ABSTRACT
The challenge of multi-scale nesting and high performance computing (HPC) simulations for the dynamically evolving limited area atmospheric environments is to achieve robust real-time predictability and ensemble forecasting of high impact events. Significant advances in computation of atmospheric and environmental flows have been achieved over the last few decades. The dramatic increase in computer power has facilitated developments of nonhydrostatic mesoscale numerical weather prediction (NWP) codes that have capabilities to resolve small-scale atmospheric processes. This was achieved by implementation of nesting techniques with multiple domains resolving horizontal scales ranging from few to 100 km, and by the improvement of sub-grid scale parameterizations. Among these models, the advanced research version of the weather research and forecasting model (WRF-ARW) is a next generation mesoscale NWP model (Skamarock and Klemp, 2008). It is the first fully compressible conservative-form nonhydrostatic atmospheric model suitable for both research and weather prediction applications. The WRFARW model represents the latest developments following a particular modeling approach that uses time-splitting techniques to efficiently integrate the fully compressible nonhydrostatic equations of motion. The integration scheme uses a time-split method to circumvent the acoustic-mode time-step restriction, where the meteorologically significant modes are integrated by using a third-order Runge-Kutta (RK) scheme (Wicker and Skamarock, 2002). The spatial discretization typically uses a fifth-order difference for advection, and the vertical coordinate is based on terrain following hydrostatic pressure coordinate.
