EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Comparison of paradigmatic gravity wave models for ocean and atmosphere

Uwe Harlander
Uwe Harlander
  • Brandenburg University of Technology (BTU) Cottbus, Aerodynamics and Fluid Mechanics, Cottbus, Germany (

It appears that oceanographers and meteorologists have different pictures in their minds when they speak about internal waves. The reason might be that in both communities different paradigmatic gravity wave models based on different simplifying assumptions are in use.  For the oceanographer, internal wave beams are rather common, a feature virtually unknown to the atmospheric scientist.  In contrast, wave packets traveling upwards in the atmosphere is the standard picture for the meteorologist.  The mathematical origin of such a different view is that for time harmonic waves, the underlying boundary value problem for internal waves in the ocean is hyperbolic but elliptic for atmospheric flows.

In the present paper we discuss the consequences that result from these two different types of boundary value problems. Wave focusing is a rather 
generic process for hyperbolic problems and we argue that the latter should also be of interest to meteorologists in view of new findings that indeed 
a significant part of the internal waves in the atmosphere travel downward. We further apply some of our findings to new laboratory data on inertial modes arguing that an additional shear flow leads to an elliptic boundary value problem and beam-like wave fields, typical for the inertial waves without a shear flow, become mode-like.       

How to cite: Harlander, U.: Comparison of paradigmatic gravity wave models for ocean and atmosphere, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7222,, 2020

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Presentation version 1 – uploaded on 20 Apr 2020
  • CC1: Comment on EGU2020-7222, Wolf-Gerrit Fruh, 08 May 2020

    Thank you very much.   A very instructive presentation!

    Just to check:  slide 13 with the horizontal equatorial plate: In the text above Figure 11,

    1. you say it is an equatorial horizontal plane but in the caption it is a horizontal plane 4 cm above the equator (what are the sphere dimensions?)

    2. Would those be waves initiated by a barotropic instability of the tangent cylinder Stewartson layer?