Wind speed

Wind speed affects weather forecasting, aviation and maritime operations, construction projects, growth and metabolism rates of many plant species, and has countless other implications.

[4] For historical reasons, other units such as miles per hour (mph), knots (kn),[5] and feet per second (ft/s) are also sometimes used to measure wind speeds.

These include the pressure gradient, Rossby waves, jet streams, and local weather conditions.

The pressure gradient, when combined with the Coriolis effect and friction, also influences wind direction.

[citation needed] The fastest wind speed not related to tornadoes ever recorded was during the passage of Tropical Cyclone Olivia on 10 April 1996: an automatic weather station on Barrow Island, Australia, registered a maximum wind gust of 113.3 m/s (408 km/h; 253 mph; 220.2 kn; 372 ft/s)[6][7] The wind gust was evaluated by the WMO Evaluation Panel, who found that the anemometer was mechanically sound and that the gust was within statistical probability and ratified the measurement in 2010.

], the second-highest surface wind speed ever officially recorded is 103.266 m/s (371.76 km/h; 231.00 mph; 200.733 kn; 338.80 ft/s) at the Mount Washington (New Hampshire) Observatory 1,917 m (6,288 ft) above sea level in the US on 12 April 1934, using a hot-wire anemometer.

The anemometer, specifically designed for use on Mount Washington, was later tested by the US National Weather Bureau and confirmed to be accurate.

[8] Wind speeds within certain atmospheric phenomena (such as tornadoes) may greatly exceed these values but have never been accurately measured.

[9] Using this method, a mobile radar (RaXPol) owned and operated by the University of Oklahoma recorded winds up to 150 metres per second (340 mph; 540 km/h) inside the 2013 El Reno tornado, marking the fastest winds ever observed by radar in history.

[15] A device consisting of a vertical pillar and three or four concave cups, the anemometer captures the horizontal movement of air particles (wind speed).

Electronic circuits inside measure the time it takes for the sound to make its journey from each transmitter to the corresponding receiver.

[19] Historically, wind speeds have been reported with a variety of averaging times (such as fastest mile, 3-second gust, 1-minute, and mean hourly) which designers may have to take into account.

An anemometer is commonly used to measure wind speed.
Global distribution of wind speed at 10m above ground averaged over the years 1981–2010 from the CHELSA-BIOCLIM+ data set [ 1 ]
The original anemometer that measured The Big Wind in 1934 at Mount Washington Observatory
Modern day anemometer used to capture wind speed.
FT742-DM acoustic resonance wind sensor, one of the instruments now used to measure wind speed at Mount Washington Observatory
Anemometer on an outdoor stage set, to measure wind speed