Intensification of submesoscale frontogenesis and forward energy cascade driven by upper-ocean convergent flows

Area of Science:

• Oceanography
• Climate Science
• Fluid Dynamics

Background:

• Upper-ocean fronts are key to global climate, influencing oceanic energy and material transport.
• Mesoscale frontogenesis is understood, but submesoscale (0.2-20 km) mechanisms, vital for vertical transport, remain understudied.

Purpose of the Study:

• To investigate the drivers of submesoscale frontogenesis.
• To understand the link between submesoscale frontogenesis and oceanic kinetic energy and vertical transports.

Main Methods:

• Analysis of year-long mooring array data from the North Atlantic.
• Quantification of submesoscale frontogenesis rates and horizontal convergence.
• Examination of seasonality and scale dependence of these processes.

Main Results:

• Direct observational evidence links submesoscale frontogenesis to convergent flows.
• Frontogenesis rates and convergence show strong seasonality and scale dependence, peaking in winter and at smaller scales.
• Frontogenesis correlates more strongly with convergence at smaller scales, indicating convergence as the primary driver.

Conclusions:

• Convergent flows are the main drivers of submesoscale frontogenesis.
• Submesoscale frontogenesis is linked to enhanced kinetic energy cascades and vertical velocities.
• Findings emphasize the need to parameterize submesoscale processes in climate-scale ocean models.