In addition to a good and accurate weather station, an ideal measurement of the various weather parameters also requires a completely open siting, without any obstacles in the vicinity. Unfortunately, the latter is not always possible. Codes indicate how a measurement in our network may be affected. Below we explain how the weather stations in our network are assessed. General exposure (E) Note: hereafter you will often find a term such as 10h. This means a distance that is 10 times the height of the obstacle, 5h is 5 times the height of the relevant obstacle.
General exposure (E)
![]() Site ratings only relate to the location of the temperature and precipitation instruments, which ideally should be at ground level. Sensors for sunshine, wind speed, etc. are best exposed as freely as possible, and roof or mast mountings are usually preferred. Roof assemblies for wind measurement are again not recommended due to turbulence around the building, unless they are high above it. Installation guidelines are based on a multiple of the height h of the obstacle above the sensor height; the norm is a minimum distance of twice the height (2h). So for a rain gauge 30cm above the ground, a 5m high building should be at least 9.4m away (5m minus 0.3m, x 2), and a 10m building should be at least 17m away of a thermometer screen (10 meters minus 1.5 meters, x2) ![]()
![]() Precipitation measurement (R)
Wind measurement (W)
Overall rating
Note that wind is not included in the overall rating. (image: Vlinder-project University of Ghent) Last update: 08 July 2022 - 09:00 |