The total for June 2010 was 279 hr (KZS), which 'rectifies' to a CSR
figure of 338 hr.

I recorded 316 hours of sunshine for this June with a R&D type sun sensor.

How would that compare with the old CSR?

Thinking about it, the R&D sensor would not record as much sunshine during
days with frequent sunny intervals. But I cannot imagine the CSR would
record sunshine to within 10 - 15 minutes after sunrise and before sunset,
as my R&D does. I did think that over time the two differences cancel each
other out and the values would be pretty similar.

Whatever the outcome, this June was certainly sunny and there were days
where the sun shone through thin, high cloud but there was too diffuse a
shadow for the R&D sensor and it failed to record as much sunshine as there
really was. Maybe a CSR would have registered more sunshine under those
conditions. Are there any studies to determine the differences? If I had a
CSR I would certainly trial them side-by-side.
_____________________
Nick
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk