Internal waves play an important role in the dynamics and mixing of the ocean interior. It is known that internal waves may be generated by flow over an uneven bottom. On a regional scale, accurate knowledge of the true ocean bathymetry may be available or may measured directly. On a basin scale or global scale, our knowledge of the true ocean bathymetry is limited. Advances in computing architecture now permit the horizontal resolution of basin scale and global ocean models to exceed our knowledge of the true ocean bathymetry. With limited data, interpolation of available data produces a smoother ocean floor than what we may reasonably expect.

One possible solution is to generate an empirical sea-floor roughness based upon sediment thickness, sea floor spreading rates and direction to simulate expected abyssal hill structure on the ocean floor. The sea-floor roughness generated in such a manner produces an abyssal hill structure with a characteristic horizontal length scale of 2-10 km and characteristic heights 100-200 m. Using a 1/12 and 1/25 degree global ocean model (HYCOM) we investigate the effect of adding empirically derived abyssal hills to the sea floor on the generation of internal waves produced by tidal forcing. At 1/12 degree the horizontal resolution of the model is at the upper end of the abyssal hill length scale but does produce an increase in internal wave activity. We also investigate the effect of increasing the horizontal resolution to 1/25 degree to better resolve the abyssal hill structure.