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.
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:
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:
- 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.
- 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.
- 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.
- Set the data logger to start logging either immediately or at some start time in the future. Put the waterproof cap back on
- Affix the datalogger to the vehicle mount using the strap provided.
- Put the vehicle mount on the top edge of your vehicle window and close it for a tight fit.
- 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.
- Drive the route, trying to maintain a fixed speed.
- Have your passenger note landmarks/locations in a logbook as you drive so that you can correlate with temperatures later.
- Optional – take a logging GPS unit with you if you want exact positions and time.
- 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.
- 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.
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:
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: http://weathershop.com/usb2-UHI.htm
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:
http://www.climate-skeptic.com/2008/02/measureing-the.html
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.
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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
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 weathershop.com:
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
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.
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?
Oversampling.
(If you roll a zillion dice the average will be a reliable 3.5 even though a die is only “accurate’ to one pip.)
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.
See:
http://en.wikipedia.org/wiki/Lapse_rate
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
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.
Hu McCulloch (05:18:02)
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I would trust ducttape over velcro for an $85 instrument
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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
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:
I hope that formatted well….
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
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.
Ole Humlum has done a similar experiment in Norway and Scotland and published the results on his website – http://www.climate4you.com/
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?
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.
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.
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?
Jeremy Thomas (07:21:20) :
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.
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.
Larry
“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 🙂
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
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 surfacestations.org 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.
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.
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.
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?
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
Very well done Anthony.
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.