Libration Induced Gravity Waves on Enceladus
Daniel Abdulah, Massachusetts Institute of Technology
On Enceladus, a global subsurface ocean and exterior ice shell form a coupled system shaped by a variety of processes, including tides. Tidally forced librations of topography on the underside of the ice shell against a stably stratified ocean can induce internal gravity waves. Using the linearized Navier-Stokes equations, an analytical solution to this system is derived via spectral methods for three types of topography. The resulting flow agrees closely with numerical solutions using the MIT General Circulation Model (MITgcm) to solve the time-dependent nonlinear equations of state. Analytical estimates of power dissipation from these waves are compared against dissipation parameterizations in the MITgcm. The gravity wave mechanism for dissipation of tidal energy may explain periodicity in the south polar surface topographical pattern known as tiger stripes.
Abstract Author(s): Daniel Abdulah, Wanying Kang