After reviewing over 1000 USHCN stations in the United States as part of my surfacestations.org project, I have often thought that I can’t find anymore surprises in the train wreck that is our surface observing network. Apparently I’m wrong.
Can you spot the problem between these two aerial photographs? Click for a larger image.
The answer is below.
This is another moment of serendipity, spawned by an interesting comment from physicist Dr. Robert Brown at Duke University, who was lamenting the differences in temperature in the Raleigh Durham area in this comment:
I continue to be struck by temperature differences in my very local sample space. For example, in Durham the NWS temperature is predicted to reach roughly 100F. Yesterday it was reported to have reached 101F. That’s warm for this time of year, although not unheard of, and last week it was cold, next week it will be cool to cold again. However, I subscribe to the Weather Underground service and keep a tab open on it all day, and it lists some 20-30 “local weather stations” belonging to citizens. In it I’ve noted a strange anomaly.
If you visit it right now:
http://classic.wunderground.com/cgi-bin/findweather/getForecast?query=27705
At the instant I’m typing this, the Durham (RDU Airport) temperature is reported to be 88 F. Since the NWS prediction is 99F (same page) and it is just after 1 pm, the NWS prediction seems a bit unlikely. However, if you scroll down to the list of area weather stations, a strange anomaly is revealed. First, only one weather station on the entire list reads 99F — Westglen, which is actually very near to my house. Westglen and my own household outside thermometer agree if and only if my thermometer is directly in the sun — true for part of the morning (mine isn’t a “weather station” — it is a radio thermometer just hanging on a rail of my deck 2 meters or so from the house, and it spends some part of the day with direct sun on its top).
I responded here at 2012/05/03 at 11:42 am, and as I responded, I thought I’d get a look at the RDU ASOS station, and I got a surprise in doing so:
@RGB, you may find this post interesting – airport ASOS stations have all sorts of issues, not the least of which is that after they fail and set new records, the records remain.
RDU is part of the climate record:
Strange that they felt a need to paint the asphalt near the ASOS station white:
http://maps.google.com/maps?hl=en&ll=35.89239,-78.782031&spn=0.000744,0.000873&t=h&z=21
Drag that view to kick it into 45 degree mode
Here it is before the painting:
WUWT?
WUWT indeed. Painting the asphalt white around the temperature sensor? It seems too bizarre to contemplate. Yet the closeup photographs don’t lie:
Here’s the Bing maps image from 2010 in closeup, with all the location instruments labeled:
And a further closeup from 2010, notice the dark cracks in the asphalt near the station:
…and here’s the Google Maps image from 2012, note the cracks are still there but it appears the asphalt near the station has been painted white:
Wow, can you say “albedo change”?
Here’s the two side by side along with the identifiers from NCDC’s MMS database:
This is the source of those ID numbers: https://mi3.ncdc.noaa.gov/mi3qry/identityGrid.cfm?setCookie=1&fid=14333
And here’s the GISTEMP selector page, showing they use the same station for their climate work: http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?lat=35.87&lon=-78.78&datatype=gistemp&data_set=14
And here’s the graphs from GISS before (Raw) and after adjustments (Homogenized) overlaid. There’s that signature cooling of the past again:
Source:
http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=425723060000&data_set=14&num_neighbors=1 (homogenized)
Dr. Robert brown made a further reply of interest at 2012/05/03 at 1:12 pm
Hi Anthony,
I’m not sure why they painted it, but if you zoom out on the location and note the following (from the RDU History site, section on “the 80s”):
Terminal A opens to great fanfare in 1981.
Trans World Airlines begins service in 1984 as the sixth carrier to serve RDU passengers.
American Airlines begins service in 1985 as RDU’s seventh carrier.
RDU opened the 10,000 foot runway 5L-23R in 1986.
The Federal Aviation Administration (FAA) Air Traffic Control Tower opens in May 1987.
American Airlines opens its north-south hub operation at RDU in the new Terminal C in June 1987, greatly increasing the size of RDU’s operations with a new terminal including a new apron and runway. American brought RDU its first international flights to Bermuda, Cancun and Paris Orly.
I started school at Duke in 1973. At the time the airport was a single terminal and serviced maybe two or three airlines with infrequent flights. Cary was still a sleepy little town outside of Raleigh, and so was Morrisville. Most of highway US-70 was still forested between Durham and Raleigh. There was just one runway, and it was a small one, so the planes that came and went from RDU were similarly small.
In the 1980s, as you can see, they opened two new terminals! Terminal A was four or five times the size of the original terminal (which became Terminal B and is still there and still functioning, although for some reason they’ve closed Terminal A and are ready to tear it down). If you back off on the overhead map you post you can easily see the relative sizes — Terminal B is at the east corner of Terminal Blvd, with A running southwest of it and C the BIG terminal — bigger than A and B combined — due west of the two on the other side of the Terminal Blvd U. The old runways are still there on the Southeast side. The “new” runway — built in the early 1980′s and completed in 1986 — is clearly visible west of Terminal C.
Note that it is huge. As they say, 10,000 feet long. It may have even been built that long partly so that RDU could land a B-52 — in the late 70s a friend of mine was a B-52 pilot located in Goldsboro and he said that RDU wasn’t likely to be a nuclear target because its runway was too small to land a B-52, and somebody in SAC may have decided to nudge it somehow for strategic reasons. Then look at where they located the weather station — right there at the end of the big runway, with the entire airport complex to the south and a big expanse of hot asphalt runway a hundred meters or so away.
And there are so many better places! Probably the best place is the southeast corner of the complex, over next to the William B Umstead State Park, in that patch of ground past the National Guard. But even where they built it, they could have gone across the street and put it in the open patch in the woods a quarter mile or more away from the actual runway and it would have been better.
Now, look back at the GISTEMP record for the site. That peak in the early 90s was sure impressive (although check out 1890! WUWT too!) but it strangely enough happened just after they built a huge new runway and started landing a lot more, and bigger, planes at RDU. Did I mention that from 1987 to 1996, RDU was the US North-South hub for American Airlines, so basically every flight up or down the east coast ran through RDU? Or that they began international service with flights to e.g. London, Paris, Bermuda in that time frame? It was probably the single busiest stretch of air traffic in the entire record — flight numbers have gone down since (the cold war ended abruptly, no more need for big runways for B-52s and:-) they shut down the hub.
Even with a half a degree jump from the “are we starting the next ice age” hysteria of the early 60s — an event that they failed to “erase” from the RDU record, at least — what fraction of the jump was due to the steady blanket of CO_2 and water being dumped every five minutes all day long as jumbo jets were burning huge volumes of gasoline taking off literally over the top of the weather station? What fraction of it is due to the warming of air as it passes over the hot summer asphalt of at least one square mile of almost unbroken buildings and asphalt that lies due south of it, beginning a mere 100 or so meters away? What fraction of it is from the further CO_2 enhancement from the eight lanes of jammed rush hour traffic that uses the roads that bracket the airport on three out of four sides now? Only one of those roads was even there in the 60′s, and what is now I-40 was a lightly travelled four lane highway in the 70s (I once drove a friend from Duke to the airport in 10 minutes flat to catch a flight — try that now!)
And with all of that, we see less than 1.5 C warming from the coldest part of the record (your choice 1890s or 1960s). And
for any linear trend fit, even given the warming in the very late 90s, is visibly going to be what, 0.01, across over 100 years.
If you look at personal weather centers located just a tiny bit further away from concrete in that general vicinity, they generally record temperatures around 1C cooler than RDU. It was almost cow pasture and forest back in the 1960s, after all. And there goes all of the land-use based warming, along with it.
rgb
Couldn’t have said it better myself. I put a call into the MIC at the RDU NOAA Weather Service Forecast Office to inquire about why the surface albedo around the ASOS turned GISS climate monitoring station has changed dramatically, and if he was aware of it. No reply yet, but I’ll add an update if I hear anything from him.
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Won’t the white paint make for better measurements? –AGF
I would question how much of albedo that is. Some white paints appear black in infrared.
@agfosterjr
It isn’t about making it better, it is about consistency of the observations…things like this can induce step changes in the data, which are often unaccounted for.
And, over time, that white paint will get dirty, and turn darker again, introducing a trend bias.
Keeping any weather station site surroundings identical over time is the best practice.
Cooler, maybe, but *better*? I don’t think so. You want the albedo around a climate monitoring station to be as close to the natural terrain as possible. An airport weather station is not designed for climate monitoring. It is designed for monitoring conditions at the runway so planes can be configured with the right operating parameters. They need to know how hot it is, for example, to get an idea of stall speed or at what speed to rotate up off the runway. For that sort of thing you WANT a station as close to the runway as possible. If it is reporting a temperature that is too cool, it could possibly lead to an accident by causing an aircraft to rotate too soon or approach too slowly.
The Google Earth image I get today — dated 7/5/2010 — shows even more white area with no marks, breaks, or any thing else. Very strange.
Yes Anthony, I’m puzzled by the claim that anomalies in the temp record are just as good or better than the actual temp measurements for determining trends. Does anyone know what math is used to justify this? They must be taking the first derivative of the measurements but changes in surrounding station conditions would surely effect the temp derivative calculation.
My friend Doug G. was flying home to Philly from RDU on the last flilght of the day back when it was a small and unpopulated place. He checked in at 5:00 PM, checked the time against his ticket and strolled to the boarding gate for his 6:00 PM flight. The plane was pulling out as he reached the gate.
Surprised, he went back to the check-in counter and asked, “Why did my plane leave an hour early?” and pointed to the large clock in the lobby which read 5:10.
She replied in a chiding Southern drawl, “Eveahbody knows that clock is an hour slow!”
Apparently it is not only the clock that is behind the times in RDU.
Gene @2:24
Albedo from albus for white. The white of an egg from albumen, and so on. IR would seem not to be an issue.
Anthony Watts says:
May 3, 2012 at 2:26 pm
[…]
Keeping any weather station site surroundings identical over time is the best practice.
Is that even possible, in 99.99% of cases?
False and erroneous information becoming part of the official record is also common in census tracts. I sometimes do genealogical research and discover errors fairly frequently. Also happend in death certificates too, when the deceased has lied about their age.
To crosspatch,
As a retired naval aviator who has flown into RDU many times, I agree with you. Airport weather stations are not placed to monitor climate change. They are there to measure the present conditions near the runway. It would be interesting to see if there was a step change in the temperature when the pavement was painted. My guess is that there is no statistical significance in any difference.
The real question is why would you put black asphalt around your temperature sensor in the first place?
Weather stations at airports are designed to provide weather useful for air movements in and out of the airport , and that is all. The idea you can take their values and spread them far wider simply makes non sense , especially when you consider that airports are in no way typical of their local areas. For instance they can be the only tarmac for miles around or the only big open area in a crowded city .
Using them makes about as much sense as using weather stations at steel mills and they being surprised that trend to read a bit high . Frankly there used not becasue there a good idea nor that that they meet the standards required but becasue their available, their a free resource and one whose maintenance is the airports problem . There a cheap but rubbish way of collecting weather data for wider areas .
More likely crushed limestone, not paint.
REPLY: I thought about that…but the cracks in the asphalt are clearly visible, they likely would have been covered over. – Anthony
RE the 10,000 ft runway.
Augusta GA’s runway is also 10,000 and it is still a small airport. The reason is so it could accommodate C-5 Galaxy’s and other large military airlift planes. Augusta is home to Ft Gordon and close to Ft Stewart. Savannah (home to Ft Stewart) also has 10,000 ft runways.
Ft Bragg is closer to Fayetteville – another 10,000 ft runway airport, but I believe it is still close enough to Raleigh Durham to be useful as an alternate field.
Jay;
As noted above, climate monitoring is the poor second cousin at airports. They want to keep the planes from crashing, period. Which means: “What is the air over the runways doing?” Which is of little or no use metroclimatologically.
Something looks ‘funny’….. the building to the right is a correspondingly brighter ‘white’ also.
Is this a ‘false contrast’ issue with the photo…. or did they paint the building and ‘have a little paint left over’ so they painted the parking lot also??!!!
Having spent over 32 years working at YYZ, I’d like effects of burnt rubber to be explained.
Can be a major stink if the wind is blowing the “wrong” way.
Guys, you do not seam to realise the possible consequences of this story: the AGW proponents might suggest everything be painted white to mitigate “the global warming”. The ultimate solution! Poor black people, though… (lol)
I lived in Raleigh and/or Durham for over a decade. The readings from RDU were ALWAYS rediculous. Easily 3-5 F higher than any other reporting station. They set the all time high one summer of 105F, found all the grass had died around the station and refused to make any correction to the record.
Seems to me ASOS and GISS have cross purposes. An ASOS needs to report important factors like density altitude where the field temperature is important, that is the temperature the aircraft actually encounter. You need that sort of information to calculate whether you can get off the ground before you reach the end of the runway.
I just went back to double check what other people said, and I’m repeating some ideas a bit, but in a different way. Add us all up, and it may be clearer.
@John F. Hultquist
I am familiar with the meaning of ‘albedo’, but I appreciate the reinforcement. The point here is that it is unlikely that the airport authorities chose to do this for the visual effect. Thermometers “see” in a much wider spectrum than we do, so it is not entirely incorrect to think of albedo in a broader sense, and that is indeed how many people use the word:
http://scienceworld.wolfram.com/physics/Albedo.html
So you should not be shocked when you hear an expression like “radar albedo”; it is no less sane than “black body” or “white noise”. They are expressions of how we perceive things — whether directly or mediated by instruments.
As some of us have guessed, the purpose of that white-looking stuff could be to make the thermometer readings correlate more closely with the density altitude at the runway. I would think that adjusting the temperature computationally might be an easier fix, but perhaps a lot of exposed asphalt in the vicinity of the thermometer, distributed in a non-uniform manner, makes it more random and faster-changing than the actual air density above the runway. If it really works, we should simply admire the hack. They certainly did not do that as a means to study climate.
Here’s an interesting source of data on “cool paints”. They have a higher albedo (if you pardon the expression) than commonly used paints, even though they are not white.
http://www.basf.es/ecp1/Spain/es/function/conversions:/publish/upload/02_Products_Industries/02_Solutions/paint_cool.pdf
I would guess you are right. From a flight operations standpoint the difference wouldn’t be enough to make any difference. From a climate monitoring standpoint, 1 degree of change is huge when we are talking about 1.5 degrees of global warming over 150 years.
Of course it reached 99°F at RDU on May 3, 2012. Just ask any tax-paid climatologist with authority and creditials. I know all surrounding stations report 81°F to 88°F but that is not the point. The official temperature is 99°F and is now carved in stone. That is how it is done so live with it. And don’t off trying to upset the apple cart, it just won’t work, too many tax dollars are resting on these high temperatures. OK’s Will Roger and Wiley Post airports do the same all of the time, sorry you just noticed your local problem. The only thing that matters is anomalies and accurate temperatures are meaningless, haven’t you noticed yet?
Anthony,
We need our own network.
Is that one of those things that’s easier said than done?