Pacific and Atlantic multidecadal variability in the Kiel Climate Model

Abstract

Pacific decadal variability (PDV) and Atlantic multidecadal variability (AMV), the two leading decadal modes of observed Northern Hemisphere sea surface temperature (SST) variability, are investigated in a multi-millennial control integration of the Kiel Climate Model (KCM). It is shown that the two phenomena are independent modes in the model and can be easily separated by Principal Oscillation Pattern (POP) analysis of model SST. PDV-related variability covers the whole North Pacific with strong signals in both the mid-latitude North Pacific and the western Tropical Pacific. Strong signals are also simulated in the eastern Indian Ocean Sector. PDV's memory, however, resides in the North Pacific and is linked to the subtropical gyre. The AMV mechanism is related to the Atlantic meridional overturning circulation (AMOC). A stochastic mechanism applies to both PDV and AMV. © 2010 by the American Geophysical Union.