"CHRIS KIDD" wrote :
"Philip Eden" philipATweatherHYPHENukDOTcom wrote:
"CHRIS KIDD" wrote:

Birmingham Winterbourne (anomalies based upon 1881-2006 means)

snip

Interesting to note that once again Birmingham Winterbourne has not
shown all-time records as the CET has - in fact since 1971 the
CET-Birmingham has shown an increasing bias which now shows that the CET
is +0.4 warmer than Birmingham...

Chris, are the data normalised, so that the major site change in,
when was it, 1979? does not influence your results? I notice
the mean min anomaly for February is much smaller than
the general anomaly in the Midlands, which is what one would
expect if you are joining Winterbourne and Edgbaston without
homogenising the records. For various reasons, Edgbaston
enjoyed high minimum temperatures. That would also explain
why you are finding a bias in recent decades.

The difference between CET and Winterbourne has been a gradual,
but steady process over the last 27 years - not a jump - which seems to
imply that it is not the change in station location.

That doesn't really answer my question. Are you using
an unadjusted Edgbaston/Winterbourne record for your
statistics?

Philip