Formation of a Garrett-Munk-like internal wave spectrum in an eddying ocean by wind forcing alone

An idealized reentrant channel model is utilized to investigate whether wind forcing alone can generate a Garrett-Munk (GM) internal wave (IW) spectrum and where the bulk of the IW energy comes from. It is shown that high-frequency winds can easily generate a GM-like IW spectrum in an eddying ocean without sophisticated model settings. During the formation of a GM-like spectrum, energy transferred from mesoscale eddies to IWs is comparable to that from submesoscale motions. In the pycnocline, IW energy is partially absorbed into mesoscale eddies, which may partly explain why only a small portion of wind-induced IWs penetrates into the deep ocean. This study complements previous study that tidal forcing alone can generate a GM-like IW spectrum. These two studies together imply that a GM-like spectrum can be easily generated through a forcing agent alone, suggestive of a reason why it is ubiquitously observed in the ocean.