I’ve been aware of this for a couple of days on our Sea Ice page, but hadn’t done anything about it since I wanted to see if it might change. When blogger Kate of Small Dead Animals noticed it and published on it, I figured it was time to start asking NSIDC some questions.
Compare this NSIDC Arctic Sea Ice extent chart…
…with this from Cryosphere Today:
The NSIDC plot has since intersected the 2007 line, but CT has no new images up since 10-27-10:
It certainly appears that there is more ice in 2010 than 2007 on the Cryosphere Today page. CT hardly ever responds to email, so I didn’t even bother asking them why the discrepancy. NSIDC’s Walt Meier though, takes our concerns seriously and responded rather quickly to my questions:
~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: Walt Meier
To: Anthony
Subject: Re: you might have a problem
Sent: Oct 29, 2010 8:42 AM
Hi Anthony,
Thanks for the heads up. I looked at it and it doesn’t look like there
is any problem.
As we went through before with Steve [Goddard], looking at the images can be
misleading because they’re not on an equal area projection. There is
more ice in the central Arctic this year, but less in the Beaufort Sea,
Canadian Archipelago, and Baffin Bay. These areas roughly balance each
other out.
I also recall Cryosphere Today having an issue of changing their images,
so I don’t know if you can consistently compare them anyway – it looks
like their 2007 image is missing some ice. Attached is our concentration
images from 2007 and yesterday and there doesn’t look like much
discrepancy (apologies for the different image sizes).
walt
~~~~~~~~~~~~~~~~~~~~~~~
I fixed the size differences, and here they are:
Of course we don’t have the daily extent data from NSIDC, since they so far have refused to publish it (they do give monthly though) so, we have to be content with image comparison rather than data comparison with NSIDC.
=======================================
Walt, as I said before, you really should publish the daily data. Consider how this looks: NSIDC director Serreze screams “death spiral” to the media while at the same time holds back publicly funded data. It is the same sort of bull-headedness that got CRU in deep trouble. – Anthony
=======================================
UPDATE: Reader Lee Kington provides this blink comparator version:
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Does it really matter when the range of variability is so narrow on the way up or on the way down ?
The significant divergences are at maximum melt and maximum extent. The rest is a product of primarily regional weather conditions.
We’ve seen two years recovery of sea ice at minimum (then a small step back due to an El Nino and residual warmth in the Atlantic from 30 years of positive PDO) but then most likely further sea ice recovery to come.
Let the alarmists hold their comments until we at least match the 2007 melt again. If that happens with a quiet sun and a negative PDO and AMO then even I would be rethinking.
When they have everything to gain by just waiting and watching (and everything to lose) why must we tolerate mere blather in the meantime ?
2010 looks like more ice.
Next time I shall speak out earlier. I noticed this yesterday and thought maybe my thought processes were a bit off then forgot all about it. I said to myself – don’t believe your own lying eyes. :o)
Well it looks to me like there is more ice too particularly at high concentrations but presumably that does not show up in the graph which simply shows the area with at least 15% ice.
So there are two different interpretations but the 2010 ice growth looks much more robust than 2007.
Kindest Regards
Isn’t thes sea ice charts all processed information? I’ve asked repeatedly if anyone has ever had primary data from these satellites so that people can check up on the results. Is the community now going to accept secondary data without complaining about lack of transparency? No point in worrying about it or really discussing it seriously if there is no way to check up on the results.
IJIC also shows that the rate of ice extent increase has slowed considerably in the last 10 days or so.
Their figures for October 29th. :
2007, 7,800,469 km2
2010 7,841,094 km2.
Looks like a “wash” to me.
Thanx Dr. Walt. At least you have the decency to take time to help us understand your processes and viewpoints.
I wish other scientists in the climate field would realize that the general population is quite educated today, as even compared to my parents generation. Take the time to explain in a civil manner and your message will go further!
Interesting discrepancy, and nice of Walt to respond to clarify. NSIDC and IJIS are in agreement. Currently Arctic sea ice is very close to the level of 2007 for this time of year (which was the modern record low for this time of year). Arctic sea ice is still some 1.4 million sq. km. below the longer term (30+ year) running average and has not been above that average since 2004.
I’ve noted that the IARC-JAXA graph has now stopped at 7,635,156 km2 (October 25, 2010).
I’ve been watching for weather conditions up there to be more favorable for Ice growth & a few days ago I started to see consistent colder F-casts for the areas that need to have Ice expansion beginning this weekend into next week.
If what I am seeing is correct then we should see a good upswing in the Graph this weekend but especially early to mid week….I Hope!
Anthony here is a blink comparison gif of the two images:
http://s247.photobucket.com/albums/gg136/BigLee57/OctIceBlink2.gif
Would not believe anything except DMI. Anyway OT but is it possible that the constant increase in SH ice extent (5-6 years?) be responsible for the massive cooling occurring over South America for the past 5-6 years and more recently for months now in Australia? Are cold fronts extending colder air much further north (in my view). Could Goddard and/or Tisdale do an analysis of temperatures in these locations for past 5 years?
http://wxmaps.org/pix/temp8.html
http://wxmaps.org/pix/temp7.html
The SSMI data seems to be telling another story:
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
I might not ever get any responses but I’m having fun!
fishnski says:
October 19, 2010 at 3:17 pm
….Meanwhile..The arctic has turned Less cold & from what I can tell will stay that way for a few. I was surprised to see the gain we had yesterday & I hope i’m surprised again tomorrow & the next but i’m thinking not. Any thoughts??
Aren’t we getting a bit paranoid about every little up and down of ice extent…it is getting comparable to the one or two hot days=global warming or one or two cool days=global cooling nonsense! The daily or weekly small ups and downs are irrelevent really!
In the size-adjusted image it also looks like the pixels in 2010 represent higher percentages in many areas than in the older image. Maybe the CT image’s percentage processing is rating higher than it “should” and the NSDIC method is seeing areas with lower percentages of coverage. Yes, I know the NSDIC’s threshold is way below what CT is showing.
Definitely has that old death spiraling look to me…seriously and someone forgot to update the daily numbers at JAXA for the last week. Maybe their hands were occupied elsewhere.
It’s not just this, there was also the divergence between JAXA and NSIDC, regarding the minimum extent. Eyeballing them on the Sea Ice page (what a resource), it looks like 3-400,000km^2, but I’m pretty certain there was a graph posted here showing a difference of 600,000km^2 from nothing in 2006. Sadly, Dr Meier never addressed this in his posting here.
I had a look at the sea ice page late last night before I went to bed and noticed that the amount of ice on the satellite image didn’t match what the graph was showing. I was very tired and thought that i would check again today and then email you (I wasn’t sure if my eyes were working correctly).
JAXA shows more or less the same thing, about roughly equally extent. So I think you have the wrong story here.
What I’m wondering about is that the SSMI data shows 2010 with clearly more extent than 2007. This raises some questions about the reliability of the ice cover datasets prior to 2002 and whether data from the newer and older instruments can be reliably compared.
The Canadian Arctic is definately above average, by nearly 16 degrees C in some places.
Taken from Environment Canada charts for week ending Oct 25.
Past 7 Days
Hudson Bay Mean Normal Above Ave
Iqualuit 2.4 -1 3.4
Coral Harbor -0.8 -13.6 12.8
Churchill -1.1 -7.3 6.2
Moosonee 1.4 -0.4 1.8
Inukjak 1.4 -3.9 5.3
Kuijjuaq -5.4 7.4 2
Nain 4.1 -3.6 7.7
E Arctic
Eureka -25.3 -29.3 4
Resolute -7.6 -21.2 13.6
Clyde -4.6 -13.4 8.8
Hall Beach -0.6 -16.3 15.7
W Arctic
Point Barrow -4.8 -15.6 10.8
Inuvik -9 -16.3 7.3
Kugukuk -7.1 -14.2 7.1
Cambridge Bay -3 -18.7 15.7
The E Arctic lost more ice than it gained last week:
http://ice-glaces.ec.gc.ca/prods/CVCSWCTEA/20101025180000_CVCSWCTEA_0005262801.gif
I don’t get this why would the satellite images be missing any ice for 2007 these images have been posted on the website since 2007 .Why has nobody queried this before now?
Given that the story is always about extent and area one wonders why an Equal Area projection isn’t used in these displays ….
in reply to Mike Sphar @ur momisugly 2:17pm
“Definitely has that old death spiraling look to me…seriously and someone forgot to update the daily numbers at JAXA for the last week”
They are still updating the numbers in the data file, which can be accessed by clicking “Download data”, just not the main page.
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