Wind speed: Encyclopedia - Wind speed

Wind speed

Wind speed is the speed of movement of air relative to a fixed point on the earth. It usually means the movement of air in an outside environment, but the speed of movement of air inside is important in many areas, including weather forecasting, aircraft and maritime operations, building and civil engineering. High wind speeds can cause unpleasant side effects, and strong winds often have special names, including gales, hurricanes, and typhoons. See the Beaufort scale for a discussion of this.

Wind speed - Measuring Wind Speed

Wind speed may be measured by a variety of tools. The anemometer, consisting of a rotating vane, has been the most common method of measuring speeds close to the ground for hundreds of years. The can fix his position relative to the ground and knowing from instruments his movement through the air can estimate the wind speed and direction over the time he has been flying. Such reports can be used to confirm wind speed forecasts. The development of accurate electronic navigation systems, including inertial navigation and GPS enable this calculation to be done automatically. Modern GPS and inertial systems often include a direct readout of the current windspeed and direction.

Wind speed - Speed and Velocity

Technically Wind speed is given by

where u, v, and w are zonal, meridional, and vertical components of wind velocity. Except in unusual circumstances (e.g. in cumulus updrafts), the vertical component of the velocity is much smaller than the horizontal component.

Adapted from the Wikipedia article "Wind speed", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki