Critical reflection and abyssal trapping of nearinertial waves on a ßplane
Winters, K.B.; BouruetAubertot, P.; Gerkema, T. (2011). Critical reflection and abyssal trapping of nearinertial waves on a ßplane. J. Fluid Mech. 684: 111136. dx.doi.org/10.1017/jfm.2011.280
In: Journal of Fluid Mechanics. Cambridge University Press: London. ISSN 00221120; eISSN 14697645, meer
 
Author keywords 
ocean processes; stratified flows; waves in rotating fluids 
Auteurs   Top 
 Winters, K.B.
 BouruetAubertot, P.
 Gerkema, T., meer



Abstract 
We consider nearinertial waves continuously excited by a localized source and their subsequent radiation and evolution on a twodimensional betaplane. Numerical simulations are used to quantify the wave propagation and the energy flux in a realistically stratified ocean basin. We focus on the dynamics near and poleward of the inertial latitude where the local value of the Coriolis parameter f matches the forcing frequency sigma, contrasting the behaviour of waves under the traditional approximation (TA), where only the component of the Earth's rotation aligned with gravity is retained in the dynamics, with that obtained under the nontraditional approach (nonTA) in which the horizontal component of rotation is retained. Under the TA, assuming inviscid linear wave propagation in the WKB limit, all energy radiated from the source eventually propagates toward the equator, with the initially poleward propagation being internally reflected at the inertial latitude. Under the nonTA however, these waves propagate subinertially beyond their inertial latitude, exhibiting multiple reflections between internal turning points that lie poleward of the inertial latitude and the bottom. The numerical experiments complement and extend existing theory by relaxing the linearity and WKB approximations, and by illustrating the time development of the steadily forced flow and the spatial patterns of energy flux and flux divergence. The flux divergence of the flow at both the forcing frequency and its first harmonic reveal the spatial patterns of nonlinear energy transfer and highlight the importance of nonlinearity in the vicinity of nearcritical bottom reflection at the inertial latitude of the forced waves. 
