Oceanic control of multidecadal variability in an idealized coupled GCM

摘要: Idealized ocean models are known to develop intrinsic multidecadal oscillations of the meridional overturning circulation (MOC). Here we explore role ocean–atmosphere interactions on this low-frequency variability. We use a coupled model set up in flat-bottom aquaplanet geometry with two boundaries. The is run at three different horizontal resolutions (4°, 2° and 1°) both atmosphere. At all resolutions, MOC exhibits spontaneous variability timescales range 30–40 years, associated propagation large-scale baroclinic Rossby waves across Atlantic-like basin. unstable region growth these through long wave limit instability shifts from eastern boundary coarse resolution western higher resolution. Increasing enhances atmospheric interactions. In particular, simulated annular mode becomes significantly correlated 1° An ocean-only simulation conducted for specific case underscores disruptive but not essential influence air–sea This study demonstrates that an leading changes by about 2 years (as found resolution) does imply originates