It doesn’t necessarily mean anything that the last update was May 6, so it may just be a coincidence.

This doesn’t appear to be from data originating with the Defense satellite F-15 which has been experiencing SSMI problems.

“NCEP Ice Concentration (MODIS Ancillary Data)”
“The NCEP global Ice Concentration product is produced once daily from
the Special Sensor Microwave/Imager (SSMI)”
http://gcmd.nasa.gov/records/GCMD_SEA_ICE.html

“MODIS (or Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard the Terra (EOS AM) and Aqua (EOS PM) satellites”
http://modis.gsfc.nasa.gov/about/

It appears NSIDC started time stamping their arctic sea ice extent figures. I believe that has been a topic of concern on WUWT before. Sorry if this is old news!

REPLY: Nope, you are the first to notice. I suppose it would be too much for them to credit WUWT for suggesting this on more than one occassion, but it is nice to know they read. – Anthony

Something like that would be useful to know”

The ice is floating and moves… there is no permanent ice, it just moves on out of the Arctic and melts. So it is more a matter of ice which manages to be located in lucky places and gets to live longer.

(twiddle)

Here we go, have fun
http://cersat.ifremer.fr/news/scientific_results/global_mapping_of_arctic_sea_ice_drift_a_unique_database

Still, something like “2nd year is usually ~100% thicker than 1st year ice. 3rd year ice is usually ~50% thicker than 2nd year ice. 4th year ice is ~25% thicker than 3rd year ice. 5th year and greater is pretty much indistinguisable.”

Something like that would be useful to know.

Agreed; but there might be a reason to choose another:
1) If you travel to some place and wonder if you have enough gas.
2) If you wonder about surviving an operation.

Answer: 1) by car 1 SD; by Skyhawk 100% 2) for cancer: maybe less; to remove a mole: 3 SD

Results 1 – 10 of about 11,000,000 for 2009 record snow. (0.24 seconds)

Well, you did it without the quotes, not as you indicate here. That means any article with any of the words, which obviously give you 11 million hits. But if you try it as shown, the number of hits are considerably less:
Try this instead

Results 1 – 10 of 10 for “record snow 2009″. (0.39 seconds)

Which doesn’t prove anything, except you have to do such “Google surveys” carefully….

Forgive me, but how can we accept the data from the NSIDC as uncorrupted and reliable?

Dr. Meier’s comments reflect his observation a steady decline in arctic sea ice for quite a while and he isn’t yet convinced that the recent recovery will reverse the trend. I don’t recall him ever speculating on the cause of the trend, so he shouldn’t get lumped in with the CO2 crazies. His data passes every check I know of for being legit and his recent mea culpa was textbook perfect.

Real data has warts — sometimes embarrassing ones. Phony data is just too perfect. Real data from multiple sources is easy to check and thus holds to a higher standard.

You can trust the sports scores in the NY Times.

And the skeptic in me also wonders why ±2 StdDev instead of ±1 StdDev?

Because this corresponds to the 95% confidence interval which has been standard in statistical analysis for a very, very long time.

Good points you make there. I noticed the same thing on the NSIDC May 4 posting.

1-They seem to have toned down the ‘spin’ in the way they wrote up the report.
2-Mr. Goddard might be having an impact as they included a graph with a ±2 StdDev shaded area, similar to the ±1 StdDev that’s been shown at NANSEN. And the skeptic in me also wonders why ±2 StdDev instead of ±1 StdDev? Is it to give themselves some breathing room in case the ice extent goes much above the 1979-2000 mean?
3-While the April Extent graph for the period still shows a downward trend, I think it’s noteworthy that it also shows that this year’s level is the highest in seven years, as is apparent in the AMSR-E graph.

Now all that remains is to see what the ice looks like in September; whatever happens between now and then will be the result of storms and variations in wind and ocean currents moving the melting ice about.

In a recent email I said
“Making a rash prediction based on known amsr-e daily data so far this
month, April, the month northern extent data you will be producing will
be 14.55 +-1%”

And I see the published figure is 14.58
I’ve not updated AMSR-E data here yet, maybe it is closer.

Here is a very wide plot of the two datasets as monthly plotted on top of each other. Making that clear, raw AMSR-E daily data and NSIDC monthly compensated by a fiddle factor for each month.

The compensation could be improved but this is good enough for now.

http://www.gpsl.net/climate/data/sea_ice/northern-ice-extent-combined-raw-2009-04-28a.png

13.58
—- = 14.55 or of course reversed
0.933

To 3 dec places these are the monthly compensation figures for all the dataset, is consistent over the overlap years. The graph assumes this is so over all time for the longer dataset. Valid? No way of knowing or do you have a way of cross checking?

Nov 0.932
Dec 0.922
Jan 0.942
Feb 0.939
Mar 0.925
Apr 0.933
May 0.926
Jun 0.926
Jul 0.933
Aug 0.990
Sep 1.000
Oct 0.878

Meier has said in reply to an email that the dataset match problem is for ice area, extent is not the problem. This makes sense.