Modulation by the Atlantic Multidecadal Oscillation of the intensity of the interannual seesaw between the Somali and Australian cross-equatorial flows

The decadal variation of the intensity of the interannual opposite connection (seesaw) between the Somali and Australian cross-equatorial flows (CEFs) is investigated. During the period prior to the mid-1960s, and after the early-2000s, the intensity of the interannual seesaw connection is significantly weaker relative to the period between. Such interdecadal shifts in the interannual seesaw intensity bear a resemblance to the decadal shift in ENSO’s strength, and can be further attributed to the phase transition of the Atlantic Multidecadal Oscillation (AMO). When the AMO is in a positive phase, the ENSO amplitude reduces and the seesaw strength becomes weakened, and vice versa. The historical simulation outputs of the CMIP5 models are used to verify the connection, and a similar result was obtained. Thus, the notion that the intensity of the interannual opposite connection (seesaw) between the CEFs is modulated by the AMO is robust.