Friday, January 09, 2009

Minus 30 must not be cold enough any more (updated)




What is up at the NSIDC? According to their charts, new ice has not formed in the Arctic for more than a week. This is despite temperatures which, according to the laws of physics, ought to be quite cool enough to put a bit of a crust on the skating pond.

Apologists and alarmists, step forward please to explain why we deniers should be worried.

UPDATE Jan 7/09 from NSIDC.
The explanation is "at least in part" about high pressure systems and low pressure systems doing what they do, ie settling in long enough to arrange themselves to set up strong winds. In this case the winds were from the south (ie comparatively warm) but were strong and persistent enough to keep the edge of the ice from advancing.
Reasons for December's pause in ice extent change

December's week-long pause in expansion of the ice cover appears to have been caused, at least in part, by an anomalous atmospheric pressure pattern. High pressure over Alaska and the European Arctic, coupled with unusually low pressure east of Greenland and over eastern Siberia, brought warm southerly winds over much of the Arctic Ocean. The southerly winds helped keep the ice edge from expanding southward. In addition, warm sea surface temperatures, at least in the Barents Sea, inhibited ice formation.

You can compare the NSIDC areal extent and the AMSR-E extent charts above.

7 comments:

PKD said...

Apologists and alarmists, step forward please to explain why we deniers should be worried.

Well I'm not either of those things Half, but if you can't be bothered to read NSIDC's own analysis from 3rd Dec as to why the ice growth has slowed, then I can't see why I should explain it to you! ;)

Thanks for the brickbreaker tips BTW, any idea how to get past Level 24? - not that I manage to get to it very often! Some of those levels need stupid amounts of luck to get past...

Halfwise said...

I have read the NSIDC explanation, PKD, and it leaves me, shall I say, cold. It is minus 30 C in the Arctic and new sea ice is not forming? Why did new sea ice form when it was -10 but not -30? Will "stopping climate change" fix this?

I am always suspicious of visual anomalies in charts. A week of flat readings is unprecedented, and points to data problems not to warming problems or latent heat. Other ice extent measures (see http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent.png for instance) show a flattish spot for a couple of days that a strong wind could have caused but the freezing continued. Bad data, methinks, PKD.

Re Brickbreaker, I went through 9 lives today on Level 16 and lost my final one on level 18. I don't think any of the levels post L16 take any special strategy. Use Gun wisely if you get one.

PKD said...

Well, now you can read NSIDC's own explanation Half on thier site. Obviously they are standing by their data!

Halfwise said...

Yes I saw that when they posted it. A reasonable explanation. Who knew that air pressure could keep ice from forming?

PKD said...

I knew pressure does change melting and boiling points, but I thought it'd take a lot more pressure than you'd get in atmospheric changes.

PKD said...

Kudos for the update Half!

I guess one thing that is confusing me right nowabout NSIDC's current graph is why last years line now has a retraction in ice extent in Jan 08.

Yet the one you took the snap shot of has no such retraction? Why are they changing last years year virtually a year later?

Bizarre.

PKD said...

Ah - now I know - now we've flipped years, the line is now updated to last years, instead of the year before...I think!