On most days I often find a difference of 1-3°C between town and the outskirts, so 0.2°C for UHI for the past 40 years does sound less than generous.
Guest essay by Tom Barr
Central England Temperature stations, long considered a benchmark, have been affected by land use change and urbanisation
During the eighteenth and nineteenth centuries, a cool period which coincided with snowy winters and generally cool summers, the temperatures fluctuated widely but with little trend. From 1910, temperatures increased slightly until about 1950 when they flattened before a sharp rising trend began in about 1975. Temperatures in the most recent decade (years 2001-2010) were slightly higher in all seasons than the long-term average.
The answer is blindingly obvious, from above: they are all subject to considerable modern local urbanisation immediately to the North, including heated greenhouses designed to replicate a Mediterranean climate.
The Met Office relies upon just three weather stations to record the Central England Temperature: Stonyhurst (Lancashire), Pershore (Worcestershire) and Rothamsted (Hertfordshire). http://www.metoffice.gov.uk/climate/uk/about/archives
The Met Office averages these three temperatures and makes a 0.2 degrees…
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