Guest Post by Willis Eschenbach
[see Update at the end of this post]
I got to thinking about the (non) adjustment of the GISS temperature data for the Urban Heat Island effect, and it reminded me that I had once looked briefly at Anchorage, Alaska in that regard. So I thought I’d take a fresh look. I used the GISS (NASA) temperature data available here.
Given my experience with the Darwin, Australia records, I looked at the “homogenization adjustment”. According to GISS:
The goal of the homogenization effort is to avoid any impact (warming or cooling) of the changing environment that some stations experienced by changing the long term trend of any non-rural station to match the long term trend of their rural neighbors, while retaining the short term monthly and annual variations.
Here’s how the Anchorage data has been homogenized. Figure 1 shows the difference between the Anchorage data before and after homogenization:
Figure 1. Homogenization adjustments made by GISS to the Anchorage, Alaska urban temperature record (red stepped line, left scale) and Anchorage population (orange curve, right scale)
Now, I suppose that this is vaguely reasonable. At least it is in the right direction, reducing the apparent warming. I say “vaguely reasonable” because this adjustment is supposed to take care of “UHI”, the Urban Heat Island effect. As most everyone has experienced driving into any city, the city is usually warmer than the surrounding countryside. UHI is the result of increasing population, with the accompanying changes around the temperature station. More buildings, more roads, more cars, more parking lots, all of these raise the temperature, forming a heat “island” around the city. The larger the population of the city, the greater the UHI.
But here’s the problem. As Fig. 1 shows, until World War II, Anchorage was a very sleepy village of a few thousand. Since then the population has skyrocketed. But the homogeneity adjustment does not match this in any sense. The homogeneity adjustment is a straight line (albeit one with steps …why steps? … but I digress). The adjustment starts way back in 1926 … why would the 1926 Anchorage temperature need any adjustment at all? And how does this adjust for UHI?
Intrigued by this oddity, I looked at the nearest rural station, which is Matanuska. It is only about 35 miles (60 km) from Anchorage, as shown in Figure 2.
Figure 2. Anchorage (urban) and Matanuska (rural) temperature stations.
Matanuska is clearly in the same climatological zone as Anchorage. This is verified by the correlation between the two records, which is about 0.9. So it would be one of the nearby rural stations used to homogenize Anchorage.
Now, according to GISS the homogeneity adjustments are designed to adjust the urban stations like Anchorage so that they more closely match the rural stations like Matanuska. Imagine my surprise when I calculated the homogeneity adjustment to Matanuska, shown in Figure 3.
Figure 3. Homogenization adjustments made by GISS to the Matanuska, Alaska rural temperature record.
Say what? What could possibly justify that kind of adjustment, seven tenths of a degree? The early part of the record is adjusted to show less warming. Then from 1973 to 1989, Matanuska is adjusted to warm at a feverish rate of 4.4 degrees per century … but Matanuska is a RURAL station. Since GISS says that the homogenization effort is designed to change the “long term trend of any non-rural station to match the long term trend of their rural neighbors”, why is Matanuska being adjusted at all?
Not sure what I can say about that, except that I don’t understand it in the slightest. My guess is that what has happened is that a faulty computer program has been applied to fudge the record of every temperature station on the planet. The results have then been used without the slightest attempt at quality control.
Yes, I know it’s a big job to look at thousands of stations to see what the computer program has done to each and every one of them … but if you are not willing to make sure that your hotrod whizbang computer program actually works for each and every station, you should not be in charge of homogenizing milk, much less temperatures.
The justification that is always given for these adjustments is that they must be right because the global average of the GISS adjusted dataset (roughly) matches the GHCN adjusted dataset, which (roughly) matches the CRU adjusted dataset.
Sorry, I don’t find that convincing in the slightest. All three have been shown to have errors. All that shows is that their errors roughly match, which is meaningless. We need to throw all of these “adjusted datasets” in the trash can and start over.
As the Romans used to say “falsus in unum, falsus in omnibus”, which means “false in one thing, false in everything”. Do we know that everything is false? Absolutely not … but given egregious oddities like this one, we have absolutely no reason to believe that they are true either.
Since people are asking us to bet billions on this dataset, we need more than a “well, it’s kinda like the other datasets that contain known errors” to justify their calculations. NASA is not doing the job we are paying them to do. Why should citizen scientists like myself have to dig out these oddities? The adjustments for each station should be published and graphed. Every single change in the data should be explained and justified. The computer code should be published and verified.
Until they get off their dead … … armchairs and do the work they are paid to do, we can place no credence in their claims of temperature changes. They may be right … but given their egregious errors, we have no reason to believe that, and certainly no reason to spend billions of dollars based on their claims.
[Update – Alaska Climate Research Center releases new figures]
I have mentioned the effect of the Pacific Decadal Oscillation (PDO) below. The Alaska Climate Research Center have just released their update to the Alaska data. Here’s that information:
Figure 4. Alaska Temperature Average from First Order Observing Stations
In the Alaska Climate Research Center data, you can clearly see the 1976 shift of the PDO from the cool to the warm phase, and the recent return to the cool phase. Unsurprisingly, the rise in the Alaska temperatures (typically shown with a continuously rising straight trend line through all the data) have been cited over and over as “proof” that the Arctic is warming. However, the reality is a fairly constant temperature from 1949-1975, a huge step change 1975-1976, and a fairly constant temperature from 1976 until the recent drop. Here’s how the IPCC Fourth Assessment Report interprets these numbers …
Figure 5. How the IPCC spins the data.
SOURCE: (IPCC FAR WG1 Chapter 9, p. 695)
As you can see, they have played fast and loose with the facts. They have averaged the information into decade long blocks 1955-1965, 1965-1975, 1975-1985 etc. This totally obsures the 1975-1976 jump. It also gives a false impression of the post-1980 situation, falsely showing purported continuing warming post 1980. Finally, they have used “adjusted data” (an oxymoron if there ever was one). As you can see from Fig. 4 above, this is merely global warming propaganda. People have asked why I say the Alaska data is “fudged” … that’s a good example of why.
Say what? What could possibly justify that kind of adjustment, seven tenths of a degree? The early part of the record is adjusted to show less warming. Then from 1973 to 1989, Matanuska is adjusted to warm at a feverish rate of 4.4 degrees per century … but Matanuska is a RURAL station.
Yes a rural station near a glacier as shown in the backdrop to the graph, definitely could have an effect.
John S (18:22:22) :
“Since people are asking us to bet billions on this dataset,”
Trillions, Willis. Trillions.
==========
Yep, you got that right.
Never mind that almost every county, state and most countries are bankrupt. The really scary part, is just how big a “trillion” is, and how fast they are spent.
Isn’t this just the same type of GISS adjustment we’ve seen in blink charts before? Adjust older temps down and newer temps up to create a larger trend. Looks like business as usual.
“Until they get off their dead … … armchairs and do the work they are paid to do…”
Can we call them crooks yet?
Still too early?
Let me know when we get to the prosecution stage of the global warming fiasco.
Robert and Willis
I appreciate both your perspectives, but not your tones. Science provides data, which can always be challenged. Both should be done politely, without accusation. As soon as the tone becomes strident, it becomes very difficult to change a position, and science becomes politics.
Anthony is more tolerant than I am. I would be inclined to snip all disrespectful text in articles, and comments. For example:
EdB (18:36:02) [snip … disrespectful]
That might bring the tone down enough to actually debate the science.
I’m pretty sure Peter O’Neill (17:12:34) is correct. The rural station got adjusted here because of the night lights.
So all Eschenbach needs to do is check the trends at the surrounding dark rural stations, because they’re the ones in the driver’s seat for long term trends. Which is what he should have done in the first place. Instead of “Not sure what I can say about that, except that I don’t understand it in the slightest. “, another couple hours of work would have provided the understanding he was seeking.
GP (18:18:01) :
That’s always a good question. If the change in method causes such a little change, why bother doing it? Well, it could be more important in certain regions. It may make little difference to the global numbers, but there could be individual grid points where the effect is stronger. This is actually often true of adjustments in general.
To everybody who’s annoyed that the GISS adjustments sometimes increase the warming trends in urban/town stations: The surrounding rural stations are the drivers. So whatever the trend is at the rural station, then GISS is going to impose that trend on the urban station.
Sometimes the rural station could truly be warming faster than the urban station. Just because a station is in a UHI doesn’t mean the UHI effect will increase over time. There could also be inhomogeneities in there that mess with the trend at either urban or rural station. A station move can easily obscure the true trend.
In addition the fudged sea level claims are being withdrawn: http://www.guardian.co.uk/environment/2010/feb/21/sea-level-geoscience-retract-siddall
Please disregard my previous comment as you posted the same thing as I was typing it.
What happens when you take away cloud cover and precipitation?
You get a warming effect and draught.
Just in certain regions of our planet.
But, winds can carry away this to other areas.
Is “Robert” Gavin’s screen name?
REPLY: No different person, he’s in the health care biz – A
The justification of adjustments – this is what is being glossed over, even in the skeptical blogs, or at least not stressed and/or focused upon enough. Where are the records of the adjustments?
Perusing through HARRY_READ_ME I got the impression that nobody really knows, as Harry was finding out that the programs were largely undocumented. How do you document a version adjustment when you are not aware that the program is adjusting or stomping data?
You should be aware, however, when looking at vintage 19th century data that 1880 can be juxtaposed or overwritten by 1980, data included. I’ve come across this in Solar data, so I suspect that some of the programs used in climate data have been imported from other efforts.
Not everything that happened to the data was intentional. Some of it was just plain unforseen. Never operate on the original copy of anything.
Willis Eschenbach (19:07:43) :
“How could satellites produce information useful for adjusting Matanuska downwards in say 1940? ”
They don’t. The GISS logic: if the station is currently urban or peri-urban, then it’s safest to not trust the trends at that station, over any time span. Let the surrounding rural stations take charge over the entire history of that station.
___
“The fact that it is graded as “Urban” or “Suburban” today means nothing about what it was like in 1920. If it was still rural in 1920 (and there is absolutely no question that it was), why should the 1920 value be adjusted? This procedure makes no sense. ”
But you know it went from being rural to urban or peri-urban at some point in time. So there’s a possible UHI trend in there somewhere in time, and you want to avoid it. If there is a station that is rural now, it probably always was. Let it do the driving.
That said, I prefer the NOAA thinking on this issue, over GISS’s approach. I look forward to GHCN v3.0. If you actually bother to compare the stations against each other, you can probably detect when the UHI trend took place. That’s what NOAA does.
___
“Bangui is the capital of the Central African Republic, population half a million, ”
This is an interesting point. Urban areas in poor parts of the world will lack nightlight. I wonder if they’ll let the GHCN ‘U’ rating override the nightlight data in such cases.
____
“I can think of no theoretical justification for that procedure. At least GHCN requires that their adjusting stations be correlated with the adjusted station, but GISS make no such requirement. And if you are going to weight by distance, wouldn’t correlation be likely to fall off by the square of the distance?”
The justification is in Hansen/Lebedeff (1987). Looking at the graphs of correlation vs distance, linear seems pretty fair.
carrot eater (19:17:26) : “To everybody who’s annoyed that the GISS adjustments sometimes increase the warming trends in urban/town stations: The surrounding rural stations are the drivers. So whatever the trend is at the rural station, then GISS is going to impose that trend on the urban station.”
I wish you could prove that statement. Or are you just a true AGW believer. If they are truly “the driver” then recent temps should be lowered not past temp, with the result of increasing the trend. And why get rid of rural reporting stations. For example, if rural stations are truly “the driver” as you claim how is it that the SF airport is the only station for northern California. And did they adjust for dwindling fog?
SteveGinIL (18:18:55) :
To be good science, the reasons for instrument adjustments need to be spelled out and documented as part of the methodology AND KEPT WITH THE PROGRAM OR DOCUMENTATION USED. If this is not done, calling these people “scientists” doesn’t equate them to those I’ve known and worked with. For work this sloppy, they would have been found out in very short order and canned.
Steve. How right you are. It didn’t happen here in N.Z. Instead we got a Phil Jones type response. No surprise really given Jim Salinger’s pedigree.
Here is how some of that ‘lack of good science’ played out in the House of Parliament in NZ on February 17th . last in question and answer time. It is an example of obfuscation by the Minister ‘protecting’ his department. Nobody should be fooled.
9. JOHN BOSCAWEN (ACT) to the Minister of Research, Science and Technology: Does the National Institute of Water and Atmospheric Research maintain an up-to-date schedule of adjustments of all changes made to the raw temperature data that are used in calculating the official series “Mean annual temperature over New Zealand, from 1853 to 2008”, published on the institute’s website; if not, why not?
Hon Dr WAYNE MAPP (Minister of Research, Science and Technology) : The “Mean annual temperature over New Zealand, from 1853 to 2008” analysis, which was referred to by the member, does make adjustments to the raw data from the seven stations. The reason that is necessary ………. The original methodology to do so was developed in Dr Salinger’s PhD thesis, which is also publicly available.
John Boscawen: Given that we have been through the information the Minister refers to and found no schedule of adjustments, can he point to where in this mass of information it is contained; if he cannot, can he commit to table in Parliament the simple schedule of adjustments?
Hon Dr WAYNE MAPP: The member is correct; there is a complex range of information on the institute’s website. The methodology for the site changes is published in the peer-reviewed International Journal of Climatology, ………….“Adjustment of temperature and rainfall measurements for site changes”. The huge volume of information indicates that this is quite a complex area.
Hon Rodney Hide: I raise a point of order, Mr. Speaker. With great respect, the Minister did not answer the question. The question is a very simple one. It is not about the methodology; it is about the simple schedule of adjustments. In his answer to the primary question he said that the schedule was on the institute’s web page, amongst this mass of information. We have been through it. There is no schedule of adjustments. So the Minister was asked whether he could point to the actual schedule of adjustments, not the methodology, and if he could not, whether he could table in the House the schedule of adjustments—not the methodology; the schedule.
Mr SPEAKER: I hear the honourable member, and I am sympathetic to the member’s point of order, because the question was on notice. The question asks specifically whether the institute maintains an up-to-date schedule of adjustments of all changes made to the raw temperature data. It does not ask why changes are made to raw temperature data, or how those changes are made; the primary question asks whether the institute maintains an up-to-date schedule of the adjustments made. That information should be available, and I believe that the House deserves an answer. I invite the Minister to give the House an answer.
He still only got a BS answer even after all that.
Doug
It seems to me that Robert doesn’t understand the difference between raw temperatures and adjusted temperatures. We are arguing that the real temperatures may be just fine, but the adjustments seem to make no sense, yet the public pronouncements about warming are based on adjusted temps.
Also, if the Matanuska temps are from the Palmer experimental farm, it is a long way from the built up part of the mat. valley. It is really rural and shouldn’t need any UHI adjustment unless the sensor is in the parking lot.
Jim Steele (19:36:55) :
“I wish you could prove that statement.”
Read and run the code, if you don’t believe me.
____
“If they are truly “the driver” then recent temps should be lowered not past temp, with the result of increasing the trend.”
The Anchorage trend was decreased, so you got what you wanted there.
As for what happened in Matanuska, you’ll have to examine the surrounding rural stations within 500 km. Hopefully Willis updates by putting those up; it is all that you need to close the puzzle.
Once Matanuska got classified as periurban due to the nightlights, then it lost driving privileges.
___
“And why get rid of rural reporting stations. For example, if rural stations are truly “the driver” as you claim how is it that the SF airport is the only station for northern California.”
Where do you get that? Looks like a ton of stations in Northern CA to me.
Lon Hocker
Following your logic,Anthony should have snipped Robert’s first comment,then the “tone” would not have been lowered.I thought Willis was rather restrained after being told
“No, you were dead on: you don’t understand what’s going on in the slightest”
Atlantic City State Marina, 159
#6 in the world?
David L. Hagen (17:43:11)
Per your citation it was 1990, not 1900.
Robert (17:43:04)
Y’know, Robert, you misconstrued my meaning entirely. I was trying to restate it in words of one syllable, so you might get it. I prefaced it by saying “what I meant was” to contrast it with your fantasy about what I meant.
As to your question, I fear I don’t have an answer. I don’t know any arguments that say that adjusting a perfectly good rural temperature record down and then back up by three quarters of a degree is a reasonable plan.
However, if you have them, bring them on.
David L. Hagen (17:54:40)
Unfortunately, that doesn’t really help. It is the population for the entire borough, not for the location where the temperature station is located. Good find, though.
3×2 (18:14:12)
Yes, the “AES” stands for “Agricultural Experimental Station”.
carrot eater (19:51:12) :
They don’t use the rural stations in N. Calif to compute the GIStemp, or whatever it is they call that 8-bit Atari Graphics map. Haven’t you been listening? The rest of the State could be buried under 100 feet of snow with howling subzero winds, but if SF is warm & sunny, the map will show a warm anomay.
More snow expected in Texas tomorrow & into Tuesday. Another round of cold slap for the NE.
Reno, NV broke a snowfall record today with 12 inches dumped.
Peter O’Neill (18:46:56)
Call me crazy, but I find it hard to laugh about dragging 1920 Matanuska data into the 21st century just so it can be adjusted …
Many thanks for your efforts. Could you post the stations used to adjust Anchorage? Much appreciated.
As someone who has spent a reasonable amount of time in Alaska, including the Matanuska valley, it’s “Matanuska” with one “n”, and the spelling error is from GISS/GHCN. Not surprising, as their station lists contains many such errors. QC ‘R US … not.