Esler, JG; Polvani, LM; Scott, RK; (2006) The Antarctic stratospheric sudden warming of 2002: A self-tuned resonance? Geophysical Research Letters , 33 (12) , Article L12804. 10.1029/2006GL026034.
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The extraordinary Antarctic stratospheric warming event of 2002 was characterized by a remarkable vertical structure, with the vortex observed to divide at upper levels in the stratosphere but not at lower levels: such 'partially' split vortex events are relatively rare. A simple, yet fully three-dimensional, model is constructed to investigate the dynamics of this unique event. Planetary waves are excited on the model vortex edge by a lower boundary forcing characterized by two parameters: an amplitude h(F) and a frequency omega(F), measured relative to a stationary frame. For realistic forcing amplitudes, a partial vortex split resembling that observed during the 2002 event is found only within a specific, narrow band of forcing frequencies. Exploiting the relative simplicity of our model, these frequencies are shown to be those causing a 'self-tuning' resonant excitation of the gravest linear mode, during which nonlinear feedback causes an initially off-resonant forcing to approach resonance.
|Title:||The Antarctic stratospheric sudden warming of 2002: A self-tuned resonance?|
|Open access status:||An open access version is available from UCL Discovery|
|Additional information:||Copyright 2006 by the American Geophysical Union|
|Keywords:||Polar vortex, Southern-hemisphere, Simulations, Evolution, Dynamics, Waves|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Mathematics|
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