Installing Wind Sensors
Wind sensors, or anemometers, will produce the most accurate data when they are sited in an area where the wind blows without being obstructed by any nearby objects. Many home weather station users would be hard-pressed to meet the World Meteorological Organisation’s standard placement, which is 33 feet (10 m) above the ground with no interferences at or above that height. A compromise is usually the most practical outcome for home weather station installations.
To give you a little insight into what heights deliver accurate information, the National Weather Service only accepts data from wind sensors that are 23 feet (7 m) above ground or, if the sensor is sited on a roof, 10 feet above the most exposed part. The accuracy is also dependent on the presence of local obstructions, such as buildings and tall trees. The simple fact is that finding an ideal site is difficult; it is up to you how far you want to go with finding a suitable place for your wind sensor.
Once a site has been located, the mast of the wind sensor should be mounted exactly perpendicular to the ground(use a bubble level to ensure that it is vertical) and the wind direction indicator should be faced north. Instead of using a GPS, you should correct the direction of the indicator according to a magnetic compass that has been adjusted by the magnetic declination of the area. If you’re not too familiar with the term “magnetic declination” or the process of correcting a compass to true north, Wikipedia can help.
When raising the mast, there are a number of things to keep in mind. For one, you will need to have access to the sensor for occasional maintenance and maybe replacement so don’t place it somewhere that is exceedingly difficult to get to. If you decide to put it on the roof, position it where it does not threaten to compromise the roof’s integrity. The installation must be sturdy so that icy precipitation and/or high winds do not tear the mast away.
The installation of your wind sensors requires a degree of carefulness, for the sake of the sensor as well as your own safety. Be sure to follow the manufacturer’s recommendations and use your common sense to keep yourself as safe as possible. Make sure that you are in no danger of falling or even grazing any power lines. The sensor should never be in a place where it could fall and contact a power line, either. Never work on your wind sensor when it is hazardous to do so, like when it is very windy or the surface is slick.