Guest Post by Willis Eschenbach
Recapping the story begun at WUWT here and continued at WUWT here, data from the temperature station Darwin Zero in northern Australia was found to be radically adjusted and showing huge warming (red line, adjusted temperature) compared to the unadjusted data (blue line). The unadjusted data showed that Darwin Zero was actually cooling over the period of the record. Here is the adjustment to Darwin Zero:
Figure 1. The GHCN adjustments to the Darwin Zero temperature record.
Many people have written in with questions about my analysis. I thank everyone for their interest. I’m answering them as fast as I can. I cannot answer them all, so I am trying to pick the relevant ones. This post is to answer a few.
• First, there has been some confusion about the data. I am using solely GHCN numbers and methods. They will not match the GISS or the CRU or the HadCRUT numbers.
• Next, some people have said that these are not separate temperature stations. However, GHCN adjusts them and uses them as separate temperature stations, so you’ll have to take that question up with GHCN.
• Next, a number of people have claimed that the reason for the Darwin adjustment was that it is simply the result of the standard homogenization done by GHCN based on comparison with other neighboring station records. This homogenization procedure is described here (PDF).
While it sounds plausible that Darwin was adjusted as the GHCN claims, if that were the case the GHCN algorithm would have adjusted all five of the Darwin records in the same way. Instead they have adjusted them differently (see below). This argues strongly that they were not done by the listed GHCN homogenization process. Any process that changed one of them would change all of them in the same way, as they are nearly identical.
• Next, there are no “neighboring records” for a number of the Darwin adjustments simply because in the early part of the century there were no suitable neighboring stations. It’s not enough to have a random reference station somewhere a thousand km away from Darwin in the middle of the desert. You can’t adjust Darwin based on that. The GHCN homogenization method requires five well correlated neighboring “reference stations” to work.
From the reference cited above:
“In creating each year’s first difference reference series, we used the five most highly correlated neighboring stations that had enough data to accurately model the candidate station.”
and “Also, not all stations could be adjusted. Remote stations for which we could not produce an adequate reference series (the correlation between first-difference station time series and its reference time series must be 0.80 or greater) were not adjusted.”
As I mentioned in my original article, the hard part is not to find five neighboring stations, particularly if you consider a station 1,500 km away as “neighboring”. The hard part is to find similar stations within that distance. We need those stations whose first difference has an 0.80 correlation with the Darwin station first difference.
(A “first difference” is a list of the changes from year to year of the data. For example, if the data is “31, 32, 33, 35, 34”, the first differences are “1, 1, 2, -1”. It is often useful to examine first differences rather than the actual data. See Peterson (PDF) for a discussion of the use of the “first-difference method” in climate science.)
Accordingly, I’ve been looking at the candidate stations. For the 1920 adjustment we need stations starting in 1915 or earlier. Here are all of the candidate stations within 1,500 km of Darwin that start in 1915 or before, along with the correlation of their first difference with the Darwin first difference:
WYNDHAM_(WYNDHAM_PORT) = -0.14
DERBY = -0.10
BURKETOWN = -0.40
CAMOOWEAL = -0.21
NORMANTON = 0.35
DONORS_HILL = 0.35
MT_ISA_AIRPORT = -0.20
ALICE_SPRINGS = 0.06
COEN_(POST_OFFICE) = -0.01
CROYDON = -0.23
CLONCURRY = -0.2
MUSGRAVE_STATION = -0.43
FAIRVIEW = -0.29
As you can see, not one of them is even remotely like Darwin. None of them are adequate for inclusion in a “first-difference reference time series” according to the GHCN. The Economist excoriated me for not including Wyndham in the “neighboring stations” (I had overlooked it in the list). However, the problem is that even if we include Wyndham, Derby, and every other station out to 1,500 km, we still don’t have a single station with a high enough correlation to use the GHCN method for the 1920 adjustment.
Now I suppose you could argue that you can adjust 1920 Darwin records based on stations 2,000 km away, but even 1,500 km seems too far away to do a reliable job. So while it is theoretically possible that the GHCN described method was used on Darwin, you’ll be a long, long ways from Darwin before you find your five candidates.
• Next, the GHCN does use a good method to detect inhomogeneities. Here’s their description of their method.
To look for such a change point, a simple linear regression was fitted to the part of the difference series before the year being tested and another after the year being tested. This test is repeated for all years of the time series (with a minimum of 5 yr in each section), and the year with the lowest residual sum of the squares was considered the year with a potential discontinuity.
This is a valid method, so I applied it to the Darwin data itself. Here’s that result:
Figure 2. Possible inhomogeneities in the Darwin Zero record, as indicated by the GHCN algorithm.
As you can see by the upper thin red line, the method indicates a possible discontinuity centered at 1939. However, once that discontinuity is removed, the rest of the record does not indicate any discontinuity (thick red line). By contrast, the GHCN adjusted data (see Fig. 1 above) do not find any discontinuity in 1941. Instead, they claim that there are discontinuities around 1920, 1930, 1950, 1960, and 1980 … doubtful.
• Finally, the main recurring question is, why do I think the adjustments were made manually rather than by the procedure described by the GHCN? There are a number of totally independent lines of evidence that all lead to my conclusion:
1. It is highly improbability that a station would suddenly start warming at 6 C per century for fifty years, no matter what legitimate adjustment method were used (see Fig. 1).
2. There are no neighboring stations that are sufficiently similar to the Darwin station to be used in the listed GHCN homogenization procedure (see above).
3. The Darwin Zero raw data does not contain visible inhomogeneities (as determined by the GHCN’s own algorithm) other than the 1936-1941 drop (see Fig. 2).
4. There are a number of adjustments to individual years. The listed GHCN method does not make individual year adjustments (see Fig. 1).
5. The “Before” and “After” pictures of the adjustment don’t make any sense at all. Here are those pictures:
Figure 3. Darwin station data before and after GHCN adjustments. Upper panel shows unadjusted Darwin data, lower panel shows the same data after adjustments.
Before the adjustments we had the station Darwin Zero (blue line line with diamonds), along with four other nearby temperature records from Darwin. They all agreed with each other quite closely. Hardly a whisper of dissent among them, only small differences.
While GHCN were making the adjustment, two stations (Unadj 3 and 4, green and purple) vanished. I don’t know why. GHCN says they don’t use records under 20 years in length, which applies to Darwin 4, but Darwin 3 is twenty years in length. In any case, after removing those two series, the remaining three temperature records were then adjusted into submission.
In the “after” picture, Darwin Zero looks like it was adjusted with Sildenafil. Darwin 2 gets bent down almost to match Darwin Zero. Strangely, Darwin 1 is mostly untouched. It loses the low 1967 temperature, which seems odd, and the central section is moved up a little.
Call me crazy, but from where I stand, that looks like an un-adjustment of the data. They take five very similar datasets, throw two away, wrench the remainder apart, and then average them to get back to the “adjusted” value? Seems to me you’d be better off picking any one of the originals, because they all agree with each other.
The reason you adjust is because records don’t agree, not to make them disagree. And in particular, if you apply an adjustment algorithm to nearly identical datasets, the results should be nearly identical as well.
So that’s why I don’t believe the Darwin records were adjusted in the way that GHCN claims. I’m happy to be proven wrong, and I hope that someone from the GHCN shows up to post whatever method that they actually used, the method that could produce such an unusual result.
Until someone can point out that mystery method, however, I maintain that the Darwin Zero record was adjusted manually, and that it is not a coincidence that it shows (highly improbable) warming.
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Is there a record of the number of corrections for inhomogeneity and what direction these are in? An assessment of the formal guidelines used should be revealing – are there more reasons to adjust data upwards than down?
The GHCN, GISS, HadCrut and all there are tries to find the trend line in any global temperature mean. Why would that require any adjustments at all apart from those trying to adjust for biases induced by human activity. That would be solely UHI-effects or land use changes I would assert.
For example, a specific station time of observation would have a trend line which would look the same or at least as much erroneous regardless of the time of day it was observed? The trend for a 3 o clock observation would contain as much global warming as any trend for a 5 o clock series of observation, wouldn’t it?
I try to read all the rationale for adjustments but cannot make any sense out of it. The gridding for example, what is that for? The neighboring station mumbo-jumbo, how is that justified? It seems that when the task is to try to find a trend line in a global mean temperature, all the data should be included since any error in the data would go in both direction. The Darwin station for example, wouldn’t there be a station somewhere in the world that has a funny up spike in 1939 the compensates the Darwin down spike?
As a long time engineer, I try to find KISS solutions an all similar problems, the “state of the art ” science in this field has complicated matters beyond recognition.
I would love to be educated on this.
Great work!!
Has there been any reaction to your open letter to the Ecomomist?
Amendment:
I read the abstract of the Peterson paper, it seems to me that the method described therein is to be able to find the actual temperatures, i.e. the absolute values that are comparable with other stations, when such comparison is needed/wanted/called for, it wouldn’t apply to finding high pass filtered temperature trends, why would it?
Maybe I am jumping to conclusions, I always do that…
“You still haven’t recognised the most cogent criticism of Giorgio Gilestro, who showed that if you looked at the whole distribution of GHCN adjustments, and not just one station, the distribution is fairly symmetric, with stations almost as likely to have the trend adjusted down than up. ”
Cogent? GG appears to believe that if a merchant pushes down on one arm of the scales as heavily as he pulls up on the other, that that’s a fair transaction.
Someone else posted the graph above from RomanM’s analysis, here:
http://statpad.wordpress.com/2009/12/12/ghcn-and-adjustment-trends/
How you can look at that timewise adjustment ‘trend’ and pretend this is innocent is beyond me.
@Ken Seton
Station records that are unclear labeled resemble GM food in the US and Canada:
from the label you do NOT know what you are dealing with.
Nick Stokes (22:46:31) :
Willis,
You still haven’t recognised the most cogent criticism of Giorgio Gilestro, who showed that if you looked at the whole distribution of GHCN adjustments, and not just one station, the distribution is fairly symmetric, with stations almost as likely to have the trend adjusted down than up….
YOU miss the point entirely. There is absolutely no reason to adjust these records period. There is no reason to adjust ANY of the records unless a very good VALIDATED reason exists. Saying some pie in the sky method was used to do the adjustment does not justify tampering with the data.
I ran a quality lab. If I look at graphs of chemical analysis and find one does not “match” the typical data does that mean I have reason to “adjust ” the data or do I go look for the actual cause? If I do not find a problem with calibration, sampling method or whatever am I justified in arbitrarily “correcting” the data. Do I place the corrected numbers on the Certificate of Analysis or do I take it the data is telling me something – like the product should be rejected.
I’m still left with a couple of questions.
For those who say that individual stations don’t matter, the global stats will sort things out
If, when scaled globally, local “adjustments” have no real impact … why bother “adjusting” in the first place? Adjustments at the individual station level obviously do impact both regional and global results. Especially if the end result is in the 1/10th degree range.
Specifically for Darwin adjustments.
If you take the difference between the “winter” and “summer” means over the entire record (25/28 from v2.mean) as being about 3°C. Is a 2.25°C “adjustment”, in any direction, at any point, even physically possible?
To put the level of Darwin adjustment in context. If you applied it to Helsinki the “Darwin adjustment” level would be around 17°C. ({v2.mean} ((summer 17) – (winter -6))*0.75) over almost 200 years.
Both adjustments seem pretty much impossible.
(real Helsinki adjustment looks to be (peak/trough) +1.25 to -0.7 (in nice clear edged steps) over 200 years – pretty much neutral overall)
Dear Mr Eschenbach
Another erudite post please keep up the good work. Is there any chance of you revisiting your work on the CET record?
Sorry my hobby horse as always been that a global temperature as such is a nonsense given the spread of data. Howver temperature records of individual countries could show if an area is warming or cooling.
Your forensic work has the beauty of showing that hockey stick graphs are being mad up out of measured temperatures, just as in New Zealand.
In the past four weeks, we have an area of Australia where a hockey stick can be demonstrated to have been manufacture, Russia where they say that much data has been ignored and badly manipultated, New Zealand.
You couldn’t make this up, they did.
*************
Nick Stokes (22:46:31) :
Willis,
You still haven’t recognised the most cogent criticism of Giorgio Gilestro, who showed that if you looked at the whole distribution of GHCN adjustments, and not just one station, the distribution is fairly symmetric, with stations almost as likely to have the trend adjusted down than up. The average upward adjustment to trend was 0.0175 C/decade; much less than the Darwin figure.
***********************
Nick: An adjustment histogram just hides the actual adjustments – it is meaningless. Why? Because WHEN the adjustment is made is key. If most of the downward adjustments are made before half the time of the total length of the record and most of the upwards adjustments after half the time, then the trend up will be enhanced. I’m really tired of this statistical shell game and this isn’t the first time I’ve seen these histograms trotted out as proof of fairness. They are bogus and designed to deceive.
Your’s and other independent analysis will soon be irrelevant if Gordon Brown and other world leaders have their way.
Excerpt:
A new global body dedicated to environmental stewardship is needed to prevent a repeat of the deadlock which undermined the Copenhagen climate change summit, Gordon Brown will say tomorrow.
The UN’s consensual method of negotiation, which requires all 192 countries to reach agreement, needs to be reformed to ensure that the will of the majority prevails, he feels.
The Prime Minister will say: “Never again should we face the deadlock that threatened to pull down those talks. Never again should we let a global deal to move towards a greener future be held to ransom by only a handful of countries. One of the frustrations for me was the lack of a global body with the sole responsibility for environmental stewardship.
“I believe that in 2010 we will need to look at reforming our international institutions to meet the common challenges we face as a global community.” The summit failed to produce a political agreement among all the countries. Delegates instead passed a motion on Saturday “taking note” of an accord drawn up the night before by five countries: the US, China, India, Brazil and South Africa. ”
End quote
Gordon Brown (UK ) is following the “Belgrade Process” script. Right on schedule. http://www.timesonline.co.uk/tol/news/uk/article6963482.ece#… .
So Aussies did their own..I would not say “Hockey Stick” but “Kangaroo Tail”
Glenn (19:50:45) :
Ah. That would make the region the fastest warming area claim in the world, if memory serves, topping the Arctic and Siberia. About 3 times the global surface estimate in any event.
Last I heard, all the warmining the warmists were claiming was 0.6. So, this would be 10 X that.
Norm in Calgary (22:56:52) :
…. I’m not sure how they would manage to record CO2 dropping enough to make a difference, unless they manipulate the data, but they’d never do that; or they claim the positive multiplier effect also works as a negative multiplier effect in reverse so that a teeny drop could save the world.
That is REAL easy. Mauna Loa has active vents putting out CO2. The official CO2 numbers we get are “calculated” to remove the amount of CO2 contributed by the volcano.
Nick Stokes (22:46:31) :
“I am sorry, but I still find it a bit odd that adjustments to temperature balance out. I would expect there to be a bias in one direction or the other.
When you say ‘balance out’, I presume that you mean over the entire instrumental temperature history. ”
Couldn’t you get a balancing out even if, let’s say, the pre 1960s (I choice that year arbitrarily) temperatures were adjusted significantly lower and the post 1960s were adjusted significantly higher?
Has anyone tested this possibility?
Bold are my highlight, italics my comments.
1120593115.txt
From: Phil Jones xxxxxxxx
To: John Christy xxxxxxxx
Subject: This and that
Date: Tue Jul 5 15:51:55 2005
Also this load of rubbish!
This is from an Australian at BMRC (not Neville Nicholls). It began from the attached article. What an idiot. The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998. OK it has but it is only 7 years of data and it isn’t statistically significant.
The Australian also alerted me to this blogging! I think this is the term! Luckily
I don’t live in Australia.
[1]http://mustelid.blogspot.com/2005/06/first-look-at-scs-msu-vn52.html
Unlike the UK, the public in Australia is very very naive about climate change, mostly because of our governments Kyoto stance, and because there is a proliferation of people with no climate knowledge at all that are prepared to do the gov bidding.
Australian farmers and Aboriginal people know all about floods and droughts. This urban [snip] wants us to believe it’s caused by cow farts.
Hence the general populace is at best confused, and at worst, antagonistic about climate change – for instance, at a recent rural meeting on drought, attended by politicians and around 2000 farmers, a Qld collegue – Dr Roger Stone – spoke about drought from a climatologist point of view, and suggested that climate change may be playing a role in Australias continuing drought+water problem. He was booed and heckled (and unfortunately some politicians applauded when this happened) – that’s what we’re dealing with due to columists such as the one I sent to you.
Need I say more? The useless [snip] thinks he can teach Australians about the climate of a continent he has never set foot in.
It appears Nick Stokes only answers the easy questions. I think that pretty much demonstrates his INTENT. His only reason for being here is to insert some measure of doubt. Sorry, Nick, not working.
Yes, Darwin is a single station … but … we have all of New Zealand in doubt, we have all of Scandinavia in doubt, we have most of Russia in doubt and it seems just about every time anyone looks at a new location it has been adjusted upward by a questionable amount.
I don’t think there’s much doubt left anymore.
Good work, Willis.
Some issues that require reconsideration:
“Next, some people have said that these are not separate temperature stations. However, GHCN adjusts them and uses them as separate temperature stations, so you’ll have to take that question up with GHCN.”
GHCN treats these as ‘duplicate’ station records, not as separate stations. You need to understand what that means, and how it affects how these data are ultimately used in the global anomaly calc.
“While it sounds plausible that Darwin was adjusted as the GHCN claims, if that were the case the GHCN algorithm would have adjusted all five of the Darwin records in the same way.”
That is not true. The GHCN algorithm could easily operate differently on different records, even if they are very close (or perhaps even if they are identical) in their values.
The records are of different lengths. This could easily change which ‘neighboring’ stations correlate with the records and thus which stations are used for the identification of discontinuities and application of adjustments. Even when the same stations are used for the adjustment, record length may also affect how discontinuities are identified and how adjustments are applied. You may not yet conlcude that the standard GHCN adjustment proceedure was not correctly applied.
“Next, there are no “neighboring records” for a number of the Darwin adjustments simply because in the early part of the century there were no suitable neighboring stations. It’s not enough to have a random reference station somewhere a thousand km away from Darwin in the middle of the desert.”
You repeat your mistake of the first analysis, by applying your own criteria for suitability, rather than GHCNs. GHCN does not appear to have any specific distance limit. GHCN appears to only be concerned if the stations are in the same ‘region’ (climatalogically) . You cannot say that GHCN did not apply its standard method. You need to ask.
“Here are all of the candidate stations within 1,500 km of Darwin that start in 1915 or before, along with the correlation of their first difference with the Darwin first difference:”
Which Darwin first difference? The correlation between any given station and any of the five Darwin duplicate records may be very different. Which one of the five do you report here? What do the other four look like?
“Now I suppose you could argue that you can adjust 1920 Darwin records based on stations 2,000 km away, but even 1,500 km seems too far away to do a reliable job. So while it is theoretically possible that the GHCN described method was used on Darwin, you’ll be a long, long ways from Darwin before you find your five candidates.”
So?
The assertion is that stations within the same ‘region’ are sufficient for use as reference stations, when making homogenizations of datasets desgned to be used at ‘regional’ or larger scales. You have not addressed that, not that it matters one whit to your claim that the adjustment wasnt applied correctly.
“1. It is highly improbability that a station would suddenly start warming at 6 C per century for fifty years, no matter what legitimate adjustment method were used (see Fig. 1).”
True. This is a potential indictment of the adjustment method, not proof that the adjustment wasnt properly applied. Note that to serve as an attack on the adjustment method, you would need to demonstrate that the adjustment method was properly applied here, and that the adjustment had a significant effect on the temperature measurement *at regional and larger scales*.
Recall from our previous discussions that the GHCN method specifically allows for oddball results that do not track local temps. They assert that these weird adjustments are rare (i.e. ‘highly improbable’ results are consistent with the methodology), and have little if any effect on the aggregate results.
“2. There are no neighboring stations that are sufficiently similar to the Darwin station to be used in the listed GHCN homogenization procedure (see above).”
Simply put, you have not shown that. You conclusion is not warranted.
“3. The Darwin Zero raw data does not contain visible inhomogeneities (as determined by the GHCN’s own algorithm) other than the 1936-1941 drop (see Fig. 2).”
Are you sure you applied that completely and correctly?
“4. There are a number of adjustments to individual years. The listed GHCN method does not make individual year adjustments (see Fig. 1).”
I believe that you may be incorrect about that.
“5. The “Before” and “After” pictures of the adjustment don’t make any sense at all. ”
Sense with respect to what? If your claim is that the GHCN methodology was not applied, then you must prove that they do not make sense with respect to the GHCN methodology. You have not done that.
If your claim is that the GHCN methodology is not sufficient for estimating long term trends at large scales (regional and larger), then you need to prove that the adjustments do not make sense with respect to estimating long term trends at large scales (regional and larger). You have not done that either.
At this point, all you have proven is that they do not make sense to you. If they do make sense with respect to the methodology and its stated goals, then all you have proven is your own ignorance.
“Call me crazy, but from where I stand, that looks like an un-adjustment of the data. They take five very similar datasets, throw two away, wrench the remainder apart, and then average them to get back to the “adjusted” value?”
When did they average them to get an adjusted value?
“The reason you adjust is because records don’t agree, not to make them disagree.”
That may be a successful line of attack – you have to demonstrate the effect on the aggregate result first.
“And in particular, if you apply an adjustment algorithm to nearly identical datasets, the results should be nearly identical as well.”
The datasets are not nearly identical. They differ greatly in length.
“So that’s why I don’t believe the Darwin records were adjusted in the way that GHCN claims.”
Once again, you are over reaching. Your conclusions are not properly supported. As shown above, they are founded in part on your (potentially valid) criticism of the GHCN method, which does not demonstrate that the method was not applied correctly. You need to learn to separate those two issues.
As shown above, your conclusions regarding manual adjustment are also founded in part on your own ignorance regardin some aspect of the method. You really need to ask GHCN to document the specific adjustment for these station records, and replicate them yourself, before making such claims.
“I’m happy to be proven wrong, …”
I doubt that. Being proven wrong would be very embarassing to you. And the rest of us.
“… and I hope that someone from the GHCN shows up to post whatever method that they actually used, the method that could produce such an unusual result.”
Uh, yeah. Thats what GHCN does. Troll all of the blogs on the planet, looking to see if anyone is talking about them. And then rush out to defend themself against yahoos that call them criminals.
If you have a question (and you do) of GHCN – ASK.
“Until someone can point out that mystery method, however, I maintain that the Darwin Zero record was adjusted manually, and that it is not a coincidence that it shows (highly improbable) warming.”
Over reaching and illegitimate accusation of wrongdoing. Invites another spanking, such as you received from the Economist. Stop setting yourself up… and the rest of us by extension.
Rabe (01:17:17) : said
I wonder how average temperatures are calculated. It’s not even ingenious let alone scientific. Why don’t we measure those average temperatures directly? Here is how it would work:….
Yes I have always wondered why they do not use the temperature in caves. I remember from my college caving days Indiana caves are 54.5 F year round, while Texas is around 70 and England was somewhere in the 40’s.
I wonder if the caving societies around the world would have records. I helped collect cave fauna for a caving buddies PhD Thesis and I am pretty sure the temperature was one of the data points recorded. This was in 1969 to 1972.
The more threads I read re: anything factual, the more I see how some individuals tour the “sites” and simply throw tear gas canisters into the discussion.
No. I think that the adjustments are made for a good reason. I’m answering the suspicion that they are done to deliberately enhance warming. The fact that the nett trend is small means that they don’t have that effect (or only to a small extent). Crudely, if someone was trying to rig the effect, they aren’t doing very well.
The net trend in DARWIN (the station under the microscope here) is anything but “small” we are talking here about an adjustment of almost the difference between “summer” and “winter” not “oh we painted the SS the wrong colour” or “oh we moved site from PO to airport”.
I don’t believe for one minute that there is one conspiracy looking to “rig the game” but it often looks like a hive mind trying desperately to “run the game into extra time”
Don’t get me wrong here – where somebody (a critic?) has pointed to a paper that sheds light on the subject in hand (DARWIN), I am more than willing to read. My problem is that I see why Willis started all this thread and all most of the critics have done is to point to the chirping cricket under the elephant so far.
Mann Jones scam has only been exposed widely for 30 days. It will spread and crumble further.
It will take a huge surge or crusade for them to even partially recover.
The quality control in the gathering recording business for the Meth, CRU and NASA is just not there.
If I were an Aussie, I would be very perturbed about now.
A homogeneity adjustment of over 2 degrees centigrade in a stair step fashion of about one half degree every decade? Right!
How can there be any reasonable explanation other than it has been intentionally manipulated?
Now do other stations indicate similar adjustments have been made?
How has this station adjustment affected temperature statistics for the continent?
Rob Vermeulen (02:42:36) :
Is weather undeground also adjusting its values?
Rob, This summer, I found that the high and low temp for my area, as reported by Weather Underground, changed by 2-3 F (higher) when reported as the high and low for the area the next day. There is no way I could have missed the low since I get up before dawn, check the weather and then go feed my animals.
Nick Stokes:
“If the adjustment moves trends up and down almost equally, they won’t reinforce anyone’s preconception.”
Not necessarily true.
These data have not only magnitude, but a spatial and temporal component. That the adjustments have a nearly equal distribution in magnitude does not demonstrate that they have an equal temporal distribtion, or an equal spatial distribution.
It is entirely possible, in fact likely, that data represented in GG’s graph could have the ‘ups and downs’ at opposite ends of the time period, and/or that the ‘ups’ may be applied to larger areas in the area-weighted, aggregate temp estimate. The analogy above of a push up on one end of the balance beam and an equal push down on the other end is an apt illustration.
Another unwarrented conclusion…
Nick Stokes,
GG doesn’t prove anything.
If Darwin’s adjustments don’t adhere to Peterson then GG would need to show that the offsetting cooling adjustments ALSO don’t adhere to Peterson. If the offsetting cooling adjustments DO adhere to Peterson, then it’s obvious we have a problem.
In fact, we have a problem even if the cooling adjustments don’t adhere to Peterson – wouldn’t you agree?