Mark Johnson, Chief Meteorologist of WEWS in Cleveland writes:
A friend of mine, Justin Berk, a local TV Met in Baltimore, MD had this story to tell today:
“There’s something fishy going on at BWI (Baltimore International Airport),” he says. Hourly obs at BWI airport (April 12, 2012) never went higher than 59 degrees.
(See the obs from BWI below – Anthony)
But, he noticed the official high temperature was listed as 62 degrees.
“There’s no way a jump of 3-4 degrees occurred and then fell back down between obs,” he added. Why the discrepancy? Justin called the local NWS office.
For a brief 10 minutes, the steady NW wind that persisted all day at BWI shifted to a westerly direction. That allowed the HEAT from the nearby runway to provide a quick 3 degree warm-up between hourly obs. Once the winds shifted back to a NW direction, the temperature fell back to 59 degrees.
The NWS employee concurred that the extra warmth came from the runway.
Global Warming is real (thanks to poorly-sighted thermometers)! This is the second time Justin observed a false high temperature reading this week at BWI.
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I followed up on this, and his story checks out.
First the table of high/low for the day from BWI:
Source: http://www.nws.noaa.gov/climate/getclimate.php?wfo=lwx
And here are the hourly observations for the day from the BWI airport ASOS station:
Source: http://www.nws.noaa.gov/obhistory/KBWI.html (downloaded at 2AM EST 4/13)
Here in what the BWI ASOS station looks like along with compass points added:
Source: http://binged.it/HC0WPG
And here is a view looking to the west:
Source: http://binged.it/HFgGmM
Seems an open and shut case. This is not the first issue with weather observations at BWI, they also have issues with measuring snow, and I reported here:
BWI snow record rescinded: Another reason why airports aren’t the best place to measure climate data.
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UPDATE: 3PM PST 4/13/12 The Capital Weather Gang tries to avoid the siting issue with an alternate explanation. This from comments.
I’ve posted a different perspective on this at washingtonpost.com: The case of the curious temperature spike at BWI airport: asphalt or the sun?
REPLY: Anything to avoid UHI it seems with you guys. As for sun/wind debate. It could very well be both. Asphalt absorbs sunlight pretty well. More sun coupled with a shift of wind to the asphalt area can easily make a quick 3 degree jump. Sunlight by itself on grass, not so much. You didn’t mention albedo in your article so I’ll assume you don’t understand it.
Bottom line – airports are a poor place for temperature observations used for climate purposes, as they aren’t representative and are very dynamic with land use changes, and, see this detailed analysis.
http://wattsupwiththat.com/2012/04/13/warming-in-the-ushcn-is-mainly-an-artifact-of-adjustments/
Airports are part of USHCN.
– Anthony
Pete Olson says:
April 13, 2012 at 12:52 am:
‘poorly sited’, not ‘sighted’
Pete, I’m sure many of them are poorly sighted as well.
Sure would be interesting to see a collection of USAF obs taken taken downwind of the runway just after ten tankers and ten bombers had completed a MITO (minimum interval takeoff). At least to old SAC types.
THe BWI and Raleigh-Durham stories show how this is perfect for maintaining a steady boost to global temps: our economy will continue on, we will have our population expand, and the invisible hand of the marketplace will make air travel cheaper (in the long run) and or the gains to be gained by traveling will be lucrative enough that air travel will steadily grow. Steady air travel growth means more heavily utilized runways, and more parking lots.
Siting thermometers at airports is abt the best way to build in a steadily increasing bias. Freeways are not good, because in busy areas they will tend to hit their max traffic pretty early on. Suburban sprawl might be OK but you don’t exactly know which way the sprawl will move, or what mix of use will happen where. between green space, residential, and commercial.
The airport is the one centralized location to have local temp build steadily across time.
The problem is that the average temperature for that day at that location is the average of the high and low. This is what Hadley and GISS use for calculating the extent of global warming or cooling. The implied assumption is that the temperature varies smoothly and gradually from the day’s high to low and the next high, etc. and that the high and low can be averaged to determine the mean temperature for that 24 hour period. If the true high were actually 59, then the average temperature would be 48, not 50. And if you think that 2 degrees is a trifle, remember that the temperature anomolies are reported to the nearest 0.01 degree (for better or worse). Now, how many sites need to be affected in a similar manner over the course of a month to move that month’s anomoly by 0.02 or 0.05?
I had a discussion with a retired meteorologist last night. He too is firmly in agreement that AGW is a crock.
I am the guy that first reported this (Justin Berk) and have noticed it for years. I have made many attempts to get NWS to acknowledge it, which sometimes is met with the response that a tech certified that it is accurate. I did get a response today that I will write about on my Examiner.com page and will be posted on my Facebook page for conversation. I’d like to chat with anyone else who sees the scientific importance. If +3 degrees is not such a big deal in these conditions, consider that these conditions of prevailing wind and afternoon sun occur more than 50% of the year. Doing some crude estimates, 1/2 the days and 1/2 the daily temperature extremes would results in +.75F higher results over the course of a year (on average). Wouldn’t that throw off our data set since ASOS was implemented for much of the nation… umm around 10-15 years ago?
Anthony, you and I both wrote about the 106F reading in the summer of 2010. I wish you would have linked your story here. You pointed out the exhaust from the structure just west northwest of this ASOS with exhaust. This is similar Chicago’s temp jump in ’97 or ’98 after they moved their sensor next to the exhaust from the building. They had to go back and adjust it after some diligent scientists placed heavy scrutiny.
Please contact me on my FB page to chat https://www.facebook.com/pages/Justin-Berk-Meteorologist/54875673475
I encourage many of you to check out http://www.surfacestations.com to see how many weather stations are not complying with NWS/NOAA standards in the US. It is alarming!
* Note that nearby Weatherbug stations are almost always cooler and they are calibrated. I wanted to do a comparative study for my former TV station last spring, but we never made it happen. What caught my attention was a date over the weekend with a +4F spike over hourly observations. If wind gusts must be a 1 minute average, why don’t we have a criteria for how long a temperature is measured to qualify. The spike based on a one tome reading seems inaccurate considering the history with the wind direction. Heck west-southwest is worse. When we get back into the 80s on Sunday and Monday, look out. Many have asked if we can hit 90F on Monday. Honestly- I don’t think so, but based on this ASOS site, all bets are off.
Re Gail Combs says:
April 13, 2012 at 5:21 am
and
Bill Tuttle says:
April 13, 2012 at 6:37 am
The GISS figure headings caught my eye. The link labeled Norfolk International Airport shows GISS figure heading “Norfolk/Int., (36.9 N, 76.2W)” The link labeled Norfolk City shows GISS figure heading “Norfolk/Nas (37.0 N, 76.3 W)”
Is it possible that Norfolk/Nas is actually Norfolk/NAS as in Naval Air Station, Norfolk? I checked the coordinates of the airports with Google Earth, and the rounded values closely match the GISS coordinates, which is consistent with NAS Norfolk being northwest of Norfolk International. The city itself is generally north of the airport.
If Norfolk/Nas is indeed Norfolk NAS, it would be worthwile to investigate the differences between station locations that result in such large differences in readings.
So what about all the days when the wind is blowing from the west ALL DAY LONG? The max temp and highest hourly temps will be in sync, and it will never be detected that the temp is being influenced by jet engines. NWS may or may not adjust this day, after being called on it. But they won’t be called on all the days when the influence of 200 hot jet engines and hundreds of acres of asphalt is the “norm”.
And what about all the other stations at airports, at water treatment plants, within 10 feet of buildings, near busy roads, etc.? Jesus, after the work of Anthony and the volunteers of the surface stations project, how can ANYONE, with a straight face, point to the temperature record and claim it as PROOF that the planet is warming?!So what about all the days when the wind is blowing from the west ALL DAY LONG? The max temp and highest hourly temps will be in sync, and it will never be detected that the temp is being influenced by jet engines. NWS may or may not adjust this day, after being called on it. But they won’t be called on all the days when the influence of 200 hot jet engines and hundreds of acres of asphalt is the “norm”.
And what about all the other stations at airports, at water treatment plants, within 10 feet of buildings, near busy roads, etc.? Jesus, after the work of Anthony and the volunteers of the surface stations project, how can ANYONE, with a straight face, point to the temperature record and claim it as PROOF that the planet is warming?!
Damn, if I could put 89% of the thermometers that make up the official temperature record of the US inside my refrigerator, I could “prove” that we are in the middle of the worst ice age this planet has ever seen.
Damn, if I could put 89% of the thermometers that make up the official temperature record of the US inside my refrigerator, I could “prove” that we are in the middle of the worst ice age this planet has ever seen.
2-3 ° F max temperatures in between the hourly temps are routine for the KIAH the weather station at Houston Intercontinental particularly in the summer.
My father inlaw flies free flight model planes at the Randolph AFB auxilary air field in Seguin, Tx. (on weekends when the airfield is not being used). They commonly launch from an abandoned runway. He uses a thermocouple with digital readout to look for thermals. He who knows how to launch into a thermal wins.
I have observed 3 ° F; spikes when a gust of wind comes along. The spikes last no more than a minute followed by cooler air. I haven’t really thought about it before but we are on the runway and the airfield is not builtup like IAH. My point is that it might not be just the concrete but maybe the open field that is the source of the hot air. I was not paying much attention to whether the gust was across or along the runway. Admittedly, not enough observation here for any conclusions.
This is no attempt to discredit UHI. More a point that point by point near surface air temperature measurement in general is a lousy way to determine global temperature trends.
I think the point made earlier that at some point in time all temperature measurements were made manually on the hour (as determined by the individual) then, I suppose, recorded by circular analog charts, and now recorded digitally on some frequent basis. So there is a bias introduced over time. Perhaps Anthony could address the evolution of weather station instrumentation. Or provide the link in the likely event that he has already covered the topic.
rgbatduke says:
April 13, 2012 at 5:45 am
This happens at RDU as well. An interesting consequence of this is appearing. I subscribe to Weather Underground and keep its page open in a browser panel all day. Recently I’ve noted an interesting discrepancy between the NWS forecasts for RDU and reality….
_________________________
Just to add to what you were saying, I am about 30 – 45 mins southeast of RDU in the country. It was 30F when I got up yesterday (5AM) and there was ice on the water tanks compared to your “… 5 am, the temperature outside was 35 F…”
I should also say using Wunderground, you can not prove we are having “Global Warming” around here.
Central North Carolina (Sanford) Monthly temps over 90F for 2004 & 2010
April 2010 (1)………..April 2004 (6)
1day – 91F……………..2 days – 91F
…………………………….4 days – 93F
In 2011 the April highs ranged from 55F to 86F we did not see temps over 90F (91F) until May23th!!!
So far in 2012 we have had highs ranged from 60F to 84F. Right now it is a chilly 67F.
Dear exNOAAMan
I have buckets of data
Here’s the KDMH Plot since the beginning of the year http://www.theglobalthermometer.com/igraphs/stations/KDMH.png
and here’s KBWI
http://www.theglobalthermometer.com/igraphs/stations/KBWI.png
ignore the 30C + peak at the beginning of the year I have to strip this out of all the USA data as NOAA (helpfully) redesigned their website for USA only weather stations and it took me a little while (2days) to begin to capture the new non-METAR style data 🙂
It’s a work in progress I needed a second, unadulterated, opinion with which to push back on the scaremongering. So far I’ve proved that the first 3 months of this year were warmer than last but that’s hardly a shock 🙂
Happy to provide the raw data to anyone who would like to squeeze the truth out of it
Dave
I’ve posted a different perspective on this at washingtonpost.com: The case of the curious temperature spike at BWI airport: asphalt or the sun?
REPLY: Anything to avoid UHI it seems with you guys. As for sun/wind debate. It could very well be both. Asphalt absorbs sunlight pretty well. More sun coupled with a shift of wind to the asphalt area can easily make a quick 3 degree jump. Sunlight by itself on grass, not so much. You didn’t mention albedo in your article so I’ll assume you don’t understand it.
Bottom line – airports are a poor place for temperature observations used for climate purposes, as they aren’t representative and are very dynamic with land use changes, and, see this detailed analysis.
http://wattsupwiththat.com/2012/04/13/warming-in-the-ushcn-is-mainly-an-artifact-of-adjustments/
Airports are part of USHCN.
– Anthony
“Anything to avoid UHI it seems with you guys?” C’mon Anthony. I wrote a detailed blog discussing its prominent role in DC summer temperature trends. Is there a global warming signal in Washington D.C. summer temperatures?
Excerpt: “it would appear, a large fraction [of the warming] is due to urbanization with some smaller, more nebulous contribution from greenhouse gases.”
Don says:
April 13, 2012 at 9:20 am
You are testing the difference between sites over a rrealtively short time frame. What if, in the absence of a putative UHI bias at BWI, its ‘real’ temperature profile (ie. prior to its develpment as a major hub which someone above noted took place during the1970s) was significantly lower than the site you compared it to?
In those circumstances, you are in fact highlighting the UHI bias by pointing to a lack of statistical variance in comparing a naturally warmer site not influenced by UHI with a naturally colder site (influenced by UHI?
So indeed, you are right to say it is “not an open and shut case”. But not for the reason you identify.
Furthermore, I made the point earlier that widespread and inappropriate use of linear interpolation to fill in data gaps between sites may provide for a statistical transmission mechanism in which UHI bias is propagated systemically throughout the temperature record.
In addition, as air traffic and tarmac area increases, the frequency of UHI bias at directly effected sites (eg. BWI) will incease through time, in effect, amplifying the bias transmitted by interpolation through the record.
So it might even be the case that your statistical comparison of sites is invalid because it fails the necessary assumption that the sites (data) are independent. That is, the data from each site could very well be directly related through interpolation.
It seems that many assume that UHI is really a localised problem effecting only those sites directly concerned. But that is not justified. Again, linear interpolation works to propagate a UHI bias throughout the recorded temperature record.
Surely, this must have been identified by now…?
Don, thanks for the SD calc.
That is not what I would have expected. Is the SD stated for all data or just Max temp?
Could you show SD for Min temp and Max if the previous was the SD for all data?
I agree with you, the SD should be higher at an airport in my opinion.
The more I think about it (see my comment above) the more the ugly truth dawns on me that the land surface temperature record has been systematically corrupted.
UHI bias at some monitoring sites has been transmitted to all other sites in space and through time through the inappropriate use of linear interpolation. The pre-requisite of statistical independence of data in spatial and in time series analyses is NOT satisfied. The monitoring sites are all linked by UHI and interpolation in space and time and the time series analyses generated from these data are INVALID.
The land surface temperature record is correctly regarded as a work of fiction and ought not be used for anything other than highlighting the misdeeds of crooked climate scientists. It most definitely should NOT be used to determine government policy.
Being a bit of a weather nerd, I regularly check the local BOM temperature readings from Canberra airport during the day and night. Apart from the factors others have mentioned, the airport is unrepresentative of the surrounding area in that it is devoid of trees, flat, and surrounded by turf farms (grass doesn’t mind airport noise). As a result, the extremes in summer and winter are magnified.
Also, weird things happen, like the temperature rising up to 2 degrees C for no apparent reason in the middle of a cold, clear night for about an hour and then falling back again. It can’t be planes because there is a curfew. At other times, the readings just drop out altogether for a period (they are updated every ten minutes). Anyway, the bottom line is that our ‘official’ temperature records are based on these dodgy figures.
Given that reliable little weather stations are cheap as chips these days, plus, as rgb pointed out, lots of people have their own, it is a mystery why such third rate data is still considered acceptable. As Prof. Brown pointed out, averaging a bunch of these readings, something that could be done on a laptop these days, would produce much more reliable data even allowing for individual siting issues.
RE
johanna says:
@ur momisugly April 13, 2012 at 4:37 pm
“Given that reliable little weather stations are cheap as chips these days, plus, as rgb pointed out, lots of people have their own,…”
——————
Mmmm. But imagine if the Get UP! crowd or some other mass activist pro-GHG movement decided to manipulate the dataset, eg., by siting the devices on tens of thousands of window sills across the nation… if the activist flock was large enough… how could mass deception be controlled.. because let’s face it, these cults are defined by the capacity for mass deception.
Been there, done that. Early on in my career with Environment Canada, I was a “meteorological technician” (fancy name for professional weather observer). Even after winning a competition for an office job, I still did a couple of relief stints at YVR (Vancouver Int’l A) as an observer, when people were on course or on vacation and the place was short-staffed. This was in the early 1980’s.
One afternoon, the temperature suddenly jumped a few degrees on the temperature sensors. The regular observing routine included a comparison between the automatic sensor, and a regular mercury dry bulb every 6 hours (syno hour). This wasn’t a syno hour, but I went and checked anyways, and the mercury thermometer had gone up as well. Not only that, it definitely felt warmer outdoors. When I got back into the office, I noticed that the wind had turned around. Instead of being a light sea breeze from Georgia Strait, it was now a light land breeze from Richmond.
This probably happened a lot, but as a temporary relief observer, I wasn’t that familiar with the vagaries of the site, and it was new to me.
This discussion makes me think of the George Carlin hippy dippy weatherman routine where he states “temperature at the airport is 88 degrees, which is stupid because I don’t know anybody who lives at the airport”. Given the problems that Mr. Berk has noted, and George Carlin’s astute observation, perhaps airport temperatures should only be used for things pertaining to airport operations.
Jay Davis
Scott,
I just ran it for maximum temperature, as that’s what the author suspected was problematic. FWIW, there was an even closer match between BWI and relatively nearby Beltsville:
Mean annual high temperature at Beltsville: 65.76°
Mean annual high temperature at BWI: 65.76°
Standard deviation in daily high temperatures:
Beltsville: 18.259°
BWI: 18.292°
Scott,
I ran the numbers of BWI vs. Beltsville for the low temperatures:
Average low:
Beltsville: 45.73°
BWI: 45.96°
Standard Deviation:
Beltsville: 16.987°
BWI: 16.880°
johanna said: “Also, weird things happen, like the temperature rising up to 2 degrees C for no apparent reason in the middle of a cold, clear night for about an hour and then falling back again.”
That can happen on partly cloudy nights. A patch of clouds canl prevent heat from leaving the earth as quickly as it would without the clouds. When combined with a small amount of horizontal air movement from a warmer (cloudier) location or a bit of mixing from warmer air aloft (given radiational cooling causing a temperature inversion), the near-ground air temperature can pop up a degree or two for seemingly no reason.
@ur momisugly Steve Mosher,
thanks for that.
As a quick aside, may I say that I was sure I knew your name, but due solely to my ignorance, I couldn’t place it. A quick Google search turned up the following link, which you may well have seen – but there may well be others like myself who would benefit from the reminder. http://blogs.telegraph.co.uk/news/jamesdelingpole/100022057/steven-mosher-the-real-hero-of-climategate/
Sadly, Google searching for me tells you nothing about me. I have no such claim to fame, being merely a private citizen earnestly trying to be well informed.
This is not the only area in which I am profoundly ignorant, of course. Please accept that I’m not being disingenuous when I ask “specifically who is the ‘they’ that you’re alluding to, and why are you confident that they really do do this?”
As a separate matter, your brief explication of UHI asserts that it is a function of wind speed and direction. My mental image of UHI is that of cities spreading out in all directions around thermometers, which would mean thermometer readings would rise regardless of wind direction, or , it seems to me, speed. Accordingly UHI would show up in the record.That’s what I understood Roy Spencer’s map of ‘Global Warming’ vs city size to prove. http://wattsupwiththat.com/2012/03/30/spencer-shows-compelling-evidence-of-uhi-in-crutem3-data/
Of course, its more likely that I’m wrong than that you are. Still, could I ask you to clarify where I’ve gone wrong?
I noticed the same thing a few years ago for the Allentown airport. I was watching closely because the forecast high was advertised to set a record. Then, like now, the media were hyperbolic about “RECORD HIGHS!”
Here’s the Weatherunderground link to the data for the day in question.
http://www.wunderground.com/history/airport/KABE/2010/4/7/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA
Note the very subtle bump in the temperature curve slightly after 2 PM, which appears to briefely top out somewhere above 90F. If you look at the hourly readings (usually recorded at nine minutes before the hour for some reason), the record has a “non-hourly” reading entered for 2:16 PM of 87.8 F. This is the highest reading on the tabular data, yet the recorded high for the day is 92 F, which I guess coincides with the little temperature blip on the graph. This was indeed recorded as “a record”. At about the same time, the highest wind gust of the day was recorded.
Two private weather stations in the vicinity shows no such blip.
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KPAWHITE2&month=4&day=7&year=2010
http://www.wunderground.com/weatherstation/WXDailyHistory.asp?ID=KPACOPLA2&month=4&day=7&year=2010
Neither of the non-airport locations got above 90 F, nor did the smaller airport on the other side of town:
http://www.wunderground.com/history/airport/KXLL/2010/4/7/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA
Not being as pro-active as Justin Berk, I didn’t call the weather service, but I did send a polite e-mail asking about the blip. I received back a somewhat polite response that basically said “We know what we’re doing, sir.”
As others have pointed out, although the daily temperature readings recorded at “official” weather stations are then subject to further processing and stuck into temp-o-matic algorithms for temperature trend analyses, the raw data are used for purposes of reporting “RECORD HIGHS!”