Karin.Grust - British Hydrological Society

doi: 10.7558/bhs.2012.ns24
UK trial of the OTT Pluvio 2
Karin Grust 1* and Dave Stewart 2
1
Scottish Environment Protection Agency; 2 Environment Agency
*Email: Karin.Grust@SEPA.org.uk
Abstract
The OTT Pluvio 2 is a gravimetric raingauge which works according to the weighing balance
principle. This paper reports on trails of this equipment carried out by The Environment Agency and
SEPA, in cooperation with the Met Office, to assess performance, accuracy and reliability. Detailed
comparisons and analyses for both trials against other co-located raingauges are presented.
Introduction
The OTT Pluvio 2 is a gravimetric raingauge. It works
according to the weighing balance principle. Digital outputs
(impulse/0.1 mm and frequency/status) and a serial interface,
freely configurable as SDI-12 or RS-485, are available for
transferring the data.
The Scottish Environment Protection Agency
(SEPA), in cooperation with the Met Office, has undertaken
a Pluvio 2 trial at Eskdalemuir in the Scottish Borders. The
Environment Agency (EA) has carried out a trial of this
equipment at Tryweryn in North Wales. OTT Hydrometry has
supported both trials, providing support and installation of a
Pluvio 2 with a 200 cm 2 rim area and a 1500 mm m -2 collection
bucket. All Pluvio 2 data used for these investigations are data
collected from a Pluvio 2 without a rim heater.
Purpose of the Pluvio 2 trials
The purpose of the Pluvio 2 trials is:
• to compare performance against existing technology;
• to test the equipment as a potential low maintenance
raingauge in remote areas that will allow reduced frequency
of site visits compared to existing practice for tipping
bucket raingauges (TBRs);
• to investigate the instrument accuracy and reliability to
allow its operation without the need for a comparison gauge
e.g. a monthly check gauge;
• to assess its performance in measurement of solid
precipitation.
Pluvio 2 performance criteria
An observer-read daily raingauge was the reference for the
daily rainfall total. The Pluvio 2 performance is measured by
its deviation to the observer-read daily gauge over a period of
one month and should not exceed 10% (SEPA) and 8% (EA).
These data were quality controlled by the Met Office. The
observer-read data were replaced by the Met Office quality
controlled data for comparison when it became available.
For the SEPA trial, the Pluvio 2 performance is also
measured by its daily and monthly performance comparison
to other automated raingauges which are four different,
commonly used TBRs installed at the test site within close
proximity of the Pluvio 2 .
The EA 8% comparison is further refined as follows:
• Rainfall > 25 mm in period: within 8%
• Rainfall < 25 mm in period: within 2 mm
Note 1: the following condition applies: there has not been
any snow during the check period.
Note 2: The ‘period’ is currently one month at Tryweryn.
The trial will be considered a success if the Pluvio 2
• performs within 8% (EA) or 10% (SEPA) of the observer
read daily raingauge;
• meets or betters the TBR performance criteria over the
period of the trial;
• requires less maintenance than the TBR in order to provide
confidence that it will extend the interval between site visits
required compared to TBRs;
• data can be successfully collected via logger;
• data can be successfully collected from site via existing
telemetry infrastructure;
• data can be successfully saved into the existing data archive
(WISKI 6 and WISKI7) from either loggers or telemetry.
Test sites
Eskdalemuir
The SEPA test site is located at Eskdalemuir Observatory in
the Southern Uplands of Scotland, Dumfries and Galloway
at an altitude of 242 metres (NGR: NT 235 027). The site is
operated by the Met Office and the British Geological Survey
(BGS). Eskdalemuir Observatory is a meteorological station
and involved with atmospheric pollution measurements
as well as seismic and magnetic observations. The site is
representative for the climate of inhabited areas of high
ground in the northern United Kingdom.
A Pluvio 2 was installed in a pit of about 50 cm depth.
With a total instrument height of about 100 cm, the collection
rim of the Pluvio 2 was about 50 cm above the surface. For
the evaluation of the rainfall data quality from the Pluvio 2 ,
a daily raingauge (read by a Met Office observer at 9:00
UTC) was installed in close proximity to the Pluvio 2 . This
gauge was used as reference check gauge. Furthermore, in
the same area of the test site four different types of tipping
bucket raingauges were installed (ELE, Casella, Rimco and
SBS 500). The daily reference gauge, as well as the TBRs,
were installed on the ground surface with a rim height of
approximately 30 cm. This is the general installation height
in the SEPA raingauge network. The comparison data in
this paper include those from the daily reference gauge, the
BHS Eleventh National Symposium, Hydrology for a changing world, Dundee 2012. ISBN: 1903741181
© British Hydrological Society
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Pluvio 2 weighing raingauge and the four different types of
TBRs. All TBRs were calibrated at a single simulated rainfall
intensity of about 14 to 21 mm hour -1 .
Data from all automatic raingauges were recorded by
a D7141 Dynamic Logic data logger at 15-minute intervals.
The Pluvio 2 was configured for non real time logging. For the
data analysis in this paper, daily and monthly totals as well
as 15-minute data from a heavy rainfall event in May 2011
have been used. On-site air temperature, wind speed and wind
direction recordings were considered during the data analyses.
The Pluvio 2 trial at Eskdalemuir started in November
2009. At the beginning of the trial the Pluvio 2 was undermeasuring
rainfall by 5 to 10% compared with the daily read
reference gauge. With its collection rim being higher off the
ground than the rim of the daily gauge, it was thought that
wind was responsible for the discrepancies. To reduce the
wind effect on the Pluvio 2 , a wind shield was installed in
November 2010. However, the performance of the Pluvio 2 did
not improve. Significant performance improvement occurred
with the Pluvio2 firmware upgrade (to version 1.27.2) on the
16th May 2011. Therefore, in this paper the data analysis is
based on the data collected from the 17th May 2011 onwards.
Tryweryn
The EA test site is located at Tryweryn Dam in North Wales at
an altitude of 255 metres (NGR: SH 881 399). The automatic
raingauges are operated by EA staff and the daily gauge is
read by a Welsh Water member of staff.
The equipment on site consists of
• Fenced compound
• Instrument house
• Manually read daily storage gauge
• Casella TBR, 2 mm tip, 400 cm 2 rim area, providing time
of tip data, connected to a Dynamic Logic 700 telemetry
outstation
• Casella Tipping Bucket Raingauge, 0.2 mm tip, 400 cm 2
rim area, providing time of tip data, connected to a data
logger. These backup instrument data were not used
for comparison. Both TBRs were calibrated at a single
simulated rainfall intensity of between 10 and 15 mm hour -1
• Pluvio 2 , 200 cm 2 rim area, unheated rim, with rim 1 metre
above ground level. This provides rainfall data at 1 minute
intervals. Firmware version was version 1.27.2 throughout
• DuoSens logger system with solar panel / battery power
supply and enclosure
panel and battery combination is sufficient to provide power
throughout the winter periods.
Data analysis
Monthly data analysis
Monthly rainfall totals from the Pluvio 2 at Eskdalemuir
and Tryweryn in comparison with a daily read reference
gauge and one or more different types of TBRs (Figure 1)
show a good performance. Monthly totals at Eskdalemuir
from December, January and February are influenced by
snowfall, resulting in suspect data from automatic raingauges.
Therefore, precipitation data from these months have
been excluded in the monthly performance evaluation.
Monthly rainfall totals of the Pluvio 2 are predominantly
slightly lower than the totals from the daily reference gauge.
The monthly %-difference between the daily
reference gauge and automatic raingauges at Eskdalemuir
and at Tryweryn (Tables 1 and 2) provide further information
about the performance of the Pluvio 2 . Compared with the
reference gauge, all automatic raingauges at Eskdalemuir,
including the Pluvio 2 fulfil the success criteria of 10% (SEPA)
and 8% (EA) during months without snowfall (Table 1) (see
Trial success criteria). On average, all automatic raingauges
were under-catching monthly rainfall totals. The Pluvio 2 and
three of the four monthly gauges achieved results within
–2% of the observer’s readings. The ELE was under-catching
monthly rainfall totals by 5%. However, examining the
amplitude of variation, the ELE provides the most consistent
monthly measurements with an amplitude of variation of
3.2 mm; this is followed by the Pluvio2 with an amplitude
of variation of 5.7 mm from the observers readings over
seven months, as shown in Table 1. The reason for better
Monthly rainfall totals [mm]
350
300
250
200
150
100
50
0
ELE Casella
Rimco SBS 500
Pluvio2
SEPA daily
Data accuracy
affected by snowfall
In February 2012 it was discovered that a problem with the
telemetry outstation configuration rendered a significant
proportion of the data unusable. Data from the back up
DouSens logger was examined and it too was found to
have problems, possibly due to a dirty contact in the cable
connection. It also suffered from power supply problems.
All data from the summer of 2011 have been lost. Data are
available for the following periods from the DouSens logger
as a pulse output from the Pluvio 2 :
• 6 January 2011 – 16 April 2011
• 2 November 2011 – ongoing. This period includes missing
data for the 7 – 10 January 2012.
Met Office quality controlled daily observer data
have been used up to 16 April 2011. Raw data have been
used for the later period but will be substituted with quality
controlled data when this becomes available.
There was significant data loss from the DuoSens
logger during November and December 2010 and four days
were lost in January 2012. This raises a doubt that the solar
2
Monthly rainfall totals [mm]
350
300
250
200
150
100
50
0
Figure 1
Jun-11
Jan-11
Feb-11
Jul-11
Mar-11
Aug-11
Apr-11
May-11
Sep-11
Jun-11
Oct-11
Jul-11
Nov-11
Dec-11
missing data
Aug-11
Sep-11
Oct-11
Jan-12
Casella
Pluvio2
EA daily
Nov-11
Dec-11
Feb-12
Jan-12
Monthly rainfall totals of the Pluvio2 in comparison with a daily
read reference gauge and one or more different types of TBRs
(ELE, Rimco, Casella and SBS 500) at Eskdalemuir (top) and
Tryweryn (bottom).
Mar-12
Feb-12

Table 1
Monthly difference [%] between SEPA daily reference gauge and automatic raingauges (snow free months only).
Greatest and lowest differences of each raingauge are highlighted.
Eskdalemuir ELE [%] Casella [%] Rimco [%] SBS 500 [%] Pluvio2 [%]
June 2011 -3.7 3.4 4.3 2.0 0.2
July 2011 -5.9 -1.3 -0.5 -1.65 -1.6
August 2012 -3.2 1.6 1.7 0.5 -0.2
September 2011 -3.6 -2.2 -1.9 -1.8 0.2
October 2011 -6.4 -6.2 -3.4 -5.1 -1.0
November 2011 -6.2 -6.1 -4.8 -5.1 -5.5
March 2012 -6.3 -3.4 3.4 -0.2 -5.6
Average difference [%] -5.0 -2.0 0.2 -1.6 -1.9
Amplitude of variation (mm) 3.2 9.6 9.1 7.2 5.7
Table 2
Monthly difference [%] between EA daily reference gauge and automatic raingauge.
Greatest and lowest differences of each raingauge are highlighted.
Casella [%] Pluvio 2 [%] Comments
January 2011 -12.0 -0.1 Data from 6th onwards
February 2011 -12.7 -1.2
March 2011 -11.5 -14.2*
April 2011 4.3 14.5* Data from 1st to 16th
November 2011 -0.2 0.0 Data from 2nd onwards
December 2011 -4.2 -2.6
January 2012 -6.6 -3.4
February 2012 -9.4 -4.3
Average difference [%] -6.5 -1.4
Amplitude of difference variation [mm] 17.0 28.7
* Difference may be due to observer error at the end of March and beginning of April.
performance consistency of the ELE and Pluvio 2 raingauges
could be performance differences at varying rainfall
intensities. Analyses of raingauge performances at different
intensities are required to examine this further.
Daily data analysis
Cumulative daily rainfall totals The daily performance of
the Pluvio 2 at Eskdalemuir and Tryweryn using cumulative
daily rainfall totals in comparison with other raingauges is
shown in Figure 2. Cumulative daily rainfall totals measured
by different types of raingauges at Eskdalemuir cover 301
snow free days from the 17th May 2011 to the 31st March
2012 (Figure 2a). Periods of suspect data during winter due to
snow precipitation have been excluded in this analysis. The
measured daily rainfall totals from Pluvio 2 , Casella, Rimco
and SBS 500 raingauges show similar and consistent results
for the observation period. The cumulative rainfall total of the
SEPA daily reference gauge from the 17th May 2011 to the
31st March 2012 was 1670.7 mm. Automatic raingauges were
under-measuring rainfall totals by about 3 to 6% (Table 3).
The performance of the Pluvio 2 with an under-catch of 3.4%
was very satisfying.
Cumulative daily rainfall totals measured at
Tryweryn cover 235 days from the 6th November 2010
to the 29th February 2012 (Figure 2b). This period was
characterised by an intense rainfall event in February 2011
(data from the 17th April 2011 to 2nd November 2011 are
missing). The TBR significantly under-measured during
this event. Before and after this event all three gauges show
excellent comparison.
Correlation analysis The correlation analysis of daily
rainfall totals of the Pluvio 2 gauges at Eskdalemuir and
Tryweryn with the on-site daily reference gauge shows strong
correlations of 99.61% and 98.69% respectively. A strong
correlation between raingauges installed in close proximity
was expected and the correlation of the Pluvio 2 with the
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daily reference gauge is better than the correlation of TBRs
with the daily reference gauge. There are two outliers in the
Treweryn data. On both of these occasions the Pluvio 2 did not
record rainfall measured in both the daily raingauge and TBR.
The missing data at the site (see Figure 2b) were caused by
a ‘dirty’ data lead connection. One of the affected days was
close to the end of the first set of data and the other soon after
data restarted. It is possible that the unrecorded data by the
Pluvio 2 on both of these days was a manifestation of the more
serious problems during the period of missing data.
Sub daily data analysis
The significant two-day rainfall event at Tryweryn (Figure 3
and Table 4) had a maximum rainfall intensity of only around
5 mm hour - 1 but was accompanied by gale force winds. It
might be expected that the higher rim height of the Pluvio 2
would have resulted in it under-catching. In fact it shows
excellent comparison with the daily gauge total for the same
period. The TBR shows significant under-catch against both
of the other raingauges. During a later high rainfall intensity
event (10 mm hour -1 ) on 2nd January 2012, without strong
winds, all three raingauges provided very close rainfall totals
of around 45 mm in 24 hours.
During higher intensity rainfall events
(> 5 mm hour -1 ) at Eskdalemuir the cumulative rainfall
recordings from the Pluvio 2 and the TBRs at 15-mins intervals
are very similar, with a trend of the Pluvio 2 recording slightly
higher event totals than the TBRs (Table 4). It is not clear
whether the Pluvio 2 or the TBR readings during this event
are more accurate. The Eskdalemuir heavy rainfall event
on the 23rd May 2011 happened from 03:00 to 10:30 and
occurred therefore within two water days. It appears that the
windy conditions on site with recorded wind speeds of about
24 miles hour -1 during the event have had no negative impact
on the accuracy of the Pluvio 2 data. The two-daily rainfall
totals shown within brackets in Table 4 provide the totals
from all test gauges for comparison. Interestingly, the twodaily
total for the Pluvio 2 is slightly lower than that of most

a)
Cumulative daily rainfall [mm]
1800
1600
1400
1200
1000
800
600
400
ELE
Casella
Rimco
SBS 500
Pluvio2
SEPA daily
200
b)
0
17 May 06 Jul 25 Aug 14 Oct 03 Dec 22 Jan 12 Mar
1600
Cumulative daily rainfall [mm]
1400
1200
1000
800
600
400
Pluvio2
Casella
EA daily
missing data
200
0
06 Nov 26 Dec 14 Feb 05 Apr 25 May 14 Jul 02 Sep 22 Oct 11 Dec 30 Jan
Figure 2
Cumulative daily rainfall totals from different types of raingauges at Eskdalemuir (top) and at Tryweryn (bottom)
Cumulative rainfall totals [mm]
120
Pluvio2
100
Casella
80
60
40
20
0
00:00 12:00 00:00 12:00 00:00 12:00
Figure 3 Cumulative rainfall totals during heavy rainfall events recorded at 15 Minute intervals at Tryweryn on the 5th and 6th February 2011.
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Table 3
Cumulative rainfall totals from different raingauges at Eskdalemuir from 17th May 2011 to 31st March 2012 and at Tryweryn from the 6th
November 2010 to 29th February 2012 (some missing data) and their differences to a daily reference gauge.
Es k d a l e m u i r
Tr y w e r y n
Raingauge SEPA ELE Casella Rimco SBS 500 Pluvio 2 EA Casella Pluvio 2
reference
reference
Rainfall total [mm] 1670.7 1569.0 1611.4 1622.0 1614.4 1614.3 1372.8 1194.8 1272.4
Difference [mm] - 101.7 59.3 48.7 56.3 56.4 - 103.4 21.6
Difference [%] - 6.1 3.5 2.9 3.4 3.4 - -7.5 -1.6
Table 4
Cumulative rainfall totals of heavy rainfall event Tryweryn on
the 5th and 6th February 2011(48 hour event) and Eskdalemuir
on the 22nd and 23rd May 2011 (7.5 hour event).
Cumulative rainfall Cumulative rainfall
totals [mm]
totals [mm]
05 + 06 Feb 2011 23 May 2011
(Tryweryn, 48 hours) (Eskdalemuir, 7.5hours)
Pluvio 2 109.7 37.1 (50.3*)
Casella 95.2 35.8 (50.6*)
ELE - 35.4 (49.2*)
Rimco - 36.0 (51.2*)
SBS 500 - 36.6 (51.2*)
Two-daily total
(reference gauge) 111.4 53.5
* Two-daily total [mm]
other automatic raingauges.
The impact of the strong winds on the TBR
performance in the February 2011 event at Tryweryn may
be site specific. Results from both trials suggest that further
observations of high intensity rainfall events and events with
high winds would be useful for the further evaluation of the
Pluvio 2 with regard to its recording accuracy.
Comparison of snow data
The performance of raingauges during snowfall events has
been analysed at Eskdalemuir. A snowfall event in December
2011 (Figure 4 and Table 5) is representative for the overall
performance of the Pluvio 2 and TBRs in comparison.
On the 4th December 2011, 15 cm of snow were
ELE
Casella
Rimco SBS 500
Pluvio2 SEPA daily
Recorded daily precipitation totals [mm]
60
50
40
30
20
10
0
Temp
04 Dec 05 Dec 06 Dec 07 Dec 08 Dec 09 Dec 10 Dec
10
5
0
-5
-10
-15
-20
Temperature [°C]
Figure 4
Daily precipitation measured by different raingauges at Eskdalemuir and hourly
temperatures measured at Eskdalemuir from 4th December to 10th December 2011.
Note: SEPA daily measurement on the 6th December is a 48 hour cumulative snow water
equivalent for the 5th and 6th December.
Table 5
Daily precipitation recordings from different raingauges during a period of snowfall, snowmelt and rainfall in December 2011 at
Eskdalemuir
Date ELE Casella Rimco SBS 500 Pluvio2 SEPA daily Snow [cm]**
04 Dec 0.8 0.8 0.8 0.6 12.5 11.2 11.0
05 Dec 2.6 0.6 1.6 0.2 7.0 missing 16.0
06 Dec 12.4 15.0 18.4 0.4 8.0 18.0* 11.0
07 Dec 35.8 43.0 31.8 28.8 26.7 27.5 7.0
08 Dec 10.0 10.0 10.6 10.4 9.8 11.3 -
09 Dec 0.2 0.2 0.2 0.2 1.6 missing -
10 Dec 10.2 10.0 9.6 10.0 9.5 10.7* -
Precipitation total [mm] 72 80 73 50.6 75.1 78.7
* Cumulated total over 2 days
**Automatic snow depth recording at Eskdalemuir at 5:50 UTC (snow depth value displayed within it’s water day i.e. the value measured
on the 5th Dec at 5:50 UTC belongs meteorologically to the 4th Dec).
5

ecorded at Eskdalemuir: this translated into a snow water
equivalent of 11.2 mm measured from the SEPA daily
reference gauge. With 12.5 mm the Pluvio 2 recorded a similar
snow water equivalent as the daily gauge whereas all TBRs
were snow blocked and failed to measure this precipitation
event. With temperatures having dropped below 0 °C over
night, TBRs remained blocked or recorded precipitation too
low. The accuracy of the Pluvio 2 snow water measurement is
unknown as no SEPA daily snow water equivalent is available
for the 5th December. The 48-hour totals of the SEPA daily
gauge (18 mm) and the Pluvio 2 (15 mm) on the 6th December
suggests that the Pluvio 2 is slightly under-catching. The
second half of the 6th December and the 7th December were
characterised by a temperature increase, some precipitation
and snow melt occurring in the TBRs. This resulted in overrecording
of precipitation by the TBRs on the 6th and 7th
December. Further precipitation on the 8th December appears
to be recorded correctly by all raingauges.
Results
Results from Eskdalemuir
The results from the Eskdalemuir Pluvio 2 raingauge trial are
summarised as follows:
• The monthly performance of the Pluvio 2 fulfil the trial
criteria of 10% and better (on average under-catching
rainfall by 1.9% per month)
• Daily rainfall totals measured by the Pluvio 2 were (on
average) under-catching by 3.4%. The TBR performance at
Eskdalemuir was similar to the performance of the Pluvio 2 .
• A strong correlation exists between daily rainfall totals
measured by the Pluvio 2 and the daily reference gauge.
With no outliers, the correlation of the Pluvio 2 is slightly
better than the correlation of the TBRs.
• The most consistent monthly measurements were achieved
by the ELE TBR and the Pluvio 2 .
• The Pluvio 2 is able to measure snow precipitation.
Values appear reliable, but not as accurate as for rainfall
precipitation values. The Pluvio 2 outperforms all TBR
gauges during snowfall events.
Results from Tryweryn
• The Pluvio 2 displays very close comparison against the
daily gauge.
• The TBR under catch of 7.5% may be due it being
calibrated at single rainfall intensity of around 10–15
mm hour -1 rather than across a range of intensities, as
recommended in recent laboratory and field trails of
automatic raingauges in the labortatory (Lanza et al., 2006)
and in the field (Lanza and Vuerlich, 2009).
• A good correlation exists for the Pluvio 2 compared with
the TBR but the trend line gradient again shows the TBR
under-catch.
• The Pluvio 2 has passed the trial success criteria, but with
concern for the two days of very poor performance.
• The Pluvio 2 performed very well in comparison to the daily
gauge during the event at Tryweryn on the 5th and 6th
February. The TBR significantly under-measured this event.
Conclusions
• The Pluvio 2 outperforms TBRs when compared to the
storage daily reference raingauge.
• The Pluvio 2 raingauge compares very well with the TBR
during a high rainfall intensity storm, albeit based upon
examination of a limited number of events only.
• Where a solar panel / battery power is used then this must
be sufficient to last through the winter without power loss.
• The use of a Pluvio 2 can provide an opportunity for time
saving compared to a TBR through reduced site visits and
calibration effort.
• Calibration checks for the Pluvio 2 are easily completed
in the field and take considerably less time to undertake
compared to a TBR; 5 minutes in the field compared to
around 2 hours for a TBR.
• Pluvio 2 data can be successfully collected from sites via
existing telemetry infrastructure.
• Pluvio 2 data can be successfully saved into the existing
data archive (WISKI 6 and WISKI7) from either loggers or
telemetry.
• The windshield installed temporarily over 12 months at
Eskdalemuir did not appear to improve data collection. This
may be site specific.
Recommendations
• Due to the relatively high cost of the Pluvio 2 it should be
deployed where it provides maximum benefits, e.g. remote
locations, logger only sites or where dual TBRs might be
considered.
• The Pluvio 2 rainfall catching orifice is 100 cm high —
considerably higher than a regular TBR or storage gauge.
Although the results from these trials do not indicate any
issues arising from this, consideration should be given to
installing the base on a sunken concrete slab.
• The Pluvio 2 should only be deployed at sites with low
vandalism risk.
• Provided the Pluvio 2 is part of a telemetry system, site visit
frequency in comparison to required TBR maintenance
visits can be significantly reduced, depending on the typical
UK annual rainfall at the site or any other site drivers.
• Where a Pluvio 2 is to be installed with a solar panel and
battery power then if on telemetry it is suggested to set a
low power alarm. The solar panel and battery should be
sized adequately to provide power throughout the winter.
• Further observations of high intensity rainfall events and
events with high winds would be useful for the further
evaluation of the Pluvio 2 with regards to its recording
accuracy.
Acknowledgements
Thanks to Simon Wills (OTT Hydrometry) for the provision
of the Pluvio 2 and installation support at both test sites,
Eskdalemuir and Tryweryn. Many thanks to Ian Dawson
and Billy Jagger (Met Office) for good cooperation and
their thorough daily raingauge readings at Eskdalemuir. We
would like to thank our SEPA colleagues Stuart Smith and
John Scott and EA colleagues Steven Roberts and Christina
McKay for their help with raingauge installations, logger
configurations and maintenance as well as for general
discussions.
• The Pluvio 2 has passed the success criteria at both trials.
• The Pluvio 2 raingauge shows very close relationship with
the storage daily reference raingauge over the period of
both the Tryweryn and SEPA trials.
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References
Lanza, L., Leroy, M., Alexandropoulos, C., Stagi L. and
Wauben. W. 2006. WMO laboratory intercomparison of

ainfall intensity gauges,.Final report. WMO Geneva.
Lanza, L.G. and Vuerich, E. 2009. The WMO Field
Intercomparison of Rain Intensity Gauges. Atmospheric
Research.
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