Mass, Clifford, University of Washington
A major issue with WRF,
and many other modeling systems, is the tendency for high wind biases and
overmixing under stable conditions.
In this presentation a variety of approaches are tested to deal with
such PBL issue in WRF.
First, an improved subgrid scale parameterization is tested, one that
increases drag based on the subgrid-scale terrain variance, but which decreases
its impact as stability decreases or wind speed increases. Second, ultra high
vertical resolution is tested for a range of cases to determine whether this
improves the definition of low-level inversions and thus decreases mixing under
stable conditions. Finally,
the influence of running WRF at ultra-high resolution (1.3 km horizontal grid
spacing) is evaluated. This
presentation will present a summary of these experiments and suggest the most
fruitful avenues for further research and testing.