2015 minimum overview, part 1

A week has passed by since the melting season ended and the minimum on all sea ice extent and area graphs has been reached. During this week I've been collecting images that show various aspects of this year's melting story, which will be accompanied by short explanations/interpretations.

Such an overview must inevitably start with an image showing the shape of the ice pack, and the University of Bremen has put up a great sea ice concentration map that also shows the ice pack outlines at the end of record melting seasons 2007 and 2012, as well as the 1981-2010 average:

2012 (cyan) clearly had less ice, but there are a couple of spots where this year had less ice than in 2007 (red). The September graph for ADS-NIPR/JAXA sea ice extent shows how close 2015 came to the lower years, slipping right below 2011 and ending in 3rd position:

The same can't be said of the Cryosphere Today sea ice area graph. 2015 ended relatively low there too, but at the top of the bundle of trend lines, in 6th position:

The reason for this was an early refreezing of melt ponds and leads in the centre of the ice pack, and dispersal of ice floes on the Pacific side of the Arctic that didn't get compacted, as evidenced by the CAPIE graph (a measure showing how compact the ice pack is; the higher the percentage, the more compact) with its spectacular climb during this crucial last phase of the melting season:

Here are two further bar graphs that show how much extent and area was lost over the entire melting season, by subtracting the minimum from the maximum:

Total loss doesn't deviate much from previous years in the 2006-2015 period, but keep in mind that the maximum was relatively low and early (see here).

I'm still somewhat surprised that the melting season ended as low as it did, given the relatively slow start it had. As we say in Dutch, a good start is half the work, and in the case of melting seasons this means that a warm and sunny May and June precondition the Arctic sea ice pack (through melt pond formation and anomalously warm sea surface temperatures), and this preconditioning in turn makes record low minimums possible.

The reverse is also true, but this year showed us that a warm July can still compensate such a lack of preconditioning. At the same time I must add that during June there was quite a bit of preconditioning going on in a very sensitive zone, namely the Beaufort and Chukchi Seas (the places where thicker multi-year ice gets transported to over winter), while the rest of the Arctic was cold and somewhat cloudy.

If you want to read back the details, I refer you to the three monthly analyses I posted to compare this year's surface air temperatures and atmospheric pressure (May, June, July) with those of previous years. These temperature rankings, compiled by Dr. Andrew Slater of the NSIDC (found at his personal website), also give an idea of how 2015 fared:

May was cold, though not as cold during rebound years 2013 and 2014. June was warmer relatively speaking, but it was during July that 2015 hit a home run, coming in second after 2007. Who knows what would've happened, had this temperature anomaly continued into August, but it obviously didn't.

Still, average temperatures don't tell us anything about how the heat was distributed. For that I've turned to NOAA's Earth Science Research Laboratory daily mean composites page to retrieve SLP and temperature anomaly distribution maps for 2015, as well as the top 3 years, May through August:

It's clear that 2015 can't really compete with the top 3 years, not when it comes to temperature. With regards to sea level pressure 2015 is somewhat similar to 2007 and 2011 (2012 is a bit skewed towards lower pressure because of the Great Arctic Cyclone, I think), but if you look carefully, you'll see that the yellow and green depicting high pressure are further away from the Beaufort Sea, which means the Beaufort Gyre played less of the role it did during 2011, let alone 2007, when massive compaction and export of ice through Fram Strait caused a stunning new record at the time.

The latest analysis on the NSIDC website shows a more detailed head-to-head comparison of 2007 and 2015, from the start of June to the end of August:

Basically, 2015 was on average colder than 2007 and had less favourable winds for compaction and Fram Strait transport, but still managed to end up a stone's throw from the 2007 minimum. This suggests that the state of the ice is such nowadays that less favourable conditions for melting still suffice for a low minimum. We can't be sure this is the case until more favourable conditions, similar to those of 2007, 2011 or 2012, happen again. And chances are they will in years to come with all that heat being released from the Pacific Ocean.

I'll have more to say about the state of the ice (and snow) in part 2.

Comments

[Jim Hunt]

Thanks for the comprehensive overview Neven. Are you prepared to speculate yet about what 2016 holds in store for the sea ice in the Arctic? Apparently El Niño is brewing as we speak!

Meanwhile the Arctic Mix team aboard the University of Alaska's research vessel Sikuliaq, have been investigating other sources of heat that are already melting the sea ice in the Beaufort Sea. At the risk of repeating myself, please see:

http://forum.arctic-sea-ice.net/index.php?topic=1385

Our instruments are seeing billows of turbulence that look just like a wave breaking on the beach, but much larger. As a result, heat is being mixed up towards the surface, and the remaining ice, at a remarkable rate.
 While we hypothesized this might be happening, we have been genuinely thunderstruck by how incredibly strong the turbulence is below the surface. This heat is likely playing a substantial role in the melting of the ice that we can see all around us, growing thinner every day, and our job now is to distinguish summer melting from longer-term change.

The Sikuliaq is currently heading back to base for a change of scientific personnel. Her next voyage takes her back to the Beaufort Sea to investigate the:

"Sea State and Boundary Layer Physics of the Emerging Arctic Ocean"

[Neven]

Are you prepared to speculate yet about what 2016 holds in store for the sea ice in the Arctic?

I'm always willing to speculate, Jim, but it's easier near the end of the freezing season. Along the way we get an idea of MYI transport into the Beaufort Sea and out of Fram Strait, volume, thickness distribution, amount of snow on the ice, temperatures, atmospheric pressure and cloudiness (read: outgoing radiation), etc.

But I agree that events in the Pacific are highly intriguing. Of course, El Niño pushing out all that heat, but also the positive PDO and that so-called Blob in the North Pacific. We'll see how the Bering and Okhotsk Seas react to that (the small amount of sea ice there at the end of the freezing season was the main reason the maximum was so low and reached so early).

What interests me right now in the Arctic is the absence of spikes on the DMI 80N temperature graph. I mean, SSTs have been reasonably high this melting season (see the comparisons I did for each ASI update), but apparently this heat either hasn't been released yet or it isn't crossing the 80° boundary. The last time that it took so long for spikes to show up was in 2009.

As you can see on the CT SIA graph I posted in this blog post, the Arctic Ocean is being covered with fresh ice pretty fast, and if all that heat (also brought up by turbulence, as you say, thanks for that) doesn't get dumped in the air, but part of it stays in the water, insulated by ice and snow, this might play a role next year.

So, that's my speculation for now. :^)

[Cato Uticensis]

Neven,

A fine analysis and lots of food for thought as usual.

There is a point, though, that I have found especially interesting.

Total extension loss is in line with previous years, but the maximum has been the lowest ever. It comes as no surprise that the minimum has been quite low, considering the starting point. Just an addition/subtraction issue in the end. Although nothing is so simple when talking about sea ice, I reckon...

Anyways, I remember that several concerns were expressed in relation to the possible impact of such a low maximum onto the incoming melting season.

In my humble opinion this might have been an important factor in the evolution of 2015 arctic ice melting. When melting has started, a bigger-than-ever sea surface has been exposed to radiation. As a consequence an increasingly warmer mass of sea water has started biting the ice. We are talking about albedo in the end.

I understand and of course I do not question the prevailing importance of issues like the synoptic pattern in July or the evolution of melt ponds as I'm everything but not an expert in arctic sea ice.

I just wonder, though, if the impact of such a low maximum onto the melting season doesn't deserve more consideration in the overall analysis of what has happened so far.

[Neven]

Cato, my impression is that the maximum had very little influence on the melting season. I know several commenters speculated about how 1 million km2 less than 2012 at one point, would surely mean that 2015 would break the record, but it simply doesn't work that way. That million had simply vanished after a couple of weeks.

A maximum can be very high because during the last 2-3 weeks of the freezing season lots of thin ice is formed at the edge of the ice pack, because of wind pushing the ice outwards and low temps freezing the leads that pop up behind the floes (probably one of the main reasons of high Antarctic sea ice extent in recent years).

Conversely, a max can be low because winds are compacting the pack and temps aren't low enough to freeze the open water. But at a certain point, after the melting season has started, thicker ice is reached, and other years catch up again.

In theory though, if a max is low, say because of events on the Pacific side of the Arctic, and weather conditions are conducive to melting and absorption of radiation (sunny weather, warm temps from land because snow melts fast there) the head start could be capitalized.

We saw some of that happen this year during June, but then the weather switched and action on the Pacific side stalled for several weeks. And that's how it goes most of the time.

[John Christensen]

Great analysis, thanks Neven, and I would tend to agree on your last comment also; that max extent is less important due to the volatility of the ice edges in March.

I see that CAPIE (compactness) has reached a high level compared to the past decade, as I had mentioned on the 'Minimum and MYI' thread.

I would speculate this has two consequences:
1. DMI 80N temps will be low this fall, as there are relatively few open leads or floes near the Pole (The lack of temp spikes).
2. Since the lowest temperatures are found above relatively young ice (Just turned to 2nd year ice), this should favor a stronger increase in volume near the Pole, as the cold will more easily radiate through the thinner ice.
Whether this second impact will balance the reduced loss of heat caused by the high level of compactness is something I will not try to speculate on, but will await the next PIOMAS update eagerly.

[navegante]

if all that heat (also brought up by turbulence, as you say, thanks for that) doesn't get dumped in the air, but part of it stays in the water, insulated by ice and snow, this might play a role next year.

That's a really keen observation, the final state of the ice pack is very particular this year. But still, we wait not much, it is unavoidable that spikes show up at 80N statistics, unless very weird weather patterns stop it.

[navegante]

Yes, in fact, the rapid refreeze in the broken part of the pack did not release much heat in comparison with what is has to be released for freezing the open ocean extents.

And, the rapid refreeze of the broken ice may indeed enable the sort of heat trap that you talk about.

Sorry for double-posting.

[Cato Uticensis]

Neven, thanks for your reply.

I will grasp at the "capitalisation" concept you have made to defend my point about albedo impact at the beginning of melting season. 2 weeks more of exposure to radiation can still make a difference, can't they? Clutching at straws? Possible :)

PS: your idea about lack of spikes is really fascinating. How would you explain the fact that rather spikless re-freezing took place also in the past, like 1988, '68, '63, '59 etc.

Moreover, this trend of lower (or average) temperatures in the artctic has been ongoing since August (the histogram you have attached is self explanatory). How would you explain this and what could be the consequences in terms of refreezing?

[John Christensen]

Cato,

There is a strong correlation between the very high CAPIE index and the lack of spikes in the DMI 80N temp: The compactness of the ice does not let much heat escape from the top water layer.

This makes the behavior of the DMI 80N temp for the past few weeks very similar to how it behaved in earlier decades.

Just remember that the DMI 80N temp is based on a relatively small area and also that it tends to overestimate the temperature at 90N compared to 85N and 80N, so with the cold centered around the Pole, the DMI 80N temp will overestimate this cold.

Cold is still cold though, and it's good for freezing..

[Witold]

Hi all,

I've been lurking for a couple of years - great place thank both to host and all commenters. I am physicist and computer scientist doing science in a field remote to climate, here only an amateur.

I have scored the years according to the position on the temperature list in May-Aug period.

Pts May Pts June Pts July Pts August Year Sum4 SumJJA SumJA SumJJ
7 107 34 107 37 107 37 107 2007 115 108 74 71
27 111 33 111 33 111 35 111 2011 128 101 68 66
28 112 32 112 26 112 32 112 2012 118 90 58 58
8 98 27 98 35 98 25 98 1998 95 87 60 62
32 105 36 105 21 105 29 105 2005 118 86 50 57
36 93 37 93 28 93 16 93 1993 117 81 44 65
34 95 17 95 34 95 30 95 1995 115 81 64 51
37 90 30 90 24 90 26 90 1990 117 80 50 54
17 85 35 85 32 85 10 85 1985 94 77 42 67
30 91 22 91 31 91 23 91 1991 106 76 54 53
11 87 21 87 29 87 22 87 1987 83 72 51 50
18 99 9 99 25 99 36 99 1999 88 70 61 34
12 115 25 115 36 115 9 115 2015 82 70 45 61
35 88 20 88 30 88 14 88 1988 99 64 44 50
16 109 13 109 27 109 24 109 2009 80 64 51 40
33 110 31 110 5 110 27 110 2010 96 63 32 36
20 94 28 94 22 94 11 94 1994 81 61 33 50
23 108 8 108 14 108 31 108 2008 76 53 45 22
4 84 24 84 23 84 6 84 1984 57 53 29 47
24 104 19 104 12 104 21 104 2004 76 52 33 31
22 81 29 81 3 81 15 81 1981 69 47 18 32
14 79 7 79 19 79 20 79 1979 60 46 39 26
6 100 18 100 10 100 18 100 2000 52 46 28 28
15 89 11 89 6 89 28 89 1989 60 45 34 17
26 97 26 97 17 97 1 97 1997 70 44 18 43
2 82 14 82 13 82 17 82 1982 46 44 30 27
19 102 4 102 4 102 34 102 2002 61 42 38 8
9 114 5 114 2 114 33 114 2014 49 40 35 7
5 101 12 101 16 101 12 101 2001 45 40 28 28
10 83 2 83 18 83 19 83 1983 49 39 37 20
25 103 15 103 9 103 13 103 2003 62 37 22 24
31 80 23 80 11 80 2 80 1980 67 36 13 34
29 106 10 106 15 106 8 106 2006 62 33 23 25
1 92 6 92 20 92 4 92 1992 31 30 24 26
21 86 16 86 8 86 5 86 1986 50 29 13 24
3 113 3 113 7 113 7 113 2013 20 17 14 10
13 96 1 96 1 96 3 96 1996 18 5 4 2

Interestingly 2007 wins easily when only three months are counted towards the final score (May is excluded) with 2011 second and 2012 third, whereas 2011 wins when all months are counted, with 2012 tied with 2005 in the second place followed by 1993 and 1990 in the fourth and 2007 tied with 1995 in sixth.
In JJA ranking year 2015 is in the 12th spot, in 4 months ranking it is in the 15th spot.

From this ranking I would hypothetise that the conditions in May are mostly irrelevant to the extent/area of ice in September, on the other hand cumulative heat in JJA is a very good predictor.
Several conclusions follow.
Firstly, 2013 and 2014 were among the coldest in JJA period (36th spot for 2013 and 28th spot for 2014), no wonder that some (very fragile) rebound happened.
Secondly, 2015 was only slightly warmer than average still it managed to go nearly on par with 2007.
Finally - if next year Arctic will will get the summer weather as warm as 2007, 2011 or 2012 the results may be really disastrous - the ice may go well below 2012 levels, maybe as low as 1 mln square km.

[Cato Uticensis]

Thanks again Neven.

It looks like fresh "lurkers" like me and Witold are joining your blog. No wonder, considering the quality and the relevance of discussions ongoing here...

[Cato Uticensis]

I meant... Thanks John :)

[wayne]

Neven,

Your first figure shows 2012 minima looks almost the same as 2015, but there were different paths leading up to nearly similar final results. With more compaction, 2015 would have easily beaten 2012. We are in a new kind of melt/circulation geophysics meteorological dynamics, changing in newer ways year by year. It is very difficult task to project exactly especially when the ice morphs to newer configurations faster than the sum of our experience can reveal.

[John Christensen]

wayne,

"With more compaction, 2015 would have easily beaten 2012."

How on earth (or the Arctic) would you have 'more compaction' at the end of the melting season, when 2015 is showing some of the highest compactness rates in the past ten years??

But of course, if in principle you could pile all ice in one huge heap, then any area record would be broken..

[Martin Gisser]

Anybody else notice the growing epidemic of writing "minima" for the singular "minimum"? Strange phenomen-ummm-on. Even scientists seem to get infected.

[John Christensen]

Same thing happened a few years ago, when criterium became a bike race and no longer the singular form of criteria.. Terrible!

[Kevin McKinney]

"Anybody else notice the growing epidemic of writing "minima" for the singular "minimum"?"

I hadn't, actually--though I probably will, now that you've pointed it out.

But I've been very bothered by the redundant and superfluous double 'is':

"The fact of the matter is, is that…"

Sadly, the estimable Mr. Obama is one of the guilty parties.

Returning to the topic at hand, thanks, Neven, for another concise yet comprehensive roundup. You keep getting better.

And since we're speculating, I'm going to go with the idea that the anthropogenic warming trend, combined with additional water vapor and energy in the troposphere, will result in a warm winter north of 80, and even lower ice formation rates than 'the new normal.'

Which means PIOMAS will continue to slump throughout the freezing months. The echoes of that may persist right into the melting season.

There, pure speculation. But I rather think it could play out that way.

[navegante]

Climate R. Forcast images show spikes at North in three and six says

http://pamola.um.maine.edu//DailySummary/frames/GFS-025deg/ARC-LEA/T2_anom/24.png
http://pamola.um.maine.edu//DailySummary/frames/GFS-025deg/ARC-LEA/T2_anom/48.png

I guess it is unavoidable that air masses, tempered by large open water extent with SSTs at -1.5C, reach the North Pole, now that the Pacific side has been fully sealed by refreezing.

Those spikes are one of the most clear evidences of AGW, and consequence of prior Arctic amplification during melting season in particular. However the absence of them until now is certainly as interesting.

[navegante]

Note also that the ice pack configuration of this year is pretty "circular" shape around the Pole compared to 2007 and 2012, enabling cooling of the air by the ice mass before reaching the NP. This is just the way it turned to be. But again, it means heat transfer from tempered air to freezing ice. And so the more extended ice pack absorbs more heat as well.

Sorry for quad-posting but I find this fascinating. The implications of this initial freezing season development will be...?

[Colorado Bob]

I watched the NOVA program on the "Franklin Expedition" last night. They set sail in 1845 to finish the mapping of the Northwest passage. It was really great TV.

These ships hulls were 8 feet thick with oak and iron plate, in a sandwich.

In the middle of the show , they go to the ice core scientists , it seems Franklin set sail at the beginning of a 30 year period when summer sea ice never really melted in that dense chain of sea and land in Northern Canada.

Here's the link it's well worth watching. They found his flagship -

http://video.pbs.org/video/2365567818/

[Colorado Bob]

”Only four cargo vessels traversed the so-called Northeast Passage—a shipping lane across the northern shore of the Eurasian continent, connecting Atlantic to Pacific—in 2010. By 2013 that number had grown to 71.”

http://www.cnbc.com/2015/09/24/a-melting-arctic-the-world-is-skating-on-thin-ice.html

[wayne]

John,

"But of course, if in principle you could pile all ice in one huge heap, then any area record would be broken.. " : Ridging

For those who don't know, here is some of the rest:

Compaction like 2007 occurs over the entire melting season by what is called Arctic Dipoles. Ice otherwise spread out broken in different phases of thickness or melting compact in favorable synergistic weather conditions, the process exacerbates the over all melting significantly once water is exposed to insolation.

The first figure above show a significant extent of 2015 sea ice not compacted spread about mixed with water but likely counting as 100% coverage.

The other thing not presented is the rest of the pack appearing 100% snow white, but in various stages of melt, with thinner mixed with thicker ice with leads which is easily compactable given the right conditions. But this did not happen extensively.

All things considered, there has been no recovery since 2007, just sea ice self defense posturing, by spreading itself thanks to the new order of weather establishing itself in the Arctic. This albedo stance has its limits as 2015 has showed. In particular the lack of consolidation is revealed by the lack of anticycllones over the main pack at this time. No super anticyclone cooling of the Arctic will make the ice thinner for the next season.

[D]

Long-time lurker from glaciology, with a novel approach to communicate the 2015 minimum and the overall declines in sea ice:

https://josephmichaelshea.wordpress.com/2015/09/22/the-music-of-climate-change-ii-sea-ice/

Thanks Neven and all contributors for the great + informative discussions, and I second (third?) the comments of Cato and Witold above.

[D]

Long-time lurker from glaciology, with a novel approach to communicate the 2015 minimum and the overall declines in sea ice:

https://josephmichaelshea.wordpress.com/2015/09/22/the-music-of-climate-change-ii-sea-ice/

Thanks Neven and all contributors for the great + informative discussions, and I second (third?) the comments of Cato and Witold above.

[Eric Orr]

El Nino matters a whole lot more for the South pole than the North. The Blob and PDO though could make a difference. However, the PDO and blob effects are supposedly fairly minor compared to the massive effect that El Nino has on the various edges of the Hadley Cell. How that translates to Polar Vortex formation and collapse will be interesting. If I had to guess the effect of El Nino will more likely show up on snow cover anomalies and temperature on lower latitudes which would have a second or third order effect on Sea Ice in the Polar seas.

[Pete Williamson]

Did you notice PIomas posted a note on their website on the 2015 ice volume minimum.

http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/

"The sea ice extent minimum for 2015 was likely reached on Sept 11. Sea ice volume minimum was reached a day later with a total volume of 5670 km3 . This value is about 1200 km3 below the volume minimum of the 2014 which showed a subtantial rebound in ice volume. The value for 2015 is 300 km3 above the value for 2013 and constitutes a continuation of the long-term declining trend (see fig 1) with shorter term variability in both directions (e.g. 2012 and 2014)."

[Neven]

Hi, Pete. Yes, I noticed. PIOMAS volume will be discussed in Part 2.

[John Christensen]

wayne,

My last comment to your point about 2012 easily being broken with more compaction this year:

- At the beginning of the melting season 2015 had the highest CAPIE in a decade - this means the pack was very compact rather than dispersed
- The high pressure in July kept the pack compact rather than dispersed, the opposite of the case with the cyclones in 2013 and 2014
- Once freezing of the melt ponds had occurred early September, 2015 again had the highest CAPIE in a decade
- You can also see that the 'MYI island' remaining from the arm has decreased in size and increased in thickness, as it is compacted against the main pack - more compaction and ridging.

So your suggestion that 2015 easily could have broken 2012 extent by compacting even more (2012 minimum extent with 3.41 was 23% lower than 2015 with 4.41) is rather implausible and seemingly beyond physical reality.

[Kris]

John Christensen wrote:

... the opposite of the case with the cyclones in 2013 and 2014

Actually, we should add 2012 to the list as "the storm" in 2012 was a cyclone too, wasn't it?

OTOH, from the NASA images of the countless shelves on the loose this year 2015 it's looks clear there wasn't a firm compactness in July-August at all. Yes, it should have been according to "the rules" [high pressures], but it wasn't. Yet another singularity. :-)

[navegante]

John (and Neven),

The thing about the compaction right now: the surface refreezing at the CAB has happened very fast because a huge extent of broken ice was blown by sustained North winds. See Regional Graphs at the ASIG; CAB compactness is reaching high values, indeed the highest possible values a few days ago. However, peripheral seas are completely void of ice! They don't count on the compactness statistics at all. It is the compactness of the CAB, period. An almost "full of ice" CAB with "empty of ice" peripheral seas. Pretty peculiar.

The question is, what happens now as soon as the peripheral seas start to refreeze? Compactness back to normal.

And, possibly 80N spikes above normal start to appear.

BTW, navigating thru the DMI 80N plots of the 50's 70's 80's those spikes are always present, only that, when averaged out, this resulted one the baseline curve of temperatures. Meaning, today the Arctic is warmer.

[navegante]

John,

Another detail: compactness was record low in July.

I am with Wayne on this: should all this broken ice had been strongly compacted after the Chukchi storm, that is, end of August - early September, 2007 minimum would have been broken. Not as far as 2012 though. What we witnessed now is the fast refreezing of this area of dispersed ice (another way of increasing compactness metrics which is better for preserving the ice, I guess).

[John Christensen]

Hi Kris and navegante,

I will be happy to address your points:

- Cyclone in 2012 (GAC-2012): I did not include this cyclone, as it did not so much disperse the ice to keep the extent number up, but rather destroyed the ice (mixing and melting due to high SST in August 2012). In 2013 and 2014 the cyclones were primarily in June/July, where the SST is lower, reducing mixing/melting ice reduction, and the cloud cover caused by the cyclones is a more important factor in June/July, preventing radiative heating
- Peripheral seas void of ice in 2015: This already caused 2015 ice extent to be low, so not sure how this is relevant related to the possibility of surpassing the 2012 minimum extent..
- Compactness was very low in July: That is correct, but as you know the sensors have a hard time differentiating melt ponds from open water in sea ice area calculations, so in the main melting period the CAPIE index is influenced both by melt ponds and by the actual degree of compactness of the sea ice. You see that the CT sea ice area dropped very hard in the weeks with clear skies, where the melt pond fraction increased considerably. The July CAPIE index therefore does not give you an accurate view of the level of compactness.
- The ‘MYI arm/island’: This area mostly melted out during and just after the storm in Chuckchi as Neven has mentioned, so had very little influence on the 2015 sea ice extent minimum in September – there was simply very little ice left by September 11th to be compacted.. The MYI island that remained has now collided with the main pack, decreased in area/extent, and with some increase in height at the center, so this area is compacting
- Surface refreezing: At this point we are just starting to see the first refreezing of the surface and only in central parts of the CAB, as temperature needs to drop below around -11C before the surface will freeze. The western side of the CAB towards Chuckchi and Beaufort has not been cold enough yet for any refreeze of the surface to begin.

[Tor Bejnar]

Re possibility of potential compacting in late August/early September: the Healy reported sailing through slush for some/much of it's journey to the North Pole. I imagine that if the occasional floe of solid ice was shoved into this, the slush would pile up with little resistance. An area with 100% concentration could have 'easily' had its area reduce.

I don't think there wasn't a 'seriously compacting' event, so this idea wasn't tested.

[John Christensen]

Hi Tor,

The path of the USCG Healy to the North Pole was carefully chosen to go through the areas with the thinnest ice.

From the captains log on August 16:

"While this trip has been planned for over seven years, like all good plans, we will adapt to the environment presented. After carefully reviewing satellite ice images for months, we have decided to reverse our track due to the heavy ice conditions along 150W. This will give us a much better opportunity to conduct as much science as possible and to become the first unaccompanied US vessel to reach the North Pole. "

[John Christensen]

USCG captains log on August 30th, at 86.5N, 250 nautical miles from the Pole:

"The ice conditions continue to be lighter than anticipated. The ice is getting thicker as we continue north and there are patches of multi-year ice, but the multi-year big floes are not what they’ve historically been.[] We are now backing and ramming a few times each watch, but HEALY is able to handle the current ice conditions with aplomb"

While the ice was not a major concern to the Healy, I would not expect backing and ramming to be required in slush ice.. ;-)

[navegante]

John,

I expressed myself very poorly, sorry about that, my lame English.

In the mentioned ASIG graphs, Wipneus not only shows something similar to CAPIE (red curves) but also compactness resulting from AMSR2 data of highest resolution (blue lines). These data are less prone to being fooled by melt ponds. If you observe, July compactness was record low by these metrics too.

I was mixing two different issues. One, that the Pacific side of the pack was extremely loose by the end of August, and should compacting winds had prevailed for, say, two weeks, real ice compaction would have happened. Potentially on the order of 0.5 to 1.0 million km2 of extent loss? We can't know.

Now the compactness is by refreezing, which means more ice, and less thin FYI extent for next year, which, at the end of the day, is good news for the ice.

On a different note, I mentioned earlier that compaction at CAB was reaching maximum, and from now on a gradual refreezing and ice edge advance may take over, making metrics look more normal.

On a yet different note, forecasted for this week there is a complete mess of strong low pressure systems merging from all directions, and seizing the Arctic, which I don't have the less idea which consequences it may have.

[John Christensen]

And the last from the USCG Healy on Sept 6, when they had reached the Pole:

"Despite challenging ice conditions, we made great time through the ice this week and arrived at the “top of the world” about a week earlier than planned. The cooperation and teamwork between the deck crew and scientists has been a key to our success. HEALY encountered the thickest ice during the 200 mile transit between 82ᵒ and 85ᵒN. It was up to ten feet thick, and demanded three engines and careful ice piloting by the bridge team to keep the ship safe and transiting in the right direction. From time to time, the ice became so thick we were stopped dead in our tracks and needed to back up several hundred yards to give ourselves room to pick up speed and ram into the ice to break it. This so called “backing and ramming” is felt by the entire crew, as the entire ship rocks and rolls, and bounces as it crushes through the ice.

Though this area of thicker ice slowed us to 3 knots, we daily progressed toward the pole."

This is not an account of thin, dispersed, or slushy ice..

Also, the USCG Healy included in the same weekly report that they encountered two other ice breakers about 100 nautical miles from the Pole, at 88N, which were returning from the Pole, so they had a path of broken ice to follow to the Pole. At the Pole they spotted and joined a German ice-breaker, so that a total of four ice-breakers had made it to the Pole in one week. I did not see any comment about 'slush' ice, but with four large ice-breakers in the area and temperatures not yet low enough to freeze up the broken ice, it seems reasonable that some slush ice is generated.

[John Christensen]

Hi navegante,

NP at all.
I agree that there was a lot of dispersed ice in July due to the heavy melting going on as well as a result of the storm in Chuckchi later on.

My argument is just that the ice concerned (Primarily in Chuckchi, Beaufort, the western part of the CAB, and the CAA) nearly completely melted away and therefore did not greatly impact the Sept ice extent minimum number.

But even with low area and extent numbers by the beginning of the melting season, with weather favoring compaction in July, COULD it have compacted more, so that concentration rates were not just 100%, but also with much more considerable ridging?

Of course it could, but since the extent should have been reduced by more than 1 million km2 (1000x1000 km completely removed simply by ridging) from a number that was low to begin with to pass the 2012 record minimum, I find it very, very unlikely and not "easy" to accomplish, as was mentioned above, due to all of the factors I have mentioned.

The USCG Healy log notes seem to summarize the situation fairly well this summer, so let me refer to those again.

What the high degree of concentration holds for the freezing season: I would assume the normal logic still holds:
1. Areas of thicker ice will grow slowly and mainly by ridging as result of wind patterns, irrespective of temperature.
2. The large thin ice area around the Pole and towards Laptev should grow relatively quickly due to the low temperatures in this region - which is good for ice volume growth.
3. For the open water regions: It really depends on SST and weather in each region: CAB area for 2015 is fairly equal to 2014, Laptev seems to start freezing, which happened a couple of weeks later in 2014, and for the ESS and CAA I guess we just need to wait and see when temperatures drop.

[wayne]

John,

Physical Reality is yesterday the sea ice extent JAXA day 26 4,758,781 day 27 4,737,804 mn2. 20,000 km2 less some 10 or 20 days after minimum (depending on which official statement), after I said it would be possible. And Ships logs as you cited largely confirm the areas ice conditions we've seen on sat pictures.

The physics which did not happen was a strong compaction process over the melting season. Which entails more insolation and therefore a larger apparent melt.

We must consider compaction much more significantly making pronouncements about the state of sea ice. I would like to see a model which would calculate the true melt of each season while removing compaction process.

[TenneyNaumer]

Just wanted to point out that the sea ice melted apace in May and early June while the Arctic Oscillation Index was positive.

It turned negative for the rest of the melting season, preventing a good deal of warm air from entering the basin via the North Atlantic:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index.html

[Bill Fothergill]

Although Jim Hunt has being telling us about ArcticMix for some time, the "mainstream meedja" also appear to be getting the word out as well...

Article at ... http://www.bbc.co.uk/news/science-environment-34324439
Video at ... http://www.bbc.co.uk/news/science-environment-34365416

Whilst reading about the micro-structure profiler being used on the mission, I could not help but think of the Douglas Adams line about "Eddies in the Space-time continuum".

[Jim Hunt]

Thanks for the heads up Bill.

For further information on the next scientific mission of the R/V Sikuliaq see also:

http://forum.arctic-sea-ice.net/index.php?topic=1222.msg64017#msg64017

Jim Thomson et al. will be investigating the "Sea State and Boundary Layer Physics of the Emerging Arctic Ocean" starting on October 1st.

[Cato Uticensis]

In my opinion the "what if" exercise, however directed, is not providing much added value.

In this case, we are arguing that with more compaction a lower extension would have been achieved. Right. But talking about volume figures, @ day 258 in 2015 PIOMAS volume is 5,713 vs 3,685 in 2012. 55% more ice.

I wonder which conditions would have been necessary to get the same extension of 2012 with the current volume of ice. And to get to the resulting thickness, as well...

The point is, there is much more ice now than in 2012, and this is fact, unless we want to question PIOMAS. Moreover, ice extension is increasing quickly in September (please find the link to the latest post by BFTV http://forum.arctic-sea-ice.net/index.php/topic,1112.1000.html ).

Honestly I'm much more interested in the ongoing extension increase rather than on the missed opportunity of a record-low extension which with the current volume of ice sounds to me quite unrealistic.

I will be eagerly waiting for the next update by Neven about PIOMAS October...

[John Christensen]

Agreed Cato, and hopefully we will have Neven's 'minimum part 2' analysis also, which will focus on ice volume, I believe.

[wayne]

"So the news is that dark streaks on the surface of Mars have been analysed and are showing evidence of having been created by salty water. Clearly the next question is how much water lies under the surface of Mars?"

Its a busy news day for all things cold, Water on Mars amongst other headlines (where it gets really cold), I find NASA's finds compelling but not quite live:

http://www.theguardian.com/science/across-the-universe/live/2015/sep/28/water-on-mars-buildup-to-nasa-mystery-solved-announcement-live

There is a way to find water on Mars, and its in permafrost,
something we know very well here on Neven's blog.
So if there is permafrost the distant horizon altitude would change
for no apparent reason, especially when daily temperatures change so dramatically. Here on Earth, I can "see" the ice under rocks, because surface rocks warm up fast in the sun, but the colder permafrost just below would cool down the surface layer fast at sunset, allowing a gradual horizon boost to be visible.

If there was a great Martian ocean, there should be a lot of permafrost, of which detecting the water is made easier, even though the atmosphere there is thinner than Earth, the daily temperature variances are huge, this should make it possible to detect the presence of water on Mars.

http://eh2r.blogspot.ca/2015/04/how-to-find-underground-frozen-water-on_25.html

[wayne]

True Melting of sea ice extent or volume is at present directly muddled by compaction, consider 2006 volume drop as compared to 2007, a well known Arctic dipole melt event. Consider removing this dipole event and imagine what sea ice would be like at 2007 minimum. Those who suggest that there is sea ice recovery from 2012 must factor in compaction effects before effectively declaring a cooling and therefore recovery. 2013 was declared a recovery year ad nauseam without considering that 2013 had practically no dipole.
Comparing sea ice melts must also consider physical dynamics.

[navegante]

In this case, we are arguing that with more compaction a lower extension would have been achieved. Right. But talking about volume figures, @ day 258 in 2015 PIOMAS volume is 5,713 vs 3,685 in 2012. 55% more ice.

Cato, most of the ice volume in excess wrt 2012 resides at the core of the Central Arctic.

http://dosbat.blogspot.com.es/2015/08/piomas-july-2015.html

So one does not have to question PIOMAS in order to argue that the ice pack could have been reduced a lot more (not to the point of 2012 though IMO).

But you are right, enough with the "what if",... for the time being :-)

[Tor Bejnar]

From the ASI Forum:
The scientists aboard Healy tried to gather ice measurements along the journey but were stymied by finding slush instead of solid ice until they were within 100 miles of the North Pole, they said in a Coast Guard press release.

"It’s hard to believe how slushy the ice has been so close to the pole; this was the first area we were confident enough in the ice conditions to allow on-ice science experiments," they wrote. "Despite being thick, the ice we encountered further south was simply too soft and unstable to safely put individuals on."

http://www.csmonitor.com/Environment/2015/0909/Ice-breaker-US-Coast-Guard-sends-first-solo-ship-to-North-Pole-video

[John Christensen]

So the USCG Healy had to back up several hundred yards to gain enough speed to ram through slush.. 10 feet thick slush.. ;-) Amazing, isn't it!

[John Christensen]

Seriously though: To do work on the ice you want the ice to be flat, with no/few leads, and little/no melt ponds.
Further south they probably encountered flat ice, but with melt ponds, which is not great for on-ice work, so they had to get close to the pole, before the temperatures were low enough to freeze over the melt ponds.
Therefore, the notion that they had to get within a 100 miles of the pole to find solid ice is taken out of context (Or their own logs are completely misleading), as it is really about finding flat, solid, suitable ice to work on, with no/few melt ponds.

[Ghoti Of Lod]

JC: "To do work on the ice you want the ice to be flat, with no/few leads, and little/no melt ponds."

I often see descriptions of difficulties finding ice suitable to allow scientists off of ice breakers to do research in recent years.

Seems to me then that ice research is often being done on ice that is probably not representative of the ice pack. It certainly means the sampling is not random and not suitable for statistical (or modeling?) extrapolation.

[John Christensen]

Agreed Ghoti; I have (only once) attempted to ascend a glacier in Northern Sweden mid-August, and it was impossible with the deep slush resulting from months of thaw.
For the same reason, any serious attempt on ascending mountains are timed to be around the end of the freezing period, where temps are milder, but the ice and snow has not yet been exposed to too much sun or heat.

Enough of that, though, and back to the current and the ice: What a massive cyclone that has appeared over Svalbard, and then a smaller one in the Western Arctic. It seems like these were not forecast, but you clearly see the spike in DMI 80N temp, as the winds are from south and strong.

[Cato Uticensis]

... But what is even more interesting is the very big HP which is forecast forming in three days and persist for several days extending over almost all the Arctic.

Both GFS and ECMWF are in agreement about that (for the time being...)

[AbbottisGone]

Ok, so for example we have a headline and story like this:

Sea ice still too thick for Arctic shipping route

Despite climate change, sea ice will continue to make the Northwest Passage too treacherous to be a regular Arctic shipping route for decades, says study.

http://earthsky.org/earth/sea-ice-still-too-thick-for-arctic-shipping-route

<<

So, I AM ASKING: "Is there a counter argument for such exact words?"

[AbbottisGone]

also,

"How climate change will affect the summer ice in the Northwest Passage in the future is difficult to predict, says Haas. Further melting could cause more multiyear ice from the Arctic Ocean to drift into the passage, making it less, not more passable."

<<

This seemed a weird/maybe-not-so-weird-but certainly-interesting quote.

This may be hinting at the fact statistics have their holes...

Not sure I have a question regarding this,... just found it interesting.

[NeilT]

Tor, It's not as if this was not predicted...

http://umanitoba.ca/news/blogs/blog/2009/11/27/news-release-thick-arctic-sea-ice-goes-missing/

Rotten ice it was christened and rotten ice it is.

[Kris]

Abbottisgone stated:

So, I AM ASKING...

And why do you ask!?

Back in september 2008 NSIDC already stated NW-passage and McLure Strait would remain blocked the coming Septembers for years and years to go. We here in this very blog and alreday in the second week of August 2015 noticed McLure strait would remain blocked this year by the countless shelves on the loose.

For sure the year 2015 will be remenbered as the year of the shelves on the loose and the rotten ice.

So, why are you asking for the obvious?

[Ghoti Of Lod]

Except that the passage through Mclure Strait was open this year. M/V Andros completed both west to east and east to west passages this summer. The East to west used the McLure route.

All 7 routes through the NW passage were completed this summer.

http://northwestpassage2015.blogspot.ca/2015/09/all-seven-7-northwest-passage-routes.html

The Northwest passage is open reliably enough that there are commercial tourist cruises through it every summer.