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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 ...
Wind speed Wave height Sea conditions Land conditions Sea conditions (photo) Associated warning flag 0 Calm < 1 knot < 1 mph < 2 km/h 0–0.2 m/s: 0 ft 0 m Sea like a mirror Smoke rises vertically 1 Light air 1–3 knots 1–3 mph 2–5 km/h 0.3–1.5 m/s 0–1 ft 0–0.3 m Ripples with appearance of scales are formed, without foam crests
The radius of curvature of the sound path is inversely proportional to the velocity gradient. [50] A wind speed gradient of 4 (m/s)/km can produce refraction equal to a typical temperature lapse rate of 7.5 °C/km. [51] Higher values of wind gradient will refract sound downward toward the surface in the downwind direction, [52] eliminating the ...
At 0 °C (32 °F), the speed of sound in air is about 331 m/s (1,086 ft/s; 1,192 km/h; 740 mph; 643 kn). [1] The speed of sound in an ideal gas depends only on its temperature and composition. The speed has a weak dependence on frequency and pressure in ordinary air, deviating slightly from ideal behavior.
The apparent wind is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. [citation needed]The velocity of the apparent wind is the vector sum of the velocity of the headwind (which is the velocity a moving object would experience in still air) plus the velocity of the true wind.
ft/s 3.2808 The metre per second is the unit of both speed (a scalar quantity ) and velocity (a vector quantity , which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a time of one second .
When the maximum speed exceeds the average speed by 10 to 15 knots (19 to 28 km/h; 12 to 17 mph), the term gusts is used while strong gusts is used for departure of 15 to 25 knots (28 to 46 km/h; 17 to 29 mph), and violent gusts when it exceeds 25 knots (46 km/h; 29 mph). [4]
Airspeed is commonly given in knots (kn). Since 2010, the International Civil Aviation Organization (ICAO) recommends using kilometers per hour (km/h) for airspeed (and meters per second for wind speed on runways), but allows using the de facto standard of knots, and has no set date on when to stop.