PNNL

Abstract

The American WAKE experimeNt (AWAKEN) will take place in northern Oklahoma, USA, close to the Atmospheric Radiation Measurement Southern Great Plains atmospheric observatory. The deployment of the instruments in this observational field campaign requires the wind characteristics of the site. This paper analyzes long-term data collected by instruments at the observatory to identify the wind characteristics at the AWAKEN site. The analysis shows that this site faces high wind shear and veer events with a large number of low-level jets. A total of 7,086 low-level jet wind profiles over 6 years are examined and found to be dominant from the south and southeast. A strong impact of the Coriolis force on the wind veer is observed, which causes the wind to turn from west to east with increasing height. By identifying a strong relationship between atmospheric stability and wind shear, the wind shear at the site is predicted using the Monin-Obukhov similarity theory and validated with the observational data collected by a scanning Doppler lidar. The results show that wind speed at a height of 91 m, a proxy hub height for wind turbines in this area, can be predicted from data collected at a height of 10 m with bias of -0.35 m s-1 and 0.65 m s-1 in unstable and stable atmospheric boundary layers, respectively. The bias of the predicted wind speed is mostly in the region of low wind speed, and wind speed above 5 m s-1 at a height of 91 m can be predicted with a bias of less than 0.2 m s-1