Tuesday, July 06, 2010

2010 minimum arctic sea ice betting pool

Update 2!!
I think this is it, unless Eli and GFW and crandles wish ti reguess for reasons stated in the comments.

Update! The guesses so far are posted below. Contest will close tomorrow night once I get the kids to bed and clean up- call it 30ish hours from now. We're all a bunch of doom-glooming alarmists so far!

original post

The 2010 Arctic sea ice extent minimum prediction pool is now open.

Guesses are to be in the form of extent and sigma (a mathematical measure of uncertainty), in thousands of km2 You may use decimal places if you insist.

Your guess will define a Gaussian curve.

The function with the highest value for x=minimum daily measured ice extent (from IARC-JAXA) wins.

See the 2009 announcement, opening, and final curve for details.

I apologize for not posting on the solstice, but I was in transit from a conference in America.

This contest will close much sooner than last year's. Guesses must be submitted by the time the Earth reaches aphelion in its orbit, which the internet tells me is 11 am on July 6 (presumably UTC). Trash talking, dissembling, and boasting in the comments section is encouraged.

Figure 1. Last year's contestant curves and final 2009 minimum sea ice extent (red line).

As with last year, the winner gets to pick a topic for a silly blog post.


Anonymous said...

4000 x 1000 km2
Sigma = 100
Geologist, Non-climatologist

Thanks for doing this again!

Anne Jefferson said...

5000 x 1000 km2
Sigma = 65
Hydrophillic geologist, non-climatologist

Looking forward to seeing how wildly inaccurate I am this year.

Atwasi said...

4851 Kkm²

Sigma = 82

Geophysicist, non-climatologist


C W Magee said...

OK Atwasi, your mission is to tell me how to specify color codes to excel.

Atwasi said...

O.k., sorry, just wanted to poke a bit :D

I take something purplish then.

crandles said...

Are participants allowed to guess in the following fashion:

IARC-JAXA value for 5th July (in 1000s') - 4180 - abs(8385-IJIS value for 5th July)

Sigma 120

If explanation of this is needed, 8385 is my wild guess at 5th July value and 4180 is the reduction I am guessing from then. However, if the value falls more rapidly between now and 5 July to less than 8385 then I want to go a bit lower. So if it doesn't decline too rapidly imminently then it is expected to be around 4205.

I am hoping this is enough to say I am grabbing the area around 4205 so don't go too close to that.

Accountant, nothing more than climate-hobbyist, cyan

C W Magee said...

Atwasi, I was hoping you would know- it would be useful information.

Crandles, if you want to wait until the end to guess, then wait.

William M. Connolley said...

Extent: exactly the same as 2009, whatever that was. Sigma = 0.5 M km2. I think that is about what I'm supposed to say. I like Green, Dark Green.

Phil Hays said...

3000 x 1000 km2
Sigma 150
Engineer, Non-climatologist

Neven said...
This comment has been removed by the author.
Neven said...

4123 x 1000 km2
Sigma 80
Subtitler, Non-climatologist

PS for regular updates on the state of the ice (flashy animations and all), check out my Arctic Sea Ice blog and liven up the comment section with the intelligent analyses I can't provide.

And here's a web page I've created with all the important daily updated graphs to monitor the ice.

Peter said...

3500 x 1000 km2
Sigma = 250

Molecular biologist with no ice expertise whatsoever: make of that what you will.

Lord Soth said...

3873 x 1000 km2
Hydrographer/Systems Analyst


GFW said...

4200 (x1000 km2)
Sigma = 150
Physics PhD, non-climatologist
you pick the color

My estimate is based on a linear regression of (Sept avg PIOMAS + late spring/early summer PIOMAS anomaly) vs (Sept NSIDC avg extent), but I'll just take the same number for the IJIS min. (Sorry crandles)

Brian Dodge said...

3333 x 1000 km2
Sigma = 155

college dropout, retired tech.

My clever statistical analyses using Appleworks ranged from -200k km2 to 4300k km2, so I'm just taking a SWAG.
2009 took a huge drop in melt rate near the time of max melt and fooled a lot of people last year; weather, not climate, is the big factor for any single year, because of the change to mainly first year ice over the last decade.

crandles said...

I think I will put in my guess of
4550 * 1000 km^2
sigma 320

before anyone grabs that gap.

(GFW No worries I changed my mind upwards anyway.)

C W Magee said...

I don't have a guess from last year under your name. Last year's entrants are:

hypocentre Fischer Duae Quartunciae Nick Barnes Nick Barnes (old) Ron Schott Janne Moren Callan Bentley cope Lab Lemming Deano jyyh Sciencewoman Divalent Doc Alistair Alistair Penguin LGLW Brian Dodge Crandles James Annan Steve Bloom Chris S.

C W Magee said...

Belette, I'm assuming you meant the 2009 minimum, unless I hear otherwise.

I'll take 4600, 100, brown.

James Annan said...

Was waiting to see where the gaps are - though maybe it's best to stake a position early and scare people away?

I'll go for 4750 +- 80

phlogiston said...

5650 x 1000 km2
Sigma 125

crandles said...

Chuck that reduced my winning range from 313 to 45 but I probably deserved it.

I make the table as follows:

Est Sigma Min Max Range
Belette 5249.844 500 0 1701 1701
Peter 3500 250 1702 2213 511
Phil Hays 3000 150 2214 3166 952
Brian Dodge 3333 155 3167 3485 318
Peter 3500 250 3486 3713 227
Lord Soth 3873 100 3714 3936 222
mountainbeltway 4000 100 3937 4054 117
Neven 4123 80 4055 4212 157
GFW 4200 150 4213 4397 184
Crandles 4550 320 4398 4443 45
Chuck 4600 100 4444 4731 287
Atwasi 4851 82 4710 4925 215
Anne Jefferson 5000 65 4926 5132 206
Belette 5249.844 500 5133 7000 1867

bear in mind there were some errors last time i did this.

Roger Knights said...

5100 x 1000 km2
Sigma = 100
Retired, amateur, climate contrarian

EliRabett said...

4000 +/- 100

crandles said...

Try again with the table:

Est Sigma Min Max Range
Belette 5249.844 500 0 1701 1701
Peter 3500 250 1702 2213 511
Phil Hays 3000 150 2214 3166 952
Brian Dodge 3333 155 3167 3485 318
Peter 3500 250 3486 3713 227
Lord Soth 3873 100 3714 3936 222
mountainbeltway 4000 100 3937 4054 117
Neven 4123 80 4055 4212 157
GFW 4200 150 4213 4397 184
Crandles 4550 320 4398 4443 45
Chuck 4600 100 4444 4671 227
James Annan 4750 80 4672 4801 129
Atwasi 4851 82 4802 4925 123
Anne Jefferson 5000 65 4926 5064 138
Roger Knights 5100 100 5065 5279 214
Belette 5249.844 500 5280 5436 156
phlogiston 5650 125 5437 5916 479
Belette 5249.844 500 5917 7000 1083

crandles said...

EliRabett has exactly the same guess as mountainbeltway. Another line with the same information wouldn't go amiss but I forgot to add that.

Steve Bloom said...

Just saw LL's note at Stoat's, so maybe this is too late. Anyway:

3167 +/-150

A nice green, not a dark green that might cause me to be mistaken for an incipient Tory, but a brighter green, although not so bright as lime.

My so-called rationale: The ice has been extra-mobile lately, the already much-reduced thick ice is all over the basin, and the dipole anomaly is back, all of which I take to be indicative of a sharp new record. 25% off 2007 seems reasonable, and I've adjusted that slightly to center between two of the other complete guesses, er, I mean studied estimates.

Steve Bloom said...

Hey, the Beeb just had a brief item (somebody reporting from an Arctic science expedition) stating unequivocally that there would be a new record low this summer. Now all that remains is for my particular guess to be the right one! Can I has prize now?

C W Magee said...

The contest is nominally closed, but I've had reports of comments being dropped, so anyone who hasn't seen their comment yet and wants to repost may do so.

James Annan said...

I posted 4750+-80 yesterday. Blogger seems to be doing odd things with comments.

Dr. Lemming said...

OK, I think I'm getting on top of all the posts- posting to last year's contest is a nice trick, BTW.

GFW may reguess, as he has been mathematically eliminated. Eli's guess is invalid, but I'll let him try again because I'm nice. (and Crandles might as well also reguess, as he'll probably get eliminated by one of the above).

EliRabett said...

3900 +/- 100

crandles said...

I have GFW having a winning range of 4391 to 4397 so not quite mathematically eliminated.

However if I rebid 4450 * 1000km^2
sigma 320 then GFW will be eliminated (and can reguess to eliminate me again and then I get to reguess again).

Roger Knights said...

(I hope it's OK to post this.)
FWIW, real-money bets on whether 2010's arctic will be icier than 2009'scan be made (along with several other climate-related bets) at https://www.intrade.com

C W Magee said...

crandles, David posted 4250, 110 in last year's comment section.

Anonymous said...

Wow, Atwasi and James Annan are incredibly close!

Anonymous said...

Wow, James Annan's record is impressive:

2009 guess 5050, sigma 100, actual 5250, 2 sigma away

2010 guess 4750, sigma 80, actual 4813, .79 sigma away

average error 132k km^2 - only slightly more than the claimed sigmas of 100 and 80.

Is it time for all the experts to just give up and listen to James Annan?


William Fraser said...

You know, I really like betting pools like this, but I think the "winner take all" system you have encourages people to bet things which they don't believe.

If instead, you held a weighted raffle based on the height of each entrant at the eventual answer, you'd should get more realistic guesses for both mean and sigma.