On Thursday, 25 February 2016 10:46:00 UTC, George Booth wrote:
On 25/02/2016 10:23, John Hall wrote:
The MetO fully intend to make use of WOW information in model analyses
and a whole host of other data types. They will be able to do this due
to improved data error co-variances and some cunning mathematical
trickery which I cannot go into here. This is due to happen by the end
of this decade.
That makes me a little uneasy. Will they be able to get rid of all the
wrong data, of which I'm sure there must be a lot on WOW? And there's
also the opposite problem that, the more stringent their checks, the
greater the risk that some valid and important - but unexpected - data
might be discarded. Take the Hampstead thunderstorm in August 1975, for
instance, when a phenomenal amount of rain fell in an hour or so when
IIRC practically everywhere else in the country was dry. I can imagine
the vetting algorithm seeing a WOW report of say 160mm of rain and -
with no other reports of rain - deciding that it must be a typo for 16mm
or even 1.6mm.
Yes, these were my thoughts as well. If you look at the WOW homepage
there are very obviously a (minority) of AWS which suffer from poor
exposure and/or inaccurate instrumentation. The same thing is obvious
when looking at Weather Underground maps as well. As long as some
filtering/moderation of data from such AWS data takes place then I would
agree they have a value. I would add that all the folk I've spoken with
over the years who've set up AWS have been most conscientious in
ensuring that their data is as accurate as can be. However we now have a
lot of low cost units available which are set up with insufficient
regard for siting requirements.
--
George in Swanston, Edinburgh, 580'asl
www.swanstonweather.co.uk
www.eppingweather.co.uk
www.winter1947.co.uk
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Site requirements George?
The vast majority of WOW members measure the conditions in their garden.
Wonderful microclimates. Just what the models Will dreams about need.
Data to supply the models at 1 metre resolution.
Fantastic.
I will of course charge UKMO for my measurements. :-)
Len
Wembury, SW Devon
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