2015 SIPN Sea Ice Outlook: August report

The third and last Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice extent, based on NSIDC monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).

Scroll down to the bottom to see the results from this year's Arctic Sea Ice Forum polls that were held at the same time as the periods preceding the SIO monthly submission deadlines.

Here's the summary for the August report:

The median August Outlook for September 2015 Arctic sea ice extent is 4.8 million square kilometers (km²), 200,000 km² lower than the June and July medians. The quartile range is 4.2 to 5.2 million km² (see Figure 1 in the Overview section, below). Contributions are based on a range of methods: statistical, dynamical models, estimates based on trends, and subjective information. The overall range (excluding an extreme outlier) is 2.7 to 5.6 million km². The low end of the range dropped substantially from July (3.3 million km²), due to one new contribution, while the high end changed only slightly from July (5.7 million km²).

The median's decrease from the June and July values reflects rather rapid ice loss during July. The drop is mostly due to lower statistical and mixed statistical/heuristic contributions (Figure 2), because these methods are generally at least partially based on extrapolation from current/previous conditions whereas modeling contributions are generally not.

Read the entire report here.

And here's the figure showing all the projections (click for a larger version):

The August Sea Ice Outlook, developed by NASA's Walt Meier, has these interesting tidbits which I'd like to quote:

Air temperatures (at the 925 mb level) were much higher than normal over the central Arctic (Figure 9), 1 to 2 ˚C above average over much of the region, with small areas in the East Siberian Sea and just north of Greenland over 4 ˚C above normal. The anomalously warm region shifted in August with warmest air centered over Svalbard, extending to the North Pole. It was also quite warm in parts of the Canadian Archipelago. The only region cooler than normal was in the Beaufort Sea where temperatures were 1 to 2 ˚C cooler than the 1981-2010 average. These cooler conditions continued into mid-August, with substantial freezing of melt ponds reported from a USCG flight over the region in early August.

Currently, the ice extent is tracking below that observed in 2010, 2013 and 2014, making the daily extent the 4^th lowest in the satellite data record. The Northern Sea Route is open while significant parts of the Northwest Passage remain clogged with ice. Some channels in the Northwest Passage are opening, particularly along the famed Amundsen Route, so it may yet open before the melt season ends. Since there is still likely another month of ice loss to go, there is high probability that the September mean extent will drop below 5 million km². As of August 18^th, the extent is at 5.66 million km².

If this year's September mean does drop below 5 million km2 it would end up well below the previous two rebound years, but still in 4th-6th place, which would make it an average melting season. And an average melting season nowadays is well below the long-term average, of course.

For reference, here are the September minimums for the last 10 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

As a bonus, I'd like to add the results from the polls that were held on the Arctic Sea Ice Forum. Plenty of people took the time to vote, especially for the last poll, so thanks for that. Here are the results showing the average and the bin that received the most votes:

Added to that, ASIF commenter Steven has made the following graph, with the following explanation: For each of these boxplots, the thick black horizontal line segment represents the median; the grey box contains 50 percent of the votes (excluding the lowest 25% and the highest 25%); the dashed vertical line segment represents the overall range of the votes, except for outliers; and the small circles are the outliers.

Just a few more weeks left to go...

Comments

[EthonRaptor]

What is going on with Cryosphere Today?? It show a huge increase in sea ice area today

[Neven]

Forum consensus is that it's melt ponds freezing over, Eli (tomorrow will show another uptick and then a small 20K drop).

Read on in that topic. There's some interesting weather coming up. My hunch is that the Northwest Passage main route is going to be completely open.

[DavidR]

August 23 figures for extent are down to 5.179 M km^2 and the August decline is very similar for both NSIDC and IJIS. NSIDC has been all over the place. IJIS continues to decline steadily at between 60-70K per day as it has all month with no sign of the rate slowing at this stage.

At this stage I think we are still some way away from the minimum and a late end to the season is probable. Average decline since 2007 from now to minimum is 692K so a fourth lowest finish seems most likely.

[Tony]

The sea ice area shown in a couple of graphs here and here, suggest that area has increased in recent days. I kind of expect area and extent to be the other way round, on occasions. Anyone like to offer an explanation? The only one I can think of is that a large area of ice is becoming very slushy and spreading into previously "open" water, perhaps fooling the area calculations whilst not impacting extent.

[Neven]

Tony, read the second comment.

CT SIA has started to drop again (not showing yet on the graph), albeit slowly, about 40K in the past days. JAXA SIE keeps dropping remarkably steady, around 70K per day. And so compactness is going up sharply. I'll have more on that in the upcoming ASI update at the end of the month.

But right now it's time for cyclone watching over on the ASIF. :-)

[John Christensen]

Yes, the cyclone entering via Bering should finish off the MYI detachment and provide a good level of compaction in the Western Arctic, lowering SIE significantly, while the SIA should fare slightly better with melting ponds starting to freeze over.

[Tony]

Thanks, Neven and John. Apologies for not taking in the second comment (which I had actually read ... d'oh!).

[ChicoineMartin]

And what's going on with the southern hemisphere (http://arctic.atmos.uiuc.edu/cryosphere/antarctic.sea.ice.interactive.html)? Anybody knows why it's suddenly so low for this time of the year?

[bobcobb]

Quick question: Does anyone here specialize in following Antarctic ice?

[Kris]

More bad news: the rather primitive dykes washed away by the actual storm at
Barrow Alaska.

IIRC these “dykes” have (had) been build in 2008, when it became quite clear that due to the massive ice retreat the coast line was in direct danger from August on ...

[Kris]

By the way, there is a full archive of what is going on here at this link:

Barrow Sea(not-yet-ice) images.