Wednesday, May 9, 2012

Sea Ice Predictions 2012 Open Poll

The poll for your guesses on September 2012 sea ice extent (NSIDC) is open.  All the way to the bottom of the page.  If you'd like to explain how you arrived at your guess, please do post a comment explaining it.  If it's a substantial explanation (i.e., one I could steal research for my professional use), I'll also bring it up here to the main post.

Poll is open to the end of June, EDT.

12 comments:

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

Hi Bob,

I will just go with the estimate I made last year - 3.9 M km^2. With the decling trend in Arctic sea ice extent, if I stick with that value then one year I am bound to be correct!

Moreover I don't believe it is possible to calculate what the September ice extent will be. Who could have calculated April's ice extent shown here: http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png?

Cheers, Alastair.

Dikran Marsupial said...

Back in September 2001 at SkS I made a prediction for 2012 of 4.614637 M km^2 (+/- 1.128915). However this is based on data up to 2010, so updating the model might change that somewhat.

The prediction is a purely statistical one, using a Gaussian process regression model.

Robert Grumbine said...

Alastair:
:-) Very likely. The question being in which year?

Given how close my prediction for this year is (the statistical one, that is) to last year, and yours being the same, how about going with the same bet as last year? Over/under 4.15 M km^2, 50 quatloos?

Dikran:
Interesting method. Ok if I snarf your SkS comment and incorporate it in the body of the article above? (Duly credited, of course.) Or, if you'd prefer, you could write up something specifically for this purpose.

One question, though -- is your plus/minus one or two standard deviations? The figure looks high for it being only 1.

Dikran Marsupial said...

Please do feel free to quote the original comment at SkS, but make sure you mention it only uses 1979-2009 data, so it is quite a long range forecast by now!

The plus/minus is a Bayesian 95% credible interval, but I expect the 2 standard deviation confidence interval would be pretty much the same.

I also made a sea ice volume prediction as well, but again it wasn't a serious prediction, just experimenting with the GP software. I very much hope the sea ice volume prediction is pessimistic!

Dikran Marsupial said...

I've updated the model with data up to Sept 2011 and the revised prediction for Sept 2012 is 4.584938 +/- 1.031588 M km^2.

Neven said...

Now that IJIS is back online, I'm doubting whether I should put up a poll for IJIS daily minimum extent, or NSIDC monthly average September extent (just like SEARCH).

The former is more fun to track on a daily basis in September.

Anonymous said...

"Sea Ice Prediction"
-- by Horatio Algeranon

Ice will melt
And then refreeze
In summer and winter
If you please.

Don't believe?
Then prove it wrong
Won't have to wait
So very long.

Anonymous said...

Hi Bob,

I'll bet you Q50 that the September ice is less than 4.15 M km^2. Judging by the latest from http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png we are heading for a record low ice extent this year.

Cheers, Alastair

tonylearns said...

I am going to go with 4.9 just because I often call myself a skeptic on these blogs under the assumption that the bering freeze will slow things down a little bit, and I like the idea of those who believe ACC is a scam gloating once again that not breaking the record minimum is proof that that the arctic is in full recovery mode.

L Hamilton said...

For the June SEARCH call I sent off my guess of 4.3 for NSIDC, motivated by a simple Gompertz model shown graphically at Neven's place:
http://neven1.typepad.com/blog/2012/06/naive-predictions-of-2012-sea-ice.html

L Hamilton said...

My ensemble of Gompertz predictions seemed to do reasonably well last year -- slightly low for NSIDC extent, right on for Uni Bremen extent, close for NSIDC area, and too high for PIOMAS volume. It seems worth sticking with this approach for at least another year, so I'm going with these predictions for 2012:
NSIDC extent, 4.3
NSIDC area, 3.0
PIOMAS volume, 4.0
CT area 1-day, 2.7
Graphs and a description of the method (including confidence intervals) Neven's:
http://neven1.typepad.com/blog/2012/06/naive-predictions-of-2012-sea-ice.html