Turbulence measurements over complex terrain

Horizontal turbulence measurements obtained from 22 wind sensors located on 9 towers in a mountainous coastal area are described and categorized by stability and terrain. Vector wind time series are high-pass filtered, and lateral and longitudinal wind speed variance is calculated for averaging times ranging from 15 s to 2 h. Parameterizations of the functional dependence of variance on averaging time are discussed, and a modification of Panofsky's (1988) uniform terrain technique applicable to complex terrain is presented. The parameterization is applied to the data and shown to be more realistic than a less complicated power law technique. The parameter values are shown to be different than the flat terrain cases of Kaimal et al. (1972), and are primarily a function of sensor location within the complex terrain. The parameters are also examined in terms of their dependence upon season, stability, marine boundary-layer height, and measurement height.