On 31/03/2013 12:17, ron button wrote:
The current temperature variations around the country seem to illustrate the
considerable differences from place to place in certain weather conditions .
Today for instance my temp goes up and down with every passing cloud ,as my
screen is on a south facing slope which before the trees come into leaf gets
a good cooking at this time of the year .
At George Booths Epping site about 6 miles north of here ,his 1140z temp was
3.7c whilst mine 5.6c !,which I think raises several questions about the
validity of record breaking events throughout the years.
The 2003 August 10th heatwave record seemed to be dependent on which side of
a hedge the screen was positioned,and I noticed that day a variation im my
garden of nearly 3 degrees dependent of where my thermometers were placed.
As there are millions of variations as to where thermometers can be placed
( excluding the obvious rude ones) perhaps we can take some records with a
large pinch of salt ??.
Stephen Burt of COL and Philip Eden have done some work on this I think so I
would not be so presumptious as to question their findings of course .

RonB


As you say much research had already been done on this, notably the
Brogdale record warmth. Every reading is unique to where it was recorded
and reflects the micro climate at that particular place. I made
recordings, in a screen, during the 62/63 winter. The screen was not on
a stand so the low temperatures, however impressive, were of limited
value. In my current setting I suspect temperatures are, if anything,
slightly on the warm side. Differences between our readings, well we've
got similar instrumentation but 100' higher altitude here and 20 yards
from open countryside. The ground is cold and the last of the snow cover
only cleared yesterday.
From time to time I see weather station setups in my travels. The
majority suggest that they have been sited as well as they could under
the circumstances. I've also come across units, particularly VP2, at the
top of chimneys, TBR and all. I belong to CWOP and this is quite a
common practice in the US.
If you look at the UKMO WOW site the majority the amateur weather
stations are currently showing with +/- 2° of each other but there are
some which are way off, one can only speculate as to the set up there.
On a similar theme I recently compiled a list of annual rainfall totals
for the Epping area back to 1860. I used my own figures back to the
1970's but the rest of the data came from the books of the British
Rainfall Organisation. In this case there is no one weather station
which recorded over this period although all credit to the Nicholl and
Hart families who clocked up a century of readings between them. I ended
up with a lot of data which I plan to put on the website. However it's
the variation in annual totals between different sites within the 3
miles radius which was a bit of a surprise. Again, a variety of factors
possible here.
So, as you say, a pinch of salt is required.


--
George in Epping, west Essex, 350'asl
www.eppingweather.co.uk
www.winter1947.co.uk