Energetics of internal tides over the Sangihe-Talaud ridge - Sulawesi sea

Abstract

An estimate of energetic barotropic and baroclinic tides over Sangihe-Talaud ridge (STR) - Sulawesi Sea is carried out by using a three-dimensional ROMS (Regional Ocean Modeling System) ocean model. The model is validated with satellite data. The estimate of tidal energy consists of generation, radiation, and dissipation. The model identified the generating internal tide area with strong barotropic-to-baroclinic conversion (above 10 kW/m) over S-T ridge. Away from this generating internal tides area that is in deep Sulawesi Sea basin, energy conversion is very weak (below 10−3Wm−2). Baroclinic energy is mostly dissipated in area near the coast. From the total of 9.45 GW (100%) of barotropic-to-baroclinic energy conversion, about 7.19 GW (76%) is converted into baroclinic energy through the generation of internal tide and about 4.13 GW (57%) of this baroclinic energy radiate to deep open sea. Distribution of tidal energy is highly dependent on topographic features. Estimate of strong vertical eddy diffusivity (KV) over the steep S-T ridge varies between 10−3 and 10−2 m2/s, in contrast to the weak KV in deep flat Sulawesi basin of about 10−4 m2/s.