Tower Distortion

The term 'tower distortion' refers to the distortion in the airflow caused by the presence of the meteorological tower on which the instruments are mounted. The wind tends to decelerate upwind of the tower, to accelerate as it goes around the tower, and to decelerate markedly in the lee of the tower, where a separation bubble often forms.

The term 'tower shading' refers only to the most pronounced of these effects, which is the shading that occurs downstream of the tower. The term 'tower distortion' is a more general term that encompasses all of these effects.

To detect and to minimize the worst effects of tower distortion, resource assessment teams often install two wind speed sensors at different boom orientations at each measurement height on a meteorological tower. This ensures that at least one of the two sensors is well exposed to the wind at all times. In Windographer we refer to such pairs of sensors as colocated wind speed sensors or colocated anemometers.

Tip: The Tower Distortion window allows you to explore the effects of tower distortion, and the Flag Tower Shading window makes it easy to flag data points affected by tower shading.