The proper place and way of installing sensors is important for the purpose of obtaining reliable and valid data.
Installation guides have been suggested by the World Meteorological Organization, the National Meteorological Service and the U.S. National Weather Service.
These suggestions are summarized below:
Wind Direction and Speed
- The standard height for wind measurement is 10 m above ground level. In some particular applications (as in the fight against forest fires), it is carried out at 6 m.
- The distance between the sensor and any obstruction (natural or artificial) must be at least 10 times the height of the sensor.
- If the sensor is mounted on a building, it must be installed 1.5 times the height of the building, in order to move it away from the area where the air flow is disturbed.
- In tall buildings, this cannot always be accomplished, so it is recommended to mount them on a 3.5 to 5 m. high and on the side of prevailing winds.
- If the sensors are mounted on a support on a tower, the support must be longer than 2 times the diameter or diagonal of the tower. It must also be installed on the side of prevailing winds.
Temperature and Humidity
- The standard height for mounting these sensors is 1.25 to 2 m, above ground level, although special requirements may use other heights.
- The floor under the sensors should be short grass or natural ground, but never concrete or asphalt.
- The area under the sensors must be open at least 9 m. in diameter, should also avoid steep slopes, hills and holes.
- The distance between the sensors and any obstruction (natural or artificial) must be at least 4 times the height of the obstruction.
- If mounted on a tower, the support must be at least once the diameter or diagonal of the tower.
- Temperature sensors must have the suction inlet down.
- The location on a high platform or roof of a building is convenient.
- The place must be free of obstructions capable of causing shadow on the sensor.
- Colored walls, or artificial sources of radiation should be avoided.
- The rain gauge should be mounted so that its base is horizontal. Normally it is installed with its mouth at 1.5 m. ground.
- The surface around the sensor must be of natural vegetation or gravel. It must not be pavement since it can cause splashes.
- The distance between the sensor and any obstruction to the wind must be at least 2 times the height of it.
- In open areas it is advisable to use wind shields.