On 25/01/2020 21:04, N_Cook wrote:
On 25/01/2020 19:40, Bernard Burton wrote:
I have put together some notes on the recent near record anticyclone over
southern UK, speculating on its cause.

http://www.woksat.info/wwp/atmthk02.pdf


Its given me the opportunity /(necessity?) to generate a tidal curve for
southampton, for generating tide tables for Southampton for 2020 onwards.
Its not generally appreciated that the Admiralty/UKHP (Royal Navy by any
other name) , "premier" tide prediction service, has gone to pot for
Southampton recently.
300,000 printed tide tables for Southampton 2020 printed and all wrong.
With the extended calm weather I've been generating reliable harmonic
constants for Southampton . I suspect the trouble started with building
the Cowes breakwater, or deep dredging of Southampton Water for the
biggest contained ships or maybe even the dredging of Pompey area for
the new battleships, ;loads of unknowns.



I should say I suspect its a GIGO situation , not the fault of the
Admiralty/UKHO.
A hundred years ago the same thing happened, the Admiralty used the
Southampton tide-gauge plots as data source for the pulleys and wire
tide "computer". But no-one knew the tide gauge float was soft bottoming
out on silt build up in the stilling well, hence false data , resulting
in false tables and complaints from purchasers of the tables/
operationally critical users.
Currently the main Southampton tide-gauge has been reading c0.1m too
low, but no one there realises, by simply comparing with the EA Woolston
tide-gauge (plus 2.74m) for example. This is probably due to water
ingress into the air delivery pipe to the bubbler, but no one must
routinely purge the line with compressed nitrogen.
Perhaps the sampling period for the Admiralty data also contained
similar erroneous readings, again more unknowns.

--
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