ELFT HÍRADÓ

[StatFizSzeminar <statfiz AT glu.elte.hu>]

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                    ELTE TTK Fizikai Intézet
                STATISZTIKUS FIZIKAI SZEMINÁRIUM
                  

     SZOKÁSOSTÓL ELTÉRŐ HELYSZÍN: É 0.89 (Jedlik Ányos terem) 

                      2012. április 27.
                        péntek 13 óra

                      
                      Harry L. Swinney
                           
                University of Texas at Austin
                     
         "Dynamics of oceanic internal gravity waves"

Tidal flow over continental shelf breaks and ocean bottom topography 
generates internal gravity waves. These internal waves account for a 
significant part of the energy budget of the oceans and hence play a 
role in determining climate. Our group is conducting laboratory 
experiments, numerical simulations of the Navier-Stokes equations, 
and analyses of ocean data to understand the generation, propagation, 
and scattering of internal waves. One study indicates that the angle 
of the Continental Slope is selected by an internal wave resonance 
phenomenon, which yields Continental Slope angles of only a few 
degrees, much smaller than the angle of repose. To investigate 
internal wave propagation in the deep ocean where the buoyancy 
frequency decreases rapidly with increasing depth, we have analyzed 
thousands of sets of measurements of salinity and temperature vs 
depth at different locations in the oceans. We find that that 
downward propagating internal waves often do not reflect and scatter 
from the ocean floor as is generally assumed. Instead, at a "turning 
depth" (where the local buoyancy frequency equals the tidal 
frequency), the internal waves are reflected. Below the turning depth 
the internal waves are evanescent [King et al., J. Geophysical 
Research (2012)]. While experiments and models are yielding insights 
into internal wave dynamics, many important phenomena such as wave 
breaking and mixing remain poorly understood, thus providing 
challenges for future research.
 

                             honlap:
                   http://glu.elte.hu/~statfiz

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