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.)
Steven mosher says:
June 3, 2010 at 9:45 am
It’s a bit more complex than that. As I showed above, that satellite is in fact used for ice area studies. However, as you pointed out, it’s not the only one.
[sarcasm] Gosh, here I was planning to just hit the delete button if it was adverse, because nobody would ever possibly notice that or follow up in a public discussion on WUWT or find out from another source … but you’ve set me on the right path, I have seen the light and I repent of my sinful thoughts. [/sarcasm]
So far, no answer, but you’ll get the full text as soon as I know. At present, I’m trending more towards your point of view, but all the dogs aren’t hung yet …
A layman says; We need keep track of the temp of the ocean floor. My guess this has allot to do with deep earth magma flows. The earth’s core is one big induction furnace with the Sun being the power source. During active phases of the Sun, the earth’s core heats up and the interior flows change. Think about the recent volcanic activity in the area. There have been too few articles in this area. It really has to be added to the mix.
Steven mosher says:
June 3, 2010 at 9:45 am
Now that you are contacting the scientist in charge of the correct one, I’m looking forward to his response.
Well if the Magic Java example is anything go to by it takes a lot of digging and checking to get anywhere near the truth… especially when you have to resort to FOI requests…..
I think WUWT has also demonstrated that it takes a lot more than the word of the scientist in charge to verify any climate related data these days… a whole lot more!!!!
I get the feeling that satellite data is the last bastion of faith for the average sceptic of climate science. I am more sceptic.
I am unlikely to remove all my clothes and bend over just because I am told to do so by a person wearing a white coat with a stethoscope around their neck…. If they say “Trust me, I’m a doctor” then I am more likely to tell them to take a hike… And if an onlooker says “Trust them, they know best” then I hope their words are based upon verified data – not faith – otherwise they will be asked to take a hike as well.
Interesting stuff, I hadn’t looked at this thread before today.
First thought of course what what they had changed about the data gathering ? I suppose you have to believe the data, before you can attempt to understand it.
Gail Combs says that in fact the sensors have changed. Well hopefully someone will chase that down to see what really happened.
I did find Dr David Barber’s on the ‘ground’ observations to be persuasive as to correct remote sensing. I think we’ve been referred to his clip before; seems like that where we forst heard of rotten ice. I had heard of it before from an ex Navy nuke-Sub chap, regarding the appearance and disappearance of that slushy stuff.
The explanations about the effect of a big open ocen hole; such as what happened in 2007; for whatever reason it happened, I can see somewhat how that could change the behavior; because of an anomalous amount of open water.
Willis gave a graph of SSTs; and unlike Willis, I believe there is a hint of the same appearance of a somewhat annual signal; maybe starting around 2005, or even 2004. Not as crisp a signal, as the ice but even my rather lousy eyes seem to think they see a signal appear. Mind you, I have looked at one hell of a lot of noisy oscilloscope traces in my time; and specially in recent years of ones that have pronouced 1/f noise signatures; so maybe I see things that aren’t. Well age can do that.
But bottom line is, I would not be surprised to learn, that someone has a cause and effect linkage explanation for how these two can interract once a really train wreck situation like 2007 shows up (and once again; maybe it doesn’t matter how it happened.)
Outsiders like me are always trapped by the data availability. I’m naturally skeptical of odd results, and tend to want to get down to the bare metal, to find out what really happened. Unfortunately, so much of modern data collection seems to happen in the machine shop. When I was more experimental; if we read a thermometer or measured the length of a coax cable; for some strange reason; we actually wrote down the number that was indicated on the thermometer; or the yardstick.
Evidently, in todays experimental world you can’t tell how good the hay is, until you run it at least once, through the horse.
As to bringing in the Antarctic Continent to this matter; I don’t see any point in that. Why would anyone ever expect some linkage between two totally different environments. Yes if we were seeing several degrees rise in what some say passes for a mean global temperature; then I would expect some common meltings; but absent such a large temperature shift; I don’t think they are linked.
But I think that one would dismiss Arctic ocean SSTs in regard to this (apparent) effect, only at great risk.
Of course the length of the data stream is still pretty short; so I guess that means that Sept 2010 is going to be of even greater interest. Will it return to ‘normalcy’ or will it crash ? Damned if I know but I’m sure going to be watching.
I got a good feeling watching that Dr David Barber clip. The polar bear fur threw me off at first; but once he opened his mouth and started to tell his story; he looked clean shaven to me.
I’m still nervous about the sensor issue that Gail raised; I sure hope they haven’t gone and done anything silly that they haven’t told us about; or if they have; maybe they can come here and tell us what they did.
Maybe if barefoot girl gets done with her Mai-Tai, she might tell us what she knows; since she said she is in the loop on these instruments and that data.
I sure hope this isn’t the data; I get so tired of trying to keep up with the value de jour for the Pyramid Inch. And I’d be even happier if they just wrote down the number that is read on the thermometer; instead of ‘educating’ it.
George E. Smith says:
June 4, 2010 at 9:25 am
Interesting stuff, I hadn’t looked at this thread before today.
First thought of course what what they had changed about the data gathering ? I suppose you have to believe the data, before you can attempt to understand it.
Gail Combs says that in fact the sensors have changed. Well hopefully someone will chase that down to see what really happened.
The sensor referred to is the Aqua AMSU channel 4 which isn’t used for sea ice monitoring, they use the other channels to create a synthetic channel 4 in much the same way that UAH create a synthetic LT channel to remove the influence of the stratosphere. The two different datasets plotted above show the same effect but are compiled using different sensors which suggests that it isn’t sensor change that is the issue.
Malaga View says:
“I think WUWT has also demonstrated that it takes a lot more than the word of the scientist in charge to verify any climate related data these days… a whole lot more!!!!”
So if we contacted the scientist and he said that the algorithm HAD changed, then you would not take his word. You cannot have your skepticism both ways. You basically have this situation.
1. You have presentation of data that disconfirms Willis’ “null hypothesis”
2. You have the following choices:
A. Accept the data and reject the null
B. Reject the data and keep the null
C. Accept the data and MODIFY the Null.
The decision about which to do is largely a pragmatic question. But there are always additional checks that we like to make. For example, if we found out that the alogorithm had been changed, then we would probably give more weight to option B. But, we would have a new path of investigation. what was the algorithm and how did it change. Speculating about these things is not really scientific behavior and I don’t think you gain credibility as a critic of climate science by being unscientific yourself.
george smith.
The issue on the table is the falsification of the Null. I will point out that the Null Willis puts forward is not very well formed. Its not quantitative. However, it’s clear that if this data holds up the pattern we see is unprecedented. That it would seem should pique peoples curiousity. Abduction, it’s called.
Steven mosher says:
June 4, 2010 at 12:07 pm
You cannot have your skepticism both ways.
Sorry but i am sceptical both ways… reading WUWT just reinforces that view!
Speculating about these things is not really scientific behaviour and I don’t think you gain credibility as a critic of climate science by being unscientific yourself.
Sorry but I find climate science very unscientific… and I have no desire to gain credibility in climate science as that would be like gaining credibility with the inmates of a lunatic asylum…
PS
I don’t believe all inmates of a lunatic asylum are crazy… some are fairly sane… the problem is that it drives you crazy trying to tell the difference…
“”” Phil. says:
June 4, 2010 at 9:57 am
George E. Smith says:
June 4, 2010 at 9:25 am
Interesting stuff, I hadn’t looked at this thread before today.
First thought of course what what they had changed about the data gathering ? I suppose you have to believe the data, before you can attempt to understand it.
Gail Combs says that in fact the sensors have changed. Well hopefully someone will chase that down to see what really happened.
The sensor referred to is the Aqua AMSU channel 4 which isn’t used for sea ice monitoring, they use the other channels to create a synthetic channel 4 in much the same way that UAH create a synthetic LT channel to remove the influence of the stratosphere. The two different datasets plotted above show the same effect but are compiled using different sensors which suggests that it isn’t sensor change that is the issue. “””
Thanks Phil,
I don’t want to wear out my brain wondering about something; if somehow they switched balls on me; and didn’t say so.
I can believe that a somewhat sudden change like the 2007 ice extent ‘meltback’ might change the whole behavior; and I wouldn’t be surprised if somebody claimed that the sea surface temperatures were involved; as some ‘tipping point’ had been breached.
Not the foggiest idea why though; but it will be interesting to watch. And my eyes do see vague ghosts of a similar change in Willis’ SST graph; but as I remarked before that could be just accidental since the odd behavior record is not that long yet.
Makes for an interesting fall coming up anyway.
Thanks again.
George
“”” Steven mosher says:
June 4, 2010 at 12:10 pm
george smith.
The issue on the table is the falsification of the Null. I will point out that the Null Willis puts forward is not very well formed. Its not quantitative. However, it’s clear that if this data holds up the pattern we see is unprecedented. That it would seem should pique peoples curiousity. Abduction, it’s called. “””
Well Steven; you aren’t about to see me get un curious; I’m about as piqued as anybody. But also as I said utterly clueless as to what might cause such a change; but would not be surprised if it involves some SST linkage. So not throwing mud at Willis or anybody.
UPDATE: Sorry, there is no update. Still no answer from the good folks at the satellite site as to whether there were changes circa 2007.