PIOMAS June 2018

Before kicking off this latest PIOMAS update, there's a little piece of information I'd like to share: A massive cyclone is passing through the Arctic right now. The cyclone has bottomed out about half a day ago at 966 hPa, which is slightly lower than the 968 hPa storm we saw at the end of August 2016, and slightly higher than the Great Arctic Cyclone of 2012 (963 hPa). Even though pressure levels are similar, this current storm can't match the other big ones when it comes to longevity. But at the same time, bear in mind it's only June, and not August.

And also remember what IARC chief scientist John Walsh said back in 2012:

This past week’s storm was exceptional, and the occurrence of Arctic storms of extreme intensity is a topic deserving closer investigation. With reduced ice cover and warmer sea surfaces, the occurrence of more intense storms is certainly a plausible scenario. The limitation at present is the small sample size of exceptional events, but that may change in the future.

I think it's safe to say it's changing.

Here's an image of the moment this current cyclone reached its lowest pressure, according to Environment Canada:

I will soon discuss the consequences of this storm for the ice pack, and apologize for not having started writing regular ASI updates yet (too busy).

Okay, now for the PIOMAS update.

-----

Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:

According to the PIOMAS model, volume decrease for May 2018 has been below average: 2285 vs 2650 km3. This means that 2018 is 5th lowest right now, and the difference with last year has grown to a massive 1915 km3, which is 299 km3 more than last month. It has also been overtaken by 2012, which saw a huge volume reduction in May. Likewise for 2016 and 2011, with 2010 not far behind now either.

Here's how the differences with previous years have evolved from last month:

Here's how things are looking on Wipneus' version of the PIOMAS graph:

Despite May 2018's below average volume decrease, there has been a small downtick on the PIOMAS sea ice volume anomaly graph. The trend line will probably dive below the linear trend at some point:

What's interesting, is that there hasn't been an indication of below average melting for JAXA sea ice extent, being second lowest on record for most of the month of May. The consequence for PIJAMAS (a crude average sea ice thickness measure, which you get by dividing PIOMAS volume with JAXA extent) is that it's also relatively high for the time of year, compared to most post-2010 years:

The exact same thing goes for the Polar Science Centre thickness graph:

Even though we're only one week into June, it's already interesting to look ahead at what this month may bring volume-wise. Not only because of the short-lived, though intense storm, but also because of the current weather forecast. After bottoming out over the Kara and Laptev Seas, the ECMWF model has the storm moving over the Central Arctic, to slowly fade out over the Beaufort Sea. Meanwhile, high pressure takes over on the Siberian side of the Arctic (images retrieved from Tropical Tidbits):

Those isobars between the low and high pressure areas, especially in the 24-72 hours timespan (first three images), represent strong winds that will further pull away the ice from the Siberian coast, most of all in the Laptev region where there is already a substantial patch of open water for the time of year, at the same time bringing in lots of heat and sunshine to the entire eastern half of the Siberian coast.

The reason that all of this is interesting, is that according to PIOMAS the ice is thicker along Siberian side of the Arctic when compared to the 2011-2017 period:

This means that if this kind of weather persists during the second half of June - which remains to be seen, of course - 2018 could be moving back to third place or so. This, in turn, will have consequences for the rest of the melting season. But that's something we'll discuss, if and when it happens. Right now, everything is open.

Comments

[wayne]

Hi Neven,

Is PIOMAS having difficulty with sea ice thickness in some areas? Am I suppose to believe that there is 1.5 meters thicker sea ice in the Barents sea area, must be from always water measured in the past? Usually of latest years quite open with water for a great chunk of winter?

Using temperature anomalies and precipitable water, these questions needs answers or counter arguments:

http://eh2r.blogspot.com/2018/06/some-piomas-ice-thicker-with-warmer.html

[John Christensen]

Thank you for another great update Neven!

I am noting for the past three months:

Year Feb 28th May 31st Relative gain March-May '18
2007 -2429 -1880 549
2008 -3121 -2867 254
2009 -3203 -2420 783
2010 -2295 -218 2077
2011 -825 528 1353
2012 -1073 420 1493
2013 -1269 -487 782
2014 -1231 -286 945
2015 -2849 -1490 1359
2016 -949 690 1639
2017 1034 1915 881

I will do some more review of this soon.

[John Christensen]

And sorry for my miserable graphics skills!

[wayne]

I have always suspected PIOMAS being very conservative with volume estimates, here is some proof:

http://eh2r.blogspot.com/2018/06/novaya-zemlya-region-did-not-have-time.html

So I suspect the real volume of the entire ice pack to be overestimated. Makes sense given the smaller sea ice extent numbers and especially the very warm Arctic Ocean winter just past.

[John Christensen]

wayne,

I do not agree with the points made above:

"I have always suspected PIOMAS being very conservative"

Well, DMI has a higher volume estimate, picking up more close-to-shore ice than PIOMAS I believe.

"Come June there was no evidence of multi year sea ice migrations, it is just new sea ice. It is conservative to estimate that this ice had only 3 months to accrete, which is definitely not possible to thicken so quickly beyond 150 cm,"

The sea ice clearly does not thicken to 150 cm due to the accumulated freezing of sea water: It happens via wind and current driven ridging. Nothing spectacular about that given the weather in the region in the past few months.

[wayne]

John,

"The sea ice clearly does not thicken to 150 cm due to the accumulated freezing of sea water: It happens via wind and current driven ridging. Nothing spectacular about that given the weather in the region in the past few months."

Ridging is an obvious effect of great lengths of time, I don't see it here, it does not show well at all... Rather it is thin sea ice, easily broken, the red +1.5 m anomaly should be uniform throughout, according to evidence presented, Novaya Zemlya Island is an anti-ridging natural enclosure as well.

[wayne]

I have added a bonus PIOMAS red zone thick ice feature loaded with open water for most of May 2018. explain this one John :)

http://eh2r.blogspot.com/2018/06/novaya-zemlya-region-did-not-have-time.html

[John Christensen]

Hi wayne,

I'd agree for northwest NZ on the Barents side: The DMI volume chart also does not indicate much sea ice here.

For Kara: Here we saw temperatures considerably below normal for March and April, combined with storms, likely considerable precipitation, which submerges sea ice and more rapidly builds new ice as mix of snow and freezing sea water on top of ice.
The Kara ice pack during those two months moved from the Siberian side to NZ and back a few times, which helps with ridging and the DMI chart today is in reasonable agreement with PIOMAS here, so if not fully accurate I would still find the estimates reasonable as any model estimate could be.

[wayne]

Yes John

Kara Sea has signs of significant melting about:

http://eh2r.blogspot.com/2018/06/kara-sea-ice-appears-to-have.html

There is more action everywhere over the Arctic Ocean...

[wayne]

Thank Goodness for the SWITCH in pressure scenery, cyclonic clouds shade the sea ice from most direct sun rays over the gyre area. This switchover was projected in April, came about as I expected, about mid June. It is a great accomplishment in projecting the future, I must say this myself, because I am certainly working to get the Nobel prize in achieving something while being ignored :)

http://eh2r.blogspot.com/2018/06/arctic-ocean-circulation-switchover.html

[Susan Anderson]

Currently large amounts of the surface at the North Pole are above freezing
https://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=200.94,92.16,1416/loc=96.248,89.958

Also, significant warmth @ western Greenland and northeastern Canada, fwiw.

[wayne]

And

Thin sea ice covered with thick snow playing games with our eyes and also algorithms

http://eh2r.blogspot.com/2018/06/sea-ice-delusions-by-thick-snow-carpet.html

The key is judging how mega ice pans break up...

[wayne]

Greening sea ice is a sign of melt ponds, particularly strong on the Russian side of the Pole this melt season, with open water pretty much exceeding 2012.

http://eh2r.blogspot.com/2018/06/the-current-green-line-border-between.html

[AnotherJourneybyTrain]

https://www.scientificamerican.com/article/judge-orders-epa-to-produce-science-behind-pruitts-warming-claims/

Al Gore told us this stuff will take atleast 20 years!!

[wayne]

2012 melt is in the cards by mainly one reason, the speed of sea ice velocity in the Beaufort sea area, twice as fast at peak before cyclonic switchover:

http://eh2r.blogspot.com/2018/06/speed-of-2018-beaufort-sea-ice-velocity.html

[AnotherJourneybyTrain]

https://robertscribbler.com/2018/06/13/stronger-slower-hurricanes-spell-big-trouble-in-a-warming-world/

Also, Wayne, when was this 'cyclonic switchover'?

[wayne]

About June 8 or 9, is when the gyre became dominated by cyclone(s) as opposed to anticyclone(s).

[John Christensen]

Amazing that a headline with "CO2 Shortage" should appear - and sorry in advance for the highly irrelevant piece of news Neven! ;-)

https://www.theguardian.com/business/2018/jun/20/co2-shortage-could-hit-uk-beer-and-chicken-supplies-during-world-cup

[John Christensen]

Sea ice related:

Neven, your regular bi-weekly updates on melting progress are very much missed, will they be forthcoming or will you focus on the monthly PIOMAS updates and combine as open threads?

So far for June I have noted:
- Weather stays 'blend' without any significant highs or lows, which overall is good for the ice cover
- DMI reported that the 80N average temp. moved into melting territory one day later than average, which also is good
- DMI sea ice volume for June has been trending above 2004-2013 average with below-average sea ice melting for the fourth consecutive month, which is rather impressive given the relatively warm winter and very low SIA/SIE this spring

In summary, I am still satisfied with my 4.85 - 5.35 (V3) Sept average SIE provided on June 8th.

Rob,

Will we see your updated estimate soon?

[wayne]

The speed of sea ice over the Beaufort and other areas has increased extent by scattering sea ice over already open water, by misfortunate lack of adjusting to the new reality of collapsed sea ice from within, extent increases in some regions but of course no new ice was created.
There is a vast difference between 2012 though:

http://eh2r.blogspot.com/2018/06/2018-shake-and-bake-sea-ice.html

If solar forcing is similar to 2012, so will be extent, although by rather different geophysical means.

[Rob Dekker]

John said :

Rob,

Will we see your updated estimate soon?

My estimate relies on Rutgers Snow Lab numbers for land snow cover, and NSIDC "area" and "extent" numbers for sea ice, as an estimate of the 'albedo' of the Northern Hemisphere.

Unfortunately, most of these numbers are only available on a monthly basis, so I still can't give any daily updates. May numbers projected 4.65 M km^2 for September, and the June numbers will be clear in the first week of June.

[Rob Dekker]

the first week of July that is.

[Rob Dekker]

The ARCUS SIPN report is out for predictions of Sept SIE based on May data :

https://www.arcus.org/sipn/sea-ice-outlook/2018/june

Interesting is that the median is 4.6 M km^2, pretty close to my estimate of 4.65.

[wayne]

Even PIOMAS measures a year by year gradual but certain decline in sea ice volume, extent numbers should be lower.
Although it is possible that sea ice extent may be emaciated and scattered enough to show higher extent come minima, I dont think so because I see the thinner sea ice in its pulverization wakes, there is the matter of a strong gyre current which garanties compaction, so this years minima should be in the 3's M km^2.

As one example of thinner sea ice we look at the Canadian Arctic, despite being under the coldest air in the Northern Hemisphere first year sea ice is currently collapsing:

http://eh2r.blogspot.com/2018/06/2012-2018-what-is-difference-over-all.html

[John Christensen]

"the first week of July that is"

I'm looking forward to that Rob, thanks.

DMI SIV tracks along 2014 level, which IMO is nothing less than amazing - since the SSW event late February the Arctic circulation has stabilized to a degree, where there is no trace left of the record-breaking heat of 2016.

SIA, SIE and volume have all recovered to 2015 or 2014 levels, which certainly was not in the cards as late as mid-Feb, when the SSW event commenced.

I see strong parallels to the SSW event in the winter 2012/13, which also resulted in significant solidification of the Arctic circulation with reduced heat inflow in both summers of 2013 and 2014.

[John Christensen]

Forecast-wise it seems like we will see more action with a high broadening across the CAB for the few days followed by a massive low entering from Barents.

[Tim]

Meanwhile, it has been several days since I've seen anything out of https://ads.nipr.ac.jp - JAXA (ADS-NIPR) sea ice extent. Is there a long-term problem there?

[Neven]

According to their Twitter feed it's a server problem. Given that other sources using AMSR2 data are still up and up-to-date, I expect it will be solved at some point.

[Robert S]

Melt ponds appear to be developing pretty quickly in the Beaufort over the past few days.

[wayne]

Yes Robert S

Because of current partial in duration Arctic Dipole, but with highest sun elevation possible, kiss Beaufort sea ice Goodbye much quicker than I expected, Kara is about to disintegrate completely as well, all the while CAA has still snow on the ground. Rob and John's sea extent predictions need be seriously revised, heck even mine which is slightly more sea ice than 2012 minima, may be wrong. The most crucial moment will come when High pressure ridge from Alaska is stable and spawns anticyclones over the Gyre.... Got a bone to pick with super computers perhaps tonight, they are very good but fail when they do not have correct observations.

[John Christensen]

Hi wayne,

There's too much ice in the water, not enough high pressure in the forecast, Greenland is cold and Siberia has warmed up, so no chance for 2018 to surpass the level of melting seen in 2012, which would be needed to catch up with 2012..

[wayne]

You forget about Gyre speed John

Too much ice is a misnomer when its spread out and turning badly broken> It seems also the best measuring methods, never have adjusted to this new reality, some people like to be fossils, I like studying them with the latest concepts and instruments.

[wayne]

Yes, there are those who prefer using old outdated methods and are satisfied with it, all the while the carpet is being pulled right under their feet. Amazing Gyre speeds where not part of the old sea ice days, we need to be aware of the new nature of sea ice or risk not understanding how serious the situation really is.

http://eh2r.blogspot.com/2018/07/formula-1-arctic-gyre-48-nautical-miles.html

[gkoehler]

Hi Wayne
No need for personal attacks. Put your methods to the test, give us a number for September minimum so we can evaluate the skill for your methods vs. the others listed in ARCUS SIPN.
-Glen

[wayne]

Hi Glen

I already posted my estimate many times over, please read it just above. As far as personal attacks are concerned, I have been attacked more times than many here, I don't care, because it is not the person I am attacking , it is their lack of mobility, adherence to failing methods, it is their concepts I denigrate, of which a concept is not a person.

[wayne]

The reason why most of us fail in predicting sea ice extent at minima is simple, we do not measure it properly in its current emaciated fluid broken up thinner state. That is why I do not use numbers , these numbers are wrong. They are helpful, guide us well, but wrong. So if one wants to make predictions on exact numbers and gets it right with current stats, I'd like him or her to buy lottery tickets for me. It is more wise to compare year to year, 2012 was radically different than 2018:

http://eh2r.blogspot.com/2018/07/dark-bering-sea-ice-trap-super-melting.html

So I read that there is more ice than 2012? 12 wasn't turning as fast, was scattering less, it was a different circulation year, but now we have open water traps, such as much more open Bering Strait.....

Bottom line for sea ice extent, I quote Shakespeare , a great scientist of words, "to be or not to be" , 1 square meter resolution open water detection, none of this 15% once upon a time when sea ice was one massive block rule.

[Robert S]

Wayne: Do you have access to any 1m remote sensing products for that area? I could certainly run open water detection on specified areas (doing the whole arctic would need more computer power than I can dedicate to it), but the best imagery I can get is 10m multispectral.

[wayne]

Yes we all do have access Robert

But it takes money.....

A proud Canadian product RADARSAT, a request say once a month during the freezing season, and twice a month during the melting season, funded say by a foundation, suggest Bill Gates foundation, a rather great man by his work with Malaria and other projects, would certainly help... Such resolution product can cross check JAXA, and correct as much as help improve the Japanese system a great deal.

[John Christensen]

No worries; I do not see the comments above by wayne as personal attacks - the issue appears to be with the Arctic research community overall.

Some comment on 2012:
Neven had a great observation in “ASI update 8: it shouldn't, but it does”:
- “I'm basically going to say the same thing as I did in the last ASI update: Weather patterns haven't been conducive to sea ice decrease, trend lines on graphs should be stalling, but they don't.”

The discussion then went on to say that the overall deconstruction of the ice pack could cause a new reality, where melting will just increase no matter the weather conditions, which is a reasonable assumption. Except that we saw in 2013 that an ice pack in poor condition could sustain the onslaught of the melting season with exceptional weather patterns in place.

So, IMO what really caused the exceptional melt of 2012 (Which offers also some guidance on how/when this could be repeated):

1. Early initiation of surface melting temperature level
2. Persistent high-pressure and extensive Greenland ice sheet melting during melting season
3. Late season (August/Sept) strong Arctic low

On these:
1. Early melting start: DMI 80N shows that 2012 had a very early start for the 80N avg. to reach the melting point, about one week before norm: http://ocean.dmi.dk/arctic/meant80n.uk.php
Note that DMI 80N reached the melting point one day later than average this year
2. Greenland ‘heat dome’: As reported by many (E.g. NSIDC: https://nsidc.org/cryosphere/icelights/2012/12/what-caused-last-summer%E2%80%99s-greenland-surface-melt ), an exceptional heat dome developed over Greenland in July 2018, which caused very extensive melting and a significant reduction in albedo, which caused an enormous and warm air mass to develop, which at times delivered strong heat to the Arctic sea ice surface
3. Late season Arctic storm: Of course we had the GAC2012 to wrap things up, with a strong low of significant extent and duration to split up the broken ice pack further, isolating many areas of the ice, which were totally annihilated in a matter of a couple of days.

In comparison with 2012 we have in 2018 seen a relative improvement in ice volume of 1,200 km2 from March to May in addition to the later start for melting from the DMI 80N metric.
For Greenland, just check out this comparative view, where you see the effect of the 2012 heat dome compared to the unusual summer snow fall across the ice sheet in 2018:
http://polarportal.dk/en/greenland/surface-conditions/

We don’t know about August storms yet, but again: There is too much ice in the water and not enough heat in Greenland or above the ice pack to allow 2018 to melt even more rapidly than 2012 and catch up with those record levels.

[Neven]

In 2012 I learned that a good beginning is half the work, as the Dutch say.

JAXA is back up. According to an ASIF member:

JAXA is back up. July 1st extent is 9,282,553 km^2 putting it 461K behind the record low for that day. It is in 8th place 276K behind 6th.

The June decline was just 1,459,260 making it the lowest since 2015 and the third lowest in the Jaxa record since 2003.

[wayne]

Neven

"The June decline was just 1,459,260 making it the lowest since 2015 and the third lowest in the Jaxa record since 2003."

I expected a slow down in April, I also projected many events which came through. Which as far as it goes makes me confident that traditional methods suffer from conservatism momentum.

"In 2012 I learned that a good beginning is half the work, as the Dutch say."
and so it was, the maxima was quite low wasn't it? Wasn't sea ice at lowest extent for months? Don't you think that this tendency to stay low at maxima explains a trend of sorts? Is the minima the only thing to consider? By the way 2012 had the 3rd lowest daily decline in sea ice extent compared to 2012-2018, 2013 was 2nd place out of 7, 2014 was in first place, does this mean that 2013 and 14 would have had the lowest minima ever? :) Neven knows better.

John

"the issue appears to be with the Arctic research community"

You got to be crazy kidding? To the contrary, the issue is with the people unwilling to do research and accept that their own methods drastically require some improvements and are quite happy explaining things the same wrong way again and again. The research community is so small I applaud any work or effort done here.

In order to make progress, flaunting continuously a faulty theory like "the AO is a great predictor in sea ice decline", while during a mainly positive AO during the entire month of May there was the greatest presence of an anticyclone over the Arctic Ocean in recent memory. lol mate

As far as current extent trending, I don't think I am understood, if you have fast movement of sea ice, it spreads out more, every single year sea ice shows its very interesting complexity :

http://eh2r.blogspot.com/2018/07/velocity-driven-sea-ice-apparent-slow.html

Not explaining why or how the trends are strange is not interesting at all. In fact renders the subject obtuse and ripe for misinterpretations.

[wayne]

"By the way 2012 had the 3rd lowest daily decline in sea ice extent compared to 2012-2018"

make that 4th during the last 14 days.....

[wayne]

2013 was 2nd place out of 7, 2014 was in first place, in decline with daily 90 and 104 K respectively.....

[Hans Gunnstaddar]

https://wxclimonews.com/2018/07/02/extreme-heat-event-in-northern-siberia-and-the-coastal-arctic-ocean-this-week/

Wayne, 'Extreme Heat Event in Northern Siberia and the coastal Arctic Ocean This Week'

By Meteorologist Nick Humphrey on July 2, 2018

"This isn’t typically what I would write about in this blog, as I typically cover threatening ocean storms. However, this has implications for the Arctic Ocean and possibly mid-latitude weather. An extreme heat event for this particular region…with high temperatures of greater than 40 degrees F above recent normals…will impact the coast of the Arctic Ocean (specifically the Laptev Sea and Eastern Siberian Sea) Wednesday-Friday. This will generate maximum daily temperatures as high as 90-95 degrees near the open ocean coast!"

"I’ve looked over the European model and there appears to be general agreement over the intensity and timing of this extreme event. It is absolutely incredible and really one of the most intense (forecasted) heat events I’ve ever seen for so far north."

Should be interesting to see how this plays out.

[wayne]

Thanks for the info Hans

There is a very strong Alaskan anticyclone which is part of this mix, much feared for the sea ice over there. A Low on Kara sea coast also advects this warm air deep over East Siberian sea ice, As we know the sea ice got compacted against the Siberian coast, which is the last barrier left to open the NE passage quickly. So this sea ice appears to be apparently not so vulnerable, but if loaded with snow cover expect rapid disintegration.

July 2 JAXA drop was 93,957 km2 impressive given the scattered state of sea ice.

Sea ice-scape comparison between 2018 and 12 is amazing to observe:

http://eh2r.blogspot.com/2018/07/massive-more-static-ice-pans-or-fast.html

It leaves a profound question as to which scape melts fastest? The rapid moving or static one? The answer can be found in 2007.

[wayne]

A Nordic friend of mine helped me find about +400k km2 extra sea ice in Baffin and Hudson bay, the net difference between 2018 and current #1 lowest in extent. Lets we not forget the coldest Cold Temperature Vortex in decades over the CAA shaping weather to this day, such as current East North American heat wave - this warmth was foreseen in April as opposed to supercomputers predicting a Western North American warmer anomaly- this CTNP has also left a sea ice imprint impeding an early break up of the Northwest passage...

[John Christensen]

wayne,

From your comment:

"Too much ice is a misnomer when its spread out and turning badly broken> It seems also the best measuring methods, never have adjusted to this new reality, some people like to be fossils,"

It seemed like you were linking 'fossils' to measuring methods (SIE?, PIOMAS?).

If you were referring to my comments (From 2016??) about the possible influence of AO, then the reference was too subtle for me to detect, so thank you for clarifying, although I find it highly irrelevant for the ongoing discussion.

There will clearly be enough of a high hovering above the Beaufort to cause rapid in-situ melting in coming days, which reminds us of 2007, but I do not see this having a major impact on the overall state of the pack - after all sea ice as far south as Beaufort has melted out completely or nearly completely for many years now.

[wayne]

John

"There will clearly be enough of a high hovering above the Beaufort to cause rapid in-situ melting in coming days, which reminds us of 2007, but I do not see this having a major impact on the overall state of the pack - after all sea ice as far south as Beaufort has melted out completely or nearly completely for many years now."

Not necessarily melting rapidly, but gradually incrementally faster with especially respect to replenishment speeds which are greater than 2007. There is also the issue of sea ice thickness, as to compare 2007 with 2018:

http://eh2r.blogspot.com/2018/07/massive-more-static-ice-pans-or-fast.html

even 2007 sea ice pans appear larger.

[John Christensen]

The DMI forecast has significant reduction in thickness for parts of Beaufort in the next four days:

http://ocean.dmi.dk/anim/index.uk.php

[wayne]

Are any of you tired of loosing at computer chess?

http://eh2r.blogspot.com/2018/07/supercomputers-are-no-good-at-flipping.html

Rejoice we are still better than the weather models, can beat them regularly.....

[John Christensen]

New PIOMAS data is out..

2018 melting rates for June significantly below June 2012 - as expected.

[wayne]

PIOMAS is useful John

But not always accurate:

http://eh2r.blogspot.com/2018/07/possible-rudimentary-ice-thickness.html

Virtually all the areas once marked in deep red -(thicker than normal sea ice - for the Northeast passage are open water!

[Rob Dekker]

Most of you will know that since 2013, I use the "whiteness" of the Arctic in June as a predictor for how much ice will melt out between June and September.

http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html

Specifically, I use three variables to make this prediction :
- Land snow cover in June
- Ice 'area' in June
- (Extent - Area) in June, which represents the amount of 'water' in the ice pack in June.

A combination of these variables, each one of which affects the 'albedo' of the Northern Hemisphere, represents how much solar energy gets absorbed by the Northern Hemisphere in summer, and this correlates remarkably well with September sea ice cover.

Details of this method is described in one of my entries into Arcus Sea Ice Prediction Network :

https://www.arcus.org/files/sio/25738/sio-2016-july_dekker.pdf

This year, land snow cover in June was quite high compared to recent years :

Also, ice 'area' is quite high in June (in between 2014 and 2015) and the ice is still fairly compact.

As a result, prediction for Sept 2018 September sea ice extent is quite high at 5.19 km[sup]2[/sup], with a standard deviation of 340 k km2.

My gut feeling this year tells me that this an upper bound, but it's fairly clear that given the past performance of this method, it is highly unlikely (less than 2.5% chance) that Sept 2018 will end up below 4.5 M km2.

Here is what this hind-cast method did for the past 26 years :

Comments and suggestions on this method are welcome in the "Re: Land snow cover effect on sea ice" thread :

https://forum.arctic-sea-ice.net/index.php/topic,292.msg162415.html#msg162415

[Rob Dekker]

Argh. I messed up the formatting.
Sorry, I got used to the 'edit' feature on the forum.

To see the pictures, you have to click through to the forum link of this post :

https://forum.arctic-sea-ice.net/index.php/topic,292.msg162415.html#msg162415

[Neven]

Thanks, Rob. I fixed the images.

[Rob Dekker]

Thanks for fixing the images, Neven.
I'll be more careful next time.

Let me note again that my gut tells me that this 5.19 prediction is probably an upper-bound. Especially since the May prediction, using the same method, came in much lower at 4.65.

So maybe June was just a bad month for melting, and July and August may iron things out. Yet I have to go with the math, which suggests it is unlikely that Sept 2018 will end up below 4.5.

[John Christensen]

Hi Rob,

Thank you very much for update on the Sept NSIDC Average SIE with the 5.19 prediction - V3 I assume.

This fits nicely with my much less data based prediction of 4.85-5.35 back on June 8th, which I am now even more comfortable with.

[Robert S]

Wayne: I know the radarsat product... but the $ are the problem...

[John Christensen]

Hi Rob, you said:

"I use the "whiteness" of the Arctic in June"

This approach makes a lot of sense, as the overall albedo effect in the month with maximum inbound radiation relates to the amount of heat generated in the region and therefore overall melting level.

Have you considered including the albedo effect of the Greenland ice sheet?

http://polarportal.dk/en/greenland/surface-conditions/

As you see from the link, the month of June saw an unusual high level of precipitation combined with relatively low temps, causing vast areas of the ice sheet having an fresh snow layer with improved albedo effect.

Let me know if I should try to contact DMI to obtain a quantitative measure of the Greenland ice sheet albedo effect.

[Hans Gunnstaddar]

https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_visual.png

Black & white Bremen link shows some black (ready to melt) areas in Baffin Bay, where Arctic ice meets the Atlantic, and big areas in Kara & Chukchi side of ESAS. Black areas building recently, so we could see a move by extent graph closer to 2012 in the next few days.

[Hans Gunnstaddar]

http://nsidc.org/arcticseaicenews/

The following day's extent graph does show it dropped a little closer to 2012.