Based admittedly on a limited sample (2/2), the R&D sunshine recorders
seems to suffer from slight over-recording in unbroken sunshine, by
1-2%.

This is easily identified if you log the pulses to a datalogger, when
an hour of unroken sunshine will more often than not show up as 1.01
or 1.02 hours (i.e. 101 or 102 pulses per hour), but the overcounts
are much less easily identified if only the daily total is available.

On recent sunny days, my unit has over-recorded by a little more than
1% - for example on 2 June 15.39 h (corrected to 15.20 h by changing
all hourly values 1.00 h to 1.00). Normally this doesn't make very
much difference, but on days with unbroken sunshine it can produce a
total considerably closer to the astronomical daylength (i.e. sunrise
to sunset) than is actually the case. These units are much better near
the horizon than a Campbell-Stokes recorder, but even with clear
skies, no dew and a good horizon in my 8 years of using one it seems
they are unlikely to pick up more quickly than about 15 minutes after
sunrise, and stop about the same before sunset (corresponding to just
2-3 deg of solar elevation).

Those of you with R&D units might care to note carefully the displayed
total duration as shown on your unit over a few hours on a day with
unbroken sunshine to see whether yours does the same. Over 5 hours,
say, timed accurately (within a few seconds) I suspect you'll see
5.05-5.08 hours.

I'd be interested in whether my suspicions are correct - feedback
welcome.

--
Stephen Burt
Stratfield Mortimer, Berkshire

For those of us that use the R&D sunshine detector, and who determine the
sunshine hours using the analogue output of the recorder, which is an
unambiguous 'on/off' voltage, via an analogue to digital converter, such as
the Pico logger, the actual time that the recorder is in the 'on' state can
be determined very accurately, to better than the nearest half second. On my
set-up, using this method, the daily values of accumulated sunshine
displayed on the meter compared to the actual duration are 1.15% greater, in
agreement with Stephen's findings below. I know that some of you already use
the Pico logger method, but for others who may be interested, it is a
worthwhile upgrade to the R&D recorder.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.woksat.info/wwp.html

wrote in message
...
Based admittedly on a limited sample (2/2), the R&D sunshine recorders
seems to suffer from slight over-recording in unbroken sunshine, by
1-2%.

This is easily identified if you log the pulses to a datalogger, when
an hour of unroken sunshine will more often than not show up as 1.01
or 1.02 hours (i.e. 101 or 102 pulses per hour), but the overcounts
are much less easily identified if only the daily total is available.

On recent sunny days, my unit has over-recorded by a little more than
1% - for example on 2 June 15.39 h (corrected to 15.20 h by changing
all hourly values 1.00 h to 1.00). Normally this doesn't make very
much difference, but on days with unbroken sunshine it can produce a
total considerably closer to the astronomical daylength (i.e. sunrise
to sunset) than is actually the case. These units are much better near
the horizon than a Campbell-Stokes recorder, but even with clear
skies, no dew and a good horizon in my 8 years of using one it seems
they are unlikely to pick up more quickly than about 15 minutes after
sunrise, and stop about the same before sunset (corresponding to just
2-3 deg of solar elevation).

Those of you with R&D units might care to note carefully the displayed
total duration as shown on your unit over a few hours on a day with
unbroken sunshine to see whether yours does the same. Over 5 hours,
say, timed accurately (within a few seconds) I suspect you'll see
5.05-5.08 hours.

I'd be interested in whether my suspicions are correct - feedback
welcome.

--
Stephen Burt
Stratfield Mortimer, Berkshire

My R&D sunshine recorder actually under-recorded by about 10% when I first
got it. This wasn't brought to my attention until a few cloudless days had
happened and I also compared my records with a couple of reasonably close
stations which showed significantly higher sunshine levels.

There is a way of adjusting the clock counter on the circuit board of the
unit, and by taking 1 hour slots of unbroken sunshine and a stopwatch you
can actually get the adjustment pretty much spot on.

I now use a datalogger which eradicates any timing issues but at the end of
a sunny day with say, 10 hours of sunshine, the R&D unit display is usually
within a minute or two at the most of the datalogger.
________________
Nick.
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk

wrote:

I'll second that Stephen, just got back from Rye and in the 4 days I
have had to use the ADC-16 Data logger the total on the R&D Console is
9.30 hours, whereas adding the data from the spreadsheet produced from
the logged data totals = 9.37 hours. For consistency I tend to make a
guestimate of the % relative to any individual days count so the total
will = 9.30. eg 1.47 ~ 1.46, 5.46 ~ 5.42 & 2.44 ~ 2.42. My 1st day (5th)
recorded no sun at all.

Amazed at the difference in weather at home in Southend-on-Sea, to the
glorious sunshine we had at Rye ;-)

--
Keith (Southend)
http://www.southendweather.net
e-mail: kreh at southendweather dot net

Amazed at the difference in weather at home in Southend-on-Sea, to the
glorious sunshine we had at Rye ;-)

--
Keith (Southend)http://www.southendweather.net
e-mail: kreh at southendweather dot net

That's the south coast for you

Completely [OT] all this

All along the south coast the sea is sort of there.
The sun is sort of shining through a sort of salt-sea air.
There's a sort of "shall we" or "shan't we", a sort of "yes" or "no",
A sort of rolling up of trouser legs and a dipping of the toe.

All along the south coast the day is sort of bright.
At least it's sort of brighter than it sort of is at night,
A sort of "should we" or "could we", a sort of "yes" or "no".
It could be sort of fun. We ought to sort of have a go.

All along the south coast they're turning out the lights.
It's sort of past 11 o'clock; we've sort of seen the sights.
There's a sort of "shall we", "dare we", a sort of groping of the
thighs,
A sort of gasp of sort of pleasure, a sort of burst of sort of sighs.

All along the south coast the waves beat on the shore.
They sound, well, sort of different now than they sort of did before.
There's a sort of "did we" or "didn't we", a sort of smoothing down of
clothes,
A sort of "better take you home now, do you think it sort of shows?"

All along the south coast we sort of settle down.
It's just as sort of good as any other sort of town.
Only now we're sort of older, we sort of stop at home.
We paint the walls and mow the lawn and leave the world alone.

All along the south coast the sea is sort of there.
The sun is sort of shining through a sort of salt-sea air.
And all along the south coast can still be sort of seen,
A corner of sort of England that's forever sort of green.

(Jeremy Taylor)

Not like me to turn all poetic, but I think it's a great little ditty,
takes me back to the great days at the Pipers Folk club in Botallack
in the late '60s, saw people like Steeleye Span, Ralph McTell, Jasper
Carrot etc. before they were famous and went downhill. Also saw Jethro
Tull when they 1st started, they didn't go downhill. (Sorry, drifting
off weather onto one of my other main interests) Missed The Beatles at
Newquay sadly - I was a bit young to venture so far.

Graham
Penzance
(where it's been a thoroughly miserable day - weather wise)
www.sennen-cove.com/today2.htm