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Compared to over water, maximum sustained winds over land average 8% lower. [12] More especially, 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 is between 10% and 30%. [8] [13] [14]
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 ...
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).
Where V srm is the max wind speed corrected for storm speed, phi is the latitude, and S is the size parameter. [5] S is more specifically defined as the ratio of tangential wind at a radius of 500 kilometres (310 mi) to its value under a Rankine vortex model.
[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 speeds over 75 miles per hour are classified as “hurricane force,” capable of pushing moving vehicles off the highway, overturning mobile homes and peeling off roofs. The average wind ...
The power law is often used in wind power assessments [4] [5] where wind speeds at the height of a turbine ( 50 metres) must be estimated from near surface wind observations (~10 metres), or where wind speed data at various heights must be adjusted to a standard height [6] prior to use.
At times, multiple vortices swirled within the tornado, which lasted for about 45 minutes and traveled about 44 miles. For less than a second, the researchers calculated wind speeds of more than ...