Radar observation of internal wave and current interactions

The airborne side-looking radar images from archives of the Space Research Institute (Moscow, Russia) are used for internal wave studies. Effects of bottom relief, density and current fields on surface manifestations of internal waves are analyzed separately. The effect of bottom topography is found to be negligible for available data. Internal waves transformation by horizontal inhomogeneities of the density field is estimated theoretically. It is shown that this effect is rather weak as compared with the effect of current on internal wave propagation. Within this approach specific features of internal wave surface manifestations (wave front delineating, asymmetry, possible breaking events etc.) are treated as a result of anomalous internal wave kinematics, in particular, of the so-called effect of internal wave trapping by large-scale inhomogeneities. “Barriers” for internal wave propagation are identified in some cases and treated as domains of effective sinks of internal wave energy. This phenomenon is detailed for Kamchatka current area