Not only has siting of weather stations near urban heat sources have been a real issue for weather measurement stations worldwide, but so maybe has the recently implemented automatic electronic weather measurement instrumentation.
It seems that these new automatic systems are highly sensitive. As reported here at NTZ, one German weather instrumentation expert conducted an 8.5 year side-by-side comparison test of the new automatic electronic temperature measurement system and the former mercury glass thermometer. That test showed that the new automatic thermometers produced a mean temperature for the period that was a whopping 0.9°C warmer than the mercury thermometer. That result could possibly in part explain why Germany’s annual mean temperature jumped by a similar amount from 1985 to 2000, i.e. the period that Germany transitioned over to automatic measurement.
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