The Effects of Remotely Generated Internal tides in Regional Model Simulations of the California Current System.

In regional high resolution model simulations, frequency-wave number spectra lack energy near the tidal bands when compared to observations. One possibility for this discrepancy could be the lack of remotely generated internal tides in the regional simulations. In this study, we consider the impact of remotely generated internal tides on energetics in regional simulations of the California Current System (CCS). The CCS is an eddy-rich mid-latitude region, where energetic NIWs and internal tidal waves coexist. High resolution realistic regional simulations are carried out using the Regional Ocean Modelling System (ROMS). The ROMS simulations are boundary-forced with offline data from the Hybrid Coordinate Ocean Model (HYCOM). The HYCOM simulations are realistically forced with tides and atmospheric forcing. We will use simulations with 8 & 4 km horizontal resolution and 41 layers. We consider the following boundary forcing fields from HYCOM: (1) surface tides with and without mesoscales, (2) internal tides with and without mesoscales, and (3) surface tides and internal tides with and without mesoscales. Our initial objective is to interpolate the 3D HYCOM fields to the ROMS boundaries and perform some test simulation to check for spurious waves and currents. Next we will perform the simulations with the different boundary forcings and diagnose the energetics and wave-eddy interactions.