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Finally some calming news from that infernal PIOMAS data. Now if only it would also start to get thicker.

John Christensen


Thank you for another great update on PIOMAS.

One question: With daily Arctic ice volume for May 2013 showing less decline than the long term average daily Arctic ice volume, would you know how the negative anomaly was increased in May? Seems contradictory, unless some of the variables differ between the two calculations.

With daily Arctic ice volume for May 2013 showing less decline than the long term average daily Arctic ice volume,

They don't. May 2013 decline was 2.186 [1000km3].

The 1979-2001 average is showing something less than 2.

Seems contradictory, unless some of the variables differ between the two calculations.

They do differ, the "official" anomaly graph calculates the normal upto the last full year, so currently 1979-2012.

I get confused from this sliding ever changing "normal".

Wayne Kernochan

Not sure if someone has noted this, but please see http://www.dailykos.com/story/2013/06/05/1213506/-Russian-Arctic-Researchers-Await-Rescue-on-Shattered-Sea-Ice-Battered-by-Storms . They seem to be more pessimistic than Neven about Sept. ... - w

Jai Mitchell

It looks like the current value has trended outside of the error bars on the high end. This is probably due to the below normal temperatures so far.

The volume decline rates appear to be trending along the rate of 2004 and, to a lesser degree, 2007.

The temperature graphs for these years show the real declines occurred after late July.


John Christensen

Dailykos certainly seem pessimistic.

Average temperature at 80N the first week of June is -2 to -3 Celcius, and still Dailykos has:

Unseasonably warm 0°C air pulled in by an Arctic storm is allowing the north pole web cam's internal heat to melt ice on the lens cover on 3June, 2013.

It would not have to be more than 1-2 degrees C warmer than average to allow this to happen, so cannot be very unseasonable...

Al Rodger

John Christensen.
The PIOMAS anomaly dropped about 400 cu km through May with the 1979-2011 anomaly base. The average shown in the PIOMAS volume graph additionally includes 2012 which dropped like a stone through May and so would reduce that 300 cu km figure a bit. And the average 1979-2012 could be a tad 'schematic' in nature.
Even so, if you scale the graph with tangents of the average & the 2013 line, the anomaly is increasing. I got a rough figure of 150 cu km from a quick bit of line-drawing.
When trying to do such an assessment just visually, your eye will tend to be attracted away from the 'average' curve positioned directly above the 2013 May figures resulting in a comparison partly with the steeper June figure.


Thanks for that link, Wayne K. I have a more extensive reply over at the post concerning the evacuation of the Russian research station.


I wonder if melt water from Greenland and CAA glaciers is beginning to provide some protection to the ice via rejuvenation of the Cold Halocline? Purely speculative, but we can expect this kind of negative feedback during periods of rapid glacial melt. My gut is that it's probably too early for that kind of response. But last year's Greenland melt was very substantial.

Chris Reynolds

Wipneus, or anyone else using gridded PIOMAS data.

I'm pondering emailing Dr Schweiger and asking if we could have thickness updated to June in July instead of update to July in August.

Comments anyone?


I also wonder if Piomas gets some of their data or comparisons from mass buoys?

Of interest is a thick 343 cm mass buoy showing accretion when the surface temperatures got warmer all while when it was really cold no thickening, in fact slight thinning, fascinating!

If the sonar used is not calibrated with ice temperature the reading would actually show these apparent irregularities.


3 meter ice should not grow, apparently to some in the know.


Chris, it would indeed be nice to have it earlier. The July data would come too late to use it for the Sea Ice Outlook projections.

Remko Kampen

Speculations galore. Wild one on sweet water from Greenland ice melt by Robertscribbler, but 500 Gt is truly massive. What is it compared to river flux from Siberia and Alaska?

I have a wild thought too. I'm wrestling with the idea that Crack in fact might be Good for You. Maybe the curious cracking events in late winter have led to spread with those broad polynyas freezing over. Then a fairly cold Arctic spring en now albedo is holding things fast.
I do feel there is a bad mistake in my reasoning here.
Anyway, volume is not in thickness but in area this time.

What I expect this summer is the by far greatest single vertical drop in sea ice area ever witnessed. Catastrophe, mathematically meant. Area can hold out precisely until overall thinning has reached a threshold. The lot may still vanish this September.
Wild speculations.

Remko Kampen

Well, Chris, it is re the climate canary's health by now time for such a monitoring measure.

Chris Reynolds


I'll do it after I've done my blog post.

R. Gates

Call me a Doubting-Thomas, or Doubting Gates, but I take no comfort in the current data, and in fact the ratio of the volume to the area ratio has me the most concerned about what I've called the coming "Cliff" and what Remko called "greatest single vertical drop in sea ice area ever witnessed."

The Arctic is great at providing head-fakes, and doing the exact opposite of expectcations, and then suddenly reversing that on a dime, but now that expectations are as fractured as the ice itself, what indeed would be the "exact opposite"?

I expect PIOMAS to follow extent and area off the same Cliff, albeit we'll not see it until after the normal processing delays. In other words, we'll have to watch the plunge twice!

Glenn Tamblyn

PIOMAS has been climbing relative to 2012 for some months now. With all the cracking we have seen in that time, how much might that have impacted on this - lead opens up then freezes over, more ice?

John Christensen

Thanks Al - I see what you mean.

Also in agreement with many comments that "volume is in area, not in thickness", and that this should lead to amazing drops once the Arctic area heats up further.

Still: As referenced from article on 2007 melt, what appears to be dramatic in summer melt is the heating of an open sea surface by sun radition and then for wind or currents to cause ice to pass over the heated top water layers. In this respect, while area is fragile indeed, it is still a cover, so will keep dramatic top water layer heating at bay - as long as the ice lasts. Another week, another day..
It should be possible next month to better assess whether area indeed will have made any difference at all.

John Christensen


I would agree that the strong freeze in late February, combined with the cracking event must have led to very extensive (i.e. above normal) heat exchange between water and atmosphere, and therefore increased ice volume generation. It has then been assisted by a relatively cold late spring, which appears to have delayed melting in some areas for a short while.
So yes, ice is there, but it is young and will melt fast.


I was taking an evening sweep over the ECMWF forecast and what do I find, an arctic megastorm going all the way down to 965 hPa, bringing back traumatic memories from early August 2012.

Fortunately, this is forecasted to happen 216 hours from now, and is therefore, taken in consideration the low accuracy of the forecasts that go beyond 7 days, not to be taken very seriously yet.


PAC (Persistent Arctic Cyclone) 2013 is now at 975-980 mb, hardly a slacker. Been watching it churn through the central ice all day long.

That 965 mb low you see on June 14 is the same storm...

Jai Mitchell


on the PIOMAS volume 2005-2013 plot there is a key slope inflection point where the thickness/area accumulation breaks horizontal from the 30 degree slope increase.

Is there a name for this point in the cryo-lexicon?

have you tried to pull it out of the data an plot it as an additional predictive tool?

what ever it is (end if ice accumulation phase?) it seems to be happening around the summer solstice prior to 2008.

then in 2009 a shift occurred which has been progressing since then, going from (about) June 3rd in 2009 to May 25-May 31 for 2010 to 2012 and now May 1 in this year's data.

John Christensen

The cyclone:
Average air temp at 80N is now -3C, top layer water should be about -1.8C, so wonder how much mixing/Ekman pumping will take place?
What happened to steady, on-going summertime melting?

Chris Reynolds


Note that PICT isn't really thickness. I call it 'calculated thickness' and have error analysis on a per month basis with PIOMAS gridded data I can provide if needed.

The upward slope of thickness: Volume increases more than area implying thickness increase.

Levelling: Volume and area changing at similar rates, implying no change in thickness, loss mainly horizontal.

This is all related to the behaviour of PIOMAS as seen in the anomalies.
Note the inflection for 2010 to 2012 around the solstice, the spring melt ends and anomalies go upwards. i.e. probably due to ice edge being further north volume loss change after the solstice is less than volume loss change of the baseline period.



Would you mind:

Stik piben ind!

There is enough noise on this blog already.



Artful Dodger

Jai Mitchell wrote | June 05, 2013 at 22:38

"there is a key slope inflection point where the thickness/area accumulation breaks horizontal from the 30 degree slope increase. Is there a name for this point in the cryo-lexicon?"

Hi, Jai

I don't believe so. I suggest we adopt the term "Ni", after "the knee of a graph" and "the Knights Who Say "Ni!" ;^)


Jai Mitchell


so, in previous years, at the solstice, the rate of ice area loss was at maximum and only then the rate of proportional volume declines became equal to the rate of area loss.

and once this maximum rate of area loss began to slow then the thicker ice was lost due to surface and perimeter melt.

now, since the collapse of multi-year ice last year, the average thickness is more like the actual thickness, the proportion of thicker ice being much smaller now.

and so average volume is declining at the same rate as the area is declining even before melt is occurring.

it also seems to indicate an increased sensitivity to insolation, convective currents or downward longwave radiation as first year ice becomes a higher proportion of the total ice volume.

Kevin O'Neill

Jai - and don't forget that the snow cover anomalies are also dropping off the charts. This removes a buffer zone of cooler temps around the arctic basin.

Now when weather systems suck warm air into the arctic that air hasn't had to pass over miles and miles of snow. The ice receives the full brunt of +10C, +15C even +20 C warmth.

We should see precisely that scenario over then next week or so.


@ John

Transitions like these are never neat. Storms are heat/cold engines. So should we be surprised?

John Christensen

Agree: It appears that while the NH temperatures in the 55-65N band are going up and in some areas are quite high, it creates a kind of insulation of the central Arctic, keeping the temperature slightly below average here. If that is what is going on, the low could potentially stay in place for a while or get recreated with welldefined iso-bars, until finally the summer temps will spread across the Arctic north?
Sorry, if I offended you with loads of ignorance and will keep comments appropriate and to a minimum. Or I should have chosen appropriate stuff like Eurovision quotations..


John, I think P-maker's point was that there are two blog posts concerning the cyclone and this one is about PIOMAS. He could've been more subtle, and even I don't always manage to stay perfectly on-topic either, so it's not a huge problem. But in principle we have the New map on the block post to talk about the cyclone. Or the ASIF.

John Christensen

Got it, thanks Neven.


Looking at last nights Uni Bremen AMSR2 chart, it would appear that there is either significant melt pooling or significant melt and breakup happening almost at the pole itself.

Time will tell I guess but, as has been said already, the Arctic likes to surprise...


Back to topic...

I think Chris Reynolds provided some excellent insights/speculation in his most recent blog.

This slower than record volume melt for May puts us at 3rd lowest moving into June. So we have a slow start to volume melt. If it's a cooler June and the persistent storm has less impact, then it's unlikely we'd see a new record in volume come September.

But that thin ice makes it difficult to say we're out of the woods yet.

Chris Reynolds


I see the 'collapse' of MYI as being in 2010, and that as being the reason for the more aggressive spring melts since then. This year I think the spring melt just hasn't had chance to happen due to the cold.

In the summer as concentration drops the error between PICT and the PIOMAS average thickness increases. Here's the last few years percentage error between PICT and PIOMAS average thickness, rows are months.

Year 2009 2010 2011 2012
Jan 1.96% 0.19% 0.24% -0.79%
Feb -1.69% -2.40% -2.47% -1.40%
Mar -2.51% -2.93% -2.03% -2.29%
Apr 0.12% -1.78% -0.93% -1.31%
May 3.78% 2.60% 3.56% 3.48%
Jun 9.92% 9.70% 8.61% 11.52%
Jul 26.21% 28.24% 23.38% 26.76%
Aug 35.16% 31.40% 36.04% 31.13%
Sep 27.62% 29.71% 24.00% 23.53%
Oct 23.14% 17.92% 17.67% 16.02%
Nov 11.01% 7.14% 7.76% 7.99%
Dec 6.12% 3.26% 3.65% 3.35%

The errors continue to be high into the autumn, I'm not sure why.

I think you've misunderstood what I was saying, probably because I wasn't clear enough. Consider what PICT is showing, A is area (CT Area), Volume is PIOMAS volume, PICT is a notional thickness.

PICT = Vol / Area.

Throughout the year both Vol and Area are changing, they change least at maximum and minimum. So with Vol and Area changing how are we to interpret PICT.

If PICT is level then Area and Volume change at the same rate.

If PICT decreases then Volume is being lost at a greater rate than area, this requires a thinning of PICT to balance the equation.

If PICT increases then volume is increasing faster than area, this requires a thickening of PICT to balance the equation.

What PICT shows in pre 2010 is what Kevin O'Neill and I termed 'the roof', implying that CT Area and PIOMAS volume were dropping at commensurate rates. You are correct that an element of the explanation for this is less thinning of thick ice holding up the volume, and most melt coming from horizontal recession of the pack.

After the 2010 volume loss, which caused a massive reduction in thick ice biasing PIOMAS grid box thicknesses upwards, PICT shows a drop throughout the summer, implying that the area loss in these summers is being outstripped by volume loss.

I expect PICT to exhibit the same behaviour this year. If that happens we can be more confident that the failure of the spring melt development in May is due to weather, not a change of the fundamentals that have caused a post 2010 shift in the seasonal cycle of PIOMAS.


Neil, a great North Pole melt is possible at about this time of the year because the ice is first year thinner, except its very cloudy, which is still not good for sea ice long term. If this overcast coverage continues till early August, the ice will be so frail it will be blown away to bits by any storm. This is what happened last year, the illusion of extent gets shattered by all the rot under the top of sea ice.

Mass buoys do not seem to be accurate enough to display any melting or change of phase of the under ice. They indicate more accretion when its practically impossible for it to happen, if the good people at Piomas rely on its data, they should recalculate and shave a few cm (which is a rather large amount of ice volume), because its rather melting at bottom, not freezing. Say its -5 C on the surface and there is 1.5 meters of ice insulating the -5 from the -2 at its bottom. How can there be any ice forming? Rather the ice is warmer and displays an apparent false accretion.

And so says the ice Horizon! Long life to boundary layers!

Pete Williamson

" It could mean that either winter weather still has enough of a punch to restore the ice pack "

I'd been wondering about that. With the lines in graphs 4 and 5 running parallel through the freezing season it suggests to me that the ice can still put on thickness at the same rate even going back to the 1990's. Well that's how I'm understanding it, I could easily be wrong. Would that be right?

Dan Ellis-Jones

Can I ask a silly question, as I know there are many lurkers on this site, and I expect we have a few holes in our basic understanding.

What proportion of 'normal' ice melt is precipitated by warm air temperatures (i.e weathers systems dragging in warm southerly winds of say 12C), the action of strong winds, and the effect of warmer ocean currents underneath the ice?

I have looked at the weather maps for the next week/10 days, and there seems to be a continual storm, with tightly pack isobars, tracking across from the Canadian Archipelago, to western Siberia and then slowly to central Siberia - all the while over currently frozen (to whatever volume/extent/concentration)sea ice.

So what is more important to sea ice melt - the speed and longevity of the winds, or their temperature? (I realise that warm, strong and persistent winds will be death for sea ice!)

Shared Humanity

Looking at the CT image for June 6, it seems to suggest that the persistent cyclone has been pushing the sea ice up against the coast of Alaska and eastern Russia while reducing concentration in the CAB. We even see slight reductions near the CA and Greenland where much of the MYI hangs out. With volume still not dropping fast, can we determine if much or any of the MYI has been moved into the Beaufort, Chukchi, East Siberian and Laptev seas? Could this suggest a large drop in volume this year?


And with all of the discussions about the reliability of images and models, is this CT image correct or worth worrying about.


@ SH

The CT measure is the least sensitive, so you'd see any changes coming up there last. And we're seeing that now.

The other measures are certainly worthwhile, but sometimes over-state changes or come up with artifacts in day 1. They're more consistent over time. For example, if you see some large blotch of yellow (meaning thinning ice) in the Uni-Bremen measure on one day, it may go away the next. This is because the sensor can pick up different surface conditions and measure it as 'ice loss.' That said, these artifacts tend to wash out over a few days. So if the yellow blotch remains after day 3, then it's probably real.

The CICE/HYCOM thickness map is somewhat similar in that it seems to be more sensitive to an event on the first day (or in forecast) but then becomes more reliable over time (in retrospect). The thinning we see now in CICE near the CAB is probably real as it's not only now a permanent feature in the CICE measure, but shows up pretty much everywhere now. The thinning we are seeing in the thick ice off the CAA in forecast is probably exaggerated a bit. So in CICE, we'll probably see a bounce back to greens and yellows, but less in the way of reds -- meaning about a meter of thickness loss. We'll have to see it in the measure to get confirmation for this interpretation.

It's worth noting that, at this point, about all measures and the visual are picking up a thinner ice pack in the CAB. It is also worth noting that, if the storm had simply re-distributed the ice out of the CAB and on to the ice edge we would have seen sea ice extent and area measures show a bump higher or at least push toward more stable numbers. Instead, we see a more rapid fall in extent and area numbers in most measures over the past week. This is not to say that some re-distribution hasn't occurred. But it hasn't been enough to show up in the measures, where the thinning has.

Hans Gunnstaddar


Big jump in Greenland ice melt today in link above, coincidentally as 2013 Artic ice extent @


shows it is right on the cusp of when it began to dive last year. Should be interesting to watch the next few days to see it makes a similar move to 2012 or charts a new course.


I've been looking at the Barrow webcam fairly regularly. Apart from one point in May, the temp has been consistently below 0 overnight, in the morning and late evening.

However the ice is still melting, albeit more slowly with lots of melt ponds.

When these clouds disperse, that ice and it's attendant volume, is going to vanish, as the Scots say, "like snow off a dyke"....



That's a good question because it's a tough one to answer. The reason why it's a tough one to answer is because different conditions have different impacts.

1. Still, warm air (5+ C), clear skies.

Under these conditions insolation is a powerful force to melt the ice, because they allow the sun to do its work. You end up with the formation of melt ponds, which are darker in color so they absorb more heat (reducing ice albedo). These ponds also act as a lens, focusing the sun's energy downward into and through the ice. This both heats the ice and the water underneath. A very powerful force to melt ice, but you need these conditions.

2. Warm (2 C +), Windy (15 Knots +), Cloudy, Moist (Humidity 85% +).

These conditions usually happen when you get a punch of warm air from the south via our eroded jet stream. This kind of event happened when Scandinavia warmed up last week, then some of the warmer air rushed into he Arctic to feed our storm and warm the CAB a bit. Directly in the line of fire was the thin ice just off Svalbard. As the warmer, wet, air rushed up and over the ice, it melted much of it. You can see this action if you monitor the loss of ice off Svalbard over the past weeks.

3. Storm (995mb or less). Windy (large wind fields of 25+ knots). Air that is not conducive for large-scale freezing during storm conditions (-4 C+).

Storms are tricky. One reason is that Arctic storms are cold-core. Because of this, they tend to pull a bit of colder air along with them. But you get churning, upwelling, and cyclonic action that breaks the Cold Halocline that protects the ice. Further, if you have above freezing temperatures, rain will erode the surface. Lastly, these storms tend to draw in warmer air behind them which has further impacts.

4. Warm Fog (2+ C), still air, near 100% humidity.

Works for much the same reasons as a warm, wet, wind, except it's the fog that has the ability to eat snow and ice all on its own. You usually see this condition at the ice edge where the ice contacts dark, open water and where ocean temperatures in the open water regions are warmer than air temperatures.

Which one of these forces are strongest depends on how much heat and energy are present. Under hot conditions, insolation is extraordinarily powerful. Under above freezing conditions, a powerful storm can wreck havoc. If the warm, wet, wind is strong and hot enough, it can bore deep into the ice. Fog, on the other hand, is indicative of a hotter ocean which has its own implications.

A long answer and probably not as neat as you would like it. But there you go.

John Christensen


Nice summary of main summer-related weather types and how they relate to melting and reduction in volume.

For the storm factor, it should indeed be the tricky one for net volume reduction effect, due to the churning on one hand, but tendency for lower temps on the other. One additional tricky aspect: The recent and current lows must have dumped loads of snow on the ice pack below, thereby increasing albedo and delaying atmospheric contact with the ice layer. As I mentioned earlier - if given the choice - I'd prefer a low in June (considering radiation, clouds, precipitation, temps) and then a high in August with clear skies greater heat loss during the increased number of dark(er) hours.
With the current scenario it will be very interesting to see PIOMAS numbers for next month, given all the speculation and challenges interpreting the ice concentration maps.


Cloudy, cool conditions, no strong storms. I'd think that's the best set for keeping the ice from melting. And we saw that in May until this PAS emerged.

I think my opinion on whether or not the current storm is a comparably 'good' result is well known at this time. So I won't go too far into that. Current CAB ice conditions aren't looking good in the monitors, though. And we have strong insolation melt in growing regions on the ice edge. Just look at the southern CAA in Lance Modis. Lots and lots of 'blue ice.'

PIOMAS May 2013 was a positive result in a long string of losses. June? We'll see. Not looking too great from where I'm sitting at the moment.


@NL Patents
Nice, but wistful thinking. 1.98 milj sq km and a ice free NP this year. The "Clif" is near.


"Cloudy, cool conditions, no strong storms. I'd think that's the best set for keeping the ice from melting. And we saw that in May until this PAS emerged."

Not quite Robert, cloudy during the day when the sun is +20 degrees high (can be lower in warmer temperatures), clear at night releasing long wave radiation to space is the best way to spare the ice from a mega ice melt. Except nature usually does the opposite, which is clear during the day and cloudy foggy at night, very bad, worse conditions imaginable. Come past mid July, strictly always cloudy, very very bad (2012), as opposed to continuous clear skies which would bring up the minima earlier.

Facts? 2008 for instance, when it was very clear for months in the spring, the ice thickened more, then near solstice the sun was high enough to create massive melt ponds everywhere, luckily the clear air favored maintaining the ice more then melting it.


@ Wayne

I was referring to June and July when the sun is mostly present...

George Phillies

The current IJIS graph


appears to be showing the extent starting to fall off the cliff. It started higher than last year, but is currently matching last year both in extent and in slope (first derivative). However, the period of the cliff fall is sufficiently short that it might be a fluctuation.


The IJIS graph hasn't been updated the last 2 days. Hopefully tomorrow they catch up.

Stephen Pekar

The latest sea ice concentrations are astounding. Look at the loss of ice, at least 40% of open waters in some places. I have never seen anything like this so early in the season from so high a latitude.


This modest storm has really done a number on the sea ice.


Which sources have the worst or best resolution for ice extent? I'm looking at IJIS, DMI, CT, AMSR2, and NSIDC. CT, AMSR2, and DMI all show 2013 continuing on a slow trend while NSIDC and IJIS are tracking 2012 closer. I guess its hard to tell with IJIS since its behind by a couple days


Stephen Pekar, Uni Bremen SIC maps have been updated to the higher resolution AMSR2. There's definitely stuff going on down there, but don't get carried away by those yellow-green swathes that come and go. Only when they stay in place for 3 days or more and things can be seen on LANCE-MODIS satellite images as well, can you be sure that concentration in a region is indeed lower.

It's very cloudy and hazy over the Arctic right now, the ice pack is already quite slushy in places, there's some melt ponding starting to be visible on the satellite images (fast ice getting blue), and I think all those things can confuse the sensors. But things will get clearer and clearer as the melting season progresses.


For instance, the yellow and green in Baffin Bay is real. The ice there is going to melt out real fast now, but several weeks later than I had initially expected.


Also PIOMAS gridded thickness data has updated!

Compare May 2013 with 2012:


"but several weeks later than I had initially expected."

*Thank* *Heaven*...

Chris Reynolds

Thanks Wipneus,

I only sent the email last night, they must have been intending to do this anyway.

Must check my email inbox.


The plain thickness map:


Thanks, Wipneus. I have updated the post with your maps.


I'm wondering if not the Persistent Arctic Cyclone can be preventing an early season sea ice collapse by constantly pushing ice away from the main pack and into Beaufort, Chukchi, East siberian sea and Laptev, thus creating an illusion of a minor recovery, but instead resulting in a summer crash (of both volume and extent) rather than the spring crash that many here have been predicting. Personally, I can't imagine how the current situation can be positive for neither the ice volume or the general well being of the ice, especially as the storm is predicted to strenghten during the comming week.

By the way, well above normal temperatures and clear skies are in the forecast all over the Canadian Archipelago, as well as the Beaufort sea, and may be threatening to clear the CAA for snow even earlier than last year.


Did area just drop by 400k? How close to a record is the June 6-June 7 area decline. (not to incur P-maker's ire) that low has refueled and is quite powerful. I'm expecting a post tropical low today which isn't nearly as deep. I think that May volume data will end up being a blip.

Glenn Tamblyn

Whether the CAB is seeing open water, lots of slushies or masses of melt pools, it sure is unusual.

And the SW Kara is still fast asleep.

This is going to be one weird melt season.



I shall give you "ire":


(Neven, please don't watch this).

The Kraken will come from below, as you see in the video, and not from above.


Thanks for the warning. Wetted my pants again.

Jai Mitchell


Thanks for your reply, though I am pretty new hear, been lurking for about a year, I suspect that the rate of area loss and the rate of volume loss has been approximately the same at the beginning of the season (say from March 21 to June 1).

I would guess that the PIOMAS average thickness uses a different area input in their algorithm that uses a smaller total area. (perhaps they do not count surface ice moving out the fram?)

in previous cycles the rate of area reduction has been a function of the length of the perimeter of the pack. Now it looks like there will be significant pooling and holing of the pack leading to a greater (double?) amount of "edge ice" which may greatly increase the area loss.

The PICT uses a loss rate that is really based on the proportion of ice that still remains. So yeah, the thinner the MYI, the earlier that Lodger's "Ni" occurs.

Question: On your PICT graph, at what point does the thickness value indicate an "essentially ice-free state" is it around .5 meters? .25?

Chris Reynolds

On the PICT graph minimum is around day 250. If we say that essentially ice free was below a certain area (say 0.5M km^2) that area would still need volume, but it's hard to say what thickness would be implied.

PIOMAS is a model, it takes in sea ice concentration to adjust the model so that it better reflects reality. The model models Fram export.

There aren't really large holes in the pack at the end of the season. But the ice has become more fragmented. CAPIE is the ratio of CT Area and IJIS Extent. I use the term Dispersion Index for the same ratio but using monthly average CT Area and NSIDC Extent. It's done for August so that it's at the end of the season but doesn't get skewed by new ice growth in late September, montly averages are used to minimise influence of wind driven movement of the pack.

You can see that while there aren't large holes, the pack has become more fragmented. August extent was 1.35 times area, in recent years it's been 1.55 times average August area.

With regards early season area loss and volume loss. I've not got round to considering the implications of the flattening since 2010 in PICT. It is intriguing because at this time area loss is mainly outside the Arctic Ocean. Yet the post 2010 behaviour is driven by loss of thickness within the Arctic Ocean...

Very intriguing, I'd not seen that until you pointed it out.



Multi-year lurker here with ongoing appreciation to Neven and all of you who do so much to help the rest of us learn and understand.
With respect to the average thickness calculated from Piomas/area and Wipneus' map of same, .... clearly thinner ice is vulnerable to significantly greater damage/destruction from mechanical action, storms, waves, collisions, fracturing. This has been discussed at various times over the last couple of years. Question: is there sufficient correlation to determine that, for instance, all ice of, say, less than one-metre thickness on June 1 fails to survive the summer? Apologies if this is too simplistic an approach to such a complex and dynamic system but overwinter thickness in the CAB does seem to have the potential to represent yet another tipping point.


Hmmm, the thicker ice (relative to last year) in the Kara Sea is sandwiched between anomalously warm water to the west, on the other side of N.Z. island, and early loss of snow cover to the southeast in Siberia. Wonder how long it will hold out.

Chris Reynolds


Here's a plot from PIOMAs gridded data of percentage of ice melt (area weighted) for April thickness of ice.

It shows how as April thickness reduces the percentage of ice of a certain thickness reveals more open water.

I've just done the same for June here:

Veli Kallio

It is important to remember that University of Washington's PIOMAS model understates sea ice volume in comparison with ESA's CRYOSAT readings for the summer melting season.

According to late Katharine Giles, "The decline predicted by Piomas is slightly less in the autumn and slightly more in winter" than CRYOSAT observations.

CRYOSAT's sea ice volume loss is greater than PIOMAS's during melting season. On the contrary, during the winter season PIOMAS generates a smaller sea ice volume while CRYOSAT shows it larger. PIOMAS model apparently understates the summer time sea ice losses.

CRYOSAT measures the freeboard of ice floes above the Arctic Ocean water surface to conclude the thickness of sea ice by adding freeboard (above water) and draft (immersed) sea ice halves together to reach thickeness and from there the ice volume.

As the sea ice is highly fragmented in June 2013, the leads are plentiful for CRYOSAT measurements as all ice is broken up and can help to produced very detailed results.

Unfortunately, the untimely passing of Seymour Laxton and then Katharine Giles has made a major disaster for University College London's Centre for Polar Observation and Modelling (CPOM) CRYOSAT team.

As per these,

    I suggest that we are giving too much emphasis to PIOMAS for a minor improvement that may be a modeling artefact.


[Please, don't forget the / in the closing tag. N.]

Andy Lee Robinson

I just made another Arctic Death Spiral to include May 2013 and the new thing is that the soundtrack is also derived from the data to modify the spectral content and various synth parameters - I wrote an Arctic ice to midi program, with events synchronized to the video frames.

Arctic Death Spiral - May 2013

If you want to hear the data as notes, then here's a rather dissonant piano version too:

I know which I prefer!

John Christensen

One of the interesting features of this spring/early summer transition is the relatively low temperature at 80N (http://ocean.dmi.dk/arctic/meant80n.uk.php), which can be compared to the late spring/early summers of 1992 and 2004, when you look at the DMI link above.
From PIOMAS, it also seems that daily volume decline was reduced in 1992 and 2004 while temperatures were low, so makes you wonder if those years also were dominated by relatively strong Arctic lows for this season, and that with stronger ice packs, this helped to conserve the pack and reduce melting.
About 11% of the period with average temperature above freezing for 80N (same DMI link) has passed this year, and the 80N ave. temperature has stayed below freezing this far, which is impressive given the poor state of the pack and increased SST that must be occuring compared to normally having a solid cover around the Pole.

Assuming we can rely on the DMI 80N data.

David Vun Kannon

Not that anyone should really care what Steve Goddard says on his Real Science (sic) blog, but he's taken a run at PIOMAS in a couple of recent eructions.
His latest is http://stevengoddard.wordpress.com/2013/06/20/smoking-gun-that-piomas-is-crap/
(Don't click unless you have excess brain cells and no vodka.)

I replied (and it is still in moderation over there, naturally):

That might be true if all other things were held constant, but of course they aren’t constant. Ice forming from open water has to wait for a lot of energy to go into the phase transition. If the water temperature increased, then there is more heat to dispose of before refreezing begins, and less time throughout the winter for ice to thicken. Also issues with salinity.

PIOMAS does have its own ice thickness chart:

though Steve’s graph does effectively show the long term, accelerating decline. Now why would that be? Is it natural, cyclical variation, or is it…

Kevin McKinney

Couldn't resist. Since Steve's motto is "Just having fun," he shouldn't begrudge me mine, should he?

I wrote:

Perhaps you don't understand how thick ice actually forms in the Arctic. For instance, if it formed more by ridging and slabbing, in addition to simple freezing, then perhaps the thinness overall could have a significant impact on that mechanism through the loss of rigidity...

Or maybe the thickness just reflects the fact that there is a whole lot of first year ice, and precious little of the multiyear variety--the resulting mean thickness would be lower, wouldn't it?

Just a couple of random thoughts.

After all, it made lots of sense to some last year when this blog proposed that the August cyclone would bring an end to the seasonal melt.

We'll see...

Jim Hunt

I failed to take notice of David's sound advice, and like Kevin I couldn't resist just having some fun. I felt compelled to quibble with Steve's latest assertion, that the "Arctic Basin [is] Full of Ice". He has at least approved all our comments!

I was idly wondering if he might be interested in the fact that the clouds are clearing over the North Pole. Today's first rough draft from WorldView:

Click for latest WorldView version

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