Guest post by Willis Eschenbach
A few days ago, Steve Goddard put up a post called “Does PIOMAS Verify?” In it, he compared the PIOMAS computer model estimate of the Arctic ice volume with the SIDADS satellite measured Arctic ice area. He noted that from 2007 on, the two datasets diverge.
Intrigued by this, I decided to compare the PIOMAS ice volume dataset with the Cryosphere Today (CT) Arctic ice area dataset. Here is that data:
Figure 1. Arctic ice area (red line) from Cryosphere Today. Black line is a 6 year Gaussian average.
When I compared the two datasets, I expected to find something curious happening with the PIOMASS dataset. Instead, I found a puzzle regarding the CT dataset.
I compared the CT area dataset with the PIOMAS dataset, and I found the same thing that Steve Goddard had found. The datasets diverge at about 2007. So I took a hard look at the two datasets. Instead of an problem with the PIOMAS volume dataset, I found the CT area dataset contained something odd. Here is a plot of the CT daily data with the daily average variations removed:
Figure 2. Cryosphere Today daily ice area anomaly. Average daily variations have been removed.
The oddity about the data is what happens after 2007. Suddenly, there is a strong annual signal. I have put in vertical black lines to highlight this signal. The vertical lines show the end of September of each year. Before 2007, there is only a small variation in the data, and it does not have an annual signal. After 2007, the variation gets large, and there is a clear annual aspect to the signal. The area in September (the time of minimum ice) is smaller than we would expect. And the area in March (the time of maximum ice) is larger than we would expect.
I considered this for a while, and could only come to the conclusion that there was some kind of error in the CT dataset. So I decided to look at another dataset, the NOAA SIDADS dataset.
Again, I removed the monthly signal, leaving only the anomaly. Here is that result:
Figure 3. SIDADS monthly ice area anomaly. Monthly variations have been removed.
Again we see the same oddity after the start of 2007, with a large annual variation where none existed before 2007. In the SIDADS dataset the variation is even more pronounced than in the CT data.
So that is the puzzle. What has changed? Are they using a new satellite? If so, has the changeover been done properly? Since the smallest of the data has gotten smaller and the largest of the data has gotten larger, is the average data still valid? Just what the heck are we looking at here?
Despite searching, I have not been able to find the answer to this question. However, I have great faith that the assembled masses of the WUWT readership will find it very quickly. (And then some of the readers will likely tell me that this shows I am a layman and a fool, and that I should have been able to find the answer easily on my own … so sue me.)
The alarmists were right!
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png
PS. In my browser the image is showing no ice at all.
Kevin,
It was unusual wind patterns. But the long-term downward trend is due to temperature increase that can be seen in the UAH dataset that I have posted here a couple of times.
http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
Willis:
http://www.robertb.darkhorizons.org/seaice.anomaly.Ant_arctic.jpg
and notice that in some years, the S. Hem. mirrors the N. Hem., but in other years it is in sympathy.
The Antarctic Sea Ice can be just as volatile in range as is the Arctic.
http://www.robertb.darkhorizons.org/seaice.area.ANT_arctic.jpg
The Antarctic Sea Ice Area has a much greater range (diurnal I want to call it) than the Arctic.
So, though both have year-to-year variations of roughly the same magnitude, it looks much worse with the Arctic because the range is smaller.
I am willing to bet that, if there were another 5 years data prior to 1979, you’d see the same thing happening to the Antarctic.
Willis,
The pattern has definately changed. So, if the data itself is correct then you have to look outside the monitoring to find what changed.
http://www.whoi.edu/page.do?pid=12455
This looks at ocean current changes and salinity changes.
The salinity salt pattern have definately effected the evaporation cycle and made less cloud cover in the equatorial areas. These patterns seem to be changing as well. Before 1972, oceans around this planet had a constant salt content that was the same.
Our sun has changed it’s sunspot pattern around that time as well, not much solar flaring as well.
Another thing is that our species CAPTURES and holds water when no other species had in the past and this is TRILLIONS of gallons a day.
Stephan says:
June 1, 2010 at 2:30 am
It’s too cold here in Brazil, the cold made it to the southern Amazon. This is very rare and it has happened three times this year. Brazilian station in the Antarctic Peninsula was very cold in the last three years http://antartica.cptec.inpe.br/ , Ferraz Climatology (. Xls)
Perhaps this is what some are fervently wishing for:
http://www.robertb.darkhorizons.org/TempGr/seaicefree.GIF
Now, that is faster than anyone could possibly imagine.
Now you see it, now you don’t.
Run for it!
Is there a similar pattern for the Antarctic ice cover? Currently, the ice cover anomaly for this date (3st May) is the highest ever for the last 30 years. http://www.iup.uni-bremen.de:8084/amsr/ice_ext_s.png with the total ice cover for both caps being at the 30 year average. Is this due to the migration of the planet’s energy by means of changing wind currents and the ocean conveyors?
DavidS says:
June 1, 2010 at 3:52 am
OMG, the Aliens just stole our Ice Cap. Independence Day.
rbateman says: (June 1, 2010 at 4:09 am) So, though both have year-to-year variations of roughly the same magnitude, it looks much worse with the Arctic because the range is smaller.
Will be very interested in responses to that thought.
Perhaps the variation would look less dramatic if we considered the total areas rather than the area anomalies. Has anyone thought of rereading Hurst’s papers and considering whether what Mandelbrot calls the Noah and the Joseph effects apply to Arctic ice coverage?
I meant 31st May, apologies. http://www.iup.uni-bremen.de:8084/amsr/ice_ext_s.png
For the fourth time cold arrives in amazonia. Usually there are fewer episodes per year lasting 1-2 days. This “chill” lasted five days.
paulo arruda says:
June 1, 2010 at 4:15 am
The southern hemisphere has been experiencing colder winters for the last 3 years, as has the northern hemi. This is MY observation and cannot base it on statistics. However it seems to be lagging behind the solar activity or inactivity, as is expected of a planet with a large thermal inertia.
I am so very sorry Willis for using nom de blog, aargh.
Comparing Arctic and Antartic from a dumb arse Pirate point of view has a basic inconsistency. The Artic is a floating Ice cube and the Antartic is actually a continent covered by Ice.
Two different baselines. The Artic actually rotates, the Antarctic don’t.
The Antarctic has perma freeze, at ground level the Arctic is effected beneath by non solid ie Ocean. It can melt in three dimensions,.
yer I know back in the box Jack
Apples and Oranges. Continent and an Ice cube maintained by gravitational and coriollis forces.
Look down not up.
DavidS
…There is…It’s King Bore’s New Ice Clothes…BTW Storlien’s snowcover DID make
it into its 10th consecutive month…Sep 29 until today, June 1 [13 cm =5 inches] Has not happened since
at least 1951… Katterjåkk’s 30something cm disappeared from May 30 until May 31…
A local Chinook…???
http://magicjava.blogspot.com/2010/04/three-valued-logic-and-irreproducible_29.html
Example: Aqua Satellite Channel 4 Virus
It helps to have an example, so we’ll be using channel 4 of the AMSU on the Aqua satellite. Channel 4 failed completely around December, 2007. In response to this, NASA created a new algorithm and has used it to synthetically create channel 4 data from October 1st, 2007 onward.
That’s what the beginning of a Death Spiral looks like for Arctic sea ice extent.
Here’s what it looks like for pair figure skating: http://tinyurl.com/242wd5u
Didn’t a AMSR fail in about 2007 when some period of ice measurements were lost? Or was that 2008?
Me I would use Antarctica for Ice Measurement, as a zero point.
Hole of a Place, Rum and Beer freeze, doxies without undies can’t be found there.
A port 5 months of the year. Only the maddest of tourists go there, warmers.
The un mad tourists fly over in a 747.
In looking at the graphs from http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
I am wondering why the sine wave is not present in all of the data prior to 2007 as the ijis data shows a nice sine wave going back to 2002.
What is it with Boffins and Instruments?
I am not surprised by the an increased seasonal cycle. If you have less sea ice in summer and normal in winter, then the seasonal cycle would be amplified. Even in a warming world, temperatures in winter will remain cold enough for ice to reform in winter. And in fact, you tend to have rapid ice formation during low summer ice years since you have a rapid exchange of heat between the open water and the atmosphere as air temperatures drop below freezing, causing an initial formation of thin, grease ice (that would show up in the ice extent). Thus, the winter extent is not showing all that much change (but the ice thickness might be and the few years of ICESat data did show the winter thickness decreasing).
The Arctic is heading towards a seasonal ice cover such as what is observed in the Antarctic, thus a larger seasonal cycle will emerge.
I had been noticing this annual extent pattern in another context — strong winter/spring #s followed by low summer #s. I have thought of two explanations: First, soot. The soot would not affect winter/early spring #s because there are no sun’s rays to work its effect. However, in the summer, the rays would lead to a quicker melt. The other option: Low volume/low thickness. I am not convinced of the validity of the #s in this second option, but it is a possibility.
Willis,
What you may not know, is that fresh water has been settling in the oceans. The ONLY water that can do this is H2 18O. This could displace the saltwater currents and change their movements.
http://www.whoi.edu/page.do?pid=12455&tid=282&cid=897