By Steven Goddard and Anthony Watts
Fort Collins, Colorado is most famous for Balloon Boy, and Boulder, Colorado is most famous for Jon Benet and Ward Churchill.
Both are hotbeds of Climate Science, with familiar names like Roger Pielke (Jr. and Sr.) Walt Meier, William Gray, Kevin Trenberth and Mark Sereeze. Both are of similar size (Boulder 91,000 and Fort Collins 130,000) and located in very similar geographical environments along the Front Range – about 50 miles apart. The big difference is that Fort Collins has tripled in size over the last 40 years, and Boulder has grown much more slowly. Fort Collins population is shown in blue and Boulder in red below.
Sources:
http://en.wikipedia.org/wiki/Fort_Collins,_Colorado
http://en.wikipedia.org/wiki/Boulder,_Colorado
Until the mid-1960s, NCDC temperatures in the two cities tracked each other quite closely, as you can see below. Again, Fort Collins in blue, and Boulder in red – with Fort Collins temperatures shifted upwards by two degrees to normalize the left side of the graph. Since 1965, temperatures in Fort Collins have risen much more quickly than Boulder, paralleling the relative increase in population.
Source: NCDC Boulder Temperatures NCDC Fort Collins Temperatures
The graph below shows the absolute difference between Fort Collins temperatures and Boulder temperatures since 1930. There is some sort of discontinuity around 1940, but the UHI imprint is clearly visible in the Fort Collins record. The Colorado State Climatologist, Nolan Doesken manages the Fort Collins Weather station. He has told me that it has never moved or changed instrumentation. and that he believes the increase in temperature is due to UHI effects.
Roger Pielke Sr. further commented:
“the Fort Collins site did have the introduction of the CSU Transit Center a few years ago, although this is well after the upturn in temperature differences between Boulder and Fort Collins started to increase.”
From the promotional photo on the CSU website, the Fort Collins USHCN weather station (below) seems reasonably sited.
However when you look at the Google Earth street view, you realize that it is surrounded by concrete, asphalt, nearby parking, and a building just 7.5 meters away (By the GE ruler tool). It would rate a CRN4 by the surfacestations rating. It also appears to have been modified since the promo photo was taken as there is a new fence with shrubbery and wood chips surrounding it.
Besides the pressure of CSU expansion, Fort Collins has seen an increase of about two degrees since 1970, corresponding to a population increase of 90,000. This is probably a little higher than Dr. Spencer’s estimates for UHI.
The Boulder weather station is similarly sited since the concrete path is just under 10 meters away.
It is at the campus of NOAA’s and NIST’s headquarters in Boulder. Anthony Watts visited the station in 2007 and took photos for the surfacestations project. Like Fort Collins, it gets similar expansion pressure due to nearby construction as seen in this aerial photo.
Here are the temperature records fro these two USHCN stations:
NCDC Fort Collins Temperatures
There is some UHI effect visible in the Boulder record below, but much less than Fort Collins.
Conclusion:
We have two weather stations in similarly sited urban environments. Until 1965 they tracked each other very closely. Since then, Fort Collins has seen a relative increase in temperature which tracks the relative increase in population. UHI is clearly not dead.
superDBA,
I measured it on Google Earth, and it is exactly 3.00 miles from the Fort Collins Weather Station (NW of the Lory Student Center) to Hughes Stadium. Did you measure by road, or by air?
Wren (20:44:25) :
The signature of UHI is the highs staying stable in their trends with the lows rising to meet them.
Natural rural signals are
a.) dry years – Highs rise as lows drop (greater diurnal range)
b.) wet years – Highs drop as lows rise (lesser dirunal range)
c) warm or cool years: Highs & lows rise or drop in unison
a & b are best viewed in separte yearly graphs.
UHI & c are best viewed in long-term graphs.
Unfortunately, we have climatologists who don’t bother to look and see what the stations/areas they are making big claims over are really doing.
They play with averages only, and totally miss the bigger picture.
Well, if that all one does, it’s easy to be misled.
And if one wants to mislead, cherry-pick the statistic that shows only what you want the world to believe.
AGW: Blindfolded science.
George E. Smith (18:15:33) :
And I almost forgot; please do let us in, on your insider information about that famous stolen e-mail.
Has someone been indicted for that theft ?
————-
If they don’t catch the person that steals your car, does that mean it wasn’t stolen ?
Here’s what a whistleblower looks like:
http://www2.vietbao.vn/images/vietnam2/phong_su/20566207_images965949_time.jpg
Wren,
It has been cold in Colorado in recent years. This winter in particular seems endless, after a non-summer in 2009. Winter started the second week in October.
<>
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png
Are a thousand days enough data points or when does your statistics say a trend is provably broken or do you even know?
Oops… mod replace previous…
R. Gates (16:34:40) :
To deny the obvious trend is to show that either you don’t know how to read simply graphs, or you have some agenda not to see a trend where it is quite obvious.
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png
Are a thousand days enough data points or when does your statistics say a trend is provably broken or do you even know?
Moemo (18:51:06) :
There are zero sunspots on my climate widget…does that mean we should be on the look out for zombies or something?
———-
No, the zombies went back to their caves:
http://spaceweather.com/
There were a few sunspot-free days recently, but thankfully, we are again protected.
http://shirtoid.com/wp-content/uploads/2009/11/zombies-hate-fast-food.jpg
Be careful in the future, they are getting very hungry…
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/2010
Concerning
Steve Goddard (15:56:30) :
Steve said “The Fort Collins site is almost exactly 3 miles east of the foothills….I hike and bike the trails west of both cities all the time including Horsetooth Reservoir, Chautauqua, Table Mesa, Mount Sanitas. Your statement that there is a “huge difference” is simply nonsense.”
Steve, perhaps you will amend your conclusion that my statement is “nonsense” when you compare these two Google Earth images, which are on the same scale…
Boulder
Fort Collins
Best Regards,
Tom Moriarty
Jim Cole (19:53:58) :
I have lived in both Boulder and Fort Collins. In both cases I was about two miles away from the weather station. The climates are nearly identical, except that Boulder tends to get more warm days in the winter and a little more snow.
But that isn’t the point. What we are discussing here is not absolute differences, but rather relative changes at each station. Fort Collins has warmed relative to its past, more than Boulder has warmed relative to its past. This is undoubtedly due to UHI.
Right now it is 39 in downtown Fort Collins and 7-12 degrees cooler at the south and east end of town.
http://www.wunderground.com/wundermap/?lat=40.53468&lon=-104.99428&zoom=12&type=hyb&units=english&rad=1&rad.num=1&rad.spd=25&rad.opa=70&rad.stm=0&rad.type=N0R&rad.type2=&rad.smo=1&rad.mrg=0&wxsn=1&wxsn.mode=tw&svr=0&cams=0&sat=0&riv=0&mm=0&hur=0&fire=0&tor=0&ndfd=0&pix=0&dir=0
Tom Moriarty,
You keep bringing up the fact that the area immediately to the west of the Boulder weather station is not developed. Isn’t that the whole point of this article? Fort Collins has grown more and is warming faster than Boulder.
Thanks for confirming my point. The Boulder station is a little closer to the mountains, but who cares? We are talking about relative changes, not absolute differences. As long as the positions are fixed at each station. What a ridiculous straw man.
Did you figure out which direction Boulder is from Arvada yet?
Steve Goddard,
It is a sad thing that you would treat somebody who actually agrees with you on your UHI point, and has said so in a previous comment, with such sarcastic comtempt.
But I urge readers to compare the two images mentioned above to see my point
Oh well.
Best Regards
Tom Moriarty
Eric Flesch (19:59:24) :
I continue to be baffled by comments like yours. Here is the view from the west end of CSU. Looks like mountains to me.
http://www.atmos.colostate.edu/
The west edge of town abuts the mountains just like it does in Boulder.
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=80525&sll=37.0625,-95.677068&sspn=54.928982,95.712891&ie=UTF8&hq=&hnear=Fort+Collins,+Larimer,+Colorado+80525&ll=40.456352,-105.644531&spn=0.834897,1.495514&t=p&z=10
It is an incredibly steep bike ride from Hughes Stadium up to the A, gaining 700 feet elevation in just over a mile. Try riding it and then tell me that Fort Collins is in the plains.
When looking at something like this, I always start by using the longest datasets that I can find. This gives me the big picture, and then I move on to a more detailed view.
So I got the population data (citations in original post), along with the unadjusted GISS temperatures from here. I subtracted the Boulder temperature from the Fort Collins temperature, and plotted that along with the populations of the two cities. Here’s the result:
Figure W1. Ft. Collins minus Boulder temperatures and gaussian average (left scale) and Populations (right scale). Darker blue line is the linear trend of the temperature differences. Photo is of Boulder City from the Flatiron Mountains.
Here’s the problem. The difference in the temperatures has been rising in a nearly linear fashion for over a century. The increase has been remarkably consistent, and does not correlate with the changes in the rate of the population increase. The differences from a linear trend are only ± 0.3°C, while the total difference in temperatures is ± 0.8°C.
On the other hand, I also looked at the amount of the correction as predicted by Spencer based on population density. To determine his corrections, I used the city areas given in Wikipedia to determine the population density. I used that with Spencer’s results to determine how much adjustment he says should be done. Since the city sizes are so similar, the Spencer correction is only ± 0.12°C.
However, Spencer still seems to be correct in concept if not in amplitude. While his correction is smaller than the actual difference between the two cities, the correlation is quite good (n=25, r^2 = 0.77, p less than 0.001, adjusted for autocorrelation). Here are those results:
Figure W2. Ft. Collins – Boulder (Gaussian avg), Spencer Correction, and Regression Result. Because temperature data are only available decadally prior to 1990, temperature results are sampled similarly.Photo is Lory Park looking towards Fort Collins
The density figures, of course, are only approximate, as the area of the cities has undoubtedly increased over time. However, these will tend to cancel each other out.
Onwards,
w.
Tom Moriarity,
You are doing it again.
It is four miles from the Weather Station to the Reservoir, but the reservoir is on the other side of the hogback ridge – and hundreds of feet higher than city. Like I told Eric, try riding a bike up to the reservoir. You won’t make it unless you are a serious cyclist in excellent shape.
Your argument is both incorrect, and a pointless straw man.
Willis,
Look closer at the data. The increase in temperatures started around 1970.
http://wattsupwiththat.files.wordpress.com/2010/03/ftcollins_temp.png
There is a discontinuity in the Fort Collins minus Boulder data indicating something is wrong from about 1940-1965.
wayne, steve, rbateman:
Exactly the same in most Australian sites- warming mostly due to rising minima, and then extremely variable from place to place. Much greater further inland, much less on the coast. None at all in some places.
Steve Goddard (21:34:42) :
Wren,
It has been cold in Colorado in recent years. This winter in particular seems endless, after a non-summer in 2009. Winter started the second week in October.
====
Sure, but has the 2009 annual mean matched previous low annual means?
Anu (10:36:08) :
Bill Gates was an arrogant jerk.
I hear all his work was a hoax, based on faked data.
Anu, Gates rightfully kept his proprietary materials, “data”, and code secret. It’s value then materialized as successful products serving an innovative need which actually created wealth, as determined by a free market of people risking their own money – by which the products are also continuously field tested.
On the other hand, Trenberth’s Climate Science “product” would require us all to buy it as is, even before any independent “laboratory testing” to assure its intrinsic value. Nor have questions as to Trenberth’s Climate Science product’s safety and efficacy been addressed by Trenberth’s Climate Science in any meaningful way.
Hence, agreeing with China and India, NO SALE!
But, Anu, given your own fear of the alleged CO2AGW disaster, I ask you again, what are you personally doing in terms of your own lifestyle to avert this alleged disaster? Since the alleged CO2AGW disaster is your own strong belief, surely you are obligated to take some very radical action to decrease your own “carbon footprint”?
Tom Moriarity,
You picked an arbitrary point in the mountains and measured the distance to it. You didn’t measure the distance to the edge of the mountains, and a couple of miles makes no difference to the discussion anyway.
I ride my bike and hike frequently up into the foothills in both cities. One of the best hikes in Fort Collins is from the football stadium up the hogback ridge and over the top to the reservoir. Why are you arguing about this?
rbateman (21:32:43) :
Wren (20:44:25) :
The signature of UHI is the highs staying stable in their trends with the lows rising to meet them.
======
Steve told me “It has been cold in Colorado in recent years. This winter in particular seems endless, after a non-summer in 2009. Winter started the second week in October.”
So maybe this signature is going away, and Boulder and Fort Collins will no longer have a UHI.
But how do you know for sure the low’s rising to meet the highs is a signature of UHI anyway?
It might be best to be non-commital. That way if the signature goes away, you can say you were never really sure it was a signature.
Tom,
One last image to make the point of what you are doing wrong with your measurements. This is Google Earth showing the west edge of Fort Collins, with the football stadium, the A, and the dam and reservoir on the other side of the hogback ridge.
http://docs.google.com/View?id=ddw82wws_463fpgdpkhc
The edge of the foothills starts one mile east of the reservoir (right behind the football stadium) and is hundreds of feet lower. It is 3 miles from the Fort Collins weather station to the foothills.
Steve Goddard (22:22:16) :
I guess I’m a serious cyclist in excellent shape then. 🙂
Actually, the first time I tried to bike up it, I had to stop for a break 5 times. 🙁 However, it’s much easier on me now (stay in low gear!) and I can make it in one go. It’s kind of fun to run it too, because then you can pass bikers on the uphill slopes. 🙂 (then they blow by you at 5x your speed on the downhills.)
Back on topic, since some people have disputed similarities between Boulder/Ft. Collins (I honestly don’t think you’ll find a much better pair of cities for UHI testing), has anyone looked at population growth/temperatures for Loveland (assuming they’re available) and compared them to these two cities? If the growth rate is significantly different from Ft. Collins, it’d make an excellent comparison as NO ONE should argue about the similarities of the two cities (assuming the monitoring sites are reasonably similar.) Just a thought.
-Scott
Steve Goddard (22:27:14)
Having at your suggestion looked more closely at the data, I agree that there is a discontinuity. My analysis shows the discontinuity is in January 1942.
However, this does not mean that the increase starts in 1970. We can see this in the trends of the Ft. Collins minus Boulder data.
The trend 1897 through December 1941 is 0.20°C/decade.
The trend February 1942-2009 is 0.20°C/decade.
The trend 1970-2009 is 0.19°C/decade.
On the other hand, the trend 1897-2009 is 0.11°C/decade, because of the discontinuity.
To find the discontinuity, I used a simple method. I fit a linear regression to the part of the difference series before the month being tested, and another linear regression to the part of the series after the month being tested. I add the residual sum of squares of both linear fits.
This test is repeated for all months of the time series, and the month with the lowest residual sum of the squares is the month with a potential discontinuity. That gave me the location of the discontinuity, which was January 1942.
w.
By the way, you can use the same method to determine (by trial and error) the amount of the discontinuity. In this case, it is a step change in January 1942 of ~ 0.6°C. Unfortunately, correcting for the step change in the differences destroys the correlation with the Spencer algorithm … go figure.
w.
A general point
Can anybody comment on the remarkable absence of any work on the other data-series that have been collected along with the thermometer readings? I am thinking of baro pressure, humidity, windspeed & direction, cloud cover/sunlight records, as well as rainfall.
After all, if we are looking for evidence of the changing bio-environment, to my mind it is more likely to be defined by changes in precipitation patterns than these increasingly suspect air-thermometer records.