Final September Sea Ice Outlook Poll For 2012

[BornFromTheVoid]

This will be the last poll that we'll be submitting to ARCUS this year, for the Sea Ice Outlook. Like the last poll, the guess is for the MEAN monthly sea ice extent for September, based on the NSIDC data. The submission date is September 4th, so get your votes in soon please!

Here are the September means for the last 6 years

2011 = 4,610,000

2010 = 4,900,000

2009 = 5,360,000

2008 = 4,670,000

2007 = 4,280,000

2006 = 5,900,000

Here's a graph of the past monthly September extent since '79.

Current extent (as of the 30th) stands at 3,792,710km2, with the lowest point so far being the 29th, at 3,752,510km2.

We're currently lowest on record by nearly every measure of sea ice by quite a long way.

September is typically a month of net extent growth though, and so finished higher than it starts in the majority if years.

For some perspective on how rapid the ice has dropped over the last 6 weeks, the mean extent for August is likely to be close to 4,800,000km2, which is lower than all but 3 September mean monthly extents.

How low will this September go?

*if I have any of the data or figures wrong on this post, let me know and I'll edit it!

[Gray-Wolf]

I think I've got to play safe on this one. Even though I think this reads very low I'm going for the 3.6 figure. I think it will be achieved after a rapid slowdown followed by a lower lat. L.P. mashing the newly formed ice and revealing the last reductions in the main ice body.

After this season who's to know where to put there tick esp. with so many folk being so wide of the mark earlier?

Wowser is all I can say!

[BornFromTheVoid]

I went for 4.1 million. Still a new record, but I think there is a lot of low concentration ice still floating about that may quickly freeze together over the coming weeks, giving the extent a big bump. I also think the minimum will be very early this year, simply as all the ice left is in the high Arctic, which is already below freezing and as we saw on the Healy cam, forming some very thin fresh sea ice already. I don't think what's left of the ice is thin enough to melt out much more either, despite the +ve SST anomalies.

But I guess we'll see what happens. It will be interesting if nothing else!

[Gray-Wolf]

Sorry BFTV . So fixed on 'min's' I mistook the meaning of 'mean'.

Engage brain before voting!

2 low weeks and then a 4 and a bit and a near 5 so 4.3 as my revised vote. Sorry again for the brain freeze...time of life....gets us all in the end.....and maybe the meds.....

[BornFromTheVoid]

Sorry BFTV . So fixed on 'min's' I mistook the meaning of 'mean'.

Engage brain before voting!

2 low weeks and then a 4 and a bit and a near 5 so 4.3 as my revised vote. Sorry again for the brain freeze...time of life....gets us all in the end.....and maybe the meds.....

Wow GW, not even a new record? Seems a very conservative guess for you!?

I guess a bit of extra info, the recent dates when the 5 million mark was reached (if the extent dropped below 5 million)

2011- October 1st

2010- September 26th

2009- (N/A)

2008- September 30th

2007- October 8th

No other years dropped below it I think...

[Gray-Wolf]

I think we just have a lot of ice primed to re-freeze if there was no mix out by CAG12 and that ice is in the higher lats than past years esp around the Siberian side.

With so much ice across the Fram side there is not much room for any growth there but Russia/Bering and Beaufort?

I just do not know what think really. All I can do is compare and guess? that said DMI temps seem closer to 07' at present than 2011?

I still emote a rapid early spurt but then a very slow period up to Christmas so even if we topple anom records we can still see 5 to 6 million by the middle of Oct?

God help the Watt's if we do see a rapid take off though.....unbearable!

I'm going to have to have a proper think and come back to it! oh what a ditherer!

[songster]

Voted 3.9 on the basis of the nilas forming around the Healy. The specific figure is chosen as a wild-ass guess that we'll get something like 3.8, 3.7, 3.9, 4.3 as an early refreeze starts, giving a monthly average of 3.9 and a daily low of a little under 3.7

This may well be over-cautious, since we're voting on the NSIDC extent, which I don't think will detect the nilas until it's thickened a bit more. There's also room for more losses on the Atlantic side even as the newly-forming ice moves back towards the Bering strait.

[Gray-Wolf]

Right ,that's it no more dithering! going for 4 and I'm sticking with that. looking at the forecast over the next 2 weeks maybe we won't have the rapid uptick the following 2 weeks so 2 weeks under 4 and 2 weeks over 4 averaging at a little over 4 so 4 it is.

That was hard on me poor noggin!

[BornFromTheVoid]

Dropped my guess to 3.9 million now as the continued rate of decline has surprised me a bit.

[songster]

Right ,that's it no more dithering! going for 4 and I'm sticking with that. looking at the forecast over the next 2 weeks maybe we won't have the rapid uptick the following 2 weeks so 2 weeks under 4 and 2 weeks over 4 averaging at a little over 4 so 4 it is.

That was hard on me poor noggin!

Not a chance in hell. We're starting at 3.61, and the first week will average something like 3.55: to offset that you need a week which <i>averages</i> 4.45, meaning it'll be over 4.5 by the end of the week. I think there's only one year in the entire satellite record with that large an uptick, and it was some time back in the 80s. The average increase over the month is around 0.5-0.6 (recently much lower, we haven't put on more than 0.2 over the month since 2004.

Even with an unusually rapid uptick (as fast as any year this century), we're looking at something like this:

3.6-3.5 in week 1 (avg 3.55)

3.5-3.45 in week 2 (avg 3.5)

3.45-3.8 in week 3 (avg 3.6)

3.8-4.4 in week 4 (avg 4.1)

That gives an average of 3.7 for the month. Personally I've moved my vote down to 3.6 and suspect I'm still being too optimistic.

Edit:

Worst case? Monthly average 3.225

3.6 - 3.3 in week 1 (avg 3.45)

3.3 - 3.1 in week 2 (avg 3.2)

3.1 - 3.0 in week 3 (avg 3.05)

3.0 - 3.4 in week 4 (avg 3.2)

And I'm not even sure that's a worst case - on average we've been losing 60k/day over the last 5 days. Keep that up for another four, and my first week will be on the spot. Hold even half that rate for the second week and we're there....

This. Is. Bad.

[BornFromTheVoid]

Careful songster. With GWs guesses being too conservative, you might become the new doomsayer and alarmist on here

The scary thing is, your projections seem reasonable, yet we know that since early August this year, the ice loss hasn't exactly adhered to any reasonable loss rates.

[BornFromTheVoid]

I'll be sending off the results at around midnight, so about 2 hours left to vote...

[BornFromTheVoid]

It's been sent off now. The netweather.tv extent prediction being 3.9 million km2.

Thanks to everyone that voted!

[Killerbeast]

http://ocean.dmi.dk/arctic/icecover.uk.php

It seems very bad relating the environment around the Arctic circle. The lowest Arctic sea on record is already a fact, not a fiction. I had my reservations about it since after 2007 the summer ice showed a slight increase compared to that year, but the summer of 2012 broke all the records. I am wondering what the effect on the circulation it would have. In my opinion, the following winter is very likely to be a cold one, like 2009-2010. The excessive warmth generated around the poles won't allow the pressure to stabilize (i.e. to be predominantly high) and this could as well lead to one pattern that was predominant during the last winter. The strong Siberian anticyclone is not to be ruled out. But maybe it's too early for such radical conclusions. We have to look over the official seasonal forecasts to make final conclusions.

[songster]

Even with an unusually rapid uptick (as fast as any year this century), we're looking at something like this:

3.6-3.5 in week 1 (avg 3.55)

3.5-3.45 in week 2 (avg 3.5)

3.45-3.8 in week 3 (avg 3.6)

3.8-4.4 in week 4 (avg 4.1)

2012, 09, 01, 3.60776

2012, 09, 02, 3.58558

2012, 09, 03, 3.54015

2012, 09, 04, 3.56411

2012, 09, 05, 3.50857

2012, 09, 06, 3.48834

2012, 09, 07, 3.57635

Average for week 1 = 3.55928

Small uptick on the last day (noise or re-freeze?), but overall I'm calling that as a successful prediction. Of course, some may say that predicting if half-way through the week is cheating. To them I say PFFFFFF....

[BornFromTheVoid]

2012, 09, 01, 3.60776

2012, 09, 02, 3.58558

2012, 09, 03, 3.54015

2012, 09, 04, 3.56411

2012, 09, 05, 3.50857

2012, 09, 06, 3.48834

2012, 09, 07, 3.57635

Average for week 1 = 3.55928

Small uptick on the last day (noise or re-freeze?), but overall I'm calling that as a successful prediction. Of course, some may say that predicting if half-way through the week is cheating. To them I say PFFFFFF....

Your prediction continues to be accurate, week 2 has averaged 3.46 million.

[songster]

Well, we'll see how things pan out in the second half of the month after the minimum (surely *has* to reach a minimum soon). Right now it's between my best and worst cases, which is gratifying. Still going down though.

[Gray-Wolf]

Hat tip to you songster! I've really messed up my projections due to the ice refusing to stop melting! I'd hoped that there would be enough fresh 'skim' and cold enough temps to take us back to south of 80N by now but the 'bite' out of laptev keeps on extending poleward??

I'm sure we'll end up knowing just how much GAC12 messed with the ocean layers but it must be a part of the refusal to stop melting....along with the weather of course?

[songster]

I think my high-end prediction falls off the rails this week.

> 3.45-3.8 in week 3 (avg 3.6)

15th: 3.393

16th: 3.369

Still well above the worst case, thank Om. Now looking at at overall daily min of 3.3ish, and a monthly average of 3.5ish, I guess.

[BornFromTheVoid]

Towards the lower end of your prediction now with the, with week 3 in at 3.48.

To meet the lower end of your week 4 prediction, requires an increase of about 70k/day...

[BornFromTheVoid]

Pretty much guaranteed to finish between 3.56 and 3.59 million. Maybe the Arctic will come up with one final surprise though!?

[BornFromTheVoid]

2012, 09, 01, 3.60776

2012, 09, 02, 3.58558

2012, 09, 03, 3.54015

2012, 09, 04, 3.56411

2012, 09, 05, 3.50857

2012, 09, 06, 3.48834

2012, 09, 07, 3.57635

Average for week 1 = 3.55928

Small uptick on the last day (noise or re-freeze?), but overall I'm calling that as a successful prediction. Of course, some may say that predicting if half-way through the week is cheating. To them I say PFFFFFF....

Your prediction turned out a little too optimistic for week 4, which was 3.73. Still, pretty good going.