The interaction between ENSO and the South Atlantic Subtropical Dipole Mode

The interaction between ENSO and the South Atlantic subtropical dipole mode (SASD) is investigated using both observations and model simulations. We show that negative SASD events are associated with central Pacific El Niño events, whereas positive SASD events are associated with central Pacific La Niña events. El Niño triggers the 3rd leading mode of the Pacific-South America wave train (PSA) that causes a weakening of the South Atlantic subtropical high, which in turn generates the negative SASD events. The opposite is true for positive events. Our results also show that only central Pacific ENSO events are capable of triggering the correct teleconnection that leads to the SASD.