The North Pacific Oscillation is known to drive the North Pacific Gyre Oscillation (NPGO), and to excite Rossby waves that propagate the NPGO signature from the central North Pacific into the Kuroshio Extension (KE) region. This, in turn, is suggested to be the cause of the synchronization between the NPGO and the KE decadal bimodality as observed from satellite altimetry. In this communication modelling studies are presented supporting the hypothesis that such synchronization results from the excitation -via the Rossby wave field- of a KE relaxation oscillation, whose spatial structure and evolution is basically due to a highly nonlinear intrinsic oceanic mechanism. This is therefore a case of intrinsic variability paced by an external forcing, which is likely to be a common behaviour in climate dynamics.
Intrinsic climate variability paced by external forcing: the Kuroshio Extension bimodality – North Pacific Oscillation case
PIERINI, Stefano
2013-01-01
Abstract
The North Pacific Oscillation is known to drive the North Pacific Gyre Oscillation (NPGO), and to excite Rossby waves that propagate the NPGO signature from the central North Pacific into the Kuroshio Extension (KE) region. This, in turn, is suggested to be the cause of the synchronization between the NPGO and the KE decadal bimodality as observed from satellite altimetry. In this communication modelling studies are presented supporting the hypothesis that such synchronization results from the excitation -via the Rossby wave field- of a KE relaxation oscillation, whose spatial structure and evolution is basically due to a highly nonlinear intrinsic oceanic mechanism. This is therefore a case of intrinsic variability paced by an external forcing, which is likely to be a common behaviour in climate dynamics.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
