Weather Banter - View Single Post

Nick Gardner[_6_] · June 16th 15, 07:20 PM posted to uk.sci.weather

On 16/06/2015 16:48, wrote:
Just how reliable is that UV sensor at St Martins? I say that because using the data from DEFRA realtime UV monitoring, Camborne only managed an index max of 7.6, today and even way down south at Gibraltar it only reached 8.3, where, incidentally, it has yet to reach 10.0 this year.

I recorded a maximum UV today of 7.1, the lowest reading since the 12th.
The reason was that between midday and 14:40 it was rather cloudy and
the 7.1 occurred at 14:45.

Yesterday the UV reached 8.7 at 13:20. By 14:40 it was 7.3 which is
comparable with today. Therefore the UV, given clearer conditions would
probably have been around 8.5.

Looking at the satellite picture, Camborne may have been similarly
affected by cloud for a few hours around high sun and thus read lower
than the UV would otherwise have been.

The Isles of Scilly are renowned for having a very high UV. I went there
(in the days of non-digital SLRs - 1995 I think) and all the photos I
took during the middle part of the day had a blue(ish) tinge to them
with many of the colours 'washed-out' yet the exposure was correct.
Possibly a skylight filter would have helped but my only conclusion was
that the UV must have been very high.

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