抄録
Results are presented from ensembles of medium range weather forecast experiments designed to test and compare the effectiveness of orographic gravity wave drag and envelope orography in reducing systematic forecas errors. The wave drag parameterization used is that of McFarlane (1987). An orographic enhancement of one standard deviation of the sub-grid scale orography was used in the envelope orography experiments. The results presented demonstrate that both wave drag end envelope orography are effective in reducing forecasts, wave drag being systematic forecast errors in geopotential height field the more effective of the two. It is also demonstrated that use of the wave scheme leads to improved zonal mean wind forecasts, the improvement being similar in nature to that which has been found in previous studies involving general circulation model climate simulations.
