Internal Wave Generation by Random Distributions of Seamounts in the Ocean
Likun Zhang, The University of Texas at Austin, Center for Nonlinear Dynamics and Department of Physics, Austin, TX, United States, Maarten C Buijsman, University of Southern Mississippi, Stennis Space Center, MS, United States, Eva Lynn Comino, University of Southern Mississippi, Department of Mathematics, Stennis Space Center, MS, United States and Harry L Swinney, University of Texas at Austin, Austin, TX, United States
Abstract:
Seamounts convert tidal energy into internal wave energy. In the oceans some seamounts are in closely spaced clusters while others are isolated. For closely spaced seamounts, wave interference is pronounced, while for isolated seamounts wave interference is negligible. We use the MITgcm to examine numerically the effect of wave interference for several distributions of axisymmetric Gaussian seamounts in an infinitely deep ocean. We calculate for a periodic array of seamounts and for four random distributions of seamounts the dependence of the energy conversion on seamount separation, seamount slope, tidal direction, and the size and aspect ratio of the simulation domain. An important result is that for supercritical seamounts near other seamounts, wave interference significantly reduces the radiated power relative to that calculated for an isolated seamount and relative to that predicted by linear theory for a seamount of subcritical slope. The interference between neighboring seamounts is further examined in computations of the wave drag and vertical energy flux. Insight from this study should improve the understanding of internal tide conversion by seamounts in the global ocean.
