On Nov 5, 10:21 am, "Ken Cook" wrote:
Hi, All,

Since the Met O supplied me with their standard thermometer mount in
the screen in summer - I had always used my Casella type before - I
have had a couple of erroneous minima readings. I always have a
reasonable idea what the minimum will be from the Davis set up and can
therefore spot an error immediately.

During windy spells the min tends to shake down with the screen
vibration sometimes by a few degrees! I can use the Davis to give me a
good estimate, though.

I am working on this atm but will contact Eskdalemuir soon if there is
no improvement. Does anyone have a cure? I have set the minimum level
to offset the standard recommended 5 degree slope to the bulb and thus
negate gravity, but still no joy.

Lee slope gusts are common here and the consequent errors would make a
noticeable difference if not spotted.

I wonder how many "official" stations are so-affected and go
un-noticed?

Gusty Pennine Wave on atm (well forecast as usual) - around westerly,
gusting to 40KT and 10min means F7 going down to F2 at times. Dave,
surely it's windy with you by now up there?

Ken
Copley 253metres asl, nr Barnard Castle, Teesdale, County Durhamhttp://copley.mysite.orange.co.uk

An easy way to get round this is to set the minimum thermometer
level. This will ensure there is no bias toward the thermometer
reading low, should it be disturbed, because it would be equally likely
to read high. It is true that there would be no help from gravity
pulling the index back as the temperature falls but that is only a
small effect (sin 5° times the weight of the index, about 0.09). The
damping clips suggested by others are a good idea, too.

Tudor Hughes, Warlingham, Surrey.