University of Victoria
Victoria, British Columbia, Canada
Many models of the oceanic surface mixed layer include a small background vertical diffusivity $K_{\rm bg}$ in the thermocline below the mixed layer. Model studies have indicated a sensitivity of model output to the value of $K_{\rm bg}$, with higher $K_{\rm bg}$ leading to lower sea-surface temperature and a deeper mixed layer. It is thus important to establish whether $K_{\rm bg}$ represents mixing processes in the thermocline or is a proxy for processes omitted from the models. One such process is isopycnal heaving in the thermocline due to non-breaking internal waves. Results from an idealized model are presented, along with estimates of the equivalent background diffusivity.