Project Overview

Today, increasing capabilities to assess and predict the state of the atmosphere enable satisfying ever increasing needs for accurate prediction of flow and transport over a wide range of atmospheric scales of motion. A variety of practical problems can only be addressed through modeling techniques that encompass both the mesoscale and microscale. Such applications pose new challenges to numerical modeling, parameterization of physical processes, and assimilation of data. At RAL we address these challenges through work on applications that include calculation of transport and diffusion in the boundary layer as well as wind-energy forecasting and resource assessment.

Applications of fine-scale models at RAL address needs for: 1) optimally siting wind turbines and assessing wind resource in complex terrain; 2) calculating the building-aware Transport and Diffusion (T&D) of chemical, biological, or radiological material in the atmosphere, in response to an accidental or intentional release; 3) assessing the risk to populations from potential leaks of toxic material from industrial or transportation facilities; 4) calculating the transport of air (infiltration and exfiltration) between indoor airspaces and the atmosphere outdoors; 5) better understanding processes within the atmospheric boundary layer. Finally, RAL’s staff has recently been involved in efforts to employ the WRF model for both the mesoscale and the microscale, through the development and testing of a Large Eddy Simulation version of WRF. Future directions toward seamless multi-scale simulations through nesting of LES within mesoscale simulations in WRF include implementation of immersed boundary method.

High-resolution simulations over complex terrain result in significant wind speed variability at 15m above ground.