Ocean dynamics of rapidly rotating ice-covered satellites due to heterogeneous seafloor heating

Icy ocean worlds, moons harboring a liquid ocean beneath an outermost ice shell, are prime targets in the search for habitable environments beyond Earth, yet much remains unknown about their ocean dynamics. Spatial variations in heat flux at the ocean's bottom boundary driven by tidal dissipation in their rocky interiors can drive turbulence, modulate its circulation, and ultimately influence the habitability of the ocean. However, strong planetary rotation suppresses turbulent motions, altering transport processes within subsurface oceans. To quantify these competing effects, we conduct three-dimensional numerical simulations of convection in a rotating spherical shell. We impose three heterogeneous inner-boundary heat flux patterns, explore two Ekman numbers (rotation rates), and vary the Rayleigh number (convective driving) to capture different convective dynamics. In addition, we compare two kinematic boundary conditions— free-slip and no-slip—at the inner and outer shell radii. Our results demonstrate that an increased Rayleigh number increases turbulent transport. At the same time, polar-enhanced heterogeneous forcing with the no-slip boundary conditions generates localized convective plumes inside the tangent cylinder that enhance heterogeneity at the ice-ocean interface at higher latitudes. These preliminary findings assist in better understanding the observed variations in ice-shell thickness on Enceladus and in predicting thickness variations at Europa that will be tested by the Europa Clipper mission.