Collaborative Research: Internal tide decay mechanisms and their effects on the heat budget in the equatorial Pacific

This project will investigate the decay mechanisms of the internal tide across the equatorial Pacific and quantify how much of the vertical mixing and advection associated with the internal tide impact the regional heat budget. The investigators will use high-resolution numerical simulations of the ocean to examine the internal tides in the equatorial Pacific Ocean. The project is motivated by observations that internal tide energy is reduced in the equatorial zone. They aim to determine if this is because of dynamics of the tides themselves as a function of latitude, or whether ocean dynamics specific to the equatorial zone are responsible for interacting with the tides. This project will examine the relative importance of internal tide steepening and wave-mean flow interactions for internal tide decay. The investigators will use a set of realistically-forced, nested, high-resolution Regional Ocean Model Simulations (ROMS) of 6 km, 2 km, and 500 m during both an El Nino and a La Nina year, each with and without tidal forcing. Coarse-graining will be used to quantify energy losses out of the internal tide to the subtidal and supertidal bands. This technique will also be applied in combination with temporal and spatial filters to identify processes such as scattering and energy transfers. The same simulations will also be used to quantify how much internal tide-driven mixing and advection contribute to the regional heat budget. The proposed work will leverage both historic and current observational data in the region. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.