Low level windshear alert system
（重定向自LLWAS）
A Low level windshear alert system (LLWAS) measures average surface wind speed and direction using a network of remote sensor stations, situated near runways and along approach or departure corridors at an airport. Wind shear is the generic term for wind differences over an operationally short distance (in relation to flight) which encompass meteorological phenomena including gust fronts, microbursts, vertical shear, and derechos.