I’ve been away from WUWT this weekend for recovery from a cold plus family time as we have visitors, so I’m just now getting back to regular posting. Recently on the web there has been a lot of activity and discussions around the issue of the dropping of climatic weather stations aka “the march of the thermometers” as Joe D’Aleo and I reported in this compendium report on issues with surface temperature records.
Most of the station dropout issue covered in that report is based on the hard work of E. M. Smith, aka “chiefio“, who has been aggressively working through the data bias issues that develop when thermometers have been dropped from the Global Historical Climate Network. My contribution to the study of the dropout issue was essentially zero, as I focused on contributing what I’ve been studying for the past three years, the USHCN. USHCN has had a few station dropout issues, mostly due to closure, but nothing compared to the magnitude of what has happened in the GHCN.
That said, the GHCN station dropout Smith has been working on is a significant event, going from an inventory of 7000 stations worldwide to about 1000 now, and with lopsided spatial coverage of the globe. According to Smith, there’s also been an affinity for retaining airport stations over other kinds of stations. His count shows 92% of GHCN stations in the USA are sited at airports, with about 41% worldwide.
The dropout issue has been known for quite some time. Here’s a video that WUWT contributor John Goetz made in March 2008 that shows the global station dropout issue over time. You might want to hit the pause button at time 1:06 to see what recent global inventory looks like.
The question that is being debated is how that dropout affects the outcome of absolutes, averages, and trends. Some say that while the data bias issues show up in absolutes and averaging, it doesn’t effect trends at all when anomaly methods are applied.
Over at Lucia’s Blackboard blog there have been a couple of posts on the issue that raise some questions on methods. I’d like to thank both Lucia Liljegren and Zeke Hausfather for exploring the issue in an “open source” way. All the methods and code used have been posted there at Lucia’s blog which enables a number of people to have a look at and replicate the issue independently. That’s good.
E.M Smith at “chiefio” has completed a very detailed response to the issues raised there and elsewhere. You can read his essay here.
His essay is lengthy, I recommend giving yourself more than a few minutes to take it all in.
Joe D’Aleo and I will have more to say on this issue also.
Amino,
There really is no end to paranoia and conspiracy theories, is there. All of the stations which do not report to GSN suddenly changed their behavior. Right. Give me a break.
Rattus Norvegicus (18:30:21) :
I see you are sticking to the playbook:
GLOBAL WARMING RELIGION RULES
1- NEVER discuss the Science—avoid talking temperature data
2- Attack the Man—“I don’t feel like wading through the morass of junk on his site”
3- Repeat the MANTRA until you feel you’ve won the argument —Tamino, anomaly, Tamino, anomaly, Tamino, anomaly, Tamino, anomaly, Tamino, anomaly
Rattus Norvegicus (21:21:02) :
I’m not interested in anomaly since anyone can play with sata in that regard.
I am interested in this:
is the temperature reading of the retained stations the same as those dropped?
Amino,
Tamino’s analysis showed that urban stations were disproportionately dropped from the record.
And anna v, in the earliest periods the pre 1992 stations showed more warming than the post 1992 stations. No bias.
Rattus Norvegicus (21:21:02) :
It is asking a lot to tell me to trust anything passing through the hands of James Hansen.
Can you honestly tell me from looking at his environmental activism that he can be trusted to be unbiased in an environmental issue?
Rattus Norvegicus (21:33:46) :
Tamino…… huh, who exactly is ‘Tamino’?
Rattus Norvegicus (21:21:02) :
paranoia and conspiracy theories
What you call paranoia and conspiracy are really just legitimate questions that everyone should ask—especially since GIStemp looks so different than other data sets. and also because of James Hansen’s environmentalism and connections to politics. And also because of his failed prediction from 1988.
Science is supposed to ask all questions. Nothing is settled. Nothing is beyond debate.
Rattus Norvegicus (21:33:46) :
This video gives a quick review of James Hansen’s 1988 testimony. You will see it heavy laden with politics.
I’ll deal with a few of issues here:
1) I really don’t feel like wading through EMS’s site. He makes some really silly accusations in his posts, thing like, and this is a paraphrase, “why does GISS not use data prior to 1880?”. The answer is pretty easy, the GISS analysis begins in 1880 because that is the point where the initial analysis showed there to be adequate spatial coverage to do a valid analysis. CRU had a different opinion, but not that much different — they start in 1850. This is the sort of crap I was referring to.
2) Actually, I was discussing science. To expect a radical change in the behavior of the “dropout” stations post 1992 is silly. Yes it might be possible, but please postulate a physical reason for this. At least he high latitude stations tend to show a greater warming trend than the rest of the globe, how would dropping high latitude stations result in a warming trend?
3) I am not skilled at statistics. Neither are you. However, I have been reading Tamino for several years and he strikes me as a competent statistician. He has several published papers in the literature on time series analysis, so he can at least get past peer review, something that Anthony cannot. The methods of analysis he uses are all fairly straightforward. You might learn something about statistical analysis from reading his blog, I know I have.
4) anna v.: if you looked at the charts you would see that since the 1880’s the dropped stations show slightly more warming than the post 1992 stations. Not much of a help for your position. After the 40’s or 50’s they are virtually identical to the stations which were retained after 1992.
5) GISS makes claims about 2005 because it was statistically significantly warmer than 1998. In their record 2009 was the second warmest year by a very small amount, however it was not statistically significant. The reason for this difference is because GISS attemps to account for the arctic by estimating temperatures for the high arctic (north of 80) via interpolation. CRU does not, and the satellites do not measure above 82.5 north or south. Jones disagrees with Hansen’s methodology, surprise — he has his own way of analyzing the data, which does not include the high arctic.
I’m sure this won’t satisfy the hardcore…
Amino,
Tamino used the RAW, that is unadjusted data, for his analysis. It did not “pass through the hands of James Hansen”.
Re: Rattus Norvegicus (Mar 9 21:33),
no bias?
Something that would make a trend flatter is dropped and it is not a bias?
!!!!
Let me clarify:
looking at http://clearclimatecode.org/the-1990s-station-dropout-does-not-have-a-warming-effect/
The post removal has a hockey stick effect. flat/heat
The pre removal shows cold/flat/heat.
Trends are not given in the link so cannot judge if the anomaly trends are the same, pre and post.
Maybe the program of removal was aimed at agreeing with the hockey stick, for all we know. Maybe it is the random result of economic constraints ( difficult stations dropped). A bias there is.
In any case as I have said several times, anomalies are removed from reality (heat content) by the non linearity of the underlying heat transport system of the planet’s atmosphere, as can be seen in the latest february anomalies.
anna v (22:47:46) :
Let me clarify:
looking at http://clearclimatecode.org/the-1990s-station-dropout-does-not-have-a-warming-effect/
The post removal has a hockey stick effect. flat/heat
The pre removal shows cold/flat/heat.
An interesting point Lucia makes is that using the anomaly method the two series will converge during the shared baseline and diverge as we move away from that baseline. This can be seen in the chart he publishes but only going back in time. Any claim that it will not also happen in the future is without visible means of support.
Amino Acids in Meteorites (21:34:51) :
Please practice what you preach. Many of these comments from you are not about science, but about attacking the man.
anna v (22:47:46) :
The whole point is that the dropped subset and surviving subset give the same results, prior to 1992. This means that before 1992 at least, dropping those stations would not bias the global results. And if that’s so, why would you think it would make a big difference afterwards?
Amino Acids in Meteorites (21:33:17) :
“is the temperature reading of the retained stations the same as those dropped?”
I don’t know how many times it’s been said now, but multiple analyses show that you get the same results from either subset of stations.
I have also read that each of these multiple analyses uses different but still manipulated data, not raw data.
A link was given above to a plot where one does not get the same results. How is it possible for cold/flat to have the same trend as flat/flat?
Rattus Norvegicus (22:14:58) :
2) Actually, I was discussing science. To expect a radical change in the behavior of the “dropout” stations post 1992 is silly. Yes it might be possible, but please postulate a physical reason for this. At least he high latitude stations tend to show a greater warming trend than the rest of the globe, how would dropping high latitude stations result in a warming trend?
carrot eater (15:35:52) :
GISS only makes one adjustment, and it’s for UHI, and this is what it does:
It rather puts a damper on the idea that the missing stations were intentionally made to be missing in order to introduce some sort of spurious warming trend. And again, it gives you no particular reason to think that finding those missing data and putting them back in would have a major effect.
Aren’t you forgetting TOBS. That’s the biggest single correction they make in terms of absolute value. And it escalates in a trend to-date fashion resembling the hockey stick. And the escalation really begins post-dropout. I’m not a conspiracy theorist. But the increasing trend value post-dropout is obviously greater than anything preceding. Also you keep repeating the mantra that the pre trends are somewhat analogous and should equal the post trend ad infinitum. That presupposes your assumption that the trend is associated with a linearly (or logarithmic) increasing climate forcing and not a paradigm shift (PDO). Sound familiar?
Fill in the data for dropped stations post drop and I’ll look into it.
carrot eater (03:11:01) :
I am showing who James Hansen is.
How can telling people he is an environmental activist be an attack?
Wasn’t he arrested at a coal protest? Didn’t he testify in court that vandalism is ok if it is in the name of environmentalism?
How is the truth an attack? Does telling the truth about him make him look bad? Is that why you call it an attack? Is it wrong that people know he is an environmental activism? You don’t want people to know that?
If I had compared him to scientists that say cigarette smoke doesn’t casuse cancer that would be a smear attack.
If I compared him to people who deny there was a holocaust that would be a smear attack.
If i compared to people who still claim the earth is flat that would have been an attack.
But I didn’t do these things. I told the truth about him—that he is an environmental activist and therefore he should be questioned as to whether he can be trusted to be unbiased about an environmental issue.
…………………………………………………………………………………………………………
So tell me, is the truth an attack?
Documentation:
GISS Surface Temperature Analysis
What’s New
Feb. 16, 2010: Urban adjustment is now based on global nightlights rather than population as discussed in a paper in preparation.
Nov. 14, 2009: USHCN_V2 is now used rather than the older version 1. The only visible effect is a slight increase of the US trend after year 2000 due to the fact that NOAA extended the TOBS and other adjustment to those years.
Sep. 11, 2009: NOAA NCDC provided an updated file on Sept. 9 of the GHCN data used in our analysis. The new file has increased data quality checks in the tropics. Beginning Sept. 11 the GISS analysis uses the new NOAA data set.
This is on top of previous TOBS added between 1990-2009. I’ve always questioned why they continue to add in TOBS when almost all station times of observation were adjusted by 1995, and the correction is a one-time event for each station. From the magnitude of the TOBS correction, it appears more stations are needing correction each year. WUWT.
carrot eater (17:34:32) :
rbateman (16:34:36) :
You’re telling me about two stations someplace
_______________________________________
Oregon to be exact. Two places 18 miles apart in the same climactic valley.
One shows a warming UHI bias, one does not.
You have been going on for days about all stations do the same thing, and you are wrong.
There has been no evidence of warming in the cherry-picked stations that make up CRU for probably 15 years, and it’s a travesty. They cancelled each other out.
If we took ALL AVAILABLE stations we would see cooling the last 15 years, not the catastrophic and artificially sweetened GISS of death warming.
And what is even worse is the artificial holes in GISS data sets that are filled in with FILTEMP designed to artificially warm the trend. Holes that don’t exist in the raw data.
It was YOU who claimed that there is no difference between rural and urban data sets, they show the same thing. I just showed you Medford and Ashland, small town and big town right down the road from each other.
There is no difference before UHI sets in, but afterwards it’s as plain as day.
oh, btw…. where’s your graphs?
carrot eater (03:12:56) :
Here’s a good graphic. It shows the number of stations (out of 6000+) classified as warm. See if you can get the data from them and determine the number that are no longer included in the GISTEMP determination.
Nothing like real data to prove a point with me!
http://data.giss.nasa.gov/gistemp/warm_stations/
Amino Acids in Meteorites (07:16:56) :
When using data sets we should always proceed with due diligence regardless of how we trust the source.
“So tell me, is the truth an attack?”
It can be it can also support depends on what it tells us about a person’s work. What matters is whether it’s relevant if it points to the possibility of bias it may be relevant but nothing will beat directly testing the validity of or bias in the work under examination.
he is an environmental activist and therefore he should be questioned as to whether he can be trusted to be unbiased about an environmental issue.
That’s not a scientific question. If he were a judge, then yes, his opinion would matter. As a scientist, all that matters is whether his work is verifiable and replicable. One should absolutely question his conclusions, but science should question all results regardless of what one thinks a particular scientist’s opinions are.
You were the one saying “Attack the Man” was a bad thing to do. Someone said Chiefio’s site is difficult to read: it is. If that is “Attack the Man,” then how is “It is asking a lot to tell me to trust anything passing through the hands of James Hansen.” and “Tamino…… huh, who exactly is ‘Tamino’?” not “Attack the Man?”
Tim Clark (07:10:21) :
TOB is done in the USHCN, and is a pretty big deal there. And it does get passed through to GISS. But NOAA doesn’t do any TOB for the rest of the world, nor does GISS do it.
GISS does UHI. That’s it. And it uses raw data for all but the US.
Tim Clark
“But the increasing trend value post-dropout is obviously greater than anything preceding.”
Obvious to whom? You see a marked difference in trend, 1975 to 1990, vs 1990 to 2010? I don’t.
“Also you keep repeating the mantra that the pre trends are somewhat analogous and should equal the post trend ad infinitum.”
Because it answers most of the objections being raised here, about baselines and whatever else.
“That presupposes your assumption that the trend is associated with a linearly (or logarithmic) increasing climate forcing and not a paradigm shift (PDO). Sound familiar?”
What has that got to do with anything? For the station drop to matter, the dropped stations have to have had different trends from their neighbors in the same grid box. What has that got to do with PDOs or anything?