While NCDC’s Dr. Thomas Peterson tries to ignore UHI, from Hans Von Storch at Die Klimazwiebel (h/t to Jos de Laat) we learn that many other people are actively measuring it. WUWT reader may remember my “do it yourself UHI kit” for vehicles…now there’s one for a bike:
Studying urban heat island effect on a bike
It is long known that in cities there may be a significant climatic effect due to urbanization – thus in cities we have the interesting and challenging task of determining at least three significant drivers for change, if not more, namely the effect of the local modification of the environment as well as the local manifestation of global change due to greenhouse gases (plus, possibly other global factors). Unfortunately, systematic studies about the determination and separation of these effects – in principle a detection and attribution task – have not been done often. At least, I am not aware of such efforts; indeed even studies only on the size and distribution of the urban heat island effect (UHI) are not done often; in Hamburg, a first study was only published in the last few years – before that one could hear that in a maritime climatic environment as Hamburg, the effect would be negligible. It is not.
Now, an innovative study is about to be published – see the manuscript here: Measurement and statistical modeling of the urban heat island of the city of Utrecht (the Netherlands) by Theo Brandsm and Dirk Wolters from KNMI. The trick was, to do the year long observations by bike, as described in this abstract:
Mobile temperature and humidity measurements have been performed along a 14 km transect through the city of Utrecht (311,000 inhabitants) in the period March 2006 – January 2009. The measurements took place on a bicycle during commuter tra c and resulted in 106 nighttime profiles (before sunrise) and 77 daytime (afternoon) profiles. It is shown how the intensity of the urban heat island depends on wind direction, cloudiness and wind speed. Statistical models are constructed that relate the mean and maximum nighttime urban heat island intensity profiles to area-averaged sky-view factors and land use combined at both the micro and local scale. Sky-view factors are estimated from a 0:5 x 0:5 m surface elevation database and land use is obtained from a 25 x 25 m land use database. The models are calibrated using the mobile measurements and provide estimates of the spatial distribution of the mean and maximum nighttime urban heat island intensity in Utrecht. Both models explain more than 75% of the variance. A separate non-linear model is introduced that relates the temperature differences between the warmest and coolest part of the transects to wind speed and cloudiness.
The paper:
Brandsma, T. and D. Wolters, Measurement and statistical modeling of
the urban heat island of the city of Utrecht (the Netherlands)
Journal of Applied Meteorology and Climatology, 2012, 51, 1046-1060.
available here:
http://www.knmi.nl/publications/fulltexts/uhi_manuscript_brandsmawolters.pdf
I put a couple of the figures side by side to give you an idea of what was discovered:
David “Just look at this as a UHI example!;http://ceo.decc.gov.uk/nationalheatmap/Click on ‘layers’ – ‘total heat’ ”
It looks great, but sadly its just colourings based on guessed energy consumption.
Thanks for the link though.
Sorry pochas but you are incorrect. As more and more rural temperature stations are encroached upon by man made structures those once rural stations will show warming. The alarmists will use that as “proof” of global warming. And even a mature city still experiences land use changes. Older homes with larger yards being torn down and replaced with smaller houses grouped closer together leaving less green space around them.
I believe a control experiment for the measurement of UHI exists in the form of my home city of Christchurch, New Zealand (population c. 375,000). On 22FEB11 we had an earthquake which led to the immediate evacuation of the entire city centre (still largely unpopulated). I don’t have the expertise to conduct this study, but I offer it to anyone who does.
All the best.
Matt: “How many US Cities have experienced no poplulation growth over the last 100 years?”
Maybe already, but certainly by 2020, Detroit will have shrunk to a lower population than 100 years ago. Detroit experienced both rapid growth and decline during that time. I hope temperature records pre- and post-decline are available.
highflight56433 says:
October 10, 2012 at 8:59 am
That is a massive amount of work over a long period to come up with something that substantiates common sense. If I put ten 100 watt light bulbs in my living room, turn them all on, it will soon become the warmest room in the house; my own self-made UHI. Now all we need to do is apply the model to all the UHI temps as an adjustment. Raw compared to the model.
I tried that but the room was so bright I couldn’t read the thermometer!
@Dave says:
October 10, 2012 at 8:41 am
“Biking in Holland, who would have ever thunk it?”
But of course! And Holland is famous the world over for its breathtaking mountain biking. (Wait up! I may have something wrong there… nevermind.)
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All that sampling anywhere a bike can go. Good thinking.
I think this is a very interesting problem with much more to be discovered. Watchman’s remark raises a very interesting point. Many local variations, from whatever the cause, could make prefered sites for dwellings naturally “biased” for warmer temperatures. I guess there certainly could be a bias for selecting cooler locations in hot climates. But, to the point, I recall one morning when the radio reported temperature was -10 degrees F for the local urban location. On that particular morning I was out early and noted that in my suburban location my thermometer gave a reading of -17 degrees F. I left the house and drove across the valley and, in my “calibrated” Dodge truck thermometer, I noted a 5 mile wide pocket of air in the low lying area along the local creek drainage of a whopping -22 degrees F! I have found that routinely it can be -16 degrees F in a duck blind on the Platt river but the reported temperature for the day is barely below zero. The settlers knew that a little elevation and protection from the wind made for a more comfortable winter experience. Add some concrete and tall buildings and it becomes warmer still.
What this study shows is that there is an urban heat island within urban areas. No surprise really. The road pedaled here has not gone outside urban parameters, except for a short stretch just before they got to work where it is less built up. What this clearly shows is that the centre of this city with more offices, traffic, narrow streets, is warmer then the area where they started and finished which have slightly wider roads and a lower population density. There is no attempt made to travel from the temp station at De Bilt, the end point of the cycle trip and a major dutch weather station, to get into the real country side.
I know that in the Netherlands that would be a hard task but within 20 km of either end or starting point there is space that is classified as rural. This will have show a better extent of UHI, for the dutch situation that is, we do need to keep in mind that that country is so build up that a real comparison is virtually impossible to get.
Pochas has a point but only if nothing near the weather station would have changed in those 20 years. A new 25 level office block within 300m will have an effect on any reading, etc. Most of the temp stations that are used today show a lot more development around it compared to even 20 years ago.
Don’t miss this opportunity. Send this to your “on the BANDWAGON” Gorebull Warming friends.
Point out that it is an example of “carbon neutral” climate research.
Heh heh heh, they’ll be trapped into reading it. And before you can say, ROY SPENCER three times fast, they’ll actually aborb some sense. If that happens, then the 10:10 campaign video comes to mind.
Will the follow-up paper examine the same unit on a tricycle?
outtheback says:
October 10, 2012 at 11:43 am
“Pochas has a point but only if nothing near the weather station would have changed in those 20 years. A new 25 level office block within 300m will have an effect on any reading, etc.”
Exactly.
Very interesting paper and a fun way to do research!
A couple of months ago Anthony suggested that a human in an unheated, heavily insulated hut, in Antarctica sitting there trying to keep warm had an effect on a thermometer housed several metres away. I would like then to know what the effect of a hot sweaty human several inches away has on these results in his opinion?
Phil Jones says there is no UHI and he is a proper scientist so you are both beastly and wrong.
2 degrees. Who would have guessed.
“How many US Cities have experienced no population growth over the last 100 years?”
Saint Louis has a population of about 800,000 in the 1930’s and is now about 400,000. Other examples can be found.
It is intuitive that there is likely a limiting case for the UHI effect. But urban areas are not static. Consider an idealized urban center, with the heaviest positive influences concentrated at the core and diminishing monotonicly to the edge. In this case we suppose that at the center dT/dt as far as UHI goes is zero; no increase in positive influences will yield increases in the UHI effect. The temperature record at this location from then on will be a true reflection of the regional trends, all other things being equal (though we know they aren’t). This urban area is experiencing an annual population growth of 3.5%. Using the “rule of 70” and assuming that UHI influences grow at the same rate, the population and the UHI drivers will double in 20 years. Since it’s very difficult to grow services, housing, and employment in the congested center, the urban area will grow at the edges and in any underutilized interior areas. As the UHI factors increase, they increase the slope of the temperature record at the various historic sites.
An area started as a farm field, with a COOP station 100 ft from the house. The farm was sold, subdivided and developed. Now there is a wall within 25′ in every direction. Several properties are consolidated and an apartment building goes up with the station at the edge of the parking lot. More properties are consolidated and a strip mall is located on one side of the apartment building and a professional center on the other. The apartment building and strip mall are torn down, and a 12-story office building is erected. Now the station occupies a small plot in the middle of a very large parking lot. The professional building comes down and a 30-story financial center goes up and the parking lot is now a parking garage and the station is located on top, utterly surrounded by asphalt and concrete. Additional 20- and 40-story buildings are raised on surrounding plots until there is hardly a stitch of the natural world to be found within 1000′.
At the start, temperatures were in their natural state, but each change in land use added 0.1 degrees here, 0.05 degrees there until you top out at about 4-7 degrees C (let’s say). If your development happens to coincide with a natural upturn in the regional temperature trend, you would conclude that not only was it getting warmer, it was getting warmer faster, because thermometers in the underutilized areas were getting jacked up, and as time goes on there would be more of the thermometers showing a trend because portions of the area are showing increased UHI influences and the area is growing.
This is the thing that the data massagers don’t take into consideration. Their corrections are made without consideration of the time element involved. As far as they seem to be concerned, if there’s UHI effect today, it was there 50 years ago so we’d better cool the past. Me, I think it’s just laziness. You have to be seriously OCD to try and work that all out; someone like Chiefio, say ;-).
The population of Utrecht has grown from 100,000 in 1900 to 200,000 in 1950 to 230,000 in 2000 and finally rapidely growing to 316,000 nowadays. The larger area, once rural around the city, nowadays has over 600,000 inhabitants (the city included).
The Bilt was once a small village, but it did grow from 17,000 in 1945 to 33,000 in the nineties to 42,000 nowadays…
The KNMI meteoroligical station started in 1897 at The Bilt, outside the village. Now it is already at the edge of the village and in the main downwind direction of a growing Utrecht. One can only wonder how much the station, even as it is well sited in itself, is affected by the increasing population density in the surroundings.
The same for the KMI in Belgium, situated in Ukkel, once a rural place far from Brussels, now completely surrounded by houses of the Brussels agglomeration… There too, the temperature measurements are perfectly situated, with only grass around for some distance. But still…
Idiot comment about cities with NO population growth.
That would be like saying that Mpls/St. Paul has had “zero” population growth, as from 1970 to now..THEY HAVE had ZPG!!! However, the metro area, since 1970, has gone from about 1.2 Million residents to over 3.5 million. A considerable EXPANSION of the original UHI….
Same with St. Louis. GET REAL, get your HEAD OUT OF THE SAND. Sorry, I guess I don’t tolerate fools lightly.
UHI is not “powerful”; it is deceptive.
And how accurate is this setup? Rider gasping for breath and breathing all over the detector. More unwanted heat.
UHI despite being a true effect of cities and towns will be different for every area under consideration. This in itself would render the effect unquantifiable and unmodelable.
Hmm. So if you are travelling for some period of time during the day or night, and you do this in a consistent diection, how do you prevent the normal temperature variations during the day-night cycle from producing misleading UHI values?
D. J. Hawkins asked:
October 10, 2012 at 9:29 am
Next question: Where on this view are the stations whose temperatures are used by GISS, etc?
Just loo at the paper. The Meteo site is next to the spot maned KNMI at km 13.4.
That’s the place with the “negative deviation” – uuups?!?!
And I thought we got ’em ;-))
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ntesdorf says:
October 10, 2012 at 2:31 pm
“How many US Cities have experienced no population growth over the last 100 years?”
Saint Louis has a population of about 800,000 in the 1930′s and is now about 400,000. Other examples can be found.
****
City limits are not real physical limits. So the real question is, what is the population of the county St Louis resides in from 1930 to present? Ever heard of suburban sprawl?
[ It is shown how the intensity of the urban heat island depends on wind direction, cloudiness and wind speed.]
Urban areas are producing, absorbing and radiating energy regardless of of the above three parameters, which only cause dispersion. Therefore, it appears they are measuring only a portion of the process. Still significant.
“LazyTeenager says:
October 11, 2012 at 4:15 am”
Do you ever think before you post?