End of June Arctic Sea Ice Volume at lowest ever anomaly

[muriel_volestrangler]

http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

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More than 10,500 km3 below the 1979-2011 average (about half the volume of ice for the average for this time of year). The end of June volume is now below the average 79-11 annual minimum volume.

[hatrack]

1. Wow! That's an attention-getter!

When do we make official E&E call for sea ice coverage bets?

[HereSince1628]

2. It seems to me that the regression line gives a rosier picture than reality

If you look at the pattern of error in the residuals it's on the same side at both ends...which is to say the data is more curvilinear than linear.

It sort of looks to me like the data may actually be showing a negative acceleration (possibly a negative exponential trend, but I haven't done the stats).

[muriel_volestrangler]

3. I think you're probably right; but it's very difficult to chose a type of curve

when it's a noisy data set - and when it's an anomaly for each time of year, it gets even harder (for instance, the June anomaly, about 10,500 km3, applied to the absolute minimum level, would mean no ice at all - so for the time around September, the anomaly could never go below its present value, but at other times of year it will still be able to go lower.

But plotting a straight line is uncontroversial, so that's what they've done. It's up to us to see that a straight line isn't an adequate description.

[HereSince1628]

4. I suspect that the linear regression analysis is part of the database program

used to create the original graph, and that easy access resulted in its use. I doubt anyone thought a first order solution was all that the public could bear.

But I could be wrong.

[joshcryer]

6. A guy who goes by "Wipneus" does graphs for this (with various cases):

You can see the rest of the graphs here: https://sites.google.com/site/arctischepinguin/home/piomas

[HereSince1628]

7. Thanks.

[joshcryer]

8. You may also be interested in Neven's Arctic Sea Ice coverage:

http://neven1.typepad.com/

A lot of the commentators in the comments section saw what you saw.

[joshcryer]

5. Heh, look at 2010, 2011, and 2012 so far. That is crazy.

[limpyhobbler]

9. I'm picking out my end of the world pajamas.