Anemometer siting criteria for low level wind shear alert system

The development of an anemometer siting guide for Federal Aviation Administration use is described. The siting guide included the influence of change in surface roughness, placement within a forest with upwind fetch, the influence of 2D obstacles such as tree lines, the influence of 3D bluff obstacles such as buildings or clumps of trees, the influence of forests on winds downwind of the end of the forest, the influence of 2D and 3D isolated hills on the acceleration of flow over a hilltop, and shielding downwind of hills. A physical model study was performed in a boundary layer wind tunnel capable of simulating wind flow in the atmospheric boundary layer. Profiles of mean velocity were measured for neutrally stable wind flow over proposed anemometer sites to determine the minimum anemometer height required to escape most the shielding effects of the surroundings. Wind velocity profiles in complex terrain compared to runway wind speed are illustrated.