How Much Is The CET Affected By UHI?

via NOT A LOT OF PEOPLE KNOW THAT
http://ift.tt/16C5B6P

By Paul Homewood

Reposted from WUWT, originally published in January.

It’s old, but still relevant:

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://ift.tt/1o6Q9bs

The Met Office averages these three temperatures and makes a 0.2 degrees C negative adjustment to compensate for the UHI effect. http://ift.tt/2reFkuJ

The Met Office has made this adjustment since 1974. Bizarrely, they don’t seem to know exactly why 1974 was chosen other than being able to speculate that “It was probably around then that the effects of urbanisation began to be noticed, although this date as chosen may be slightly arbitrary”[1].

But is this 0.2 degrees negative adjustment adequate for the three CET weather stations? I suggest it may not be:

All three weather stations have material modern urbanisation starting within 100 to 200 metres in their Northern quadrant, this development being associated with the rapidly expanding research and educational institutions which control the land on which they are sited. These institutions are often built around old country houses with formal gardens sited to their South in the UK, so their commonality of orientation is unsurprising.

Rothamsted Research (f/k/a Rothamsted Experimental Station) now shelters its weather station from the North winds and warms it up by modern buildings rapidly thrown up to the NNE:

Stoneyhurst College has expanded in the NNW, and now hugely shelters its weather station from the North winds and warms it up with new building and nearby tarmacadam ball sport courts:

Pershore College has gone a step further and covered the land immediately to the NNW with heated greenhouses http://ift.tt/2rZFEKQ , car parks and new building, having a similar effect on the Pershore weather station as its two sister sites. Surely a greenhouse designed to enable “plants to flourish in a semi-Mediterranean climate” sited up wind of a weather station may have some effect?

It is not beyond the wit of man to postulate that these localised, specific effects might artificially inflate the recorded temperature. Increasing the data to a temperature not properly compensated for by the small 0.2 degrees C adjustment applied by the Met Office, thereby inflating the CET to a number more amenable to the Met Office and the IPCC.

This would particularly warm data recorded in colder temperatures, where winds are more likely to be from the North.

The Met Office plans to

“overhaul” its CET datasets during mid-2017. Included in this “overhaul” is a review as “to what adjustments have been made (e.g. urbanisation adjustments, and changes to allow for differing climatological characteristics between the different sites used over the years so as to avoid introducing any inhomogeneities)”.[2]

Not before time. The CET problem, from a birds eye view, is staring the Met Office in the face.

http://ift.tt/2kHQlRq