COL station grading scheme - 2009

How to use the form

First, please complete the section giving your observer/site details.

Then, please read the sectional notes on the form and identify which category in each best applies to your site, then select the category for each element from the drop-down menus in the left column.

Once you have selected all 7 categories, click on submit.


Observer/site details

Enter your COL station name
Enter your COL station number (look here if you do not know it.)
Enter your name
Enter your email address
Day Month Year Enter today's date

Where site photographs are required, please send them to r.brugge@rdg.ac.uk


EXPOSURE

  • Exposure ratings relate to the site of the temperature and rainfall instruments only, which should normally be at ground level. Sensors for sunshine, wind speed etc are best exposed as freely as possible and rooftop or mast mountings are often preferable.
  • Exposure guidelines are based on a multiple of the height h of the obstruction above the sensor height; the standard is a minimum distance of twice the height (2h). Thus for a raingauge at 30 cm above ground, a building 5 m high should be at least 9.4 m distant (5 m less 0.3 m, x 2), and a 10 m building should be at least 17 m from a thermometer screen (10 m less 1.5 m, x2)
  • If the temperature and rainfall sensors are not on the same site, code for the most limited sensor exposure.
Your entry for E: E EXPOSURE
5 Very open exposure; no obstructions within 10h or more of temperature or rainfall instruments
4 Open exposure; most obstructions/heated buildings 5h or from temperature or rainfall instruments, none within 2h
3 Standard exposure; no significant obstructions or heated buildings within 2h of temperature or rainfall instruments
2 Restricted exposure; most obstructions/heated buildings >=2h from temperature or rainfall instruments, none within 1h
1 Sheltered exposure; significant obstructions or heated buildings within 1h of temperature or rainfall instruments
0 Very sheltered exposure; site obstructions or sensor exposure severely limit exposure to sunshine, wind, rainfall
R Rooftop site. Rooftop sites for temperature and rainfall sensors should be avoided where possible.
U Exposure unstated or unknown

AIR TEMPERATURE

STANDARD INSTRUMENTS in this context means -
Calibrated mercury-in-glass thermometers or electronic sensors exposed in a standard pattern of Stevenson Screen, or a model of AWS screen which has been trialled alongside a Stevenson screen and been shown to provide similar or better performance than the Stevenson screen.
Your entry for T: T MEASUREMENTS OF AIR TEMPERATURE
A Standard instruments in Stevenson Screen or approved AWS radiation screen, calibration within last 5 yr, site exposure minimum = 3
B Standard instruments in Stevenson Screen or approved AWS radiation screen, calibration within last 5 yr, site exposure = 2 or 3
C Standard instruments in Stevenson Screen or approved AWS radiation screen, site exposure 1 or less
C2 Non-standard instruments and/or no or non-standard radiation screen and/or sheltered site, site exposure 1 or less
U Instruments unknown or not stated
- No air temperature measurements made at this site

RAINFALL

STANDARD INSTRUMENTS in this context means -
Standard-pattern (Snowdon or Met Office Mk II pattern) 'five-inch' copper raingauge, with deep funnel, the rim of the gauge level and mounted at 30 cm above ground level, meeting the minimum 'twice the height' exposure requirement.
Your entry for R: R MEASUREMENTS OF RAINFALL
A Standard 'five inch' manually-read raingauge, at standard height above ground (30 cm), site exposure minimum = 3
B Standard 'five inch' manually-read raingauge or calibrated 0.1 mm or 0.2 mm capacity tipping-bucket raingauge, the rim mounted at standard height above ground (30 cm), exposure = 2 or 3
C Standard 'five inch' manually-read raingauge or calibrated 0.1 mm or 0.2 mm capacity tipping-bucket raingauge, the rim mounted at standard height above ground (30 cm), exposure 1 or less
C2 Non-standard raingauge and/or tipping-bucket raingauge with capacity > 0.2 mm, and/or raingauge rim mounted higher than 30 cm above ground (30 cm), and/or sheltered site, exposure 1 or less
U Instruments unknown or not stated
- No rainfall measurements made at this site

SUNSHINE

STANDARD INSTRUMENTS in this context means -
Campbell-Stokes sunshine recorder or electronic sunshine recorder (R&D Electronics model, or the Met Office standard Kipp & Zonen CSD sensor). The instrument should be mounted in a location where it has the best possible view of the sky at all seasons.
Your entry for S: S MEASUREMENTS OF SUNSHINE
A Standard sunshine recorder, nil or very slight exposure obstruction (average obstruction 5% or less across the year, maximum 10% at any time of year)
B Standard sunshine recorder, partially obstructed exposure (average obstruction 10% or less across the year, maximum 20% at any time of year)
C Non-standard sunshine recorder or sunshine estimated from pyranometer/solarimeter record and/or very obstructed exposure
U Instruments unknown or not stated
- No sunshine measurements made at this site

TERMINAL HOURS

Your entry for H: H TERMINAL HOURS
A Morning terminal hours. Air temperature and rainfall terminal hour is between 0600 and 0900 GMT, daily temperature and rainfall values relate to standard 24 hour period morning to morning
B Midnight terminal hours. Air temperature and rainfall terminal hour is 0000 GMT daily. (This is the default on most AWS.)
C Other terminal hours. Air temperature and rainfall terminal hour is other than A or B above, or extremes do not relate to 24 hour periods
U Terminal hours unknown or not stated

OKE'S URBAN CLIMATE ZONE INDEX

These are taken from Oke, T.R., 2007: 'Siting and exposure of meteorological instruments at urban sites'. In: Air Pollution Modeling and its Application XVII, Borrego, C. and A.-L. Norman, (eds.), Springer, 615-632. There is a copy of the paper at http://www.urban-climate.org/ > Urban Climate Resources which includes more details and graphical examples of the 'skyline' which may help you to assign the correct rating.
Your entry for U: U OKE'S URBAN CLIMATE ZONE INDEX
1 Intensely developed urban zone with detached close-set high-rise buildings with cladding, e.g. downtown towers
2 Intensely developed high density urban with 2 - 5 storey, attached or very close-set buildings often of brick or stone, e.g. old city core
3 Highly developed, medium density urban with row or detached but close-set houses, stores & apartments e.g. urban housing
4 Highly developed, low density urban with large low buildings & paved parking, e.g. shopping mall, warehouses
5 Medium development, low density suburban with 1 or 2 storey houses, e.g. suburban housing
6 Mixed use with large buildings in open landscape, e.g. institutions such as hospital, university, airport
7 Semi-rural development with scattered houses in natural or agricultural area, e.g. farms, estates
U Urban Climate Zone unstated or unknown

NETWORK

Your entry for N: N NETWORK
S Synoptic site. Contributes one or more daily observations in real-time to the WMO synoptic network
C Climatological site. Contributes daily climatological data to the national climatological network (Met Office/Met Eireann), normally monthly
R Rainfall site. Contributes daily rainfall data to the national raingauge network (Met Office/Environment Agency/Met Eireann), normally monthly
- Station data not provided to other national networks apart from COL

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Last modified / 13.01.09 / r.brugge@rdg.ac.uk