High resolution boundary layer dispersion simulation study using Eulerian and Lagrangian approaches with WRF

We carry out a numerical simulation study of tracer dispersion in atmospheric boundary layer over a range of stability conditions. The dispersion simulations are based on Prairie Grass and Condors field experiments. Tracer dispersion is simulated using high-resolution large-eddy simulation (LES) with Weather Research and Forecasting model. We use both Eulerian and Lagrangian approaches and present detailed comparison of simulation results with measured tracer concentrations. The Eulerian simulations are accomplished by using passive tracer advection and diffusion algorithms in WRF while the Lagrangian simulations are carried out using Lagrangian Particle Dispersion Model (LPDM). LPDM is capable of accurately representing effects of unresolved, subgrid turbulence in LES on stochastic particle movements.

In addition to validation of WRF/LPDM dispersion capabilities with respect to spatially and temporally averaged quantities, we also focus our analysis on the accuracy of numerical simulations with respect to higher order statistics of fluctuations of tracer concentration and velocities. Accurate representation of wind and concentration fluctuations in transport and dispersion models are essential for Observing System Simulations Experiments (OSSEs) that can be used for virtual system testing for evaluation of emerging technologies.