New paper finds that aging weather stations record much higher daytime temperatures, 1.63°C higher than new stations
While we are all watching the heat wave developing in the US southwest, here is something to consider. Albedo on the surfaces of weather station shelters changes with time, something I and the volunteers have documented with the Surface Stations project. For example, here’s a aged weather station where the whitewash coating is coming off and the bare wood is becoming exposed:
Back in 2007, Pat Michaels wrote in an American Spectator column “Not so Hot“:
“Weather equipment is very high-maintenance. The standard temperature shelter is painted white. If the paint wears or discolors, the shelter absorbs more of the sun’s heat and the thermometer inside will read artificially high. But keeping temperature stations well painted probably isn’t the highest priority in a poor country.”
Now there is proof that changes in station shield surfaces affect temperature
A paper published in the International Journal of Climatology finds that aging of the solar radiation screens on weather stations is causing a large positive bias in measured temperatures of 1.63°C, which by way of comparison is more than twice the global warming of 0.7°C recorded since the end of the Little Ice Age in 1850.
According to the authors, “During the comparison [of the new vs. 5 year old] and 1 to 3-year-old screens, significant temperature differences were recorded at different times of the day. The differences, wider than the uncertainty amplitude, demonstrate a systematic effect. The temperature measured with the older screen is larger, and the maximum instantaneous difference was 1.63 °C (for 0–5 years comparison) in daytime hours.
During night-time the two AWS’s measure the same temperature (within the uncertainty amplitude). This behaviour, increasing with increasing solar radiation intensity and decreasing with increasing wind speed, is attributed to a radiative heating effect. The screen ageing has compromised the shield effectiveness introducing a significant change in the temperature evaluation.” The paper is yet another blow to the unreliable, biased, and highly upward-adjusted temperature record.
The paper: http://onlinelibrary.wiley.com/doi/10.1002/joc.3765/abstract
Comparative analysis of the influence of solar radiation screen aging on temperature measurements by means of weather stations DOI: 10.1002/joc.3765
G. Lopardo et al
Abstract:
Solar radiation screens play a key role in automatic weather stations (AWS) performances. In this work, screen ageing effects on temperature measurements are examined. Paired temperature observations, traceable to national standards and with a well-defined uncertainty budget, were performed employing two naturally ventilated weather stations equipped with identical sensors and different only for their working time. Three different tests were carried out employing different aged AWSs: a 5-year-old AWS (AWS5) was compared with a new device (AWS0), a 1 year old (AWS1) was compared with both a 3 years old (AWS3) and a new one devices (AWS00). Due to solar and weather conditions exposure a degradation of the screen reflective coating is evident for the older AWSs (5 and 3 years old) and so a qualitative estimation of how different conditions of ageing affect the temperature drift was done.
During the comparison 0 to 5 and 1 to 3-year-old screens, significant temperature differences were recorded at different times of the day. The differences, wider than the uncertainty amplitude, demonstrate a systematic effect. The temperature measured with the older screen is larger, and the maximum instantaneous difference was 1.63 °C (for 0–5 years comparison) in daytime hours. During night-time the two AWS’s measure the same temperature (within the uncertainty amplitude). This behaviour, increasing with increasing solar radiation intensity and decreasing with increasing wind speed, is attributed to a radiative heating effect. The screen ageing has compromised the shield effectiveness introducing a significant change in the temperature evaluation.
The experimental results of a further comparison, between 0- and 1-year-old screens, confirm the same conclusion showing a negligible ageing effect, within the uncertainty amplitude.
h/t to The Hockey Schtick
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Another reason why surface temps are worthless.
Cafeful, the warmists will start insisting that the stations get painted black to soak up the maximum heat levels….
NWS tweeted this today with many other tweets on SW heat wave.
://twitter.com/NWSVegas/status/351050293833768960/photo/1
https://twitter.com/NWSVegas/park-and-weather-tweets
http://www.wrh.noaa.gov/vef/deathvalley/
This is to replace above link I posted
https://twitter.com/NWSVegas/status/351050293833768960/photo/1
I have a question, how many of the weather station housings are older than 5 yrs? From what I recall of the station surveys I looked at I would have probably considered a 5 yr old housing as just a baby.
Just something else demonstrating all those hundreds of billions of dollars being spent on ‘climate change’ are totally worth it.
Can’t they make these weather stations out of white, UV resistant plastic? To be still using wood for these shelters seems almost archaic
I also looked at the Las Vegas weather stations (see above). I can’t imagine that these sites are very accurate, as close to heat sinks as they are. And to think that our entire body of surface data is based on sites like these. YIKES!
I just read yesterday that daytime maximum temperatures have NOT risen, but nightime minimums are higher, and averaging them results in the higher average readings. This was in a piece on PJ Media. I will try to find it again. What kind of paint degrades that much in just five years? The pictured Stevenson Screen appears to have been sand-blasted!
Data is only as good as the party paying for it needs it to be, as a rule. Looking for changes in the tenths, or even, ludicrously, hundredths, of degrees, with thermometers accurate to +-0.5 C, is meaningless. Tell this to a Democrat!
“The temperature measured with the older screen is larger, and the maximum instantaneous difference was 1.63 °C”
The paper is paywalled as usual. Anybody know what the mean, median, or average difference they found was, compared to the “maximum instantaneous difference” of 1.63C?
“As we have come to expect from this president on global warming and energy, yesterday’s presentation included many basic science mistakes and inappropriate cherry picking of data. For example, Obama’s assertions about abnormally high temperatures and the extent of Arctic sea ice melt are either meaningless or simply wrong. Last July, new average U.S. temperature records were set by one-fifth of a degree Fahrenheit. This is meaningless since the measurement uncertainty in most of the record is one-half degree Fahrenheit. Similarly, last July’s record temperature was not based on the highs of the day. A record was set merely because the nights were slightly less cool in July 2012 than those experienced in the 1930s. So, when the high and lows of the day were averaged, a record average was established. Nevertheless, the highs of the day in the 1930s still exceeded anything experienced in July 2012.”
This is from an article by Dr. Tim Ball and Tom Harris about Obummer’s Climate Speech.
So, correcting for old paint jobs, we are really experiencing global cooling?
Anthony,
During some of the surveys that Ellen and I made, not only were the shelters paint pealing, many were grimy with dirt. They had not been cleaned or painted in years. Even some of the automated stations had dirty and discolored covers. We found one totally covered in tall grass in Hot Springs South Dakota.
Weathering (a degradation mechanism) of materials will certainly alter their emmisivity/absorption properties… but so too will dirt deposits
Don’t those slats admit copious amounts of radiation from surrounding asphalt, etc?
The lack of whitewash is undoubtedly related to excess exportation of US whitewash to supply UK “independent” investigative panels.
now we know where that nonexistent 1/2 of a degree comes from…..
please don’t tell me they are tuning the satellites to these results…….snark/
Latitude;
please don’t tell me they are tuning the satellites to these results…….snark/
>>>>>>>>>>>>>>>>>>>>>
Heh. Have they checked the paint job on the satellites?
Can’t get at the whole paper, but it seems as though they tested four (4) Stevenson screens, aged 0, 1, 3, and 5 years. The differences appear large and one would think that NOAA/NASA would want to test lots more screens to confirm this observation. If the effect holds up, and enough screens can be tested to discern a quantitative relation with time, it would be possible to back-correct the temperature record. (We know NASA/GISS can do that, since they’ve been practicing back-“correction” for years!)
What happened to underground temperature measurement? It seems to have been well established in the 1880s. It obviously doesn’t give useful information for daily needs, but it must be the best way to compare long-term trends.
Let Nature do the averaging!
This reminds me of a discussion I had with Zeke over at Lucia’s. Zeke had an article about how the new MMTS stations had a negative bias compared to the old CRS stations.
http://rankexploits.com/musings/2010/a-cooling-bias-due-to-mmts/
This bias correction, by the way, is one of many made to the temp data. So even if the newer MMTS stations don’t have the problem, their readings are still adjusted up to make up for their supposed negative bias. This means that the above problem spreads wider than just the old stations that suffer from bad paint diminished albedo.
I asked Zeke how he knew that the problem that needed ajusting was MMTS negative bias, rather than CRS positive bias. After all, the MMTSs were coming newly calibrated from the labs, and the old CRSs were loosing their albedo. Zeke never answered that question. Much like Zeke never explained how his UHI reduction algorithms were not simply smearing the UHI effect evenly across all stations.
So is it now time to switch to white vinyl?
Although you can get metal siding with effectively-permanent bright white coating. That should make for a quickly-responsive housing.
Should there be a material upgrade, even though this style of shelter is basically obsoleted by the use of the new electronic sensors?
So homogenization should have gone the other way – the HadCrut and GISS thumbtack method of altering the temperature record (early 20th Century down, late 20th Century up) by sticking the tack in 1944 and rotating counterclockwise should have been rotated counterclockwise. Okay, let’s take the amount the 1936 high was reduced, multiply it by two and rotate it up. There, 1936 temp is still far and a way the highest in the instrumental record of the USA. I know that the Canadian record all time high was 45C at Midale and Yellow Grass, Saskatchewan in July 1937 and 44.4C at Emerson, Manitoba in July 11th, 1936 (at the North Dakota border by the way). I can’t believe that it got cooler in the central plains below the Canadian border with the US.
http://en.wikipedia.org/wiki/List_of_extreme_temperatures_in_Canada
We Canadians don’t have the budget of the US weather agencies which seem to number up to about half a dozen. This means that we didn’t reach back and cool these down at great expense. We have Environment Canada, who are as warmy as you can get but there is no way they are going to get $50M computers. So here is an experiment. Lets see what the temps were in North Dakota.
Hottest in ND was at Steele in July 6th (5 days earlier than the Emerson, MB one), 1936 at 49C (120.2F) about 300 mi southwest of Emerson, Manitoba. Probably the dickered temperatures done by GISS, NOAA, etc. are a degree cooler or so. Anyone?
Oops, should have been rotated clockwise…
Anthony, an extension to the surfacestations project: from the pictures, estimate the age of the paint job (if there isn’t logged maintenance record) and make a correction to the US average temps. Since the night time temps were unaffected, one may make an algorithm that would correct the daytime from it. Wow if we can chip off another 0.2 to 0.4C, what would that do to the divergence between IPCC forecasts and the observed and what would that do to the climate sensitivity: <0.5 per doubling?
Aren’t AWS’s like the MMTS, not Stevenson screens as pictured? No painting required, though they still might degrade.
Until the temperature anomalies exceed the rounding “errors” of the historical record, such as it is/ after adjustments.
Is there even a “known” to plug into the equation ?