Wind-flow characteristics in the turbine rotor layer of the atmosphere

Accurate, high-quality wind information at turbine rotor levels has been a constant and critical need for wind energy, and now that widespread deployment is a fact, such information is even more crucial, with large economic implications. A significant impediment to providing adequate meteorological support, including forecasts, resource assessment, turbine array effects, climate change, and other factors, to wind energy is the lack of knowledge and understanding of processes occurring in the rotor layer of the aloft, above the atmospheric layer easily measured by tower-mounted instrumentation. This lag in the state of the art of the meteorology and modeling of the boundary layer is a result of a lack of high-quality measurements in the lowest few 100's of meters of the atmosphere. Doppler-lidar systems operated by NOAA/ESRL have demonstrated the capability to provide the needed information in this layer of the atmosphere for more than two decades. This presentation will review insights gained from this instrumentation in concert with other measurement systems into characteristics of flow in this layer, using examples for both simple and complex terrain as well as over the ocean. Necessary steps to use this kind of information to advance the state of knowledge for wind energy and other boundary layer applications will be outlined.