Impacts of parameterized orographic drag on the Northern Hemisphere winter circulation.

A recent intercomparison exercise proposed by the Working Group for Numerical Experimentation (WGNE) revealed that the parameterized, or unresolved, surface stress in weather forecast models is highly model-dependent, especially over orography. Models of comparable resolution differ over land by as much as 20% in zonal mean total subgrid surface stress ( ). The way is partitioned between the different parameterizations is also model-dependent.