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Wind speeds over 99 knots are extracted by subtracting 50 from the direction and adding 100 to the speed. Thus, for example, the wind forecast for Abilene (ABI) at 30,000 feet, shown above as 7603, indicates a forecast wind of 260 degrees at 103 knots (76-50=26 or 260, and speed became 100+03=103).
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] In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in ...
In meteorology, prevailing wind in a region of the Earth's surface is a surface wind that blows predominantly from a particular direction. The dominant winds are the trends in direction of wind with the highest speed over a particular point on the Earth's surface at any given time.
Wind shear (/ ʃ ɪər /; also written windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal wind shear. Vertical wind shear is a change in wind speed or direction with a ...
[4] [11] Because of the relatively smooth water surface, wind speeds do not decrease as much close to the sea as they do on land. [12] Over a city or rough terrain, the wind gradient effect could cause a reduction of 40% to 50% of the geostrophic wind speed aloft; while over open water or ice, the reduction may be only 20% to 30%. [13] [14]
Wind speed on the Beaufort scale is based on the empirical relationship: [6] v = 0.836 B 3/2 m/s; v = 1.625 B 3/2 knots (=) where v is the equivalent wind speed at 10 metres above the sea surface and B is Beaufort scale number.
Roughness length is a parameter of some vertical wind profile equations that model the horizontal mean wind speed near the ground. In the log wind profile, it is equivalent to the height at which the wind speed theoretically becomes zero in the absence of wind-slowing obstacles and under neutral conditions. In reality, the wind at this height ...
Consequently, a wind blowing from the north has a wind direction referred to as 0° (360°); a wind blowing from the east has a wind direction referred to as 90°, etc. Weather forecasts typically give the direction of the wind along with its speed, for example a "northerly wind at 15 km/h" is a wind blowing from the north at a speed of 15 km/h ...