Surface wind
Surface wind is the wind blowing near the Earth's surface. It is measured by an anemometer (speed) or wind vane (wind direction) at a standard height of 10 m above ground in an area where the distance between the instrument and any obstruction is at least 10 times the height of the obstruction. This distance is known as fetch and is kept in order to avoid the influence of eddies.
The surface wind forecast van be seen on WeatherOnlines expert weather maps. The wind 10m chart displays the modeled average wind vector in 10 m above the ground for every grid point of the model (ca. every 80 km). Generally the actual observed wind velocity at 10 m above ground is a little bit lower than the modeled one. However, usually the computed wind velocity is pretty close to the reality. Therefore this chart is very useful for sailors, gliders, hang gliders and balloon pilots.
