Measure UHI in your town with this easy to use temperature datalogger kit

Readers may remember a couple of weeks back when I lamented that the downward economy had finally caught up to me and my little weather business. I asked readers if they’d mind if I’d showcase a weather station or two to help drum up some business. Nobody objected and many readers were very helpful and sympathetic. Thank you sincerely.

I always like to find ways to bring meteorological and climate science to the layman, hence this blog. My specialty is instrumentation, and readers may recall back in fall 2008 when I rigged up my vehicle with an NIST calibrated data logger, window mounted Gill IR shield, and a live connection to my laptop and drove a transect to measure the surface temperature. The result was this first ever graph of Reno’s UHI (Urban Heat Island) signature:

Click for larger image

That little experiment garnered quite a few comments, and I always wanted to find an inexpensive way for others to recreate what I did without having to invest in a high priced NIST calibrated probe, IR shield, datalogger, and laptop, all told which would run about $1200. That’s beyond the means of many people who might take an interest. It’s also well beyond the means of most students who might want to do something like this for their local science fair in their own hometown.

I’m pleased to say I have devised a solution for about 1/10th the cost, and I’ve just finished testing it in my hometown of Chico, CA. The results follow.

As many readers know, I sell some nifty USB dataloggers, and you may have seen this ad on the right sidebar which links to my online store.

USB Temperature Datalogger - small, compact, inexpensive, easy to  use. Many models available.

The dataloggers are inexpensive, mostly under $100, and work great for various monitoring applications where you want to gather and evaluate temperature data. Problem is, they had no way to be mounted to anything easily, and I couldn’t see an easy way to mount one to a vehicle like I did with the IR Gill shield:


The NIST calibrated temperature sensor (inside the Gill IR shield) mounted on the vehicle using an improvised window mount., Cable goes to datalogger inside, and datalogger connected to laptop.

My goal has always been to recreate this inexpensively and reliably so many of you could map UHI in your own city. Making this within reach of students and their parents was the ultimate goal. How does $84.95 sound compared to $1200? You don’t even need to take a laptop in the vehicle with you.

Some days, serendipity strikes. A discussion about US flags with fellow blogger Russ Steele made me think about this idea of using the window flag mounts commonly seen en-route to football and baseball games:

Except my version has no team flag, it flies a datalogger instead:

The window mount holds the USB datalogger up and away from the vehicle in the clear airstream.

How’s that for simple?

I spent today working this product idea out and testing it to make sure it is simple enough for anyone to recreate anywhere. Then I ran some road tests. Here’s how it works.

First we start with the USB-2 Temperature and Humidity datalogger. The reason I chose this unit over a temperature-only USB-1 version is that it already has a built in mini IR shield that allows free airflow. It reacts faster for that reason.

Next I provide a modified vehicle window mount and mounting hardware specifically to keep the USB-2 datalogger affixed, click images to enlarge:

Adhesive Velcro strip plus a removable secure strap worked best:

I ran some tests to see if I could fling the datalogger off the end. It held even after inflicting a few G’s on it at arms length.

Here’s the finished product:

The next test was to see if the datalogger was far enough out of the vehicle slipstream to prevent any temperature contamination while moving. That was evident from the data right away.

I did four daytime driving transects of my town to see if there were any hiccups or gotchas with install, driving, removal, and data download. Finding none, I wrote up some instructions:

Measuring UHI in your city:

  1. Install the software on your Windows PC (or laptop if you bring it with you in the car). Experiment with and familiarize yourself with the datalogger.
  2. Choose a route you can drive in your town that provides a good north-south and/or east-west driving transect from country, through suburbs, downtown, and back to countryside again. Use Google Earth or a similar mapping tool to assist in planning your route. Try to choose a route that will not take any more than 30 minutes to minimize ambient temperature change that may occur.
  3. Choose a clear night with no wind or light wind if possible. Later at night like 11PM-midnight is best so as to have minimum traffic and stoplights.
  4. Set the data logger to start logging either immediately or at some start time in the future. Put the waterproof cap back on
  5. Affix the datalogger to the vehicle mount using the strap provided.
  6. Put the vehicle mount on the top edge of your vehicle window and close it for a tight fit.
  7. Drive to the start point, Either wait for the pre-programmed start time or trigger the data logger to start from your laptop. It is always best to start on an easy to check period like top of the hour, quarter hour, or half hour.
  8. Drive the route, trying to maintain a fixed speed.
  9. Have your passenger note landmarks/locations in a logbook as you drive so that you can correlate with temperatures later.
  10. Optional – take a logging GPS unit with you if you want exact positions and time.
  11. Once completing the first transect, turn around and drive it again. You may wish to do several transects if time allows so that you can create an average profile later.
  12. Remove the USB-2 datalogger from the vehicle mount, plug into your PC, launch the included software and plot your results! Export the data to a spreadsheet for further analysis.

Saturday night, April 3rd, I ran my first for real UHI transect on Highway 99 from Garner Lane North of town to Neal Road South of town. I chose these points because they were safe places to turnaround and because they were both well enough removed from the population center that I expected they would approximate “rural” conditions.

After driving a transect and reverse driving it again, here is what the datalogger showed from the program that ships with the datalogger:

As you can see, the red temperature curve shows two humps, these are the two transects mirrored. First one was driving NW to SE, and the reverse (second) was SE to NW. Humidity and dewpoint are also displayed. The temperature looks a little blocky becuase the resolution of the datalogger is 0.5°C. However, given the world’s surface data is measured to the nearest degree, this is more than adequate for the purpose.

My home weather station (in town) showed light winds less than 5mph from the southeast and 50°F (10°C) when I left. Skies were clear. It was a good evening to measure UHI.

I took a voice recorder with me to note the time I started driving and the time I turned around and reversed the transect. I drove the reverse transect about 10mph faster because the first transect I didn’t want to pass a semi truck (speed limit 55mph for trucks through town) and pick up any waste heat, so I held well behind it.

Next I exported that data into my favorite graphing program ( DPlot ) and edited the starting and ending data times based on my recorder notes. I had set the datalogger at home to automatically start at 8:45 PM and I hadn’t reached my Garner lane start point yet. My actual transect began at 8:47 PM from Garner Lane at Highway 99 intersection.

Both temperature transects graphed, with annotations - click to enlarge

Then I pulled up my Google Earth and started exporting some images for reference. Here’s the normal map view of the transect with starting and ending points:

Chico, CA showing Highway 99 and transect start-end points - click to enlarge

And here’s the NW to SE driving transect overlaid onto a Google Earth 3D image looking NE so that Highway 99 appears as a “x- axis”:

As you can see, the graph matches the infrastructure character of the town fairly well, with the peak coinciding with the center of town (marked by the crosshair and label). The temperature is less in the rural outskirts of town.

So there we have it, it appears that my small college town of ~ 80,000 people has a UHI value of about 1.5°C (2.7°F) via this transect. The second return transect from SE to NW has the same magnitude, but is offset due to ambient temperature drop that occurred during the drive. When I returned home at 9:30PM, and hour later my home weather station had dropped to 44°F.

So would you like to do this for your hometown? Do you have a son/daughter nephew/niece that would benefit from a weekend science project learning about how to measure temperature and graph it to show UHI? Or, maybe you just want to do it yourself for fun and quantify what you’ve noticed for years via your automobile thermometer.

I’ll be happy to post any results here.

The only real caveat to this experiment is: don’t stop your vehicle if you can help it. Without a constant airstream, some waste heat from the vehicle might make its way to the sensor. Choose your driving route to avoid long stoplights, and I’ve found that in many cities after 11PM certain thoroughfares are “greenlighted”.

If you like this little idea or know somebody who would, please feel free to buy my little UHI measurement kit at a price most anyone can afford: $84.95 It helps me and provides more data that shows UHI to be a real, measurable, effect.

Here is the link to purchase the kit:

And yes, I do ship internationally.

Thanks for your consideration, happy motoring! – Anthony

UPDATE: Hu McCulloch reminds me of the similar experiment Warren Meyer and his son did a couple of years ago which you can read about here:

Some commenters were concerned about contamination of the data due to the vehicle. This is possible, even likely, at a dead stop. But at highway speeds of 60 mph or even street speeds of 30 mph any such contamination gets swept away in the slipstream. Essentially the thermometer has turbocharged aspiration, and is measuring the true temperature of the air being intersected. There may be issues with wast heat from vehicles ahead, but if you drive carefully and avoid tailgating, this can be avoided. Doing multiple transsects over time and averagign the runs is another way to minimize such biases.


The raw data from the USB datalogger is below, note the date format is dd/mm/yyyy.

ChicoUHILogger,Time,Celsius(°C),Humidity(%rh),dew point(°C),Serial Number

1,03/04/2010 20:45:00,9.5,58.5,1.8,010004039

2,03/04/2010 20:45:10,9.5,59.0,1.9

3,03/04/2010 20:45:20,9.5,59.5,2.0

4,03/04/2010 20:45:30,9.5,59.5,2.0

5,03/04/2010 20:45:40,9.0,60.5,1.8

6,03/04/2010 20:45:50,9.0,60.5,1.8

7,03/04/2010 20:46:00,9.0,61.0,1.9

8,03/04/2010 20:46:10,9.0,60.5,1.8

9,03/04/2010 20:46:20,9.0,61.0,1.9

10,03/04/2010 20:46:30,9.0,61.0,1.9

11,03/04/2010 20:46:40,9.0,61.5,2.0

12,03/04/2010 20:46:50,9.0,61.5,2.0

13,03/04/2010 20:47:00,8.5,62.5,1.8

14,03/04/2010 20:47:10,8.5,63.0,1.9

15,03/04/2010 20:47:20,8.5,63.0,1.9

16,03/04/2010 20:47:30,8.5,62.5,1.8

17,03/04/2010 20:47:40,8.5,62.0,1.6

18,03/04/2010 20:47:50,8.5,60.5,1.3

19,03/04/2010 20:48:00,8.5,60.5,1.3

20,03/04/2010 20:48:10,8.5,60.5,1.3

21,03/04/2010 20:48:20,9.0,60.0,1.7

22,03/04/2010 20:48:30,9.0,59.5,1.5

23,03/04/2010 20:48:40,9.0,59.0,1.4

24,03/04/2010 20:48:50,9.0,58.5,1.3

25,03/04/2010 20:49:00,9.0,58.0,1.2

26,03/04/2010 20:49:10,9.0,58.0,1.2

27,03/04/2010 20:49:20,9.5,57.5,1.5

28,03/04/2010 20:49:30,9.5,57.0,1.4

29,03/04/2010 20:49:40,9.5,57.0,1.4

30,03/04/2010 20:49:50,9.5,56.5,1.3

31,03/04/2010 20:50:00,9.5,56.5,1.3

32,03/04/2010 20:50:10,9.5,56.5,1.3

33,03/04/2010 20:50:20,10.0,56.5,1.8

34,03/04/2010 20:50:30,10.0,56.5,1.8

35,03/04/2010 20:50:40,10.0,56.0,1.6

36,03/04/2010 20:50:50,10.0,55.5,1.5

37,03/04/2010 20:51:00,10.0,55.5,1.5

38,03/04/2010 20:51:10,10.0,55.5,1.5

39,03/04/2010 20:51:20,10.0,55.5,1.5

40,03/04/2010 20:51:30,10.0,55.5,1.5

41,03/04/2010 20:51:40,10.0,55.5,1.5

42,03/04/2010 20:51:50,10.0,56.0,1.6

43,03/04/2010 20:52:00,10.0,56.5,1.8

44,03/04/2010 20:52:10,10.0,56.0,1.6

45,03/04/2010 20:52:20,10.0,56.5,1.8

46,03/04/2010 20:52:30,10.0,56.0,1.6

47,03/04/2010 20:52:40,10.0,55.5,1.5

48,03/04/2010 20:52:50,10.0,55.0,1.4

49,03/04/2010 20:53:00,10.0,54.5,1.3

50,03/04/2010 20:53:10,10.0,54.5,1.3

51,03/04/2010 20:53:20,10.0,54.5,1.3

52,03/04/2010 20:53:30,10.0,55.0,1.4

53,03/04/2010 20:53:40,10.0,54.5,1.3

54,03/04/2010 20:53:50,10.0,54.5,1.3

55,03/04/2010 20:54:00,10.0,54.5,1.3

56,03/04/2010 20:54:10,10.0,55.0,1.4

57,03/04/2010 20:54:20,10.0,55.5,1.5

58,03/04/2010 20:54:30,10.0,55.5,1.5

59,03/04/2010 20:54:40,10.0,57.0,1.9

60,03/04/2010 20:54:50,10.0,57.0,1.9

61,03/04/2010 20:55:00,10.0,57.5,2.0

62,03/04/2010 20:55:10,9.5,58.0,1.7

63,03/04/2010 20:55:20,9.5,58.0,1.7

64,03/04/2010 20:55:30,9.5,58.0,1.7

65,03/04/2010 20:55:40,9.5,57.5,1.5

66,03/04/2010 20:55:50,9.5,57.5,1.5

67,03/04/2010 20:56:00,9.5,58.5,1.8

68,03/04/2010 20:56:10,9.5,58.5,1.8

69,03/04/2010 20:56:20,9.5,59.5,2.0

70,03/04/2010 20:56:30,9.5,60.0,2.1

71,03/04/2010 20:56:40,9.0,60.5,1.8

72,03/04/2010 20:56:50,9.0,60.5,1.8

73,03/04/2010 20:57:00,9.0,61.0,1.9

74,03/04/2010 20:57:10,9.0,61.0,1.9

75,03/04/2010 20:57:20,9.0,61.0,1.9

76,03/04/2010 20:57:30,9.0,61.5,2.0

77,03/04/2010 20:57:40,9.0,61.5,2.0

78,03/04/2010 20:57:50,9.0,61.5,2.0

79,03/04/2010 20:58:00,9.0,61.0,1.9

80,03/04/2010 20:58:10,9.0,61.0,1.9

81,03/04/2010 20:58:20,9.0,61.0,1.9

82,03/04/2010 20:58:30,9.0,61.0,1.9

83,03/04/2010 20:58:40,9.0,60.5,1.8

84,03/04/2010 20:58:50,9.0,61.0,1.9

85,03/04/2010 20:59:00,9.0,60.5,1.8

86,03/04/2010 20:59:10,9.0,60.5,1.8

87,03/04/2010 20:59:20,8.5,61.0,1.4

88,03/04/2010 20:59:30,8.5,62.0,1.6

89,03/04/2010 20:59:40,8.5,62.5,1.8

90,03/04/2010 20:59:50,8.5,62.5,1.8

91,03/04/2010 21:00:00,8.5,62.5,1.8

92,03/04/2010 21:00:10,8.5,62.5,1.8

93,03/04/2010 21:00:20,8.5,63.0,1.9

94,03/04/2010 21:00:30,8.5,63.0,1.9

95,03/04/2010 21:00:40,8.5,64.0,2.1

96,03/04/2010 21:00:50,8.5,64.5,2.2

97,03/04/2010 21:01:00,8.5,64.0,2.1

98,03/04/2010 21:01:10,8.5,64.0,2.1

99,03/04/2010 21:01:20,8.5,64.0,2.1

100,03/04/2010 21:01:30,8.0,64.5,1.7

101,03/04/2010 21:01:40,8.0,65.0,1.8

102,03/04/2010 21:01:50,8.0,65.5,1.9

103,03/04/2010 21:02:00,8.0,66.0,2.0

104,03/04/2010 21:02:10,8.0,66.0,2.0

105,03/04/2010 21:02:20,8.0,66.5,2.2

106,03/04/2010 21:02:30,8.0,65.5,1.9

107,03/04/2010 21:02:40,8.0,64.5,1.7

108,03/04/2010 21:02:50,8.0,65.0,1.8

109,03/04/2010 21:03:00,8.0,66.0,2.0

110,03/04/2010 21:03:10,8.0,66.0,2.0

111,03/04/2010 21:03:20,8.0,66.0,2.0

112,03/04/2010 21:03:30,8.0,66.0,2.0

113,03/04/2010 21:03:40,8.0,65.0,1.8

114,03/04/2010 21:03:50,8.0,64.0,1.6

115,03/04/2010 21:04:00,8.0,63.5,1.5

116,03/04/2010 21:04:10,8.0,63.0,1.4

117,03/04/2010 21:04:20,8.0,62.0,1.2

118,03/04/2010 21:04:30,8.5,61.0,1.4

119,03/04/2010 21:04:40,8.5,61.5,1.5

120,03/04/2010 21:04:50,8.5,61.0,1.4

121,03/04/2010 21:05:00,8.5,60.5,1.3

122,03/04/2010 21:05:10,8.5,60.5,1.3

123,03/04/2010 21:05:20,8.5,60.0,1.2

124,03/04/2010 21:05:30,9.0,60.5,1.8

125,03/04/2010 21:05:40,9.0,61.5,2.0

126,03/04/2010 21:05:50,9.0,61.0,1.9

127,03/04/2010 21:06:00,9.0,61.0,1.9

128,03/04/2010 21:06:10,9.0,61.0,1.9

129,03/04/2010 21:06:20,9.0,61.0,1.9

130,03/04/2010 21:06:30,9.0,60.5,1.8

131,03/04/2010 21:06:40,9.0,60.0,1.7

132,03/04/2010 21:06:50,9.0,59.5,1.5

133,03/04/2010 21:07:00,9.0,59.0,1.4

134,03/04/2010 21:07:10,9.0,59.0,1.4

135,03/04/2010 21:07:20,9.0,59.0,1.4

136,03/04/2010 21:07:30,9.0,58.5,1.3

137,03/04/2010 21:07:40,9.0,58.5,1.3

138,03/04/2010 21:07:50,9.0,58.5,1.3

139,03/04/2010 21:08:00,9.0,58.0,1.2

140,03/04/2010 21:08:10,9.5,58.0,1.7

141,03/04/2010 21:08:20,9.5,57.5,1.5

142,03/04/2010 21:08:30,9.5,57.5,1.5

143,03/04/2010 21:08:40,9.5,57.0,1.4

144,03/04/2010 21:08:50,9.5,57.0,1.4

145,03/04/2010 21:09:00,9.5,57.0,1.4

146,03/04/2010 21:09:10,9.5,57.0,1.4

147,03/04/2010 21:09:20,9.5,57.0,1.4

148,03/04/2010 21:09:30,9.5,57.0,1.4

149,03/04/2010 21:09:40,9.5,57.0,1.4

150,03/04/2010 21:09:50,9.5,57.0,1.4

151,03/04/2010 21:10:00,9.5,56.5,1.3

152,03/04/2010 21:10:10,9.5,57.0,1.4

153,03/04/2010 21:10:20,9.5,57.0,1.4

154,03/04/2010 21:10:30,9.5,57.0,1.4

155,03/04/2010 21:10:40,9.5,59.0,1.9

156,03/04/2010 21:10:50,9.5,61.0,2.4

157,03/04/2010 21:11:00,9.5,61.5,2.5

158,03/04/2010 21:11:10,9.0,61.0,1.9

159,03/04/2010 21:11:20,9.0,61.0,1.9

160,03/04/2010 21:11:30,9.0,61.0,1.9

161,03/04/2010 21:11:40,9.0,62.0,2.1

162,03/04/2010 21:11:50,8.5,62.0,1.6

163,03/04/2010 21:12:00,8.5,62.5,1.8

164,03/04/2010 21:12:10,8.5,63.0,1.9

165,03/04/2010 21:12:20,8.5,63.5,2.0

166,03/04/2010 21:12:30,8.5,64.0,2.1

167,03/04/2010 21:12:40,8.5,63.5,2.0

168,03/04/2010 21:12:50,8.0,63.5,1.5

169,03/04/2010 21:13:00,8.0,64.0,1.6

170,03/04/2010 21:13:10,8.0,64.0,1.6

171,03/04/2010 21:13:20,8.0,64.5,1.7

172,03/04/2010 21:13:30,8.0,65.5,1.9

173,03/04/2010 21:13:40,8.0,65.0,1.8

174,03/04/2010 21:13:50,8.0,64.0,1.6

175,03/04/2010 21:14:00,8.0,63.5,1.5

176,03/04/2010 21:14:10,8.0,63.0,1.4

177,03/04/2010 21:14:20,8.0,62.5,1.3

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April 4, 2010 1:02 am

Great work – I doubt if Phil Jones or David Parker could have done this from their warm offices though instead of playing around with dodgy datasets about windspeeds to find the conclusion they wanted. I don’t drive but I encourage all to do this!
REPLY: Thanks. You could do this on a bicycle just as easily. As long as you keep the airflow going you’ll get a result. Yeah those guys at the top of the climate foodchain, particularly Parker, need a swift kick in the butt to get out of their office and do some real-world measurements. – Anthony

Peter of Sydney
April 4, 2010 1:29 am

Now imagine of just a one percent of cars had this system installed in several countries around the world. We would have the best method of measuring real temperature at the surface. The job of collating, processing, filtering, analyzing and reporting would be an issue but it would be far more accurate than the stationary temperature stations that are next to air-conditioners, parks, etc.

April 4, 2010 1:38 am

Since the data has a timestamp, it would be great to match it with GPS data. I’m sure the WUWT community would com up with a solution that could even plot it on Google maps! Just some software for merging the GPS data and your datalogger would be needed…

April 4, 2010 1:47 am

Very impressive.
Is this a recognised method of measuring UHI or is there an element of innovation?
How does the results with the inexpensive kit compare to those with the expensive kit?
Can you yet say whether there’s a discrepancy between the official correction for UHI for your home town and the correction your instrumentation would indicate is appropriate?
One thing about an improvement in instrumentation and access to it is that it doesn’t favour one side of the argument over the other.

Valter Ström
April 4, 2010 2:27 am

Wonderful. Absolutely.
Wonderful combination of imagination, creativity and ability.
This and similar activity, if widely spread, should remove much of the nimbus in AGW.
I have a suggestion for improvement though, concerning the temperature measurement. Many of you may know that Analog Devices sell an absolute temperature controlled current generator AD590. It is an IC for, say, ca$10 (?).
Once I selected the series resistor for optimum current measurement for the voltmeter I had at hand with 1 microvolt resolution. The result showed 1 mK resolution. I am not joking, it immediately became clear I could follow temperature variations with 0.001 K resolution.
Obviously, many considerations are important in this case, I am merely indicating that many useful variations could be implemented.
Keep up the wonderful work,
Stockholm, Sweden

There’s a voltage datalogger with 0-30v range also available. Your idea could work with that but the output would be noisy

April 4, 2010 2:28 am

Nice idea except for one thing: BIASES introduced by the surroundings.
I’m surprised that you’d —on the one hand— criticize the feds over their selection of specific weather stations, while on the other not consider the biases which will be introduced by so many uncontrollable factors such as the temperatures of:
— the pavement
— the vehicle
— the driver (who might be breathing heavily)
— the passengers (who might also be breathing heavily)
— passing vehicle exhausts
— wind currents which might cause the air temperature to remain static
— the surrounding topology of buildings, etc.
I like your idea, but in order for it to garner ~any~ degree of the scientific, one would have to have a fleet of identical vehicles AND a cameras facing all degrees of the compass such as to capture the lay of the land, and traverse the same route for several hours each day so as to acquire a replicative set of measurements.

April 4, 2010 2:36 am

We have started “keeping and eye on UHI” using a normal in-car external temperature sensor, but have always been concerned about how accurate it might be. Hmm, might have to sgn up for one of these.
Looking at Guam, I was always puzzled by the huge 1.5 degree C rise in temperature in WSMO Agana:
Wsmo Agana, G   13.6 N 144.8 E 529912170000 rural area 1956 – 2004
Having found the station location and evidence for population growth in the area, in the light of what you have shown here the ‘rural’ station location was certainly close enough to growing houseing developments to be affected by the increasing urbanisation before it was shut down. link

April 4, 2010 2:50 am

Of course, if the Governements of the world were really keen on working out U.H.I , they would put these on Public service cars. But i suppose the problem is that they are idle most of the time, not doing any work, so the result would be debatable. Haha.
It would be great to get a National Taxi Service behind this, maybe we can get a grant from the Greenhouse Office(Australia) or Obama’s Green Mafia mob.
Also another suggestion would be a National Trucking line. surely someone knows someone that could help this happen. A lot of these guys are G.P.S monitered, so it would collate???

April 4, 2010 3:13 am

Isn’t it relevant what kind of weather it is or was during the day? I would presume that an urban heat effect would be greater when sunny, be affected by wind direction, be influenced by rain etc. Would be interesting to do a few trips to measure this?

April 4, 2010 3:18 am

Off topic – but this is just the last in a succession of scandalous behaviour by our Scottish politicians.
MSPs fly out on £30,000 business-class ‘jolly’ – to talk about climate change

At a time when Scotland faces spending cuts of up to £3 billion in its budget, the parliament will today send four MSPs and two officials on a trip to New York, Boston and Washington DC.
The business-class transatlantic flights are costing in excess of £10,000, while accommodation has been booked in some of the best hotels.
The trip – described last night as an unnecessary, taxpayer-funded “jolly” – has been arranged as part of Tartan Week, even though the Scottish Government is already sending three ministers to take part in the celebrations in New York.

A C Osborn
April 4, 2010 3:25 am

899 (02:28:44) : BIASES introduced by the surroundings.
THAT is exactly what you are trying to measure, that is what UHI is.
Anthony, why not compare daytime UHI to Nighttime UHI?
REPLY: Sure why not, the beauty is that this simple system allows for different investigations. But mostly the night time signal is affected due to re-radiation of stored daytime heat as IR. Daytime UHI will be there, but lower in magnitude. – A

April 4, 2010 3:26 am

There is a lot you could do with this if it was integrated into a neural network/fuzzy logic system and monitored at single locations over a long time scale (year+). You would need at least two dataloggers – one close to the actual UHI affected station and one or more upwind/downwind of prevailing winds along with hourly(?) readings from the ASOS/MMTS/wind direction/speed/insolation.
As neural nets look at and learn from complex relationships, such an integrated system would evenually integrate the UHI affecting the actual sensor under a wide variety of temperature/weather combinations thoughout the year and could, for current systems at least, give a very accurate and real time correction. It would however be site specific. There is probably a grant proposal in this for someone.

April 4, 2010 3:33 am

Anthony, this is a great idea and if I didn’t already have a room full of temperature monitoring gear I’d buy one!

April 4, 2010 3:35 am

Nice instrument! It should be trivial to either write one’s own small program to log both position and temperature/humidity or alternatively logging both separately and match later based on time. I have to get one for my father, he is old but he serely would like to do a number of test runs around Helsinki (Finland). Me driving both chatting 🙂 .

Mike McMillan
April 4, 2010 3:38 am

I was thinking of doing this two years ago, but I was concerned about the response time and the .5 degree precision. Thought about a digital meat thermometer with .1 degree precision, but the one I had burned up in the oven.
REPLY: A logging meat thermometer? I think not. – A

April 4, 2010 3:42 am

— the driver (who might be breathing heavily)
— the passengers (who might also be breathing heavily)
Before picking fault, look at the photographs – the windows are up.
REPLY: More than that, even if the windows were down, at 60mph explain how a small breath is going to reach up to the sensor instead of getting sucked into the slipstream and instantly pushed downwind fast. – A

April 4, 2010 3:47 am

Transects which center roughly on weather stations would certainly be enlightening.

April 4, 2010 3:50 am

I think I would like to do several of Burlington, VT and Plattsburgh, NY. Two cites about fifteen miles from each other, one of which has experienced high economic growth and “global warming,” and the other of which lost a large air force base, has experience modest growth at best, and does not seem to show much “global warming.”

Chris Wright
April 4, 2010 4:26 am

A really great idea. As TJA says, it would be really useful to monitor UHI for the stations documented by SurfaceStations.
As far as I understand it, the IPCC effectively discounts UHI, possibly on the basis of a paper by Parker that used wind monitoring. To use such an indirect method seems bizarre when it’s so easy to measure UHI directly.
Anthony measured a UHI of 1.5 degrees. The presenter of the BBC Climate Wars series measured a UHI of several degrees at Las Vegas.
These UHI measurements are consistently much larger than the total claimed global warming of 0.7 degrees. Houston, we have a problem….

April 4, 2010 4:36 am

Good start on creating a global real-time dataset. No doubt the alarmists will mount the temperature sensors on the car’s exhaust pipe to achieve the results they expect.

April 4, 2010 4:43 am

Years ago on one of my many trips to sunny California, we were crusing around downtown LA , and in Hollywood with the roof down on our beautiful Mustang convertible rent-a-car. It was so hot in fact that we had to head for the beach in Santa Monica, a short 5 mile drive. On the way, once we started to escape the UHI from LA core,the temperature took a notable drop. By the time we got to Venice Beach, we had to stop and put up the roof and try and get warm. I couldn’t believe the difference in temperature. LA is in a giant basin where the heat can’t escape, but once you head toward the ocean, that is where you will get a real temperature reading. It just simply demonstrates the UHI on a massive scale in one localized area of the planet.
Fortunatly I doubt if there are any weather stations in or around the downtown area as they would be easily compromised. The UHI is real for sure.
I think it is impotant for all to remember that the planet is 70% water, and 27% desert or ice caps. With only 3% of the planet available for supporting human industrialization it isn;’t likely we can have any real effect on its climate. Also, only about 1/3 rd of the planet have access to electricity and/or running water, so we can eliminate their ” carbon footprint” . Which leaves a tiny part of the planet which is industrialized. Think about that , the next time you fly anywhere….just lean over and look out the window. The entire population of the planet could fit in an area of about 20 square miles ( not comfortably or realistically, but just a comparison )
All the best guys:

April 4, 2010 5:07 am

Hell, I ain’t going to whip up any datasets or such, but I’m going to buy one just for the absolute neatness of the concept. I’ve used the temperature only unit for a couple of months, it’s kinda addicting. Now I need humidity measurement! Jeez that a recording barometer could be so inexpensive…

Douglas DC
April 4, 2010 5:13 am

Here in La Grande, Oregon in the Northeast Mountains, I have noted the Temps involved with the local METAR stations and the AWAS at the local Airport. Last year in January I noted that while the Airport which is out in the Grande Ronde Valley , and has some but not much, in the way of physical plant activity is Two to Six degrees colder than my neighborhood- sometimes as much as ten. Around me I have the Hospital, Junior and Senior high Schools and six blocks distant is the University. All with physical plants running 24/7 it is as much as a whole climate Zone difference here. The Airport seems to run USDA zone 5 and we here in south La Grande Zone 6. The rest of the area seems to be zone 5 a&b though we are higher than the Airport. UHE is Real and Anthony, you deserve a cheer for helping US out and this article is a simple solution to a problem- great article…

amicus curiae
April 4, 2010 5:14 am

Nifty item anthony! and only one error…
it didnt take millions in funding/grants etc.
so of course it will be panned.
it didnt cost enough!
off topic, but you asked about OLd Sci am etc mags for folks to check old weather etc items?
friend in aus managed to geta stack from 1963 4 5 6 7 and early 70s.
her ebay store is EdenhopeAntiques, she could be mailed via there, I asked her to hold off adding them until wuwt folks had a chance, she was considering cutting them up:_( seems some folks collect old adverts. I shudder! destroying history for an ad?? I hope this may help someone who can afford them and has the time and knowledge.

April 4, 2010 5:18 am

Great job! Blogreaders may recall that Coyote’s (Climate Skeptic’s) son did something similar in Phoenix for his science fair a couple of years ago:, but this sounds simpler and less expensive.
It would be important to record altitude and do a standard adjustment for it — many downtowns are on rivers, so that altitude rises in both directions from the center. The picture of your route seems to indicate that the S end was in the foothills.
Latitude could also be an issue. Driving 30 miles NS doesn’t seem like far, but it takes you about 1% of the way to the N pole!
I would trust ducttape over velcro for an $85 instrument. Would this be unsatisfactory?
Daytime UHI would be interesting as well, if one could find a route with little traffic. Are freeways adequate routes, or do they create their own UHI?
REPLY: Yes Warren Meyer and his son did a similar project, thanks for the reminder, I’ll add it. A lot of that metadata can be solved using an onboard logging GPS that also records altitude. My original UHI roadkit used GPS but again my goal was to put this within reach of many financially.
Duct tape holds well but is a pain to remove and leaves a residue. This little velcro strip and clamp leaves none and the unit can be released from the mount without any fuss trying to find a seam. – A

April 4, 2010 5:18 am

Have you allowed for possible cooling effects on the sensor of varying ground-speeds (and effective “airspeeds”) of the vehicle? Or is the fact that your UHI effect was measured at 1.5C both ways considered sufficient proof that this changes nothing?
REPLY: AT 60 mph it becomes a turbocharged aspirated thermometer. If you’ve ever ridden a motorcycle at night you’ll understand this experiment better. – Anthony

Atomic Hairdryer
April 4, 2010 5:39 am

Re 899 (02:28:44) :
Nice idea except for one thing: BIASES introduced by the surroundings.

But more data is better than less data for understanding and quantifying UHI effects, especially as the current approved methods are very crude.
I like the idea of getting these fitted to fleets. Government vehicles could be a good candidate, especially if they’re already fitted with GPS trackers and time/location can be correlated with the temperature sensor data. This seems a low cost method of gaining data, especially given the funding for global warming being thrown around.

John Finn
April 4, 2010 5:42 am

Chris Wright (04:26:54) :
A really great idea. As TJA says, it would be really useful to monitor UHI for the stations documented by SurfaceStations.
As far as I understand it, the IPCC effectively discounts UHI, possibly on the basis of a paper by Parker that used wind monitoring. To use such an indirect method seems bizarre when it’s so easy to measure UHI directly.
Anthony measured a UHI of 1.5 degrees. The presenter of the BBC Climate Wars series measured a UHI of several degrees at Las Vegas.
These UHI measurements are consistently much larger than the total claimed global warming of 0.7 degrees. Houston, we have a problem….

We know that the UHI effect exists. Most of us have experienced it at sometime in our lives, particularly during very hot or very cold weather. During hot wearther, night-time temperatures in urban areas are often several degrees higher than rural areas. This, however, is not the issue.
The real question is whether the UH effect has contaminated the readings at the same location over the last 50 to 100 years and whether this has had a significant influence on the global surface temperature trend. The evidence suggests not.
1. The oceans (i.e. ~70% of the earths surface), which are not subject to UHI effects, have warmed.
2. The satellite (LT) temperature trends broadly agree with the surface temperature trends.
It’s unlikely that a UH effect can account for any more than a couple of hundredths of a degree in the global trend. Just after the climategate episode, I warned that sceptics were tending to focus far too much on the validity of the surface records and that this might result in a lost opportunity. The recent UK enquiry suggests I was right. The world has warmed over the past several decades. Arguing against this fact is futile.

April 4, 2010 5:51 am

What do you think UHI stands for?

Henry chance
April 4, 2010 5:57 am

Great idea. The temp reading build in my car varies as much as 8-9 degrees. It really drops when leaving a paved road.

April 4, 2010 6:07 am

I’ll need one of those global warming grants.

April 4, 2010 6:07 am

Off subject…but possibly applicable regarding light winds observed at airports.
For Mr. Watt’s consideration… Wind data from ASOS observation sites…taken by the new ultrasonic Ice Free Wind Sensors…are being messed up by birds and possibly bats. I have to edit the data frequently during light wind conditions, when a Hawk, or other Raptor perches on the top of the sensor head, then dives down to catch its prey. So a lot of gusts of 40 to 70 mph when prevailing winds (2 minute) are running 3 to 7 mph are due to the birds, rather the true wind flow. We don’t have time to correct each site’s data in our area…so try to do so with our primary climate sites only. It is time consuming…and we aren’t always able to do so…(eyeball adjustments???)
Just thought you would like to know. The FAA and NWS are looking into trying to fix the problem…but so far nothing has worked. They are aware of what has been going on…but still haven’t come up with an answer. Also, this has been going on without letting the public know what is going on… Oh, for the old days, when you just had to determine whether the winds were light or calm…or the cups had become frozen… Back in the days of the F420 wind set… Just a heads up…
From an HMT somewhere along the east edge of the Rockies.

April 4, 2010 6:12 am

Despite the silly response by 899, this type of geographical observation has been used to study temperature change over various terrain, for instance, Karlsson 2000. TJA’s suggestion (measuring the areas around USHCN stations) should be taken seriously and added to the database, similar to what CDRG called for here:

April 4, 2010 6:13 am

Set them up with connections to sensors in swimming pools and watch the temp. in the pool water world wide, the pools will show up via google maps.
The locations will be able to be known by all.
The small weather station can be away from the pool area.
It is a great idea to sell weather stations to raise money for this blog.
Be sure the govt./govt’s are not messing with the supply of insturments.
I for one would not put it past them to rig the thermometers and or other
insturments to “hide their decline”.
Out in the “outback” , “ranch land” , and or no pool areas use stock tanks, tanks by water wells that serve livestock.
Never allow goverments to do those things you can do for yourself and you will remin free.
They can not fight say, 500,000 independent data sources that can be proved up as true and correct.

April 4, 2010 6:15 am

All merchent ships could be also rigged up with water temp. insturments and gather data from the ocean areas.

April 4, 2010 6:17 am

May I assume that this experiment would be invalid if conducted in direct sunlight? I would think that the absolute values would be off. I am not sure what the theory would say about relative values.
REPLY: At 60 mph highway speed or even at street speeds of 30 mph biasing effects of sunlight on the sensor housing would be negligible as any localized heating is carried off in the airstream. If your vehicle stops at a stoplight, then yes you’d have an issue but it will disappear once moving again. -A

Jeff L
April 4, 2010 6:17 am

Ecotretas (01:38:15) :
See :
This website converts a standard gpx file to a text file, including the time stamp. You could read the converted gpx file & data logger file both into Excel , sort on the time data & pair the lat longs with the temp data.
Then see this link:
This link has the format you will need, which could be generated out of Excel easily & allow you to plot the temp data on a map.
In general, I think the GPS Visualizer site has all the tools you need.
Anthony, if this UHI experiment takes off amongst the community, you might want to contact the guy who run the GPS Visualizer site (link on the website) & set up a little custom app to do all of this. You could set it up on the WUWT site as a separate page which users could both upload & visualize their data, as well as other datasets from around the world. With all those datasets, it might be possible to create a much better UHI correction (relating to town size, distance from center, time of day, etc).

April 4, 2010 6:17 am

Neat, I love ‘kiss’
lots of people will have time/distance datalogger they use when running/cycling. These tend to have a standard time/position dump that can be read by google maps/earth.
There’s an app for that too on iPhone etc (free & paid) …
So it is comparatively easy to get route/speed/velocity data & then just mash them all together.
And all you hams – this looks an ideal APRS project : strip the datalogs via APRS mesage……
Next step is obviusly to merge the temp/humidiy (what chance pressure ? ) with gps.
Anyone think of doing runs that take in (multiple) weather reporting stations ?
BTW here in the UK we are not allowed to drive any distance without having to stop; our traffic planners seem to think the best way to control traffic is to make it stop, especially on empty roads late at night

April 4, 2010 6:26 am

You could sell the info to “Lloyds of London”, Ins. exchange , as they need the real data info for setting ins. rates, it being the data they now recive is bs from goverments.
Others in need or real data would also be your customers.

anna v
April 4, 2010 6:29 am

Anthony you say : And yes, I do ship internationally.
But your indicative international postal charges are very scary.
It does say that there will be an e-mail approval but it is only that I trust you, after so long on this board, that I will send in an “179.95$ finalize sale” for a 79.95 item.
I often get stuff from and the postal rates are given on the spot while ordering, and are nowhere near 100$. For example for 3 books they are around 12euros.
If you want international customers you should get something like that.
REPLY: Yes sometimes the shipping calculator gets whacked. We’ll correct it. – Anthony

keith in hastings UK
April 4, 2010 6:37 am

Good stuff but surely what is at issue are two things: has UHI changed over time for a given thermometer (so giving misleading anomalies); and has the decline in rural stations produced false average anomalies because UHI absolutes have been under (or over/sarc) estimated (and corrected for properly)?
All data is useful, but measurements over a long time would be needed, really.
REPLY: And there’s no reason why the same transect can’t be driven many times at different times of the year. – A

Steve Goddard
April 4, 2010 6:40 am

If a few thousand people got these and someone set up a database where the information could be collected, it could be a tremendous source of valuable data.
Chico UHI numbers are very similar to what I typically see in Fort Collins.
When people start using these, it is important to take transects in a way that does not introduce systematic bias. Like in to downtown in the morning and out in evening, which would both tend to make downtown look warmer due to morning heating and evening cooling. The best approach is to transect the entire city like Anthony did.
I do my transects on a bicycle, which has the advantage of very low thermal mass, and I ride on devoted bike trails where I almost never have to stop.

April 4, 2010 6:51 am

Data can be obtained with older cheaper off the shelf instruments.
example google operation igloowhite
a electronic data collection system set up
in a jungle, in a war zone, in the rain of monsoons
it worked then, something like it can be done now in this case
under wiki

Jon Jewett
April 4, 2010 6:51 am

igloowhite (06:15:27) :
All merchent ships could be also rigged up with water temp. insturments and gather data from the ocean areas.
If (a big if) “they” wanted to instrument a merchant ship for both sea temperature and air temperature, it would be relatively simple. (or navy ships for that matter.)
Both steam and diesel powered ships use prodigous amounts of sea water for cooling. It would be necessary to prove that the quantity of water flow through the cooling system while at sea was enough to prevent a measurable thermal contamination, but should that prove to be the case, installing a termal probe would be simple. I would mount it in the intake piping between the main sea suction valve and the sea water circulating pump. Alternately, you could mount it on a manhole cover on the inlet of the largest cooler availavble, although you should prove first that there is little or no thermal contamination that far into the ship.
The air probe could be mounted on the radar/radio mast and it would be perhaps 100 feet above ocean surface.
An interesting project.
Steamboat Jack

DJ Meredith
April 4, 2010 7:03 am

What a fantastic thing to do, Anthony!
I’d like to help out and suggest that for anyone needing to do a clever ‘trick’ and splice data, Scotch brand Magic Tape is available at Walgreens for only $1.99. And just like the algorithms used by NOAA, CRU and all the others for adjusting data, Scotch Magic Tape is invisible.
Seriously though, I think this is one of those simple groundbreaking ideas that could crumble an AGW house of cards.
For me here in Reno, it could be very interesting to transect I-80 and 395 at 5pm, and 5am.

April 4, 2010 7:04 am

Slightly OT:
Given, as you say, the world’s surface data is measured to the nearest degree, how can they measure global anomalies of fractions of a degree?

Jeremy Thomas
April 4, 2010 7:21 am

John Finn (05:42:45)
“The real question is whether the UH effect has contaminated the readings at the same location over the last 50 to 100 years and whether this has had a significant influence on the global surface temperature trend. The evidence suggests not.

Surely the lesson of climategate is that the “evidence” has been comprehensively manipulated (homogenized) by propagandists.
That being the case, it makes a great deal of sense to collect data first hand as Anthony has done here. There are, after all, good reasons to suspect the 100 year record has been inflated by UHI, since during that time:
– world population has multiplied by a factor of about 4
– world GDP has multiplied by a factor of about 40
Both increases have largely been concentrated in cities.

Retired Engineer
April 4, 2010 7:25 am

My RHT-10 from Extech looks a whole lot like the one from Anthony’s store (got it before I started lurking here) but the software reads out in 0.1 degrees C. Cost the same, so perhaps 0.5C is only a software limit? The sample rate is programmable and the unit can hold 16,000 readings, all with nice time stamps. My USB gps unit coupled to a netbook can do the same, so no distractions while driving. Set it and go. Post process on a spreadsheet, the GPS data should allow removal or at least take note of any stops. Set the logger’s time from the PC (Windows now sync’s up with NIST, so the clock should be good), the GPS will have exact time, all should tally.
My only complaint is I didn’t think of doing this. 🙁
A new task for Anthony’s Army: let’s verify just what the hockey stick is going on. We’re pretty sure UHI is real, now we can get hard data.

Atomic Hairdryer
April 4, 2010 7:34 am

Steve Goddard (06:40:07) :
When people start using these, it is important to take transects in a way that does not introduce systematic bias. Like in to downtown in the morning and out in evening, which would both tend to make downtown look warmer due to morning heating and evening cooling. The best approach is to transect the entire city like Anthony did.

I think some of that is data vs analysis. If this could be widespread, then one source of data may be from people’s commutes. Those generally would be pretty consistent for time of day, route and provide data over a wider timespan than more formal survey type transects. With enough loggers, that should give a higher resolution heat map than we have currently. Seems a great way to improve data collection to me, if there’s an easy way to upload it for interested parties to crunch.

April 4, 2010 7:54 am

I just ordered mine. Anthony, what an awesome idea; can’t wait until my arrives.

April 4, 2010 7:56 am

A few comments:
1) On the USB-1, the temperature sensor is located close to the LEDs and under the cap. On the USB-2 the humidtiy/temperature sensor is located near the vents, so is a much better choice for this application.
2) Don’t leave any of these plugged into the USB port on a computer for any longer than necessary – the battery draw is 1500X greater on the USB port than when it’s logging data! (Details below)
3) I see there’s an “increased accuracy” model. Is that accuracy reflected in the logged data? what you link to from the web page is identical to the USB-2. Personally, I’d much prefer increased precision (the repeatability of measurements) over increased accuracy. For measuring UHI and a lot of other stuff it would make for much smoother graphs, and the differences in nearby temperatures would cancel out most of the inaccuracy.
Having had the USB-2 exhaust the battery after a month of logging, I started looking at the current draw compared to the USB-1. I found them essentially identical, but the big surprise was that when the units are plugged into the computer, the drive power comes from the battery, not the USB port. In the computer it draws some 12 ma, when logging, only 7-8 ua. (Sigh, it looks like I didn’t save the numbers, but the 1500X is the important figure.)
That led me to buying a replacement battery, and the realization that while Radio Shack may be a good source of weird batteries, their prices are unreasonable. I included in a note to
The Radio Shack battery (a Tadiran TL-5902) does seem to have a charge, but is grossly overpriced. I see prices in 1000 units of $3.75 each, about $5 for smaller quantities. Like most Lithium batteries, they have a ridiculously long shelf life, so I think they’d be a good product for you to carry. The battery is also used as a memory keep-alive device on some Apple computers, so Apple users may be willing to buy some.
Hmm, I guess I forgot to note the battery I got from Radio Shack was a return. I was afraid the exhausted battery was what got returned, but apparently the $19.50 I spent may have included the $5.00 of battery power.
REPLY: You can get these batteries on eBay a lot cheaper. And yes, don’t leave them plugged into USB! If you take a laptop with you and get the extension cable, plug it in to start data collection, unplug, and then plug it back in when done. The increased accuracy model has a better linearity across the range, but does not have increased resolution any greater than 0.5C – Anthony

Jeff L
April 4, 2010 7:57 am

Steve Goddard (06:40:07) :
If you have a local NWS station with hourly data, that could be used to de-trend diurnal effects – maybe not perfect, but also probably not too bad
I was considering that method as I do a rural to urban commute in the AM & reverse in the PM.

April 4, 2010 7:59 am

Given, as you say, the world’s surface data is measured to the nearest degree, how can they measure global anomalies of fractions of a degree?
(If you roll a zillion dice the average will be a reliable 3.5 even though a die is only “accurate’ to one pip.)

Jeff L
April 4, 2010 8:03 am

Another thing to consider for potential data collectors if you have any topography is to use you gps so you can also make a topographic correction – standard lapse rate of 3.5 deg F per 1000 ft or 6.5 deg C per 1000m.
for details on lapse rates.
Even for a 300 ft height change, you could introduce a 0.5 deg C change – equivalent to the sampling of the device

April 4, 2010 8:04 am

Great work demonstrating the urban heat island. This makes it believable…. undeniable,even. How about a trip up a mountain that demonstrates the relation between altitude and temperature? I think I remember the relation as being something like 1 degree F per 600 feet of elevation.

April 4, 2010 8:09 am

Hu McCulloch (05:18:02)
I would trust ducttape over velcro for an $85 instrument
How ’bout this: Ducttape a female USB to to the mount … _and_ use velco for the instrument ?
..if it will work OK without the protecting cover that is..
I want one, but think I will make my own mount to save on the postage

April 4, 2010 8:16 am

Peter (07:04:30) :
> Given, as you say, the world’s surface data is measured to the nearest degree, how can they measure global anomalies of fractions of a degree?
Here’s an example. Suppose a series of temperature measurements are made, say every 10 minutes and that the temperature is rising 0.1° every 10 minutes. The recording device is very accurate, but has a resolution of only 1°. In the following, the left two columns are actual and reported for one run. The right two are the same, but with a starting point 0.1° higher. The average temperature reflects that:

Actual reported    0.1 higher reported
  20         20          20.1       20
  20.1       20          20.2       20
  20.2       20          20.3       20
  20.3       20          20.4       20
  20.4       20          20.5       20
  20.5       20          20.6       21
  20.6       21          20.7       21
  20.7       21          20.8       21
  20.8       21          20.9       21
  20.9       21          21         21
           avg:                   avg:
           20.4                   20.5

I hope that formatted well….

April 4, 2010 8:16 am

Anthony, you took care to make sure that your temperatures during the transect didn’t get artificially inflated by being too close to a truck, or to too many cars. But did you find that traffic was generally heavier near the middle of town, on either your Reno or Chico transects?
Heat from vehicles would be part of the UHI effect, but perhaps the effect of heat from vehicles, averaged over an entire city or town, might be overstated if taken from the highway, where the heat signature from vehicles would be maximized — even if you took care to be far from trucks and not too far from gaggles of cars.
Did you try other transects, on streets with less of a traffic buildup in town, to cross check your previous transects? Or was there not a visible increase in traffic near the town centers?
REPLY: Avoiding such issues is why I suggest going later in the evening. I didn’t notice of any traffic in Reno, and on Hwy 99 at 8:45 pm traffic was also light. I was not caught up in pods of traffic either direction. There’s quite of bit of turbulent mixing and entrainment due to the highway speed involved. I believe at rush hour you’d be able to see a bias, but not in light traffic. I should note that I’ve driven this route hundreds of times prior to this experiment (when I was returning home from the 11 o’clock TV news) and my car thermometer showed this effect many many times, but until last night I had never logged the data. – Anthony

Mike M
April 4, 2010 8:20 am

REPLY: AT 60 mph it becomes a turbocharged aspirated thermometer. If you’ve ever ridden a motorcycle at night you’ll understand this experiment better. – Anthony

At 60 mph I feel like a turbocharged aspirated thermometer. Just riding ~15 miles north to go home from Everett MA on the bike just after sunset can be a 15 degree drop, (I live in a bowl near a swamp). I’ve learned… Even though it’s 60 in Everett, I put my longies on anyway because it might be 45 back home. At my age riding the bike at under 40 degrees is a little too ‘invigorating’ anymore.

April 4, 2010 8:25 am

Ole Humlum has done a similar experiment in Norway and Scotland and published the results on his website –

April 4, 2010 8:27 am

Anthony, outstanding offer!
Remember the old saying about no dumb questions?
For the wizards at UAH: Don’t you already have the capability to id and measure UHI? Doesn’t your data already reflect all these little “hot spots” and “heat islands” around the globe? Or is it still a big mass or blob you can’t quite decipher and measure at the megalopolis, or any other, scale yet?

Mike M
April 4, 2010 8:36 am

Instead of GPS there are …cell towers. Plug the thermometer into your cell phone and it will automatically call Anthony every 5 minutes stating it’s location and temperature.

Gary Pearse
April 4, 2010 8:40 am

With a comparative database, one could take a measure of the economic health of a city – good times = X% higher UHI than average- bad times X% lower.

April 4, 2010 8:42 am

Anthony, thank you for your feedback. I agree that driving in late evening should do a lot to reduce any artificial increase in UHI beyond what is legitimate UHI. But wouldn’t a good way to validate your quite likely assumption would be to drive a different transect, chosen specifically for very little traffic, and see if there is any change in the results?
It seems to me that if you do so, you will buttress yourself against claims by others that you chose only one road, don’t have statistics on the number of cars, didn’t avail yourself of a simple cross check, etc. Wouldn’t it be better to do added transects and thereby demonstrate, before hand, that such critiques don’t hold water?

John Finn
April 4, 2010 9:02 am

Jeremy Thomas (07:21:20) :

John Finn (05:42:45)
“The real question is whether the UH effect has contaminated the readings at the same location over the last 50 to 100 years and whether this has had a significant influence on the global surface temperature trend. The evidence suggests not.

Surely the lesson of climategate is that the “evidence” has been comprehensively manipulated (homogenized) by propagandists.
Only the proxy evidence has been shown to be in serious doubt. The “hide the decline” trick was intended to hide the fact that the reconstructions which were used to show a relatively flat MWP period disagreed with recent temperature observations. The CRU (and GISS) crowd are quite happy to let the debate centre on the thermometer record. They’re confident that nothing’s going to alter the general conclusion to any significant degree. They are on much less secure ground on the issue of millenial climate changes. In a nutshell: there has been warming but we have no idea whether or not this has been unusual. CRU have been let off the hook.

hotrod ( Larry L )
April 4, 2010 9:12 am

Great idea/project. I would like to pick at least one of those up in the near future (after tax day).
It would be interesting to get a small group together from the same town and do a coordinated simultaneous star burst transsect with everyone starting at the same starting point (center of town). This would also provide a QC point as all should read the same temp at the beginning of the run. Then go out of town on radials, then reverse and all return to the starting point.
4-6 drivers would give you a good 3D view of the heat island dome topography in a community.

April 4, 2010 9:18 am

“Please look your address over carefully – it does not look complete. 132.8 Ship State”
Huh? – ended up in a loop, maybe something _is_ rotten in the state of Denmark 🙂

April 4, 2010 9:31 am

Valter Ström (02:27:38) :
Wonderful. Absolutely.
Wonderful combination of imagination, creativity and ability.
This and similar activity, if widely spread, should remove much of the nimbus in AGW.
I have a suggestion for improvement though, concerning the temperature measurement. Many of you may know that Analog Devices sell an absolute temperature controlled current generator AD590. It is an IC for, say, ca$10 (?).
Once I selected the series resistor for optimum current measurement for the voltmeter I had at hand with 1 microvolt resolution. The result showed 1 mK resolution. I am not joking, it immediately became clear I could follow temperature variations with 0.001 K resolution.
It is not that hard to make a thermometer with 1mK resolution. It is very hard to make a thermometer with 1mK accuracy and precision. The calibration alone would be very expensive and complicated. Wouldn’t matter much for this particular case though, as we are only interested in short-term temperature delta…
Carbon film resistors will get you 300-500 ppm/degC easy, but they are not consistent (anywhere from positive to negative coeff) and accurate calibration is a bitch.
On another note, the vortex effect will pretty much kill your precision – vortexes will heat and cool your sensor by much more then 1mk. Given unpredictability of airflow when you driving you can forget getting anywhere with 1mK.
50mK resolution is much more practical.
Still, making your own calibrated temperature logger is not worth it unless you can sell it and ther is a demand, IMHO

April 4, 2010 9:32 am

If the datalogger’s time is synchronized with the time on a GPS unit, you can later combine both temperature and GPS data. The description implies that the temperature logger contains a time-of-day log rather than an elapsed-time log.
From the GPS data, a simple program can be created to ignore the temperature when the speed has dropped below a certain minimum, and continue ignoring temp until moving faster than a certain speed for a certain time.
That should automatically remove stoplightmorphic warming. It also would remove the described procedure to start at a specific time, as any data would be ignored while you’re walking outside, connecting it, and driving onto the street.
Also, I note that the USB-RT can feed temperature data right into a laptop (which might also be collecting GPS data from a USB GPS or Bluetooth GPS device). There are USB male-to-female cables which can be used to connect a USB-RT outside the window into a computer inside the vehicle.
Anthony, will soon have a temp-and-GPS collection corner? We’re approaching summer driving season, so there is an opportunity for a lot of incidental data collection. I’m planning at least one long road trip, and if I’m instrumented then I’ll drive through the cities instead of around them.

Larry Butler
April 4, 2010 9:34 am

As we’re all, according the the warmists, on the payrolls of big oil, coal and other energy corporations, shouldn’t we all be getting the $1200 systems from them as a bribe to keep posting anti-agw on the net? I think Exxon-Mobil should send me one as I’m a staunch disbeliever and use their gas in my Honda Reflex scooter. It’s only fair.
Great system and article. I’m a retired metrologist from the US Navy, but don’t have access to the temperature/humidity test chambers any more to do a proper calibration for you and award your logger a proper USN calibration sticker. Sorry.
Keep up the excellent work and the pressure.

April 4, 2010 9:40 am

I purchased one of the data loggers about 6 months ago.
I did the experiment for Dallas just at sundown on a sunny day which is normal in summer.
I started 35 miles in the country and drove to Dallas city hall then to a city park and reverse.
One way results
Downtown Dallas = 93
City Park = 91
Country = 86
I did it again at sunup on a Sunday and got 1 degree which is the instrumentation error.
The UHI for Dallas is huge and the city park is only 2 degrees below the maximum.
Compensating for this must be almost impossible even for honest scientists.

April 4, 2010 9:45 am

Because the heat island is affected by wind, is there an accessible database of archival windspeed data? Or should we be feeding GPS, temperature, and wind data into our laptop?

Methow Ken
April 4, 2010 9:46 am

Great product for support of real-world objective science. . .:
I’ll buy one….. hmmm….:
One question 1st, if I may; for those of us who like to employ multiple-use instruments where possible:
Any reason the EL-USB-2-LCD data logger would not also work more-or-less as well on this mast; as well as the offered EL-USB-2
(perhaps with an extra velcro strip to ”reinforce” the attachment of the longer unit to the mast (which I can provide myself) ) ??
Or for that matter the ”plus” versions of these 2 units.
I see from online manuals that the LCD versions are only 0.84 inches longer. Even without doing a field test, I’m guessing that should be tolerable (at least as long as not planning on driving 110 mph).
If no contrary indications: In for a dime, in for a dollar:
I’m happy to fork over the extra $15 to get the LED readout version (which for some uses out in the boonies would be handy to have).
Guess my other option is to buy the LED version; and get my own mast (which I would also buy from U, if offered separately).
…. I know; I know: Those darn engineers again:
Never content to leave well enough alone with already adequate specs; and messing up production schedules. Been an engineer too long; can’t help myself…. ;-] Thanks.
REPLY: any of those will work, but the LCD version (not LED) really doesn’t gain you anything, and comes with a risk. If you drop it or it falls off while your are trying to secure it, the LCD display can crack. I went for simple, robust, and inexpensive. – A

Paul Nevins
April 4, 2010 9:46 am

Very well done Anthony.

April 4, 2010 10:38 am

You are going to need to keep this thread (or some other thread) open long enough for those who actually get a recording device and log some results to post them.
I will be going to Fresno next week, to visit my family, but I won’t have the recording device, and my wife would divorce me for geekiness if I tried to do it while she was with me. Otherwise I could drive California 99 from North to south across Fresno. Maybe I’ll mention it to my nephew Alec.
I can’t do it in this area (Northern Virginia) because we don’t have straight roads that go from north to south or east to west. Or diagonally either.

Methow Ken
April 4, 2010 10:53 am

Anthony replied to my wonderings about complicating the simple:
> any of those will work, but the LCD version (not LED)
> really doesn’t gain you anything, and comes with a risk.
Roger; for this specific purpose U are clearly correct.
I was also thinking of other apps, but won’t bore y’all with those thoughts.
And my bad on letting LED slip in vice LCD; LCD, of course.
> I went for simple, robust, and inexpensive.
Which in most cases is the best policy.
Thanks for answer; I’ll buy one of the data loggers from your Weather Shop.

Layne Blanchard
April 4, 2010 11:23 am

I like this gadget… If I can find the time to run the experiment. As I was imagining my route, I recall a dip under a railroad trellis next to a swamp that is a pool of cool air at night. Maybe 10 degrees cooler than the surroundings. My house sits on a hill, and (on my motorcycle) I notice increasing warmth as I climb the hill, so topography would be a useful parameter in my final analysis.

April 4, 2010 11:51 am

“— the driver (who might be breathing heavily)
— the passengers (who might also be breathing heavily)”
– gasping at straws

Jim Swanson
April 4, 2010 12:15 pm

Back when I was young and gas was cheap car clubs used to sponsor evening car rallies with puzzling maps and clues to various checkpoints. Maybe they still do. Winners got to all the checkpoints by solving the clues to location and getting there first at legal speed. This would be a good way to get a sample UHI from several individual stations. Electric or HF vehicles would produce less ambient heat as well. After the rally everyone meets for pizza and prizes.
Just a thought for fun and science sake.

April 4, 2010 12:25 pm

Will a police officer believe anything that you say after they pull you over for illegal survellience (such as driving past court houses, bridges, etc.)?

John Bush
April 4, 2010 1:21 pm

I live in a rural area of Southern England and have noticed, even without this interesting device, that my car thermometer in many winter conditions shows a one degree change in temperature when descending 100 feet over two miles from a friend’s property to mine. A completely rural trip without a suggestion of UHI. Keep going on this interesting subject.

April 4, 2010 1:35 pm

A few thoughts.
The action of air molecules (which carry the temperature energy) are not as simple as one likes to think. I used to spray metal cases with cellulose paint in a cellar with a powerful extraction fan to the outside running, and the access door closed. Despite these precautions my wife could come home from work some time later when the fan was still running and her asthma would be set off by traces of the gases that had managed to reach the ground/first floor.
I am the first to admit that the fan wasn’t driving the air at even 30mph, but the suction round the door crevices was noticeable though the door was a poor fit.
It would seem obvious that there is a considerable energy spread in the air (and cellulose) molecules giving some of them sufficient energy to more than overcome the airflow. Nevertheless if the vehicle speed is reasonably even the effect is probably the same throughout the exercise.
It might be an idea to turn off air-conditioning systems and perhaps use a car with manual transmission so there is less heat emitted. When I get out of my car after a journey I am met by a blast of hot air from the front.

hotrod ( Larry L )
April 4, 2010 1:50 pm

John Bush (13:21:09) :
I live in a rural area of Southern England and have noticed, even without this interesting device, that my car thermometer in many winter conditions shows a one degree change in temperature when descending 100 feet over two miles from a friend’s property to mine. A completely rural trip without a suggestion of UHI. Keep going on this interesting subject.

I see that sort of jump all the time on my car thermometer also. As mentioned above it depends on the relative humidity lapse rate can vary from about 3.5 deg F/1000 ft to about 5.5 deg F /1000 due to humidity. If you pass through an inversion layer the temperature step change can be much higher.
I recall while delivering news papers as teenager, it being shirt sleeve warm weather on one end of the route (early morning delivery) at about 55 deg F and bone chilling cold around 36 deg F a mile away and 200 ft lower in elevation as you passed into the cold air layer over a small river drainage.

April 4, 2010 3:54 pm

Well, after reading those responses I’m given to wonder at the lack of humor some readers might be suffering. My ‘heavy breathing’ comments were meant in jest. But at low vehicle speeds, they ~could~ become biases. In the field of science, virtually NOTHING should be discarded without sufficient prior testing.
If you people are inclined to treat others with the same level of derision as you experience from the AGW idiots, then its no wonder that you don’t have all the support you’d like. Are you people always that trigger happy?
Now, it seems to me that a far better scheme of measurement might be to get a city to volunteer to place those data loggers at discrete intervals (light poles, anyone?) throughout that location and get the county to participate so that the suburban and rural measurements might be obtained as well.
If the devices are all placed at a specified height away from the easy reach of the curious, and the positioning is such the sun strikes them only in the early morning and late evening, OR if they are sufficiently shielded inside their own little enclosure, then a decent record of daily temperatures might be obtained.
In fact, such a scheme could well be used by cities to determine weather driven hot spots and help them to mitigate those.
In fact, Anthony, you might consider asking your readers to donate sufficient funds to get such a project started, with the added bonus that after the experiment is completed, the ones who donate to the project at the level of the price of the instruments, will be given one of the data loggers, with all others being prorated.
Heck, you could even start with a small town to get the feel for things.
The benefit here: There are fewer variables for which to have to control.

April 4, 2010 3:55 pm

If grant funded this would easily be a multi million dollar study. Instead, you’ve turned it into a capitalistic idea of letting everyday folk buy this equipment and do it on their own. Great work. Of course if the Obama Administration finds out they’d find a away to attach a VAT and bring the consumer cost back to $1200.
Now if this were grant funded, I have to think it would be likely for the grantee to set it up as suggested previously (RalphieGM (04:36:59) : Good start on creating a global real-time dataset. No doubt the alarmists will mount the temperature sensors on the car’s exhaust pipe to achieve the results they expect.) to ensure being paid for the right results.

April 4, 2010 3:58 pm

“Ecotretas (01:38:15) :
Since the data has a timestamp, it would be great to match it with GPS data. I’m sure the WUWT community would com up with a solution that could even plot it on Google maps! Just some software for merging the GPS data and your datalogger would be needed…”
Haven’t noticed if anyone else has responded, but Garmin GPS software with show datapoints directly on GoogleEarth. I use this a lot and provided you have set the GPS to the correct dataset (country specific), you get a pretty accurate plot. You can even export the data in various formats and counld combine it with the temperature data I expect.
I’ll have to get me one of these and have a play…
thanks Anthony

April 4, 2010 4:26 pm

Once you have your army, use it well Anthony!
It’s obvious that a UHI would be the central point of a convection cell, but this cadre of data observed in rural regions would give insight to topological, wind speed, wind direction, etc. effect to convection cell magnitude and area proportionality. Truly interesting on the point of temperature station resolution of the regional temperature signal!
Best regards, suricat.

Barry R.
April 4, 2010 5:12 pm

This is a good idea. It’ll take a while to build up the database, but it should give a much better basis than anything we’ve seen before.
My educated wild guess on the results: Properly handling UHI will reduce the temperature increase up to 1998 or so by a few tenths of a degree, but won’t eliminate it. That will still be significant because it will make some of the higher prediction for where the temperature will end up in forty or fifty years less viable.
One interesting idea: If there is an airport within easy transit distance, it might be worth it to drive past it. You might not be able to get close enough to detect any airport generated “UHI” and you might need to be discrete. I don’t know if airport security would get antsy about repeated transits, but it’s a possibility.
Another possibility: If air temperatures are different between city and country, would that be reflected in ground temperatures? Is there a consistent relationship between average air temperature and soil temperature at various depth? That might be complicated. Soil composition, moisture, how compacted the local soil is, and how healthy the local earthworm and soil bacteria populations are might all have an impact.
That brings up another point–which is admitted drifting OT: One of the biggest weaknesses in the CO2 –> Global Warming position is causality. Even if there is global warming and even if it is caused by human activities, that doesn’t mean that it is caused to a significant degree by CO2. Has anyone quantified the impact of human activities on the ability of soil to retain heat? On the diffusion of surface heat downward? On the diffusion of heat from the ground to the atmosphere during the winter?
Heat stored in the atmosphere is a tiny fraction of the amount stored in the ground and in the oceans, and it’s a very transient fraction. If changing farming practices somehow increased the amount of heat stored in the ground, or allowed more of the stored heat to be released, then that could be an alternate explanation for measured global warming (if there is any after UHI and measuring weirdness is accounted for).
Farming practices have definitely changed over the years. No till. More irrigation. More use of petro-based fertilizers. It would be interesting to measure the impact of that sort of thing on temperature storage capacity of the ground.
Tying this back to the topic, it would be interesting to see if transits using Anthony’s instruments could distinguish between types of rural land use. Is a no-till field cooler or warmer on average than a traditionally cultivated one? Is an irrigated field warmer of cooler than a non-irrigated one? For that matter, is there a detectable difference between crops–corn versus soybeans versus wheat? Between croplands and lands used for grazing or kept in forest? Old growth versus second-growth forest?
Lots of potential in this beyond just the urban versus rural divide.

David Alan Evans
April 4, 2010 6:37 pm

I just did a few of the data points but got overall enthalpy change of 1J/g from urban to suburban.

David Alan Evans
April 4, 2010 6:41 pm

As for clamps, how about an earthing clamp? you can get them in various sizes.

David Alan Evans
April 4, 2010 6:47 pm

Forgot to say.
Enthalpy variation was circa 5%, Temp variation circa 20%

David Alan Evans
April 4, 2010 6:48 pm

Must remember that both enthalpy & temp are anomolies.

April 4, 2010 7:56 pm

Hi, I’ve been following the weather on home weather stations for 30 years now. My first one was a homemade heath kit: digital weather computer, still works. Over the last several years I’ve used the Davis Vantage Pro II with good success. I love following the weather and get about 24,000 hits a year from around the community on my web page. If you like web sites like WUWT you will love a home weather station of any sort.

April 4, 2010 8:20 pm

Looks like fun.
Just a few questions.
1) Any elevation changes across your transect?
2) You mention that stopping the car may lead to temperature increases. It’s normal that there are more stop signals in the centre of a town than on the outskirts. How do you know you haven’t just measured the concentration of stops across the transect?

April 4, 2010 9:02 pm

Please tell me that there is a Mac version of the software.
Also, there must be some graphic arts types who follow WUWT. How about a collaborative effort or even one creative volunteer to come up with a WUWT flag? (and logo??)
REPLY: unfortunately there isn’t, but you can likely run the software using the popular PC compatibility programs on Mac – Anthony

April 4, 2010 11:02 pm

Please note that the ram air temperature rise while travelling at 65 mph is about 0.5 Deg C. So one would have to subtract that from readings while travelling that fast

Steve W.
April 5, 2010 12:37 am

Great job Anthony. Two ideas:
1) How much more accurate it would be to have two people drive the same course at the same time from opposite directions (assuming that traffic was light)? The drivers would pass each other twice. I think this method would allow you to do the measurement at any time of the day, and not worry about natural temperature changes. This test would help determine if a single driver is enough.
I’m thinking about getting two of these to try it if it makes sense.
2) Would there be any benefit to time a run to pass by a fixed station at it’s measuring time? You could have this scenario: Do a run into and out of the city, passing by the fixed station at various times of the day, like 7:00 am, 2:00 pm (times it will be recording). You should be able to say what UHI bias that specific station has, but not necessarily it’s microsite bias (you can’t drive that close to it).

Chris Wright
April 5, 2010 3:48 am

John Finn (05:42:45) :
“The recent UK enquiry suggests I was right. The world has warmed over the past several decades. Arguing against this fact is futile.”
I’m a little confused. Who exactly is arguing that there has been no global warming at all in the past several decades? I certainly am not.
I’m sure you would agree that it is extremely important to know the amount of global warming that has actually occurred. The argument here is not about the reality of global warming. It’s about the actual amount.
The sceptical arguments about UHI seem to me to be very powerful. The way UHI has been handled – or ignored – by climate scientists and the IPCC is so bad that I hardly know where to begin. Recent research by McKitrick & Michaels showed a very strong correlation between local land use and population condition, and the local temperature record. Obviously, if the temperature record had been properly adjusted for UHI effects there should be no such correlation. If I remember correctly, they calculated that if the UHI had been properly accounted for, the average warming would only be half, at least for the last few decades.
I would also be curious to know why you thought the UK enquiry proves anything, except that most MP’s know little about climate science and can easily be misled by scientists who might be – shall we say – economical with the truth.
I seem to recall that the satellite measurements originally showed far less warming than the surface record. It was only after they had been ‘adjusted’ that they agreed, assuming that they actually do agree.
Those in charge of the satellite record vehemently deny that they calibrated the measurements against the surface record and that therefore the two records are completely independent. But I have to admit I’m a little – shall we say – sceptical about this. In climate science the word ‘independent’ has a rather different meaning, compared to what you would find in your dictionary.
At least until recently, the surface record was regarded as a gold standard, as it depended on direct temperature measurements. Of course, the satellites do have a local reference/calibration source but it’s still a huge jump to assume they can measure the surface temperature directly without some form of calibration from the surface record. One could almost argue that if they didn’t use the surface record for calibration they weren’t doing their job properly.
It would be sad if the one method of providing a reliable temperature record had been corrupted by calibration against another record that was completely unreliable.
As I said, nobody here seriously denies that global warming has occurred. Indeed, that modest warming has almost certainly been of overall benefit to mankind, just as it was in the Medieval and Roman periods, though sadly it may be coming to an end.
The warming has been noticeable in England. It was nice while it lasted, but now the winters are getting steadily colder and more unpleasent. It’s instructive to look at the CET record. It shows that the warming is completely unexceptional – there were warming trends very similar in previous centuries, and actual temperatures were also higher. CET is one of the best and longest temperature records and it shows nothing ‘unprecedented’. Of course, it raises one question: why didn’t the Met Office ‘adjust’ it to get the right answer?
Maybe they haven’t got around to adjusting it yet. But maybe they never will, given the current ‘climate’.

April 5, 2010 5:35 am

I am a Taxidriver in sweden, and we have experienced a cold winter.
From experince I know that winter temperatures drop 3-5 degrees in a matter of miles when travelling from a small city (20-100 thousand people) into adjacent rural areas, or forest. My thoughts have been that this phenomenon has something to do with mostly air-humidity, a greenhouse effect in essence. I have no idea where on the car the built in thermometer is fitted, close to the road I suppose.
I am now experienced enough an observer to make very good guesses, of what (higher) temperature the thermometer will read once I enter (or leave) the city by car.
A trick I use to amuse (annoy?) my customers with.
Anyway, it is great to see a more scientific approach to documenting this effect.

April 5, 2010 7:20 am

I wonder if someone will write an “app” for that… All the smartphones with USB ports could make the control a snap. You carry your phone with you anyway…., just keep the datalogger in the glove compartment, and you are ready to go.

April 5, 2010 3:05 pm

What’s this about surface temperature data having raw resolution of only 1.0 DegreeC?
How much averaging does it take to make it meaningful when the magnitude of trends being looked for is small?
My rule of thumb would be 0.1 degreeC, recognizing that is data resolution not accuracy. 0.5 is OK for your homespun proposal, which is a great idea for schools, but shouldn’t official sensors be far better?

April 5, 2010 4:18 pm

I was thinking about IR bias from the heat source you bring with you. I’m not sure of the absorptivity of the datalogger itself, but you could shield with a small disk of material below, with a small amount of gold coated tape on the bottom. Gold has a great reflectivity of IR. Gold tape is expensive, but in this small an amount, it shouldn’t add terribly to the cost.
Just a thought.

Jack Simmons
April 5, 2010 9:01 pm

why not mount such a system on all public vehicles, such as buses? Taxis? commuter trains? These run all the time. Certainly, with enough data points we could at least get trends from in city to suburbs, regardless of factors pulling us one way or the other.

Retired Engineer
April 6, 2010 8:16 am

Asking the city or any government agency to do this (on public vehicles, for example) turns the project back to the folks who brought you GISSTEMP and CRU. Much better for us amateurs to do it. Sure, it will have some errors, but with enough data from enough places, we’ll get a good picture. Driving around airports multiple times may get TSA a bit upset, but freeways through cities should be easy.
Any thoughts on how and where to send or collect results? Formats? I’m OK with spreadsheets, but Windows code is not my strong point. (If you need code for an embedded 8 bit micropower processor, give me a call.)

April 7, 2010 9:22 pm

Hey, I just did my first run and it was such a blast and I’m so pumped up I can’t even believe how fun this is! I am so excited I haven’t read everyone’s comments yet but reading the first data set reminds me of the 0th law of thermodyamics – that is – let the transducer stabilize to the outside temperature before you start the log. (duh…on me). Anyway, I live in the desert southwest right close to the open desert and I got a phenomenal UHI just based on coming in off the desert and back into town. I will not post my results yet as I want to at least run five or so samples just to make sure my set up is right but you will be hearing from me.
OT – is it just me or are “skeptics” having a lot more fun than the AGW crowd?
REPLY: We look forward to it. Thanks, – Anthony

April 8, 2010 12:21 am

Pity the software is Windows. I run Debian/GNU-Linux on more than half a dozen desk top machines and three laptops. How about porting the software to the GNU-Linux operating system?

April 8, 2010 1:27 pm

Received the datalogger yesterday and tested it for 1 hour (on my desktop) last night. After downloading the data to my PC (and plotting it), I reset the datalogger for a 24 hour run, and placed it outside.
Note: I used the °F setting and noticed that its resolution is 1°F, vs 0.5°C (obvious).
Since I can get to about 100 yards from the San Antonio International Airport temp sensor, I’ll use that point to start my runs. (The SAIA sensor is at the end of a runway, which is about 100 yards from a security fence that runs along a freeway access road – not too busy even in the daytime).
UHI question: Since UHI is larger at night, how long after sunset would show the max value? Would be interesting to check delta UHI at different times.

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