Meteorological instruments to measure wind speed and/or direction
In meteorology wind direction is reported by the direction from which it originates. For example, a northerly wind blows from the north to the south. But in oceanography we use the direction where the wind goes, like the ocean currents.
Local sensing techniques
· Anemometer (measures wind speed, either directly, e.g. with rotating cups, or indirectly, e.g. via pressure differences or the propagation speed of ultrasound signals)
· Rawinsonde (GPS-based wind measurement is performed by the probe)
· Weather balloon (passive measurement, balloon position is tracked from the ground visually or via radar; wind profile is computed from drift rate and the theoretical speed of ascent)
· Weather vane (used to indicate wind direction) also called a wind vane, is a movable device attached to an elevated object such as a roof for showing the direction of the wind.
· Windsock (primarily used to indicate wind direction, may also be used to estimate wind speed by its angle)
· Pitot tubes is a pressure measuring instrument used to measure fluid flow velocity, and more specifically, used to determine the airspeed of an aircraft.
Remote sensing techniques:
· SODAR (SOnic Detection And Ranging), or sodar, is a meteorological instrument which measures the scattering of sound waves by atmospheric turbulence. SODAR systems are used to measure wind speed at various heights above the ground, and the thermodynamic structure of the lower layer of the atmosphere.
· Doppler LIDARs can measure the Doppler shift of light reflected off suspended aerosols or molecules. This measurement can be directly related to wind velocity.
· Radiometers and Radars can be used to measure the surface roughness of the ocean from space or airplanes. This measurement can be used to estimate wind velocity close to the sea surface over oceans.