Distances and measurements in a meteorological observatory

May 4, 2019

The distances in which we place our sensors is essential in meteorological observation

Distances and measurements in a meteorological observatory

Between 1.5 and 2m

The regulations of the World Meteorological Organization (WMO) require legal and regulatory distances for the location of the sensors of a manual or automatic meteorological station.

The 1.5-2m height range is essential for the installation of most sensors, among which we highlight:

Thermometer
Hygrometer
Pluviometer
Heliograph

All this instruments should be located between 1.5 and 2m in height vs. the ground, preferably of natural origin and covered with herbaceous vegetation on the ground. If the installation of the sensors is done inside a meteorological sentry box , the base of this sentry box must be located at a height of 1.2m vs the ground. The heliograph should also be between 1.2 and 1.5m vs. the ground.
The terrain or plot, preferably 6x9m square, should be free of tall trees, instruments such as the rain gauge and rain gauge should be at a distance equal to or greater than those 9m, and in the case of low bushes at a distance greater than 2m . A distance greater than 2m with the fence and greater than 4m from any wall or wall must also be respected.

Davis Complete Wireless Agriculture Weather Station

At 10m

The anemometer is the instrument whose installation differs the most from the others. Both the anemometer (blades / propellers) and the wind vane must be installed at a height of 10m vs. the ground and preferably located at the top of a turret . We will only have one exception, and it is in the case of agricultural use, where the anemometer will be between 2 and 3m high, at a height similar to the height of the crops.

This location is basic to rid the instruments of obstacles and in the case of anemometers this is very important, since the wind is very sensitive to any obstacle that may change its direction and intensity.

Transmission range in automatic stations

In digital or automatic wireless stations we must keep in mind the maximum transmission distance of the sensors, to the data reception console, if the distance exceeds that specified in the manual, the data will not be transmitted correctly.

Normally this distance ranges between 100 and 300m, with the possibility of expanding this range with additional repeaters and transmitters, for example at Davis Instruments brand stations. In these cases the distance is extended to an additional 300m .

In domestic stations, the theoretical distance is less, and can vary between 30 and 100m, in these cases the practical distance may be less, because there is more influence from obstacles and interference.