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Abstract
Submesoscale instabilities can drive strong vertical motions and play an important role in biogeochemical cycles. High-resolution model simulations of a small (~1000x1000km) domain in the North-East Atlantic are analyzed to investigate the impact of increasing global temperatures on submesoscale dynamics in the upper ocean. In this region, vertical buoyancy fluxes from baroclinic instability are shown to have a distinct seasonal cycle and are projected to decrease under a warmer climate, consistent with a reduction in mixed layer depth. A widely-used scaling is shown to be successful at capturing both the seasonal cycle and projected future changes to vertical buoyancy fluxes. This study finds seasonal cycles of gravitational, symmetric and inertial instabilities that are consistent with previous observational and modeling studies. Results of this study project no significant change to these instability types under a warmer climate. The role of frontogenesis in the temporal evolution of lateral buoyancy gradients is explored using a frontogenesis function. The function is found to be sensitive to the use of 2D or 3D fields, indicating that further clarification is needed to understand the appropriate method for quantifying frontogenetic processes.
