Atmosphere Ocean Science Colloquium

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Mesoscale and Submesoscale Turbulence: from the Earth’s Ocean to Jupiter’s Atmosphere

Speaker: Lia Siegelman, UCSD/Scripps

Location: Online

Videoconference link: https://nyu.zoom.us/j/95566320785

Date: Monday, May 9, 2022, 3:30 p.m.

Synopsis:

Using a combination of satellite and in situ observations, and a high-resolution numerical simulation, I show that the Antarctic Circumpolar Current hosts energetic ageostrophic submesoscale fronts down to depths of 1000 m. These Deep-Reaching Submesoscale Fronts (DRSFs) are characterized by order one Rossby and Richardson numbers. DRSFs are generated by mesoscale strain via frontogenesis and are associated with intense vertical velocities of 100 m/day.  DRSFs drive a net enhanced upward heat transport and are an efficient pathway for the transport of heat, chemical and biological tracers between the surface and interior of the ocean.

I’ll discuss some intriguing similarities between ocean and Jovian dynamics. Using observations collected by the JUNO spacecraft orbiting Jupiter, I show that the large polar cyclones gain their energy from small-scale moist convection via an inverse kinetic energy cascade. Using an idealized model adapted to a polar cap, I show that the geometrical array of circumpolar cyclones forms from the free evolution of randomly excited two-dimensional turbulence.

I conclude by discussing four avenues of future research aimed at understanding the global impact of DRSFs: (1) quantify their role in transferring potential and kinetic energy across scales in the global ocean, (2) understand their contribution to vertical heat transport in the coupled ocean-atmosphere system, (3) explore how vertical stratification modulates their existence in the first 1000 m of the ocean and (4) develop a theoretical framework for frontolysis.