Large‐scale oceanic waves, triggered by atmospheric and oceanic disturbances associated with El Niño, can propagate across the Indian Ocean and ultimately affect the climate of the south‐western Indian Ocean. The slow propagation of these waves suggests the possibility of predicting downstream climate impacts in the south‐western Indian Ocean region months or years after an El Niño event.

El Niño effects are communicated to the Indian Ocean via both large‐scale atmospheric circulation changes over the southern tropical ocean basin and via disturbances to sea‐levels along the coast of Western Australia. The researchers investigated these remote ENSO influences in a state‐of‐the‐art climate model.

They found the atmospherically‐driven mechanism was responsible for most of the regional south‐western Indian Ocean climate impacts, while simultaneously disrupting the westward transmission of signals from Western Australia. This suggests that timescales for El Niño‐associated predictability are considerably shorter than if purely oceanic mechanisms were involved.

  • Paper: Eabry, M. D., Taschetto, A. S., Maharaj, A. M., & Gupta, A. S. (2021). What determines the lagged ENSO response in the South‐West Indian Ocean?. Geophysical Research Letters, 48, e2020GL091958.