February 26, 2010
U.S. Climate Data Compromised by Sensors' Proximity to Heat Sources, Critics Say
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The National Climate Data Center (NCDC) uses this massive network of sensors to determine daily highs and lows at the 1,219 weather stations in its Historical Climatology Network (HCN). The network has existed since 1892, but only in the last decade has it come under intense scrutiny to determine whether the figures it measures can be trusted.
For the past three years, a group of zealous laymen has visited and photographed nearly every one of the weather stations to determine whether they have been placed properly. And what they found is a stunning disregard for the government's own rules: 90 percent of the sensors are too close to potential sources of heat to pass muster, including some very odd sources indeed:
- A sensor in Redding, Calif., is housed in a box that also contains a halogen light bulb, which could emit warmth directly onto the gauge.
- A sensor in Hanksville, Utah, sits directly atop a gravestone, which is not only macabre but also soaks up the sun's heat and radiates it back to the thermometer at night.
- A sensor in Marysville, Calif., sits in a parking lot at a fire station right next to an air conditioner exhaust, a cell phone tower and a barbecue grill.
- A sensor in Tahoe City, Calif., sits near a paved tennis court and is right next to a "burn barrel" that incinerates garbage.
- A sensor in Hopkinsville, Ky., is sheltered from the wind by an adjoining house and sits above an asphalt driveway.
- Dozens of sensors are located at airports and sewage treatment plants, which produce "heat islands" from their sprawling seas of asphalt and heavy emissions.
"So far we've surveyed 1,062 of them," said Anthony Watts, a meteorologist who began the tracking effort in 2007. "We found that 90 percent of them don't meet [the government's] old, simple rule called the '100-foot rule' for keeping thermometers 100 feet or more from biasing influence. Ninety percent of them failed that, and we've got documentation."
