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.
========================================================
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BWI snow record rescinded: Another reason why airports aren’t the best place to measure climate data.
=============================================================
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
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UHI, as it’s well known, is a phenomenon that happens locally everywhere but, as if by magic, globally nowhere.
You sure do put a lot of effort into justifying USA as the worlds heaviest carbon poluter 😉 Respect!
Stories like this are just so mundane and lacking in glamour that the MSM will never pick up on them. There is no looming disaster and no villain, no polar bear and no photogenic hero, just the steady constant corruption of data.
Well done Anthony for taking the trouble of picking up on it but you can be sure few people outside WUWT will ever know.
They will just read that another heat record has been broken somewhere…
I’ve noticed this at other locations as well. There is big discontinuity issue when NWS shifted from Cotton Region Shelters to MMTS, ASOS etc.
‘poorly sited’, not ‘sighted’
Just goes to show what Anthony has said before – airport weather observations are collected for the use of aircraft using the runways, not as climatological records, for which they are nearly useless.
Is there no way of capturing data from the Davis WeatherLink system? The people who go to the expense of buying these stations (many of them private individuals) are likely to take care with the siting of the sensors, this network might be quite reliable.
The scientist in me immediately starts think about new experiments that might be done to improve the data at airports. Given the high aspect-ratio of the runway and the flight paths, it would be interesting to have thermometers located both at the side of, and and at the ends of runways. The effect of prevailing wind might then appear to be greater.
Also, think of all that lovely heat [and CO2 and water!] that the jets are cranking out at take off: probably biased towards the starting end of the runway. Has anybody done these relatively straight forward experiments?
It’s what they\ve telling us would happen…runway global warming
Great post, thanks. Good work by the local Mets.
This house of cards will fall soon but in spite of journalism and not because of it. It’s time to wake up and realize we are being deliberately deceived by the press establishment and not just about CAGW.
It’s what they’ve been telling us would happen…runway global warming
The real irony, is that if the climate “scientists” had been real scientists and a) looked at the data, b)admitted to themselves (or c) stopped lying) then they would have made it known that they needed a top notch metereological data collection system and that it was inappropriate in “such an important issue” to use fifth rate sites to measure data.
But these guys are not real scientists. They are quite happy to use slip-shod data where it suits their purposes, and as I said, the real irony is that a pittance has been spent on the real area of need: ACCURATE TEMPERATURE MONITORING SITES and as a result of a woeful lack of a few billions on temperature monitoring, the world is spending trillions on unneeded and unwanted and economically harmful measures which will probably cost us all many more trillions in lost economic output.
I can only liken it to a diamond dealer buying a supermarket set of scales … no that would at worst be a few percent loss. It’s more like they built a massive tower block based on a geological survey done by schoolkids using “eye spy minerals”.
Nothing to see here…move along. BoM in Australia have most of their stations next to runways, previously favoring post offices. How else can they keep up their #pocket-lining from the government.
Brings a whole new meaning to the term ‘Jet Stream’.
But seriously, since jet-fuelled thermometer readings artificially increase the range of the data readings at a given site, in a given time period, it is not hard to see how the inappropriate use of ‘linear interpolation’ for filling-in gaps in the surface temperature record (eg. at neighbouring sites) over time can compound the original (UHI) bias by introducing a systemic source of warming bias into the wider temperature record.
And as air traffic increases through time, this systemic warming bias effectively becomes self-amplifying… a bit like a virus initiating infection in one cell, replicating then releasing progeny viruses to infect other cells.
Once again, “linear interpolation” of this nature is really extrapolation by another name… or to put it another way, a statistical method for transforming science into science fiction.
Airport weather stations are intended to provide data for flights and out of the airport , so such features are not a problem for there intended purpose . Expect that now these stations data is being used for 101 things with great claims being made to its precision and how well its represents the local area.
The reality is there used, not because there a good idea, but because they exist and save actual having to set up another one that would provide valid data. They are the duck tape of weather measurement , a fair temp fix that is easy to use but is actual in no way a good nor permanent fix to the problem.
omnologos says:
April 13, 2012 at 12:24 am (Edit)
UHI, as it’s well known, is a phenomenon that happens locally everywhere but, as if by magic, globally nowhere.
#############
its rather easy to understand
1. Its a function of windspeed and direction. Note the temperature changed for 10 minutes
when the wind changed.
2. Its a function of timing. If that wind change happens at 19:54.. no change to TMAX
does UHI exist. Yup. DO you get it every hour of every day? nope. conditions have to be right.
Do you know what they do when they want to study UHI? They look for days when the synoptic conditions are such that you can actually measure it.
At this place, you nee a westerly wind at the right time of the day.
Its not a big mystery why UHI is real and why it doesnt show up in the record.
Its not a big mystery why UHI is real and why it doesnt show up in the record
It does show up in the record. It just doesn’t show up that well when you smear min/max temps over large geographic areas in the method so beloved by climate scientists.
The data is fine. The problem is the method.
RE
Steven Mosher says:
@ur momisugly April 13, 2012 at 2:35 am
—————
Nonsense.
Please address my point (@ur momisugly 2:27 am) re how inappropriate interpolation results in a self-amplifying and systemic warming bias into the temperature record…
Are you seriously suggesting that all readings taken at this site, for example, when the wind direction is from the west are culled from the record?
And what about other sites where a UHI bias may not yet have been identified?
Hello,
Sorry for my bad English, I am French.
On the map 2 D, I see the W here :
http://meteo.besse83.free.fr/imfix/wbaltimore.jpg
If the soil is very dry with a sparse grass, for the T max of the day with sun, it is warmer that the runway (in a study at Nice aeroport in France (“Topoclimatologie et habitat”, Pierre Carrega), for example, the temperature surface max in september, is 46°C for the runway for 62°C for a sparse grass with soil dry (water reserve in the soil : 9 mm for a maximum 150 mm). The night, the runway stay very much warmer that the sparse grass.
In your case, also there are some clouds and a wind variability for generate this value without runway, it is not unusual to observe these differences. Here for several stations with and without ventilated radiation shields, it is very common in the natural sites with yours conditions.
At Baltimore in this site very open for to get a good natural ventilation, there are not a big problem on the T max with a ventilated radiation shield, if the fan is good. This difference is not make by the runway (you can check with an other same station before the runway at the same distance of the runway, for this wind direction. In the Var in France, I like to do this kind of test )
Nice. Right between the runways. Jet exhaust and hot pavement. Perfect.
And what about southerly winds transporting jet exhaust heat from the adjacent runway (see pic 2)? Or for that matter easterly winds from the (same) adjacent runway?
I can’t see what the problem is. If the wind shifted and the thermometer recorded 3 degrees higher in between the reported hourly observations, then isn’t that rightly the maximum for the day? Are we arguing here that observed temperatures should be adjusted according to our preferences? (There’s already one team playing that game.) As long as past brief spikes and dips in temperatures have been faithfully recorded then these 3 degrees shouldn’t be any cause forma concern. Or am I being too optimistic that the dips haven’t been discarded by “the team” and only the spikes kept?
I’m a bit confused.
The photo shows the main runway running east/west lying to the north of the weather station. I think that the tarmac area to the south of the weather station is the mid-field cargo complex on which are parked quite a few large vehicles. Please do correct me if I’m wrong
The Google photo map shows an aircraft waiting to take off at the eastern end of the main runway, with the weather station located just south of the western end of the main runway where the aircraft leave the ground to begin their ascent:
http://maps.google.com/maps?spn=0.036009,0.046450&t=h&hl=en&ll=39.175361,-76.668332&fc=1
It seems very odd to locate a weather station just south of that part of the runway from where aircraft are taking off, particularly as they are taking off into the wind which is then being blown back towards the weather station.
It seems clear there must be a considerable UHI effect at this location. The faa map of the airport is:
http://aeronav.faa.gov/d-tpp/1204/00804AD.PDF
DavidH says:
April 13, 2012 at 3:25 am
I can’t see what the problem is. If the wind shifted and the thermometer recorded 3 degrees higher in between the reported hourly observations, then isn’t that rightly the maximum for the day?
Suppose there were nearby construction workers laying new tarmac as the wind shifted, so the spike was 10 degrees higher – still “rightly the maximum”?
As long as past brief spikes and dips in temperatures have been faithfully recorded then these 3 degrees shouldn’t be any cause forma concern
The problem is that the new mantra for alarmism-by-press-release is to count the number of new record maxima set.
RE
Andrew says:
@ur momisugly April 13, 2012 at 3:22 am
Correction: sorry, that ought to be “…northerly winds transporting jet exhaust heat from the adjacent runway….”