May 30 2008
Zeroth Order Corrections to Temperature Record
It appears that the “cooling” period from the 1930 through the 1970s was an artifact due to the way sea surface temperature was measured. James Annan says “oops”, and points out that this has been discussed at ClimateAudit before. In fact, it was discussed almost two years ago. But how will this change the temperature record? The Nature paper doesn’t actually offer a revised surface temperature data.
In the comments at James Annan’s blog, he writes:
Forest suggests knocking down the war years a bit which would be most politically convenient, McIntyre suggests warming up the post-war years a bit…
I’ve decided to look at how the record would change if the post-war years were adjusted to higher temperatures. To figure out how large a temperature I needed to add, I looked at the mean global mean surface temperatures for the 5 years prior to the step and the mean of the temperatures for the 5 years after the step. The difference would be the amount of correction needed. This is illustrated in the plot below.
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The first method of correcting the temperature time series is to simply add the difference between the two means to all the points after the step. This is a zeroth order correction to the data, and assumes that the corresponding correction when the temperature jumped pre-war has already been satisfactorily corrected. There does not appear to be a similar jump to higher temperatures around 1939, so this assumption may be okay.
However, it also assumes that whatever bias was introduced post-war has continued unchanged to the present. I also present another correction that uses the same step function as before, but then assumes that the bias introduced decreases linearly for 30 years, when the bias is assumed to vanish. This has the advantage of not adjusting temperatures in the last 20 years. I did not calculate a correction that decreased the temperatures during the war.
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The black lines represent the current values of the Hadley surface temperature. The colored curves are the “corrected” values using the methods described above. There is very little change in the “shape” of the surface temperature record. There is still a period of warming from 1900 to 1940, then no warming from 1940 to 1980, and then a continuation of the warming from 1980 to present. The only difference is that the “cooling” in the current temperatures has been replaced by “not cooling, but not warming”.
We can also calculated the effects these corrections have on the temperature trends.
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Neither correction has an effect on recent trends where less than 30 years is used to calculate the trend. The 0.5 order (blue) correction decreases the trend a little for times when there was a correction to the temperature data. While the 0th order (red) correction increases the temperature trends for when more than 60 years is used to calculate the trend.
At Prometheus, Roger Pielke Jr. shows a graph of the present (yearly) temperature anomaly and an adjusted version by McIntyre. I could not find the post where that graph comes from on ClimateAudit, but it appears that he does a similar adjustment to the blue curve above, except he assumes that the linear decrease phased down to zero in 2000 instead of 1975. This would obviously decrease the recent calculated temperature trends.
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37 Responses to “Zeroth Order Corrections to Temperature Record”
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Atmoz–
There is another issue. In the interview, one of the authors mentioned a possibility that the most recent flat trend could be due to a change over from measuring with jet inlets to buoys. If true the instrumentation issue needs to be addressed quite quickly.
[Reply: I had not heard that, although I can certainly believe it's true. Do you have a link?]
hmmm, microsite issues seem to be appearing everywhere.
What a mess.
And those who have argued for investigations into the quality of the raw data have been beaten nearly to death by those who say Science and Certified Climatologists have solved all the problems associated with the data.
[Reply: This isn't a microsite issue. It's a thermometer issue.]
And those who have argued for investigations into the quality of the raw data have been beaten nearly to death by those who say Science and Certified Climatologists have solved all the problems associated with the data.
Feh.
If these “those” were so concerned, they’d take some thermometers, anemometers and other instrumentation, go out there themselves and start taking measurements rather than pictures.
Imagine how well one would eat on the Heritage victory tour after the blockbuster paper written by “those” intrepid Galileos was published, smashing the warmer alarmist eco-weenie proof. Mon dieu! You’d be booked on Hannity, Rush, and all the usual suspects for months.
And imagine how quickly one could get funding for this instrumentation enterprise if one advertised on, say, LGF or Limbaugh for a dollar donation per. Quicker’n Dunkin’ can cave to a ululating campaign, surely.
So get it organized Dan. You’ll eat fine catered food for months.
Best,
D
D,
And if “they” did. You would concentrate your efforts on linking them to “big oil” or any belief in Intelligent design as to dismiss them out of hand.
Got your spot on Olberrmann yet?
Assessment of data quality ought to precede discussions and hypotheses. Recently, the quality of both SST and tropospheric temperatures has been seriously challenged. So, can anyone reliably report the decadal change for global temperatures citing realistic uncertainties? (Who would have thought that thermometers attatched to baloons can’t measure the temperature correctly?)
[Reply: There are problems with the surface station measurements, there are problems with the radiosonde measurements, there are problems with the sea surface temperature measurements, and there are problems with the satellite measurements. All those different errors in different instruments, yet all of the records are still almost identical when averaged over the entire globe. Sounds like a pretty robust result.]
The satellite record is not affected by buoy measurements so I doubt the recent trends are going to dissappear because of a bias in those measurements.
Pemberton,
The record is clear that I have no problem with folk going out and collecting data & writing it up. I’ve said this repeatedly at CA, to no avail**. I’ve implored ideologues to take thermometers out to UHCN stations to collect actual data. As someone with a scientific background, I have no problem with advancing knowledge.
I doubt folks will collect actual data, as it won’t change much, and there will be no Heritage Victory Tour. There is no market for Heritage Victory Tours based on data-gathering. Only cherry-picking.
Best,
D
**Seen again with the mid-C temps thing - why no write-up?
Atmoz–
It’s not precisely a thermometer issue. It’s a “where did we stick the thermometer” issue.
The other question is: what is robust? That we’ve had warming over the last century? Yes. That we’ve had warming since the 50’s? Yes.
But do the answers to those question tell us the magnitude of the sensitivity to CO2? Or tell us the most likely warming over the next 30 years?
It fine to say we the answer is “robust”. But why make this a game of jeopardy. What’s the question you are answering?
What is this “robust” quantitative result along with its uncertainty?
I almost fall over laughing every time I read remarks like these.
Since we don’t really know what the temperature of the earth is now, or at any time in the past, how can anyone make a serious statement as to what it is, or isn’t, going to be in the future??
Exactly what were the parameters of the models based on??
HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
Lucia, you and your fan club need to understand that while global temp is a useful benchmark for the GCMs, the effects and distribution of the warming are much more significant. Some rather important predictions of the GCMs are way ahead of schedule, e.g. the poleward shift of the climate zones, the increase in severe weather and the collapse of the Arctic sea ice. It would not be especially good news to find out that these effects are happening to the extent they are even though less energy has been added to the climate system than presently thought.
Regarding sensitivity, while we should not forget important results such as Jim Hansen’s with regard to the Pinatubo eruption, the paleo work is at least as important (and maybe more so) than present obs. It turns out it’s rather difficult to make a glacial cycle work with a sensitivity of much less than 3C. As well, events like the PETM become hard to drive with low sensitivity.
And then there are the carbon feedbacks:
Is the ocean CO2 sink starting to saturate, and if it is how quickly? (Note last week’s announcement of results that the oceans seem to be acidifying at a much greater rate than previously thought. That’s probably good news about the sink, but perhaps not so good news if you’re a fish or something that likes to eat them.)
Permafrost melt seems to be way ahead of schedule all across the Arctic.
Then there’s my personal favorite, the Arctic Ocean methane hydrates. Apparently (per David Archer) we’re not likely to be able to warm the oceans enough to trigger a large-scale release (a la the PETM), but it’s starting to look like trouble on the East Siberian shelf (article here, abstracts here and here).
Now, I don’t know exactly what a methane release of 150 Gt would do to the climate, but even if spread out over a century or so I don’t imagine it would be a good thing. IMHO it’s a form of insanity that we as a species seem to be willing to take a significant risk of such an outcome.
And it’s funny how Stevie Mac never looks at any of this stuff. Too boring, I suppose.
Steve Bloom:
As far as I can tell, you are arguing with some phantom in your head.
I look at zero order metrics to see whether or not the models are correctly predicting zero order metrics and benchmarks.
I am sure you are aware, that when running models it is often possible to obtain results that look qualitatively useful and still be off on important zero order metrics by a significant amount. That is one reason I look at zero order metrics. The other reason is , supposedly, there is more historic data on this.
I have also noticed the IPCC spends quite a bit of time predicting these metrics in a decipherable, quantitative way, and so those particular projections are easier to compare to data.
Rest assured, I am well aware of the melting, permafrost etc. In fact, my husband was on an IceBreaker doing research for global warming, and they were stranded when the “landing strip” melted. You can read the 1998 news article hereSo, yes, I’ve been aware of that for some time.
The fact that there are many potential interesting, thorny data isssues isn’t going to stop me from comparing model predictions from zero order metrics, which I think permit clearer easier tests of one particular aspect of model skill.
However, if you think you can make a valuable contribution comparing the IPCC concrete predictions about these other things to publish metrics, I’d be happy to read your musings. Drop a link to your blog, preprints or articles and I’ll be happy to point my readers your way.
So, Lucia, it seems you have this problem. No need to say more.
Lucia,
Welcome to Bloom County.
(Note the avoidance of addressing your point directly.)
(Note the avoidance of addressing your point directly.)
I note either desperate attempts at hoping no one clicks on the link to see the simple, clear point , or an inability to understand a simple point.
Best,
D
D
“However, if you think you can make a valuable contribution comparing the IPCC concrete predictions about these other things to publish metrics, I’d be happy to read your musings. Drop a link to your blog, preprints or articles and I’ll be happy to point my readers your way.”
Maybe you want to take a stab at Lucia’s point.
I’m afraid she’s arguing with a phantom in her head, John M. The difficulty with many if not most of the negative consequences of climate changes is that we won’t be able to concretely predict them until it is entirely too late.
There’s another good example of this discussed in the May 20th Eos. The models predict that in the last 20 years there should have been an increase in global precipitation of about 2%, whereas the measured increase has been more like 7%. The upshot is that there’s probably enough natural variability in precipitation for that to be the explanation for the discrepancy, but it’s hard to be sure at this relatively early stage.
Given this, do we have a concrete prediction of precipitation for the next twenty years? Certainly not. But should that be a basis for ignoring the models?
Maybe you want to take a stab at Lucia’s point.
Sure. Lucia confuses model predictions and scenario projections and then messes up the relevant policy responses to each. So her point is ill-informed.
The IPCC uses projections, which are not concrete.
Of course, IMHO the IPCC has not done a good job at explaining projections, but nonetheless 5 minutes of reading shows that projections are not concrete.
Projections are used in various adaptive management regimes to better coordinate policy responses [viz here, here, here, here ]. If the benchmark is not reached, then that does not falsify or invalidate the policy response - rather, the response is adjusted according to the data. This is why projections are used - to adapt & be flexible. Adaptive management.
Best,
D
Steve B–
I don’t know why you think that abstract applies to me. I think we should take action now. I am also aware that, due to the non-zero time scale of climate, the temperature will continue to rise if there is excess CO2.
I also think we should test model predictions against data, and I focus on zero order metrics.
I see no contradiction between these two ideas.
Steve B.
Good grief, what strawman are you building that anyone here wants to “ignore” the models?
The whole ruckus is because some heathens are daring to test the models. I’ve got a feeling you’d be a lot happier if they did ingore them.
No, it’s just that the monomania about “zeroth order” testing *only* is a form of insanity.
Steve Bloom: Oh?
For what it’s worth, I’ve been looking into other consensus predictions/projections that are described in a concrete fashion in the AR4. If you find a specific one described quantitatively in the AR4, drop by my blog and let me know. I’ll be glad to try to find the data to test that.
But, do remember:The projection/prediction must actually be quantitative and specifically stated in the AR4 not simply a prediction made in some underlying cited paper. Mere citation does not, after all, indicate the idea has been adopted by the consensus, and I think those don’t merit testing.
In contrast, concrete, numerical, claims any member of the public can read and understand and that make it into the technical summary seem worth testing.
Lucia, the rationale you give for your efforts lacks credibility. Based on the company you keep, you’re just another libertarian who’s worried that climate change will result in your taxes going up. It’s only true that you’re insane if you’re taken at face value. You think we should take action now, but the activity you select is one that has the sole effect of making denialists feel more secure in their beliefs? So no, really you’re just self-centered and short-sighted.
I’m so glad I’m work in molecular biology. No one calls me names or questions my motives if I want to discuss a scientific issue.
Actually that’s a perfect parallel, Clark. Consider the case of biologists who are “intelligent design” advocates or AIDS denialists (e.g. Peter Duesberg). A standard defense by such folks is that they’re just raising scientific issues. You will probably have noticed that as time passes their colleagues are becoming less and less amused.
I should clarify that Lucia has no training or experience relative to climate science. Of course she’s free to spend her time any way she likes, but that doesn’t give her the right to be taken seriously or to not have the obvious conclusions drawn regarding her motives.
geez Bloom, don’t you ever give it up.
“I should clarify that Lucia has no training or experience relative to climate science.”
That statement is incorrect and borders on a public display of s*****y. Actually, now that I think about it, it is a public display of s*****y.
The number of important physical phenomena and processes that make up Climate Science, and the supplemental areas of ‘hard sciences’ expertise needed to understand and quantify these for practical purposes, is enormous.
btw, what are your areas of training and expertise that qualify you to pass judgment on those who address Climate Science issues? Does that not also require training and experience in Climate Science and/or associated hard sciences?
Atomz is close to allowing this Blog to fall to the black depths being attained by this one and this one.
Steve Bloom–
I suggested have no right to argue by name calling, through claims of authority or anything else. I haven’t even complained. I can’t imagine anything I might say might make you change your habits.
You challenged me to test metrics other than GMST. I said I’d be happy to if you can find concrete quantitative predictions or projections for other metrics in the AR4. Should you find any, drop me a note, and I’ll be glad to test them.
Sorry… I back spaced..
I meant:
I never suggested you have no right to argue by name calling, through claims of authority or anything else.
Steve Bloom,
There are contrarians in all aspects of life. That doesn’t mean that everyone who questions is a contrarian and that legitimate scientific issues cannot be raised just because some people are perhaps OTT. The converse also obviously applies, not all climate scientists, for example, would agree with Hanson’s wilder prognostications, though they may be reluctant to admit this in public nowadays.
I’ve followed your comments on many blogs and it seems to me that you see things in a very “black and white” way. The real world isn’t like that however.
OOps spelt Hansen wrong
Nice. The old “if you don’t toe the line, you must be insane” game.
Hasn’t that been tried before?
http://en.wikipedia.org/wiki/Psikhushka
Now I see why you hate libertarians.
Lucia, I guess I had it wrong when I welcomed you to Bloom County. It should be “Welcome to The Soviet Bloomion”.
Well, tried to post a couple of times, maybe third times a charm.
Nice Steve B. The old “if you don’t toe the party line you’re insane” game.
Hasn’t that been tried before?
http://en.wikipedia.org/wiki/Psikhushka
Now I see why you hate libertarians.
Lucia, I guess it’s not “Welcome to Bloom County”, it’s “Welcome to The Soviet Bloomion.”
Steve Bloom says:
“Given this, do we have a concrete prediction of precipitation for the next twenty years? Certainly not. But should that be a basis for ignoring the models?”
Models are useless until it can be shown that they can correctly predict future events with an accuracy that exceeds that of the average tarot card reader. Your argument that the models over-predicted some metrics yet under-predicted other metrics supports the skeptical view that the models have no useful predictive skill.
If the models have no predictive skill then it is not possible to justify policies that would only make sense if one assumes that the models have skill. This does not mean we do nothing. It just means that policies should only be adopted if they make sense even if the models turn out to be wrong.
Lucia I think you may be beginning to see why there is a problem with AGW (”persons”) but more to the point more bad news for that camp
LOL
http://wattsupwiththat.files.wordpress.com/2008/06/rss_may_081.png
when will it go up again that is the question.. excuse the sarcasm not meant to be direcetd against anyone Thank you
rex,
you’d be much wiser to read sources elsewhere if you’re taking the misleading ideas that Watts and co. try to portray from graphs like that seriously.
I generally don’t like to close threads when there is an active discussion, but this has degenerated a little too much. Consider this an open opportunity to re-evaluate your comment before clicking the submit button.
Atmoz,
I respect your request and will honor it. All I ask in return is that you are even-handed in your treatment of abuse of etiquette.
If you allow one poster to call another poster insane, it’s rather predictable that the discussion will degenerate.
[Reply: As I said elsewhere, I took a week off from managing the blog. I posted as soon as I got back and read the comments in this thread. It was directed at everyone, not any one "side".]