NSIDC 2015 Arctic SIE September minimum: July poll

[Neven]

ATTENTION: There are two polls on the ASIF. One is for NSIDC sea ice extent monthly/September average minimum, the other is for Cryosphere Today sea ice area daily minimum. Make sure you are aware of the difference before voting. You can discuss various extent/area data sets in this dedicated thread.

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This NSIDC extent poll will run for 10 days (until July 12th). Until then you can change your vote. There will be a new poll next month.

Here's how things are currently looking based on data up to July 1st:



These are the September minimums for the last 8 years (in millions km2, found here):

    2005: 5.57
    2006: 5.92
    2007: 4.30
    2008: 4.73
    2009: 5.39
    2010: 4.93
    2011: 4.63
    2012: 3.63
    2013: 5.35
    2014: 5.28

You can use the comment thread below to motivate your choice, but discuss various SIE/SIA data sets in this dedicated thread.

[Neven]

On request I've added two more bins on top.

Given the major slowdown in extent decrease during June, I went up one bin compared to last month: between 5.0 and 5.25 million km2. Boring, I know. 

[Neven]

Oh, and I'd appreciate it if again at least 100 of y'all would take a minute of consideration to vote. 

Less than 100 people voted for the CT SIA minimum poll, but I've created a July poll nonetheless.

[cats]

Up a bin to 4.5-4.75 - Beaufort still looks "slushy" and might be a surprise, but everywhere else seems to me to be slow.  Guess we will see what happens this month

[Michael Hauber]

I swapped with Neven.  Last month I was a bin above at 5-5.25, now I'm going down one bin.  I think June weather while certainly not extreme for melt, does have some similarities to 2012, in that it is a mix of both heat for surface melt (but not as much heat as 12) and low pressure to open up areas of weakness.

[LRC1962]

I know nothing. Voted 3.25-3.5 last pole and did the same this time. Reason, although the weather has not been conducive to much of a melt, as shown by a very low June melt, if things do start melting in any fashion, a great plunge is set up to occur.
Given what has happened in the past few years though, weather patterns seen to be very long term in the Arctic now so that a flash melt is highly unlikely.

[jdallen]

4.25 - 4.5.

I think we are still poised to beat or tie 2011, and go as far as beating 2007.

2012 is still achievable with hot weather during July and August.

[AySz88]

Newbie's perspective: Just going for June SIPN forecasts' median (5.0) plus a bin (so 5.25-5.5).  I figure the albedo feedbacks are slightly slowed by the recent extent slowdown, meaning there's less heat around (even if some of the "extra" ice is far from the Arctic).

Edit: getting rid of the plus a bin.  Forgot about snow cover, which was low, and weather seems to suggest "more heat" arriving as Neven says.

[seaicesailor]

Given the maps Rubikscube presented yesterday and on the short-term weather forecast, no way this season can end close to 2014. Pack is in bad condition and melt front well established within the Arctic. It can advance fast now that weather abides.

4.75 to 5.0 being conservative ready to make it lower before closing. I voted 4.25-4.50 in June

[Alistair]

I am ticking with my original 3.25-3.50.  I think it has a chance of nudging record territory if warm conditions persist. DMI 80N has been consistently above 0 and there is a lot of very weak and thin looking ice out there. 
I am prepared to be proved wrong, as I have been every year recently.

[ChrisReynolds]

I swapped with Neven.  Last month I was a bin above at 5-5.25, now I'm going down one bin.  I think June weather while certainly not extreme for melt, does have some similarities to 2012, in that it is a mix of both heat for surface melt (but not as much heat as 12) and low pressure to open up areas of weakness.

I think I may do the same. Compactness indicates to me that there is potential for the likelihood to shift into the lower half of my June SIPN prediction to the 4.75 to 5 bucket. But I have got the day off and will write a blog post on June ice state, in doing so the various strands in my head will coalesce and then I will vote.

[slow wing]

  Because I don't know any better, I'll persist with last month's prediction of a strong melt season with a minimum similar to 2012, so the bin for between 3.50 and 3.75 million km2.

  Present extent & area really don't matter for predicting a minimum. It's the state of the ice in the CAB that matters, along with whatever hints we have of a weather forecast.

  It's been cloudy but windy lately, so probably better than cloudy and still but not as good as sunny. To somewhat compensate, forecasts are for strong melt-inducing weather over at least the next week or so.

  For what it's worth, a cliff appears imminent in both extent and area. This is partly due to that forecast but mainly due to catching up in the Hudson and Baffin, augmented by lots of ice that looks ready to go on the Siberian side as well as some in the CAA and Greenland, Chukchi and Beaufort Seas.

  So the extent and area graphs might take a spectacular dive very soon, but the uncertainty will still be large in the melt season minima.

  With 1-sigma uncertainties, I predict a minimum of 3.7 +/- 0.9 million km2.

[Neven]

I want to see what the impact of the coming weather will be. If there's something that resembles a cliff, I'll go down a bin again. Perhaps even two.

Because remember, everyone, you can change your vote up until July 12th.

[Richard Rathbone]

PIOMAS June melt shows pretty much what would be expected from Schroeder's assessment of May's melt ponds. My crude proxy for June melt ponds (CT area anomaly cliff) says nothing exciting happened in June, so I'm falling into line with Schroeder's May projection at 5-5.25

[ChrisReynolds]

4.75 to 5, voted.

From my blog post today:

My prediction for SIPN stands (4.51 to 5.79M km^2 central value 5.15 km^2), I see nothing that makes me think it is doomed to failure. My CT Area prediction was 3.0 to 3.8M km^2, central value 3.4M km^2.

The SIPN prediction includes years 2008 to 2011, 2013 and 2014, while the CT Area prediction includes years 2008, 2009, 2010, 2013, 2014. Using two datasets and different statistical methods these predictions are largely congruent. But both methods overshot in hindcasts for 2007 and 2012, here however my suggestion that late June compactness may predict years like 2007 and 2012 steps in, and that method does not suggest that a repeat of such losses is likely this year.

That said I think 2015 may finish at the bottom end of my range for SIPN, a small fail on the low side wouldn't surprise me (less than 0.2M km^2). Conditions in the peripheral seas suggest that although extent loss at present is at around average rates now, this may well increase over July.

[OSweetMrMath]

Is anyone else having trouble downloading data from NSIDC? I get to the downloads FTP directory, and then my connection hangs. I can't tell if this is on my end or on theirs.

Update: Looks like the problem is on my end. Possibly with OS X, since I just updated to 10.10.4. Anyway, I see that the June extent was 10.97 million sq km. Since my prediction was 11.0, this leaves my remaining predictions unchanged, at 8.1, 5.7 and 4.8 million sq km for July, August, and September.

It is possible that the slow pace of melt in June this year is setting up an extent for July which is higher than predicted. Compare this to last year, when the melt in July was slow, but my prediction for July was still accurate. Then my prediction for August turned out to be wrong, necessitating a revision of my prediction for September.

If my current prediction is off, it is more likely to be too low.

My predictions have historically been around 3 bins higher than the average. It is a bit unnerving that my current prediction, 4.75-5.0, is currently the poll average. No wait, I see it's just the mode. The median is currently 4.5-4.75, and the average is lower than that. I feel better.

[OSweetMrMath]

(4.51 to 5.79M km^2 central value 3.4M km^2)

I assume that should be central value 5.15M km^2? (Looks like you plugged in the area value in both places.)

[Daniel B.]

The melt is likely to remain low (sea ice extent high) as long as the North Atlantic remains on the cold side.

[slow wing]

I want to see what the impact of the coming weather will be. If there's something that resembles a cliff, I'll go down a bin again. Perhaps even two.

Because remember, everyone, you can change your vote up until July 12th.

Yep, i'm relying on that... 

The new PIOMAS volume is so much higher than in 2012 that I might be heading in your direction... 

[Paddy]

Sticking to my previous prediction of 4.75 to 5 for now. Will review in a week.

[ChrisReynolds]

(4.51 to 5.79M km^2 central value 3.4M km^2)

I assume that should be central value 5.15M km^2? (Looks like you plugged in the area value in both places.)

Thanks I did do that, corrected.

[Nightvid Cole]

I will stick with 3.26 M km^2 because concentration seems to be dropping ahead of schedule, thus corroborating the snow data used to make the prediction in June. I have had to carefully examine MODIS images and "mentally remove" the clouded areas from concentration plots - and the areas with a concentration low enough to melt by September seem to line up well with what was suggested by mid-June snow-cover from MyOcean. I call it a confirmation.

[ChrisReynolds]

Nightvid,

If you don't have such a program, GIMP is free and is capable of stacking layers of images. You can stack up several days of modis and use the eraser to scrub out cloudy areas, the cloud will generally move around so you end up with, for example, a week of composite image of the actual sea ice. You can then delete the oldest layer and add new layers doing the same thing to make a running series of composties.

[icefisher]

I'm sticking with my initial guess of 5.3.  Unless a major cyclone has an impact in late July or early August  SIE should fall between 5.25 - 5.35.

[Paddy]

Adjusted my vote down to 4.5 -> 4.75. 

[Neven]

Adjusted my vote down to 4.5 -> 4.75.

Good idea, Paddy. I'm going back to my initial June prediction of between 4.75 and 5.0 million km2.

I'm tempted to go one bin lower, but with 2 more days left to vote I don't think I will.

[Jim Hunt]

I'm tempted to go one bin lower, but with 2 more days left to vote I don't think I will.

Anybody else having second or third thoughts?

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#SPIE

[Daniel B.]

You may go a bin higher.  Updated sea ice extent is currently above both 2013 and 2014.  With the North Atlantic andGreenland remaining on the cold side, there does not appear to be enough heat in the Arctic to reduce the ice as much - even with the warmth streaming in through the Bering. 

[wili]

I'm sticking with 3.32-3.5. Mostly because, as recent events have shown, we're just a week or two of perfect (or perfectly wrong) weather away from matching or exceeding 2012, imho, and somebody should be holding down that end of the reasonable (imho) range of probability.

The quality of the ice is what is hard to figure in to many of the models that are based purely on historical quantity numbers.

[SCYetti]

I have just changed my vote to 1 million sq. k. I have no idea that this will actually be the case but I read Prof. Wadhams claims that this will be the year. I myself believe he has about a 5% chance of being right and our poll numbers should reasonably reflect that.

[DavidR]

I  have just put in my July SIPN prediction at 3.8 M km^2, unchanged from June. My reasons for sticking with my previous estimate include:
•   Extent and areas in the main Arctic basin are lower than 2012 and have been lower for most of the season allowing insolation to raise sea temperatures.
•   Compaction is low across the Arctic so insolation is having a greater impact within the pack leading to faster melt rates.
•   Sea and Air temperatures across the Arctic and above 80N have been high since the beginning of June, following an abnormally low May, which suggests there will be significant amount of additional thermal energy in the sea through July and August.
•   The current El Nino, which has been building since the middle of last year, is likely to keep temperatures up in the Arctic for the remainder of the melt season.
•   Hudson and Baffin Bays will melt out but will do little to reduce sea or air temperatures across the rest of the arctic so will not slow loss in those areas.
•   Temperatures for the Canadian Arctic Area west of Baffin Bay are predicted to be higher than normal over the next two months.

[slow wing]

As previewed above, I have bumped up my prediction by two bins, to the bin 4.00-4.25 million km2 due to the much higher PIOMAS volume estimate than in 2012, presumably corresponding to the greater amount of multi-year ice on the Pacific side of the Pole.

  Still predicting a strong melt from here on in though, with minimum extent the second lowest on record, behind only 2012.


With 1-sigma uncertainties, I predict a minimum of 4.2 +/- 0.9 million km2.

[seaicesailor]

I stick to 4,75 - 5 M km2. I was going to go one step down but the heat wave has had a disappointing effect on extent. Finally I don't move it.

Big guys as Reynolds and Dekker endorse me   

Big unknowns: ESS and Chukchi fast runaways or foggy stall? Will additional warm Pacific air enter the Arctic? Cyclones messing up in August? Atlantic export stalled for good? Bottom melting severely affecting MYI, how will it resist? Smoke effects? +/- 250 k

[ChrisReynolds]

Sea Ice Sailor,

Bad news. After days of thinking about it I've just dropped down to 4.5 to 4.75. However that's to reflect a reasonable chance of it being below that, and a better chance of the bin above. If I could I'd vote 4.5 to 5 as the band covering most of the probability, with the probability peaking in the 4.5 to 4.75, but with a substantial upper tail of probability into 4.75 to 4.5.

[seaicesailor]

Damn I counted on your support 

Still, a 4,5 - 5 M km2 range is as good as a 4,75 - 5 M km2 for a newbie like me. Safely far from rebound years, safely far from 2012, reasonably close to 2011/2007. I cant thread so thin 

[iceman]

I'm with Paddy, cats, Chris R and 10 others (currently) in the 4.5-4.75 bin.  Don't have as sound a basis for estimating as others here, but wanted to support Neven's goal of 100 votes.
     I think an atypical late decline in volume anomaly (mentioned on PIOMAS thread) will drag area/extent below what appear to be their current trajectories.

[Wipneus]

For Neven's 100 votes I put it my wild guess in as well.

I am convinced that we can safely count on going below 2013 and 2014. To come in the league of  2012, while not impossible, there are too many things to happen (and seem to be slow in coming), I don't think it is likely yet.

So I am betting on a recovery from the recovery and entered 4.0-4.25

[Neven]

Thanks, guys. That's the spirit! 

[Neven]

I want to thank everyone for voting again, and extra thanks go out to the 1 person who was join the voting. This month we had 107 voters (compared to 106 last month), and the average of all these votes is 4.15 million km2, up from last month's 3.92 million km2.

Next and last vote will be opened at the start of August.

[Steven]

Some updated forecasts for the September 2015 NSIDC sea ice extent:


1)  David Schroeder et al.'s updated forecast is 5.27 +/- 0.44 M km^2, see here.  But as mentioned there, they expect their forecast to be biased high.

2)  Rob Dekker's estimate is 4.6 +/- 0.37 M km^2, see here.

3)  Antoine Barthélemy et al.'s updated estimate is 4.2 M km^2, with a range of 3.1-4.7 M km^2.  See here.  This is slighly down from their earlier estimate in the June SIPN Report.

4)  (Irrelevant, but for what it's worth, my own guesstimate/vote in this poll was 4.5-4.75.)

[Steven]

September sea ice outlook: July Report
http://www.arcus.org/sipn/sea-ice-outlook/2015/july

The median July Outlook for September 2015 Arctic sea ice extent is 5.0 million square kilometers (km²), which is the same as the June Outlook median. The quartile range is 4.4 to 5.2 km² and the overall range (excluding an extreme outlier) is 3.3 to 5.7 million km².

...

While many groups chose to stay with their original (June) estimate for July, 13 of the 32 June contributions did update their September extent projection ... 6 of the 13 updated contributions show a decrease, whereas the other 7 show an increase ... There were five contributions submitted to the July report by groups who did not submit in June

[ChrisReynolds]

Steven,

Thanks, to my surprise I remain around the middle of the pack (before the drop off into low predictions starts around Blanchard Wriggleswort. I really thought there would be a drop to lower predictions by most contributors

Kay is the interesting one for me, as it reflects opinion in the sea ice expert community. Unfortunately they seem to have re-submitted based on the June poll of experts, I'd love to have seen a revised opinion taking into account at least early July. Better still I'd like to see the results of such a poll of the same people over the last week.