uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old August 28th 06, 10:00 PM posted to uk.sci.weather
external usenet poster
 
First recorded activity by Weather-Banter: Jul 2003
Posts: 943
Default Heavy rain and tipper gauges

Between 17:30 and 20:30 this evening we had around 40mm of rain according to
my automatic (LaCrosse WS-3600) weather station. According to my manual
cone-shaped gauge, which is fairly close by, we had around 18mm.

The automatic gauge is around 1 metre above ground level, and the manual
gauge is stuck into the soil.

The automatic seems to correspond well with the manual in normal conditions.

So, what's wrong? Maybe I need to replace my gauge ... again!

Also TS around 19:00. Graph of today's rain (if you read this today!) from the
automatic at http://users.aber.ac.uk/ais/weather/...hp?data=rtoday

Adrian

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais/weather/ uk

  #2   Report Post  
Old August 29th 06, 04:11 PM posted to uk.sci.weather
external usenet poster
 
First recorded activity by Weather-Banter: May 2005
Posts: 1,907
Default Heavy rain and tipper gauges

"Adrian D. Shaw" wrote in message
...
Between 17:30 and 20:30 this evening we had around 40mm of rain
according to
my automatic (LaCrosse WS-3600) weather station. According to my
manual
cone-shaped gauge, which is fairly close by, we had around 18mm.
The automatic gauge is around 1 metre above ground level, and the
manual
gauge is stuck into the soil.
The automatic seems to correspond well with the manual in normal
conditions.


.... If you have had readings that have corresponded well in the past
(over a long period), then I would suspect a 'one-off' problem with one
or other of the gauges: the declared rainfall from the LaCrosse sounds
high to me - the showers etc., yesterday were pretty heavy, but I'm not
sure we had anything quite that perky.

Try doing a test with the auto by putting a measured amount of rainfall
through it. As you had a thunderstorm, would there be any lightning
interference with the system?

Even with high-end professional kit, things can go wrong (witness
Heathrow/03772 last couple of days), so don't necessarily go out and
replace the gauge / electronics etc., just yet: might have been a
one-off 'glitch'.

Martin.

--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm
and
http://booty.org.uk/booty.weather/metindex.htm


  #3   Report Post  
Old August 29th 06, 07:04 PM posted to uk.sci.weather
external usenet poster
 
First recorded activity by Weather-Banter: Dec 2005
Posts: 170
Default Heavy rain and tipper gauges


Martin Rowley wrote:

Even with high-end professional kit, things can go wrong ...


'Bucket-bounce' even on the best TBRs can be a problem, particularly in
high rainfall rates: the bucket is filling and tipping so quickly, it
can 'bounce' part-way past the reed switch, counting two tips. Some
loggers can be set to refuse two pulses within (say) 500 msec - which
at 0.2 mm tip equates to 1440 mm/hr, which is well above the design
threshold of the instrument itself - which solves the problem.

I have two TBRs and for a while I found one was showing anomalously
high rates during close thunderstorms (one agreed with the checkgauge,
the other didn't - you always need a three-way split to be sure which
is correct) - presumably due to induced currents in the (long) cable
run. Screening the cable run solved this problem. If yours is wireless,
then obviously this won't be directly relevant, but you may find close
'sferics' induce a pulse as Martin suggests.

HTH.

Stephen Burt
Stratfield Mortimer, Berkshire

  #4   Report Post  
Old August 29th 06, 09:43 PM posted to uk.sci.weather
external usenet poster
 
First recorded activity by Weather-Banter: Jul 2003
Posts: 943
Default Heavy rain and tipper gauges

Thanks Martin and Stephen for your advice, I'll wait a bit before I decide
to replace the gauge.

I don't think the thunderstorm was quite close enough to have had an
effect on the cables, and anyway it happened again later in the evening
when no TS was around.

Adrian
--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais/weather/ uk
  #5   Report Post  
Old August 30th 06, 06:28 PM posted to uk.sci.weather
external usenet poster
 
First recorded activity by Weather-Banter: Oct 2004
Posts: 1,163
Default Heavy rain and tipper gauges

On 29 Aug 2006 21:43:02 +0100, Adrian D. Shaw wrote:

I don't think the thunderstorm was quite close enough to have had an
effect on the cables, and anyway it happened again later in the evening
when no TS was around.


My money would be on electromagnetic interference of some sort, be it
from lighting or the chap down the road doing a spot of welding...

The LaCrosse is budget kit like my Oregon. That was very prone to picking
up interference on the rain gauge until I fitted a capacitor and resistor
at the head end. This stops the "bucket bounce" problem either from rapid
tipping or very slow tipping. It also improved the immunity to
interference, thunderstorms within 20 miles would drive it potty, switch
some things on/off in the house would also be registered.

I can't remember the series and/or parrallel capacitor/resistor wiring I
used.

--
Cheers
Dave. pam is missing e-mail





Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Spiders and AWS rain gauges don't mix. Dave Liquorice[_2_] uk.sci.weather (UK Weather) 1 June 7th 09 06:05 PM
Barometric pressure and rain gauges Neil Bradley sci.geo.meteorology (Meteorology) 14 May 5th 04 08:34 PM
Barometric pressure and rain gauges Neil Bradley sci.geo.meteorology (Meteorology) 0 April 23rd 04 05:07 PM
Rain Gauges Howard Neil uk.sci.weather (UK Weather) 6 February 11th 04 11:13 AM
Testing rain gauges ? berksposter uk.sci.weather (UK Weather) 4 November 23rd 03 03:34 PM


All times are GMT. The time now is 06:40 AM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 Weather Banter.
The comments are property of their posters.
 

About Us

"It's about Weather"

 

Copyright © 2017