Impacts of Different Types of ENSO on the Interannual Seesaw between the Somali and the Maritime Continent Cross-Equatorial Flows

The impacts of different types of El Nino–Southern Oscillation (ENSO) on the interannual negative correlation (seesaw) between the Somali cross-equatorial flow (CEF) and the Maritime Continent (MC) CEF during boreal summer (June–August) are investigated using the ECMWF twentieth-century reanalysis (ERA-20C) dataset and numerical experiments with a global atmospheric model [the Met Office Unified Model global atmosphere, version 6 (UM-GA6)]. The results suggest that ENSO plays a prominent role in governing the CEF-seesaw relation. A high positive correlation (0.86) exists between the MC CEF and Nino-3.4 index and also in the case of eastern Pacific (EP) El Nino, central Pacific (CP) El Nino, EP La Nina, and CP La Nina events. In contrast, a negative correlation (−0.35) exists between the Somali CEF and Nino-3.4 index, and this negative relation is significant only in the EP El Nino years. Further, the variation of the MC CEF is highly correlated with the local north–south sea surface temperature (S...