June 19, 2007

How not to measure temperature

A lot of the temperature data that the "Global Warming" people are using comes from weather stations scattered around the USA. The trouble is that these were once in remote areas but conurbation has happened and these stations are now surrounded by parking lots, air conditioners, etc... An excellent post at NorCalBlogs discusses this and shows examples:
Watts Up With That?
How not to measure temperature, part 10

Russ Steele, a blogger in Nevada County at NCWatch is volunteering to do weather station site surveys as I've been doing. Yesterday Russ visited Petaluma California to see the USHCN climate station of record there. It used to be at the city fire station but has been moved to the airport, but apparently the NASA climate database hasn't yet caught up with that as it still shows "fire station" as the place.

Ok we have a temperature sensor strapped to a wooden deck, near a sea of tarmac.

And not only that, the building with the deck is only six feet away, and has air conditioners exhausting hot air on the south side. Prevailing wind direction in that are is from the south, so that means when wind hits that wall, it will spread out the hot a/c exhaust east and west.
Many more examples on the website including historical temperature charts from these stations showing a progressive upward creep in readings. Posted by DaveH at June 19, 2007 4:45 PM
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