Boundary Layer Processes
Where the surface of the Earth and the atmosphere interact is the boundary layer, and understanding turbulence, aerosol transport, topography, and climate within this layer is paramount to optimizing wind energy. For decades, we've applied our expertise in boundary layer meteorology to better understand interactions within the layer and address U.S. Department of Energy goals.
Early research at PNNL focused on characterizing turbulence and its impact on the dispersion of energy-related contaminants in the atmosphere. From there, we worked to better define lower boundary in climate models. Our breakthroughs have led to greater understanding of the dispersion of aerosol particles and the contribution of turbulence to the structure of clouds.
Our current work delves into the use of observations and large-eddy simulation (LES) models to improve parameterizations in numerical weather prediction models (NWPs), such as the Weather Research and Forecasting (WFR) model. This work will improve models' ability to calculate winds and turbulence at the height of wind turbines, improving the performance and use of wind power.
Boundary layers in complex terrain pose challenges to accurately calculating winds and turbulence for wind energy. NWP models cannot resolve the smallest variations in the wind, and these must be approximated within the models. Steep terrain, however, invalidates many of the assumptions that are inherent in these approximations. We are currently focusing on how these underlying approximations can better reflect the real behavior of the atmosphere in complex terrain.
Mesoscale-Microscale Coupling
The Mesoscale-Microscale Coupling (MMC) task is a major component of the A2e program and seeks to define the optimum coupling of NWP, LES, and finer-scale models within a framework scalable to high-performance computing. The overall objective is to provide the most accurate representation of winds flowing into and through wind plants. This will support the development of advanced integrated control systems that can optimize the power production of these plants. In collaboration with six other national laboratories, we are focusing on the coupled behavior of WRF and LES in complex terrain.
Wind Forecasting
In addition to contributing to Wind Forecast Improvement Project 2 (WFIP2) through its Steering Committee, we are also using a variety of sophisticated scientific instrumentation—including a sodar, wind profiling radars, acoustic anemometers for turbulence, and surface meteorological stations—to examine the physical sources of wind forecast errors. This work focuses on the relationship between terrain-induced variability of winds and turbulence and the accuracy of their numerical approximation near the surface and in the boundary layer as a whole.