Rothamsted Temperature Record Problem?
The Rothamsted Research Centre is one of three temperature recording centres of record for the official Central England Temperature. I can't spot the Stevenson screen on Google Maps but the research station is still fairly large and green. So is it a reliable source of data?
The driver of the increasing warmth in the UK is mainly the increase in the T min (Minimum Temperature - we aren't getting the cold to bring the averages down).
Here is the T min series:
Wow, quite a jump in the Tmin for Rothamsted (the solid red line).
As the Met Office notes - "the coldness of Ringway around 1993 the warmth of Rothamsted around 1993 and 2001, while disconcerting, may not be outliers in view of the expected uncertainties. That Rothamsted T min is not fully supported by Cambridge T min suggests calibration or siting biases rather than real spatial variations of min temperature anomalies. If any biases can be ascertained following further investigation of Ringway and Rothamsted, then the CET series should be adjusted accordingly." Source
I can't find any evidence that they have done any further investigations or adjustments, so the extra half a degree(?) from Rothamsted still feeds into the data.
Just eyeballing that, does it look right to you? I have no idea what is going on, is it correct or whether there is a software problem such as Steve McIntyre found with the US records, or a siting bias as the Met Office suggests or maybe something else.
Just north and north west of Rothamsted lies the Bedfordshire brick fields, an average distance would be about twenty miles away. There used to be over 130 chimneys there belching out sulphurous fumes. As we know this sort of pollution cools the atmosphere and is bad, so they have all been knocked down apart from one or two, which try to be as non polluting as possible.
This is the area in 1974:
Could this be the source of the anomalous jump in Rothamsted's temperature average, which fuels the jump in the UK record?