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Pseudospectrum of equatorial waves.
Gerrit Lohmann, Max-Planck-Institut für Meteorologie, Hamburg, Germany.
gerrit.lohmann@dkrz.de
Letter to
Physics of Fluids, 2000 (submitted)
Pseudospectra for Matsuno's equatorial approximation of tidal theory are considered.
Unlike the standard approach of eigenvalue analysis pseudospectra provide
information about the robustness of spectral properties and
the dynamics for finite times.
It is shown that the non-orthogonality of the Rossby and gravity modes introduces
transient growth and resonant amplification.
This mechanism is strongest
for long waves and waves with high mode numbers making related phenomena in the atmosphere-ocean system highly unpredictable.
It is shown that the system's transient growth and resonant amplification are
related to the Orr mechanism
in shear flow problems.
Author:Gerrit Lohmann
Webmaster:Dietmar Dommenget
(Last update: July 2000)