The Centre for Ecology & Hydrology has been measuring daily rainfall, sunshine and temperature at its Wallingford, Oxfordshire meteorological station since 1962. Observations are also made of cloud cover, present weather and visibility. This presentation was made to members of the Royal Meteorological Society's Meteorological Observing Systems Special Interest Group on 25 July 2014. Read more on the CEH blog: http://cehsciencenews.blogspot.co.uk/2014/07/royal-meteorological-society-members-visit.html

1. Introduction to CEH Wallingford
Meteorological Station
Katie Muchan, Site Manager
Royal Meteorological Society Visit - 25th July 2014
Photo:KatieMuchan

2. Outline
• Site and record history
• Current monitoring
• Analysis of the record
• Extremes in the record
• Ground level vs. Standard gauge
• Surface – groundwater interactions
• Data use

3. Site History
Starting in 1962, the site now has 52 complete years
of record for some variables (sunshine, max and min
air temperature)
Mean Temperature
Temperature(°C

4. Site History
Since the last RMS
visit in 2007, the
site has moved
twice
1962 – 2007
location
2007 – 2011
location
2011 – current
location Source: Bing Maps

5. Current site instrumentationManual Site
Wind vane and anemometer
Stevenson screen (4 x air temperature)
Soil thermometers (10cm, 30cm, 100cm)
Ground temperature (concrete and grass)
Campbell-Stokes sunshine recorder
Storage raingauges (standard and ground-
level)
AWS
Didcot AWS (air temperatures, wind
direction, wind speed, solar radiation,
sunshine)
Tipping bucket raingauges (standard and
ground-level)
Equipment Testing Area
Snowdon raingauge
Radiometers
Soil moisture probes

6. Analysis: Site Records
• Extremes recorded at the site over the last 53
years
• Most recently, the wettest winter on record
(2013/2014)
Record Day / Month Figure
Wettest month August 1977 163.6mm
Driest month April 2007 1.0mm
Warmest day 19th July 2006 35.2°C
Coldest night 14th January 1982 -21.0°C
‘Sunniest’ month June 1975 291.5 hours
‘Cloudiest’ month December 2010 12.7 hours

7. The winter of 2013/2014
• Three months of
above average
rainfall
December
2013
January
2014
February
2014
Winter
2013/2014
Total rainfall in mm 97.9 148.4 112.9 359.2
Maximum monthly rainfall total in mm
(Year*)
131.2
(1989)
118.7
(1995)
103.3
(1990)
311.5
(1989/1990)
Average monthly rainfall total in mm 57.7 54.6 37.5 148.8
% of monthly average 170 272 302 241
Photo: Katie Muchan
Photo: Katie Muchan

8. The winter of 2013/2014
• Three months of
above average
rainfall
• Total rainfall:
359.2mm
• Annual average of
595.4mm
• Previous maximum:
311.5mm
Photo: Katie Muchan
Photo: Katie Muchan

9. The winter of 2013/2014
• Three months of
above average
rainfall
• Total rainfall:
359.2mm
• Annual average of
595.4mm
• Previous maximum:
311.5mm
• Widespread and
persistent flooding
Photo: Katie Muchan
Photo: Katie Muchan

10. Analysis: Raingauge height
• ‘Undercatch’ in standard
raingauges from several
sources
• Exposure (wind) thought
to cause the largest
difference
Photo: Harry Dixon
Rodda and Dixon (2012) Rainfall Measurement Revisited,
Weather, 67. 5. 131-136. DOI: 10.1002/wea.875

11. Analysis: Raingauge height
• ‘Undercatch’ in standard
raingauges from several
sources
• Exposure (wind) thought
to cause the largest
difference
• Extensive tests in 1960s
• Both still in use on the
site today
Photo: Harry DixonPhoto: Harry Dixon
Rodda and Dixon (2012) Rainfall Measurement Revisited,
Weather, 67. 5. 131-136. DOI: 10.1002/wea.875

12. Analysis: Raingauge height
• Tests in the 1970-80s showed up to 16% ‘undercatch’ at
exposed sites
• Wallingford site: average annual difference in catch was
5.6% (1969-2006)
Rodda and Dixon (2012) Rainfall Measurement Revisited, Weather, 67. 5. 131-136. DOI: 10.1002/wea.875

13. Analysis: Rainfall, Rivers & Groundwater
• Rainfall, groundwater
level and river level
monitoring with BGS

14. Analysis: Rainfall, Rivers & Groundwater
• Rainfall, groundwater
level and river level
monitoring with BGS
• How do groundwater
levels in a shallow aquifer
interact with rainfall
events?
• Aquifer and river show
quick response to rainfall

15. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558

16. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme

17. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme

18. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme
• Small information pieces
• CEH blog post on winter rainfall
• Data included in BHS Circulation bulletins

19. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme
• Small information pieces
• CEH blog post on winter rainfall
• Data included in BHS Circulation bulletins
• Support CEH research
• Instrument testing
• Site visits
http://cehsciencenews.blogspot.co.uk/2014/03/winter-rainfall-record-wallingford-
met-site.html

20. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme
• Small information pieces
• CEH blog post on winter rainfall
• Data included in BHS Circulation bulletins
• Support CEH research
• Instrument testing
• Site visits

21. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme
• Small information pieces
• CEH blog post on winter rainfall
• Data included in BHS Circulation bulletins
• Support CEH research
• Instrument testing
• Site visits

22. Outreach and Data Uses
• Part of the Met Office
National climate network
• Site 5558
• Support National Hydrological
Monitoring Programme
• Small information pieces
• CEH blog post on winter rainfall
• Data included in BHS Circulation bulletins
• Support CEH research
• Instrument testing
• Site visits

23. Website
• Launched in
December
2012
• Near real-time
daily data
• Future plans
to add AWS
data
http://www.ceh.ac.uk/data/metsite/wallingfordmetsite.html

24. CEH Monitoring
• Wider meteorological
monitoring network
• Other CEH
monitoring networks
• Ecological
• Soils
• Vegetation
• Water
• Air Chemistry
COSMOS-UK
Chalk Rivers Biosphere-Atmosphere
Interactions
Soils

25. Thank You
Photo:HarryDixon