Crowd-Source Prediction of September Sea Ice Extent (August report)

In mid-July through early August, participants on the Arctic Sea Ice (ASI) blog posted 66 individual predictions for the mean NSIDC September Arctic sea ice extent. The median value of these 66 predictions is 3.6 million km², with an interquartile range (approximately the middle 50%) from 2.92 to 4.28 million km². Over three cycles this summer the median and IQR shifted upwards, responding to new information about Arctic conditions.

Figure 1

Individual predictions range from 0 to 4.9 million km². A stem-and-leaf display shows the complete distribution:

Stem-and-leaf plot for asi_blog
Rounded to nearest multiple of .1

  0* | 00
  0. | 89
  1* | 03
  1. | 58
  2* | 22
  2. | 5789999
  3* | 011123333344
  3. | 556666888899
  4* | 0001222333344
  4. | 555667888999

Matthew Cutler assisted in coding these responses. Following preferences expressed by blog participants, Matthew and I sent a summary of our results to the SEARCH Sea Ice Outlook (SIO). There was no formal SIO call or report for August this year, as noted on the SEARCH website:
“The Sea Ice Outlook organizers decided, with input from contributors and readers, to skip an August report this year in favor of a more thorough post-season report.”
http://www.arcus.org/search/seaiceoutlook/2013/august

Fourteen individuals or groups (including ASI) offered SIO predictions anyway, providing an unofficial August cycle. The median among these 14 predictions is 4.55 million km², considerably higher than medians from the July (4.1) or June (4.0) SIO reports. Rising ASI and SIO predictions both reflect the cool and stormy conditions that slowed ice loss over the course of summer. The unofficial August SIO distribution appears below.

Stem-and-leaf plot for sio (SEARCH SIO)
Rounded to nearest multiple of .1

  3. | 688
  4* | 112
  4. | 56788
  5* | 01
  5. | 8

Figure 2 compares ASI blog predictions with those compiled by SEARCH for their official June and July reports, and also the unofficial August results (July and August both include our ASI contributions as one point). Box plots show median and approximate interquartile range (middle 50%) of each distribution. The ASI blog predictions were consistently more pessimistic, although both sets shifted upwards. Between the July and August cycles, the ASI median rose from 3.2 to 3.6, while the SIO median rose from 4.0 to 4.55.

Figure 2 (August SIO results unofficial)

What’s next? Most obviously, a post-season comparison with the actual September ice extent, discussion of how and why various predictions differ, and ideas for improving prediction in the future. Discussion could inform a synthesis report later this fall.

Comments

[Kevin McKinney]

Thanks, Larry. Interesting to observe this--too!

[Pete Williamson]

....and, if anybody knows, the extent is presently what ATM? I don't see an actual number on the NSIDC website.

thanks

[Ac A]

My early tip is that Arctic will surprise us the next year as well! :-)

Alex

[Paddy]

@Pete,

5.632 million square km as of August 27th (you can see the most recently reported extent by scrolling over this graph: http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/).

I now reckon we were way out, and the September average will be about 5 to 5.3 million square km.

[Hans Gunnstaddar]

When it comes to predictions it's probably best to call on some old Animals lyrics, like; "I'm just a fool who's intentions are good, oh lord please don't let me be misunderstood." I don’t mean it in a religious way, just funny how certain we can be of a prediction or in this case a range of predictions only to be surprised.

For their U-tube video, here’s the link: http://www.youtube.com/watch?v=jMcbsQLp9sM

[John Christensen]

5.1m km^2

Up from 4.25 last month.

Just not enough heat in the area to slip below 5m at this point IMO.

[NeilT]

5.47 as of the 28th

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/NH_seaice_extent_nrt.csv

As can be seen there is HUGE scope for compaction which could lower it a lot. But it's unlikely right now.

The latest Bremen AMSR2 charts show that there is massive open water in the heart of the CAB. CT is showing 3.766 area.

It's hardly a rebound....

Looking at the chart, August has averaged 58kkm^2 melt per day. In the last 10 days 47kkm^2 and in the last 5 days 53kkm^2.

There is potential to go down to 4.6Mkm^2 by mid Sept. However that all depends on the melting/compaction rate continuing.

As ever this year, I believe it will be "wait and see", because we have no model or experience to extrapolate what happened this year.

[Henry1]

NeilT,

I think it would be quite difficult to get to 4.6 million sq km on extent with the amount of time that is left in the season. A 3.77 area is very high in relation to the 2007-2012 timeframe. In fact, it is slightly higher than 2009 on this date.

I do think we could make it under 5.0 million though.

[Couloir007]

This question is a bit off topic, but I figured this was the place to ask. Some time ago I read an article about an Inuit family lost at sea fishing, and only the wife survived, or something along those lines. They were caught off guard because they had never experience such rough seas given that the ice prevented it. I've googled every search phrase I can think of, but nothing is coming up. Anyone know which story I'm talking about? Thank you.

[Jim Hunt]

Welcome Couloir. This is "The New Arctic":

http://www.youtube.com/watch?v=L8IxxGWvM9s

A story along those lines is about 3 minutes in.

[Novastellar]

@Couloir Sounds familiar, but I think I saw it in a youtube video. I'm not sure how to find it though.

[NeilT]

Henry1,

Yes I think 4.6 would be very difficult to get to without exceptional compaction or exceptional warmth.

However, the scene does seem to be set for exceptional compaction.

Also to compare 2013 with 2009 for area is quite difficult. In 2009 the pack was almost solid, if thinning, throughout the CAB. Today areas being reported as solid ice are nothing more than a thin sheet on top of the water which has not melted away.

It may seem like some kind of change, but I see very little different from 2007 onwards. It's just presenting a different face we have not yet caught up with in our measurements. We don't even know how important what is happening this year will be to future years.

Time will tell.

[Fufufunknknk]

Sorry for the off topic post. I thought I remembered someone asking about the topology of Greenland and are there any exits below sealevel. I stumbled across this on the BBC about the new radar survey of Greenland.

http://www.bbc.co.uk/news/science-environment-23866810

[Hans Gunnstaddar]

http://www.takepart.com/article/2013/04/09/global-warming-melts-arctic-ocean

Couloir007, that article above has the full story. I brought it up a few weeks back to illustrate what another poster was talking about, i.e. waves getting higher in the Arctic. You know high waves are new (at least for our times) if the Inuit are not use to them.

[Boa05att]

@Coulouir It's from this video called 'The New Arctic'

http://www.youtube.com/watch?v=L8IxxGWvM9s||

[Hans Gunnstaddar]

Self-correction on post way up on
Animals song. "I'm just a soul (instead of fool) who's intentions..."

Very tired last night from compacted week, so missed that one and meant nothing by it as my prediction was too low as well. 'Love and Light' as my lovely wife always finishes correspondence.

[Phil263]

@John Christensen
5.1- 5.3 million for September average extent sounds like a reasonable expectation, not too far off 2009 (5.24 million).My prediction was 4.9 million in July down from 5.4 in May/June
Hopefully, JAXA will be back within the next few days, otherwise we might miss the minimum on that particular gauge!

[Colorado Bob]

Hidden for all of human history, a 460 mile long canyon has been discovered below Greenland's ice sheet. Using radar data from NASA's Operation IceBridge, scientists found the canyon runs from near the center of the island northward to the fjord of the Petermann Glacier

http://www.nasa.gov/content/goddard/nasa-data-reveals-mega-canyon-under-greenland-ice/

[Colorado Bob]

scientists found the canyon runs from near the center of the island northward to the fjord of the Petermann Glacier

The Petermann Glacier grinds and slides toward the sea along the northwestern coast of Greenland, terminating in a giant floating ice tongue. Like other glaciers that end in the ocean, Petermann periodically calves icebergs. A massive iceberg, or ice island, broke off of the Petermann Glacier in 2010. Nearly two years later, another chunk of ice has broken free.

http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=78556

[Colorado Bob]

Rough mass balance estimates using these scales suggest that about 80% of its mass is lost as basal meltwater, yet little oceanographic data are available to connect Petermann Glacier to its fjord and adjacent Nares Strait. Even the sill depth and location is largely unknown as modern soundings of the fjord are still lacking.[2]

http://en.wikipedia.org/wiki/Petermann_Glacier

[Colorado Bob]

I don't think we're going to like what is flowing out along the bottom of the Peterman fjord. If we ever measure it.

[toby]

I have stuck with 4.5m km^2 all summer, but that now looks unachieveable. I suppose ~5.3m km^2 is a good number, but I would still not be surprised by a dip below 5m km^2,

[toby]

Interesting (looking at the IARC-JAXA figures just out), 2013 is marginally behind 2010, by about the equivalent of an average day's melt. It is ahead of 2009 by about 5 average day's melt.

In 2010, the IARC-JAXA minimum was 4.81m km^2, in 2009 it was 5.25m km^2.

[Chris Biscan]

I got 4.86 mil. Time for a blog redemption.

[Couloir007]

Hans, Boa05att, thank you. I've never been stumped by Google so badly. I searched this site a lot, my facebook timeline, and twitter posts. It's something I thought I would have shared. Just couldn't remember where I read it.

[Sean Montague]

Can the weather in the arctic itself be considered a positive feedback loop? Are the storms stronger with more open water, which speeds ice loss, leading to stronger storms?

[LRC]

In the long term you could say yes, but as we are finding this year it can also be a negative. All we know for certain is that the weather is changing quickly especially in the last 2 years (I suffer weather triggered migraines and live near Toronto Canada and I have jump from having 2-3 a month to almost daily in the last 2 yrs. all the empirical data I need), the problem becomes that the changes result in blocking patterns that can stretch over long periods of time. These blocking patterns can mean fast melt times or ice growth times. The main certainty we do have unless that is a catastrophic event is that the weather in the long run in the Arctic will get more violent and the ice will get far less.

[Kate]

Yes, I'm eating crow pie :) I sort of wish it wasn't so. I honestly don't think anything positive will happen until the first ice free summer and then people will notice. I know it will be too late but maybe regulation then will seem like a good idea.

It's getting cold up there, it will be a big year extend wise but it really is like watching a goldfish's last gasps as it lays on the shag-pile carpet.

[Hans Gunnstaddar]

Probably too late in the season, but based on top right graph on graphs link (sea ice concentration), it appears that open water could possibly open up from Franz Joseph through to the Chukchi Sea, splitting the ice sheet into two major areas. The ice extent has dropped in the past few days just a tad from the line it was on, and if it did open up we could see a big drop in extent, plus open up a shipping channel up the middle of the CAB.

Any buyers?

[John Christensen]

@Hans,

As you see from DMI 80N temps (http://ocean.dmi.dk/arctic/meant80n.uk.php) and on ROOS (http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic) area has an earlier minimum than extent and extent dropping more than area, indicating the pack has slowly started freezing in the high north while still melting at the edges.

I would bet you that cup of coffee I have offered earlier that the central CAB will start showing real refreeze in the next week due to the temps dropping, while as said extent could still drop during that week.

[Robert S]

It'll be interesting to see what the refreeze looks like in the areas of the CAB now consisting of independent floating floes of all sizes. Already when there is a wind the bigger floes are clearing paths through the smaller ones. Could be a lot of shattering and piling of the new ice as it forms, and it may take a period of calm very cold days to get a continuous sheet and stop the process. I'm not sure what effect that will have on overall ice volume over the winter, though

[Hans Gunnstaddar]

Ok, it was worth a shot, but alas this season is going bye-bye.

[NeilT]

I've tried to find a link to the "surprise" melt out of supposedly solid pack ice. A hole the size of the UK appeared either later October or early November back around 2004-6.

I remember it at the time but can't find any reference to it now.

I'm wondering if we'll see something like that this year.