5:15 PM - 6:30 PM
[AOS11-P11] Observation of energy transfer from traveling typhoons to turbulent mixing in the ocean
Keywords:near-inertial internal wave, double-inertial internal wave, typhoon, turbulent mixing
Double-inertial internal waves are supposed to play an important role in transferring wind-induced energy from the surface layer to the deep ocean, thus sustaining the Meridional Overturning Circulation (MOC). However, the influence of double-inertial internal waves on the MOC is not fully understood due to the scarcity of observational data.
During the R/V Shinsei-maru cruise (KS-20-11) from August 4 through August 13, 2020, two typhoons passed the observation areas (in the Oyashio region) coincidentally, and the measurement of the oceanic response was carried out. Both near-inertial and double-inertial internal waves were detected with the moored ADCP. The vertical distribution of kinetic energy indicates that the internal waves at the surface are strengthened by the typhoons, and gradually propagate downward. The frequency spectra of kinetic energy suggests that double-inertial energy is enhanced down to ~600 m within the depth limitation of ADCP. Furthermore, we analyze wind energy input to each mode of internal waves, in order to examine the energy transfer process. Among them, much energy is fed into high-vertical-mode near-inertial waves below the mixed layer. The result suggests that traveling typhoons may contribute to turbulent mixing in the ocean interior through a nonlinear wave-wave interaction.
During the R/V Shinsei-maru cruise (KS-20-11) from August 4 through August 13, 2020, two typhoons passed the observation areas (in the Oyashio region) coincidentally, and the measurement of the oceanic response was carried out. Both near-inertial and double-inertial internal waves were detected with the moored ADCP. The vertical distribution of kinetic energy indicates that the internal waves at the surface are strengthened by the typhoons, and gradually propagate downward. The frequency spectra of kinetic energy suggests that double-inertial energy is enhanced down to ~600 m within the depth limitation of ADCP. Furthermore, we analyze wind energy input to each mode of internal waves, in order to examine the energy transfer process. Among them, much energy is fed into high-vertical-mode near-inertial waves below the mixed layer. The result suggests that traveling typhoons may contribute to turbulent mixing in the ocean interior through a nonlinear wave-wave interaction.