theITP dataset.
 These buoys are set in ice so although surface waters may exceed the numbers above these temps record what is happening under the ice pack.

 http://www.whoi.edu/page.do?pid=139056

[F.Tnioli]

Seeing snow cover through NPEO webcams, i wonder how much insulation early snow could provide through the winter in areas like the pole - ones which had large melt ponds, open water, barely a week ago or so, but now are covered by (visibly) significant amount of snow. If that snow won't melt this year - which, i guess, is likely - and if more snow would be added on top before real cold air of polar night sets in, i wonder how thinner ice would end up being there by the start of the next melt season. One more thing to be worried about when 2016 melting season gets sunny, eh...

[ChrisReynolds]

Killan,

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

Looking at every small blip in the CT Area graph is, I am sorry to have to say, a prime example of the sort of loose throwing around of poorly understood terminology I was complaining about. The only evidence you could cite for bifurcation in all that you marked is the 2007 sea ice loss (Livina & Lenton). But even with Lindsay & Zhang's suggested 1990s 'tipping point', I find it hard to view that as a proper bifurcation (with hysteresis) as nothing in their work suggests it was harder to reverse than to play out. 2013/14 suggests that a mere run of cold weather could have reversed it.

And this is the primary problem with your pointing out all those little ticks in the decline, having read a substantial amount of the published science on sea ice bifurcation behaviour (in models), I struggle to see more than weather driven blips, apart from the 2007 event (which was weather driven - but a bifurcation can be stochastically forced).

False. You are talking about proving, or at least getting to viable theory. We are talking on a blog. Nobody said it *is* a coming bifurcation, only that it looks like one.

Sorry, my mistake. I guess it comes from my drive to comprehend what is going on. As a lifelong nerd I have never really grasped the point of idle chatter.

[ChrisReynolds]

From the Beaufort Gyre project:
These studies indicate that the Arctic Ocean surface layer currents are consistent with the Arctic atmosphere surface layer motion, alternating between cyclonic and anticyclonic circulation regimes. Each regime persists from 4 to 8 years, resulting in a period of 8-–16 years. The cyclonic pattern dominated during 1989-1996. Since 1997 the dominant regime has fluctuated, with an anticyclonic pattern being more prevalent (Fig. 1). Figures 1-9 show annual simulated wind-driven surface ice and ocean motion for 2000 through 2008. The Arctic Ocean Oscillation index (bottom panel in Figure 1) illustrates alternation of circulation regimes at a period of 8-16 years. During anticyclonic circulation regimes the BG region accumulates fresh water and during cyclonic regimes the BG region releases fresh water and this water could be available for transportation to the North Atlantic via Straits of Canadian Archipelago and Fram Strait.

 It's possible we've seen a reduction in the circulation time post 2007.

Well that discussion of regimes is about atmospheric regimes, which I don't view as a likely candidate if the apparent emergence of a 4 year cycle in August losses is correct. The problem it that aside from seasonal cycles I can't think of a dead regular cycle in the atmosphere (or ocean), which is why I homed in on sea ice transport. This transport won't be dead regular but might be regular enough to cause a 4 year cycle which when acted upon by the dead regular cycle of insolation 'cuts off' any dither in the underlying ice motion cycle.

Anyway, I'm putting the issue aside and waiting to see what happens in August 2016. (And yes Sea Ice Sailor - I do now expect strong losses in August 2016)

PS - forgot to add, see this page (again).
http://www.whoi.edu/page.do?pid=66596
The schematic on the right shows interplaying factors, any of these, or more likely all together might cause a regular four year cycle.

[Killian]

This Summer was very warm for the Northern Hemisphere and for the Arctic in particular.

If you say so. But....
http://ocean.dmi.dk/arctic/meant80n.uk.php

[Peter Ellis]

Chris:  If I understand the ice drift hypothesis correctly, it is that the Beaufort gyre takes (approximately) four years for one full "turn".

That means we can regard the gyre effectively as four quadrants, each of which may have different melt characteristics due to different proportions of MYI.  When a particularly "tough" quadrant rotates into the Beaufort, that year will have substantially reduced melt in that area - and when a particularly "delicate" quadrant is present, you see a high melt year in the Beaufort.

If so, then it should be quite easy to spot that in the ice age model.  If you take  the images from (say) April of each year, and average the age of the ice in the Beaufort region, is there a four-year periodicity, and does it correlate with high- or low-melt years?

Another possibility that follows from this model is that years with particularly high weather driven-losses in one region will impact other regions further down the line.  For example, if the Beaufort has high melt in year 1, then the Chukchi will have weaker ice in year 2 and be more susceptible to melt that year.  The next year, the ESS might in turn be more vulnerable, and so on.  This might show up in the general anomaly plots - is there a correlation between ESS extent in one year and Chukchi extent the previous year, or Beaufort extent the year before that?

[Killian]

Sorry, my mistake. I guess it comes from my drive to comprehend what is going on. As a lifelong nerd I have never really grasped the point of idle chatter.

But being rude is OK.

Got ya.

Here's my rude comment back: More than once in my life I have been ahead of the science. Implying we know enough of the complexity of the global/arctic system as to know what you, or the studies noted, claim, rather than it being educated guessing, essentially, is hubris defined.

It's fine to tell me the evidence is weak, it is another to impugn my approach.

And I repeat: Looks like is not is. Get that before bothering to respond again. You have literally added nothing to the discussion that wasn't already implied, rather implicitly, by the use of that simple phrasing. Say the evidence is weak, don't be patronizing about it.

[diablobanquisa]

diablobanquisa

New ice at the Laptev Sea?

It looks like it just blew in there during the week.

I´m pretty sure that it's new ice, although of course I could be wrong.

[jdallen]

Sorry, my mistake. I guess it comes from my drive to comprehend what is going on. As a lifelong nerd I have never really grasped the point of idle chatter.

But being rude is OK.

Got ya.

Here's my rude comment back: More than once in my life I have been ahead of the science. Implying we know enough of the complexity of the global/arctic system as to know what you, or the studies noted, claim, rather than it being educated guessing, essentially, is hubris defined.

It's fine to tell me the evidence is weak, it is another to impugn my approach.

And I repeat: Looks like is not is. Get that before bothering to respond again. You have literally added nothing to the discussion that wasn't already implied, rather implicitly, by the use of that simple phrasing. Say the evidence is weak, don't be patronizing about it.

Calm, everyone. Let us move on.  I suggest a private email exchange to sort out any remaining differences.

[Buddy]

If you say so. But....
http://ocean.dmi.dk/arctic/meant80n.uk.php

If you take a look at the DMI charts for 2015, 2014, 2013, 2012.....you will see that the SUMMER of 2015 was almost as warm as 2012.  And certainly warmer than 2013 and 2014.

[Gonzo]

diablobanquisa

New ice at the Laptev Sea?

Gonzo

It looks like it just blew in there during the week.

diablobanquisa

I´m pretty sure that it's new ice, although of course I could be wrong.

I wish it was.  It just drifted in and stuck there.

[Pi26]

Yes, that may be true for the ice itself. But the cold air being held by it in one place it's another story. The jetstream anomalies are expected to ramp up exponentially as soon as the ice is gone.
Making weather chaos in the NH permanent.u
And we haven't touched on the issue of clathrates.plo

Its all about cooling capacity. Clearly the available cooling capacities at the arctic work different and shared. But I think global warming already is driven several times stronger by lost cooling capacities (including all glacier melting and albedo) than by burnings. Dangerous much more cooling capacity maybe lost soon.

[diablobanquisa]

diablobanquisa

New ice at the Laptev Sea?

Gonzo

It looks like it just blew in there during the week.

diablobanquisa

I´m pretty sure that it's new ice, although of course I could be wrong.

I wish it was. We are nowhere near that point on the Atlantic side, I am afraid to say. It just drifted in and stuck there.

I was referring just to the small area within the red line. August 29:




And August 31:




I'd say there is new thin ice forming and swirling there, filling the gaps between the eddies that were already present two days before.

I see a slight refreeze just in that small area (however, models forecast a warm advection in the next days, so the slight refreeze could stop)

[seaicesailor]

This Summer was very warm for the Northern Hemisphere and for the Arctic in particular.

If you say so. But....
http://ocean.dmi.dk/arctic/meant80n.uk.php

The North Pole has been as cold as always, give or take 1°F. However read below.

Daily NSIDC extent now just 54k away from securing the 4th lowest minimum on record.

Using the 5 day average, the loss from June 30th to August 31st (5,484,800km2) was the 3rd largest on record, just behind 2007 (5,568,200km2) and 2012 (5,793,400km2).

The loss over the last 2 weeks has been the largest on record.

[greatdying2]

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

How can an artifact be evidence of anything?

[jdallen]

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

How can an artifact be evidence of anything?

I think that is the point Chris is trying to make, actually.

[greatdying2]

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

How can an artifact be evidence of anything?

I think that is the point Chris is trying to make, actually.

Is it? Then we're on the same page.

But I thought he suggested that the artifact implied something about other models being correct, which to me doesn't seem to follow.

[slow wing]

Nothing really dramatic in today's U. Bremen update...

• around the Beaufort Sea region, the areas of lowered concentration continue to shift around;
• the 'forearm' projection at around 155E has thinned on the Pacific side
• the last of the ice is thinning out in the ESS channel between 70N-75N and 145W-150W (is the McLintock Channel between Victoria Island and Prince of Wales Island), leaving the ESS looking bare of ice.
  

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

[Gonzo]

diablobanquisa

I see a slight refreeze just in that small area

Oh ok, I see what you're saying. Maybe it is. Thanks for pointing that out.

[Jim Hunt]

The interesting possibility isn't just the outcome at the end of the prediction period but the trajectory getting there. Bashing the CAB above Laptev and CAB above ESS is probably the biggest remaining wild-card this season.

There is at least now agreement that there will be a 1000 hPa low spinning over the Laptev Sea later today!

[sofouuk]

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

How can an artifact be evidence of anything?

I think that is the point Chris is trying to make, actually.

Is it? Then we're on the same page.

But I thought he suggested that the artifact implied something about other models being correct, which to me doesn't seem to follow.

if the bifurcation is just an artifact of the model, there's no reason to doubt the accuracy of other models which don't show a similar bifurcation. it doesn't show the GCMs are right, it just means you can't use the lack of bifurcation behaviour to argue that they're missing sth

[Glenn Tamblyn]

The interesting possibility isn't just the outcome at the end of the prediction period but the trajectory getting there. Bashing the CAB above Laptev and CAB above ESS is probably the biggest remaining wild-card this season.

There is at least now agreement that there will be a 1000 hPa low spinning over the Laptev Sea later today!

And if anything remotely like this happens, 2007 is toast! Multiple deep lows bouncing around he basin!

[Jim Hunt]

If anything remotely like this happens, 2007 is toast! Multiple deep lows bouncing around he basin!

2007 is already (temporarily?) toast, according to JAXA at least. My preliminary musings on the 2015 minimum:

The 2015 Arctic Sea Ice Minimum Extent

which includes the latest GWC video:

[Killian]

Sorry, my mistake. I guess it comes from my drive to comprehend what is going on. As a lifelong nerd I have never really grasped the point of idle chatter.

But being rude is OK.

Got ya.

Here's my rude comment back

Calm, everyone. Let us move on.  I suggest a private email exchange to sort out any <b>remaining differences</b>.

There are none. Eggheads, and I am a variety thereof, tend to spend large amounts of time in ivory towers and forget there is a living, breathing system out there. As a studier, designer, and teacher of systems, I understand what we know of a system always lags the system itself. Some of us eggheads are uncomfortable with accepting or strongly considering anything not *already* measured. Such of us eggs spend a lot of time behind the times, but almost no time being liable to be flat our wrong. Scientific reticence serves it's purpose. However, as non-scientists, I suggest our purpose is clarity and effective risk assessment, not acting as if we are, ourselves, the scientists.

I have called SLR back in 2007, been as accurate as any WRT ASI minima, rate of change, etc., etc. Yet, I am likely the least numerate here. Point being, data is but one set of knowledge. Don't be so quick to discount those who look beyond the numbers and into the nature of the system itself, and may be more accurate, even if they can't write it as an equation.

I'll say it again, as I have said it already: 2016 or 2017 will see new ASI area and volume lows less absolutely perfect ASI building conditions the next 12 - 16 months.

There are reasons why. It's all about patterns.

Perhaps more importantly, I always try to say exactly what I mean to say. I am very unlikely to use "looks like" when I mean "is." I've not posted here in a long time. You all don't know this. Now you do.

Cheers

[Gray-Wolf]

After 2007 we discovered that the 'perfect melt storm' synoptics would appear in the basin every 10 to 20 years with the two prior to 2007 having 10 yr spacing's.

As such I'd always looked for 2017 as being the earliest opportunity to see a near ice free basin?

Should 2016 see further nino impacts over melt season ( spent KW's pushing up the U.S. west coast and entering the basin via the Alaskan current?) then the pack may well be in poor shape should the 'perfect melt storm' synoptics reappear in 2017.

[BornFromTheVoid]

The models appear to be going for a reverse dipole/+ve AO in about 5-6 days. This would likely start pushing the ice from central area back out toward Beaufort and Chukchi and could effectively end the extent melt season. The low pressure looks like a more typical +ve AO, rather than stormy, so Ican't see it causing much damage.
Perhaps just another 4 or 5 days of reasonable melting rates remaining?

[seaicesailor]

Seaicesailor, For some buoy data specifics on those Beaufort surface anomalies we have ITP buoy# 82 at 77.9 N with surface temperatures in range of  - 1 to -1.2 and for ITP buoy # 85 at 74.8 N there has been a heat spike for surface temps at above 0 to -.2 at 6 meters. This buoy continues to set records exceeding anything in the entire record of water temperatures recorded in the Beaufort Sea for theITP dataset.
 These buoys are set in ice so although surface waters may exceed the numbers above these temps record what is happening under the ice pack.

 http://www.whoi.edu/page.do?pid=139056

Bruce, Indeed. The location of the ITP 85 buoy is somewhere inside the rectangle (sorry I don't have a good painter app at hand).  This is the DMI estimate of absolute SSTs today. Note the 4+ degC that is showing up in the open ocean area adjacent to it.

[seaicesailor]

Actually, anybody has an explanation on how 4 to 6 deg C of SSTs can appear over a sizeable area of the Beaufort sea in September? No sun radiation, no high air temperatures lately either. 4 weeks ago this area was covered by ice. Can this be from the storm? Isn't is too high?
(satellite measurement error?)

[slow wing]

As is attached, MODIS is showing long cracks around 120E to 150E and extending to at least within 4 degrees of the Pole. (Cloud cover obscures closer to the Pole.)

Nullschool shows 2 low pressure systems currently at around those longitudes:
79N, 143E at 997 kPa
88N 130E at 1007 kPa (i.e. weaker).

The stronger system, further from the Pole, is also dragging ~40 kph (~25 mph) winds transversely across the base of the forearm ice pack projection.

So it will be interesting to look for any dispersion of the ice pack around there and/or further breakup.

[Bruce Steele]

Seaicesailor, To fact check the DMI I looked at a NOAA map that shows a part of that DMI SST chart.
NOAA shows 8 C SST to 70 degrees N of Pt. Hope and those temperatures align quite well with the DMI chart in that area. The King Island NOAA buoy is also recording 8C sea surface temps in the Bering Strait for a little more confirmation.
 The area south of ITP#85 has been open water for over a month now between the former arm and the pact that 85 sits in so insolation has had some time to do it's work. Although DMI blends the edges compared to the NOAA chart they seem to agree so I don't think you are seeing any satellite error. These waters are warm enough that if the pack is pushed back in that direction as Born from the Void suggests it will result in further melt . Extent up but maybe area down.

  http://www.ospo.noaa.gov/data/sst/contour/beringst.fc.gif

http://www.ndbc.noaa.gov/station_page.php?station=48114

[greatdying2]

2015 has moved into 3rd place, passing 2011 on this NSIDC extent graph.

[greatdying2]

The strongest evidence for a possible impending bifurcation has been within the extensive work of Ian Eisenman into simple models of the sea ice. This year Eisenman has published work showing that those modelled bifurcations are artefacts of the simple model, and by implication that the GCMs are correct in not showing bifurcation behaviour in the transition to a seasonally sea ice free state.

How can an artifact be evidence of anything?

I think that is the point Chris is trying to make, actually.

Is it? Then we're on the same page.

But I thought he suggested that the artifact implied something about other models being correct, which to me doesn't seem to follow.

if the bifurcation is just an artifact of the model, there's no reason to doubt the accuracy of other models which don't show a similar bifurcation. it doesn't show the GCMs are right, it just means you can't use the lack of bifurcation behaviour to argue that they're missing sth

Yes, exactly.

[crandles]

2015 has moved into 3rd place, passing 2011 on this NSIDC extent graph.

That is 5 day average. For 1 day numbers it is into 2nd place:

2012,    09,  01,      3.573
2015,    09,  01,      4.464
2007,    09,  01,      4.475
2011,    09,  01,      4.592