On 09/10/2017 19:15, Ken Cook wrote:
Wow, Norman. Another really low sunshine figure. 40 hours so far in Copley. Is your recorder well exposed or quite sheltered?
Difficult to compare sunshine as some have their electronic recorders on the top of tall masts to catch every bit of sun. My Campbell Stokes is, obviously, at a more realistic height of four feet above the ground.

Ken, my Instromet sunshine recorder is on a pole attached to the side of
the house at 9 metres (1 metre below the anemometer).

If my sunshine recorder was at 4 feet, I wouldn't record any sunshine
until 10am at the earliest and nothing after 7pm (house in the way)!

It is at that height to clear the trees at the bottom of the garden but
it doesn't clear the hills! The very best I can get is that the recorder
turns on about 30 minutes before sunrise in one of the dips between the
hills (but that is very rare). Mostly it is 40 to 50 minutes after
sunrise before the recorder will turn on. Sunset isn't so bad as the
hills to the west are further away and not so high, therefore under
clear conditions the recorder turns off about 20 minutes before sunset.

Under extremely clear conditions I can record 93% of the total possible
in the summer (less in the winter). I have recorded 95% but that is
very, very rare.

Therefore I suspect my sunshine figures are a little below the actual,
but not by a huge amount.

--
Nick Gardner
Otter Valley, Devon
20 m amsl
http://www.ottervalleyweather.me.uk