Numerical studies indicate that interactions between ocean internal gravity waves (especially those <100 km) and geostrophic (or balanced) motions associated with mesoscale eddy turbulence (involving eddies of 100–300 km) impact the ocean's kinetic energy budget and therefore its circulation. Results from these studies have never been confirmed by observations in regional or basin‐scale domains. Here we show that internal gravity waves have a spectral signature on sea‐surface height (SSH) during summer that significantly differs from that of balanced motions. These spectral differences lead us to propose a new dynamical framework that quantifies the interactions between internal gravity waves and balanced motions in physical space from SSH snapshots, and in particular the energy exchanges between them. Our results, using this dynamical framework, highlight the strong potential of future satellite altimeter missions to make critical advances in assessing the ocean's kinetic energy budget from observations in large domains.

Key Points

We exploit spectral characteristics of sea‐surface height (SSH) to partition ocean motions into balanced motions and internal gravity waves

We use a simple shallow‐water model to diagnose internal gravity wave motions from SSH

We test a dynamical framework to recover the interactions between internal gravity waves and balanced motions from SSH