The Impact of Parameterized Subgrid-Scale Orographic Forcing on Systematic Errors in a Global NWP Model

摘要: Abstract The global momentum budget for December 1993, diagnosed from a series of two-time-step integrations the U.K. Meteorological Office Unified Model, suggests that parameterized mechanical dissipation in model is underestimated. initial imbalance consistent with zonal mean systematic errors wind. Further diagnosis (i) residual largest boundary layer and over orography (ii) too much gravity wave drag applied stratosphere. Two new parameterizations are proposed to alleviate this problem. first scheme incorporating anisotropy into expression surface stress low-level breaking mechanisms such as trapped Ice waves high states. second parameterization deals form due subgrid-scale orography, process currently ignored model. This using an effective roughne...