How not to measure Temperature, part 26 – counting A/C units

There’s been some recent discussion about how only rural stations have been used in the NASA GISS analysis, and those rural stations are qualified by looking at night time DOD satellite photos, and doing a count of visible streetlights within a radius to quantify UHI potential or lack thereof. The “best” stations are labeled “lights=0”

One of those stations is Happy Camp, California, population 2182, an old gold mining and logging town located in the rugged NW corner of the state, and about 100+ miles from any major city. NOAA MMS metadata website reports data back to 1931 with 3 small distance station moves, and no changes to equipment. NASA GISS reports data back to 1914.

It looked like a good candidate to look at for a lights=0 survey. The weather station is located at the Ranger Station:

But what you can get from satellite images and databases can’t really prepare you for what you may find. I “expected” to find an old classic Stevenson Screen, probably near the Ranger Station office. Check on that. But what I didn’t expect to find was a “rural” station swimming in a sea of exhaust from 22 air conditioning units within 100 feet of the Stevenson Screen. Ridiculous, you are making this up you say? Well that would be my first reaction too.

But here they are, count them, I’ve labeled the A/C units for your convenience:

Happy Camp Ranger Station looking West from Stevenson Screen

Happy Camp Ranger Station, looking NE, Stevenson Screen visible

Happy Camp Ranger Station, looking North towards courtyard

Happy Camp Ranger Station, looking southwest inside courtyard

To help you get bearings on this walking tour, an aerial photo is available here

And the complete collection of photos is available on www.surfacestations.org

In addition to the 22 A/C units within 100 feet there are other biases too. Granted, not all 22 may be introducing a bias, but since NASA’s Dr. James Hansen counts lights near stations, to asess UHI magnitude, we can count A/C’s. If each A/C unit was 2000 BTU, that would be 22×2000=44,000 BTU of waste heat dumped within 100 feet of the Stevenson Screen where the thermometer is located.

Additionally. for other biases, positive and negative there’s the buildings, the windows, the shade trees, the wind sheltering, and the lawn sprinkler. There’s also the big parking lot to the southwest, and the Stevenson Screen is at the top of a slope and there’s a parking lot downslope.

When I mentioned to the site curator about the A/C units she said “hmm, I never thought about that” but then added, “But I can tell you that when we water the lawn, my high temps are lower”. I asked the curator what the prevailing wind direction was, and she said from the “south to southwest usually”.

Now there doesn’t appear to be much of a trend according to the NASA GISS plot, but there are some large amplitude swings and discontinuities:

Unedited NASA GISS raw data plot for Happy Camp RS

So one has to wonder, with all the observed microsite biases, what is the data really showing? One also wonders what the plot might look like if this station was better sited.

And if a lights = 0 station like this one, far removed from urbanization, has so many such micro-site biases, could others have similar problems? It looks like more hands-on site surveys will have to be done to determine the true value of lights=0 USHCN sites.