To make a long story short, and this is really a WAGNER (wild assed guess, no explanation required) what if the large amounts of SO2 injected into the northern hemisphere atmosphere by WWII and the unrestrained coal burning (see London, smog) produced huge amounts of sulfate aerosol which shadowed and cooled downwind
rural measurement sites.
Not exact matches
A new climate
measurement system that only has stations at pristine
sites away from urban /
rural areas shall be established.
In countries such as the US, most urban development / growth predates the period considered by Menne and hence when looking for temperature trends (rather than absolute accuracy in the temperature
measurement), during the period considered by Menne, one would not expect to see substantial differences between good and bad
sited stations, or between urban and
rural stations.
This qualitative approach, including
rural - urban temperature differentials with value - neutral distance
measurements, most certainly confirms AW's
site - specific Weather Station theses.
I have seen
sites like RealClimate arguing in their myth busting segments that the global temperature models are based only on
rural measurements.