Regional modeling of internal-tide dynamics around New Caledonia – Part 1: Coherent internal-tide characteristics and sea surface height signature

Abstract. The southwestern tropical Pacific exhibits a complex bathymetry and represents hot spot of internal-tide generation. Based on tailored high-resolution regional model, we investigate for the first time field around New Caledonia islands through energy budgets that quantify coherent generation, propagation, dissipation. A total 15.27 GW is converted from barotropic to baroclinic M2 tide with main conversion sites associated most prominent bathymetric structures such as continental slopes narrow passages in north (2.17 GW) ridges seamounts south (3.92 GW). bulk generated shallow waters 500 m depth critical supercritical slopes, highlighting limitations linear semi-analytical models those areas. Despite strongly dominant mode-1 more than 50 % locally either dissipates near close generation or loses coherence. remaining propagates within well-defined tidal beams fluxes up 30 kW m−1 toward open ocean. site challenge SWOT (Surface Water Ocean Topography) observability balanced motion presence internal tides sea surface height (SSH) signatures >6 cm at similar wavelengths. We show our study region correction SSH potentially increases wavelengths >160 km well below 100 km.