Road kit


I just finished testing and putting together my road kit, as seen above. Can anyone guess what it is for?


Ok I think I have enough guesses. “Coyote” nailed it pretty well. Good job Warren. The road kit is packaged for getting on an airplane, hopefully I’ll be able to explain it well enough to pass airport security. I’m going to give myself an extra hour just in case they think its a “Eludium Pu-36 Explosive Space Modulator” as Robert Coté points out 😉 in comments.

It’s a UHI transect kit. I got the idea at Pielke’s August conference on land use changes. There were a couple of UHI studies presented there, both using data from existing static weather stations. The idea gelled after some observations of my vehicle air temp thermometer while crossing Denver headed to the airport returning from a station survey the next evening.  

My experiment plan is this; by simultaneously logging temperature data and GPS readings on my laptop, I’ll be able the create a transect line. The Gill shield has a custom window clip which allows me to mount on the passenger window. The shield will be “aspirated” by driving. Should I have to stop for a signal. the GPS data will indicate a pause, and any temp data from that spot due to heat from the vehicle or others nearby can be excluded.

The temperature sensor and A/D converter for it both have NIST calibration, making them far better than the accuracy of an MMTS, but with the same resolution, 0.1°F.

The reason for the setup now is that I’m heading to Indianapolis next week, which was one of the cities presented in a study at Pielke’s conference.  Plus that, Indianapolis is nearly perfectly flat and has transect roads that match the cardinal compass points.

According to Parker 2006, “The main impact of any urban warming is expected to be on Tmin on calm nights (Johnson et al. 1991)” so that’s what I’ll be testing. Hopefully the weather will cooperate.

Coyote brings up a valid point about “I can’t figure how you deal with the time delay issue between readings.”  which I assume to mean the overall atmospheric deltaT between the start of the transect and the end. I’m hoping that at night, with little traffic, I’ll be able to drive fast enough to minimize this.  I expect that the deltaT of the transect itself will be larger than the deltaT for the time it takes to drive the transect. We’ll see. Also, I should be able to determine the deltaT for the city atmosphere for the time it takes to drive the transect from the static weather stations around the city. My guess is I’ll be able to transect the city in less than 30 minutes. I used to live near there, and knowing the city and it’s roads, I believe it’s possible.

If I do it late enough at night, say after midnight, I should be able to minimize waste heat contributions from other vehicle wakes ahead of me.

I welcome ideas and suggestions. I’m sure the usual folks will “pooh pooh” the idea, but with the help of my readers, perhaps I can minimize the weak points of the experiment.


33 thoughts on “Road kit

  1. Looks like a DeLorme Earthmate GPS LT-20 bundle, indicated by the yellow object on the upper right and the DVD. The large silvery object on the upper left may be an auxiliary antenna.
    This kit may even be part of a DeLorme GPS PostPro 2.0 & Earthmate GPS BUNDLE, capable of sub-meter accuracy. If so, the yellow GPS is the roaming unit and the silvery unit on the left is connected by a cable to a second GPS unit which is the fixed base unit. For less than $500 you would be able to locate sites within a fraction of a meter, assuming you have an accurate geodetic reference point, benchmark within a dozen miles or so and a partner to mind the base unit.

  2. Well, being a storm spotter (and occasional chaser) it appears to be a portable weather station and a GPS device. Could you be starting to explore the quality of weather measurements afar?
    Reply to Craig: since your are a storm spotter, you should see my StormPredator invention at

  3. Understand this is just my first crack at it:
    Mobile Rapid Weather Auditing Temperature Testing Station
    Or a M.R. W.A.T.T.S.
    Not great, I’ll try again

  4. Now I should put down that it’s most likely a MMTS Weather Station, that is designed to be mobile and accurately calibrated by GPS for an exact location.
    Used to calibrate other weather stations and check for accuracy across several locations?
    Missing: the push up pole to keep the MMTS station at a standardized calibrated height.
    Do I win a prize?

  5. Fred got the LT20 part right, it is a GPS (the yellow module) and while the other part looks like a MMTS unit, it’s not that exactly, though it does measure temperature.
    Jim B, sort of your acronym.
    The answer is there in the two items.

  6. definitely a portable mmts with a gps. Could be checking readings against existing stations. But I will take a different guess-
    Your going to take readings in and outside of urban areas, over different ground surfaces, to find temperature deltas. Though if that is it, I can’t figure how you deal with the time delay issue between readings. I thought once of how I might test UHI in a city by starting at 3 and driving from center out of city, taking readings every few miles. Then the next day start at 3 outside city and drive in. Then average the anomolies between the two days

  7. Ok One more then I’ll stop.
    The Scaled Kelvin, Environmentally Positioned, Transportable, Isothermal Calibrator.
    Or The S.K.E.P.T.I.C

  8. Oh. Map of US. I’m thinking too big.
    But what about distributing your road kit to some skeptical Russian or something?

  9. An Eludium Pu-36 Explosive Space Modulator and directions to Hansen’s next press conference?
    You are gonna take parallel measurements with a single calibrated module that you can use to compare to the reported data set. That way you can determine if the is any environmental bias say your sensor tracking closely -1 degree urban sensors and also tracking closely +0.5 degree with rural packages.

  10. Re: deltaT
    For each leg, turn around and drive back to starting point measuring to and fro.
    From Anthony: Splendid idea, now why didn’t I think of that? 🙂

  11. If you really wanted to take this to the next level, you could tie it into the OBD-II (on-board diagnostic) connector on your vehicle. In addition to the GPS and temp data, you could get real-time vehicle speed, engine load, intake air temperature and pressure. It could be useful in trying to determine if any measured temperature oddities were being influenced by the vehicle operation.

  12. You can calibrate time of day differences using local weather stations. Consider it a Bayesian prior probability. That is, if you need to. Send me an email and can help you if necessary.

  13. “now why didn’t I think of that?”
    Because you are not a NASA scientist (who always has all of the right answers and does not need any help thankyouverymuch.
    You are a real scientist, and real scientists often improve on ona another’s analysis of a problem.
    Strange how that works when right answers are important.

  14. Anthony:
    As a working electronics “repairman” who used to do a lot of travelling, both domestic and international, let me suggest this: Ship the package by ****** and forget trying to explain it. Something in there will look like a “tool”, and thus be not permissible. There is likely a prohibition against cables longer than 3 feet or whatever an ipod has. And if you put it in checked baggage, don’t expect to ever see it again, except at a local flea market.
    I gave up travelling for that very reason, I got tired of buying replacements for items stolen in transit.

  15. Transects good. If you had enough time same route return to start for each cardinal would allow you to average out time variance.
    What is the instrument’s sensitivity to humidity? Speed and atmospheric conditions could make temps vary wildly for what you are attempting.
    From Anthony: No sensitivity to humidity, just a calibrated thermistor in sealed plastic tip.

  16. Just check it. I go through all of the time with digital termometers (don’t look like that, though!), manomemters, tubing, cable, pitot tubes, etc. I usually have no problem carrying on digital equipment, either, as long as it passes the xray thing.
    I think you should set up a reference station somewhere outside the city during the duration of the measurements. That way you could track the temperature changes due to the time delay (maybe even adjust if needed?). If you don’t do this, I see alot of people “pooh-pooh”ing the experiment.
    BTW, I’ve never seen pooh-pooh spelled like the bear!

  17. Yes, Clayton B makes a good point that the transect needs a control set of measurements both in the city and at the endpoints that are contemporaneous with the moving equipment. You will pick up any changes in the overall UHI and will have information to adjust the transect data if necessary. Even after midnight there’s the chance of a front moving through, wind speeds and directions changing, etc. What about the network of local weather data collecting stations that TV stations scatter around their broadcast areas for realtime weather data? Can you get some temperature data from them to give you even broader coverage?

  18. Gary, I’m going to Indy to install a weather display system for one of the major TV stations…so I will in fact have access to their network.

  19. I bet there are other stations in the area you can use to teleconnect to.
    I saw a simliar ‘road trip’ ‘blues brothers’ UHI study on the web
    I think it was in Europe.. I’ll have lok see
    Might check for a CRN site around indy. And check the agri sites..

  20. Anthony,
    You’re getting pretty darn close to an area of science that I am quite familiar with, that being airborne geophysical surveying to measure magnetic field, electrical conductivity, etc.
    I’ll just focus on the magnetic sampling. The aircraft tows a sensor along a flight line, recording along the flight path at a very high sample rate. This is the part that your kit and methodology mimics fairly well. In the airborne survey many successive flight lines are flown, at a line spacing appropriate to the sensor altitude and desired resolution. All the parallel lines are tied together by flying tie lines perpendicular to the main fligh lines. The tie line spacing would be in the ballpark of an order of magnitude greater than the flight line spacing.
    I’m not suggesting this degree of coverage, but the concepts of tie lines will be useful as will the notion of levelling, a process that essentially forces the measurements to a common value at points of intersection. Levelling is done after removing the diurnal variation in the data. Diurnal variation is established by having a base station constantly recording the magnetic field during the time the survey is being performed. Because the diurnal variation in the magnetic field does not vary over a local area it is possible to remove the drift.
    Another method to remove drift in the signal is to reoccupy your starting point after completing your survey and remove the difference between the start and end temperatures, assuming a linear response over the time in question. Oh, I see Tex brought that up.
    It’s too late to modify your kit to include a base station, so you’ll have to see about finding one locally for which you can get hourly or better data. The problem with base stations is that the temperature field can vary so much spatially as well as temporally. Still having a base station would strengthen (or weaken) the assumption of a linear change in the delta T.
    OK, I’m gushing I suppose. I’d better read your posting from Indianapolis and get caught up.

  21. Don’t you realize that tooling around in a fossil-fuel vehicle like that causes *GLOBAL WARMING*???!!!

  22. Earle,
    I have it covered, there are multitudes of private weather stations in the area in addition to the official NWS readings, graphs of temp/dewp are available here:
    and here’s a sample of individual station data,
    they even have a comma delimited file output option at the bottom of the tabular data.
    Mosh thanks for the link to the paper, nice to have precedence.

  23. On the topic of reference stations, while the other private weather stations are good to have, what’s really needed is one of known character at each end of the transect, plus possibly one in the middle.
    I’m working on a battery powered temperature logger with integrated radiation shield, that has a port to download data…should be ready in a couple of weeks.
    The cost will be low enough that others can do UHI transects too, as the unit can serve as reference as well as moble station. It will be small enough to simply position on a lightweight piece of PVC or a rod pushed into ground to get a standard observing height of 1.5 meter.

  24. Great to hear you’ve got the local data well covered. I think the methodology you describe with a data logger at each end (or a route that goes from one local weather monitoring station to another) allows you to completely remove the temporal variation. I’m already thinking about how you could interpolate the delta T as a function of distance between endpoints.
    This will give you a temperature profile that will have short-term time effects removed. There is still an underlying temporal component having to do with the time of day as well as the season. It would be interesting to conduct these transects on a frequent basis throughout the year, at different times of day, to see how the profile varies.
    If you’re planning on trying multiple transects, I suggest you identify what it is you wish to further nail down. Is it to create a map of the UHI? Or is it to observe how the UHI changes between the temperature high and low? If you wish to map the UHI you should limit the variables by running transects at approximately the same time every day. And of course if you’re measuring the range of UHI it should be done over the same transect at different times of day.
    I just checked out the Meridian Hills station at and I see it captures local wind data too. Man oh man, you could have baseline data for a city and on a particularly windy day run a few transects and you could easily test Parker’s hypothesis about UHI and wind. Indianapolis looks like a great place to test that theory out, as there doesn’t appear to be any confounding water bodies or extended urban development in the surrounding area.
    Ah, science! Thanks Anthony for reviving my excitement, what with all the possibilities this test of yours brings with it. If your road kit is affordable enough, you may need to be establishing as well!

  25. Pingback: UHI is real, in Reno at least « Watts Up With That?

  26. I just bought a high speed data logger from They have 10 bit 8 channel units ±10VDC inputs + digital I/O & software for $50, for recording up to 240Hz, overkill for the application but you can slow down the sample rate. I got the one that will do 14400Hz sample rate 4 channels ($350)
    You’d have to run an instrument that you can force to have 0-10VDC outputs, but that could be done with a regular old temperature controller with analog outputs. Not sure if it’s right for the application, but with some tinkering could probably be calibrated properly for useful measurements of temperature. And it would sure be fun! has great software for downloading your track data from your gps onto maps and / or into excel… Definitely worth the $10 license.
    I’ve had lots of fun tracking stuff like this but it’s usually with some other type of sensor, though I measure a lot of temperature too, but have never done mobile measurements. There are other USB temperature recorders out there also with maybe 1 second sampling rates, though probably not traceable to NIST for the cheap ones… Have fun!
    Mike S.

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