Wind speed is measured using a device called an anemometer. The name anemometer is derived from the Greek word for wind. Accurate wind speed and direction data are critical to the airline industry and to weather forecasters. All airports have an anemometer nearby to determine if conditions are safe for planes to take off and land. Weather forecasting organizations also use anemometers to prepare local and national weather reports.
Types of Anemometers
There are several types of anemometers. The most common are the cup anemometer and the propeller anemometer. A cup anemometer has three small cups attached with rods to a rotating center pole. Propeller anemometers resemble a pinwheel with blades that spin when moved by the wind. The number of rotations per minute is registered on a counter and is used to calculate the wind speed. Most anemometers are used in conjunction with a weathervane or wind sock to determine the direction of the wind as well as the speed. Advanced anemometers, including Doppler and sonic anemometers, use more technical means to gather wind speed information and are generally used by professional weather forecasters.
Anemometers may be mounted on the roof of a building but care must be taken to ensure that the anemometer will not come loose in extremely high winds and damage the roof. Anemometers can also be placed on a freestanding scaffolding or tower. When used for official weather observations, land based anemometers are located around 10 meters off the ground. Anemometers can be purchased for home use, and are often included in home weather stations. Wind speed is measured at sea using anemometers placed on ocean buoys. Information gathered from anemometers at sea can be used to track hurricanes and tropical storms and is available online through the NOAA National Data Buoy Center.