A new option, allowing vertical grid refinement for multiple concurrently run domains, has been implemented in WRF v3.5. This option uses the vertical interpolation scheme from ndown for downscaled variables, but applies it at each time step. Vertical grids can be refined by an integer ratio, or unrelated grid levels can be defined for each domain.
Here, we validate our vertical nesting routine with idealized canonical cases and demonstrate the added benefit of using vertical grid nesting to more accurately capture vertical gradients within the nested domain. Additionally, we use vertical nesting for the real case of a 36 hour forecast in the San Francisco Bay Area, which is compared to observations.
Future work will include the addition of this code to WRF-IBM, an existing modified version of WRF that utilizes an immersed boundary method to better handle complex terrain. Vertical nesting will act as a framework for a WRF-IBM domain to nest within a WRF domain, allowing for a concurrent, nested, mesoscale to microscale simulation.