Interact: Interesting Assorted Problems Involving Geophysical Flows

Two-dimensional turbulence exhibits an inverse energy cascade, where energy injected at small scales self-organizes into large-scale coherent structures like jets and vortices. Observations from NASA’s Juno mission revealed arrays of long-lived vortices at Jupiter’s poles, forming geometric lattices unlike any seen in planetary atmospheres. Previous work has shown that such configurations can be stable in decaying turbulence, but mechanisms responsible for their formation remain unclear.

We hypothesize that Jupiter’s turbulent atmosphere, governed by small-scale forcing and planetary rotation, is sufficient to produce these lattices. To test this, we perform high-resolution simulations of the forced-dissipative, incompressible 2D Navier-Stokes equations on a rotating sphere. This setup avoids artificial boundaries and captures key features of a rotating atmosphere. Stochastic small-scale forcing produces both a forward enstrophy cascade and an inverse energy cascade. By varying the forcing scale and rotation rate Ω, we identify parameter regimes where vortex lattices emerge. Our results provide insights into the connection between turbulent self-organization in rotating, spherical 2D flow, and the formation of polar vortex lattices on Jupiter.

Funding acknowledgement

This work is supported by the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the McCormick School of Engineering, both at Northwestern University.