EGU21-3655, updated on 14 Jun 2023
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Triggering the Indian Ocean Dipole from the Southern Hemisphere

Lian-Yi Zhang1,2, Yan Du1,2,3, Wenju Cai4,5, Zesheng Chen1,2, Tomoki Tozuka6, and Jin-Yi Yu7
Lian-Yi Zhang et al.
  • 1South China Sea Institute of Oceanology, State Key Laboratory of Tropical Oceanography, Guangzhou, China (
  • 2Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
  • 3University of Chinese Academy of Sciences, Beijing, China
  • 4Centre for Southern Hemisphere Oceans Research (CSHOR), CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia
  • 5Key Laboratory of Physical Oceanography, Institute for Advanced Ocean Studies, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
  • 6Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
  • 7Department of Earth System Science, University of California, Irvine, USA

This study identifies a new triggering mechanism of the Indian Ocean Dipole (IOD) from the Southern Hemisphere. This mechanism is independent from the El Niño/Southern Oscillation (ENSO) and tends to induce the IOD before its canonical peak season. The joint effects of this mechanism and ENSO may explain different lifetimes and strengths of the IOD. During its positive phase, development of sea surface temperature cold anomalies commences in the southern Indian Ocean, accompanied by an anomalous subtropical high system and anomalous southeasterly winds. The eastward movement of these anomalies enhances the monsoon off Sumatra-Java during May-August, leading to an early positive IOD onset. The pressure variability in the subtropical area is related with the Southern Annular Mode, suggesting a teleconnection between high-latitude and mid-latitude climate that can further affect the tropics. To include the subtropical signals may help model prediction of the IOD event.

How to cite: Zhang, L.-Y., Du, Y., Cai, W., Chen, Z., Tozuka, T., and Yu, J.-Y.: Triggering the Indian Ocean Dipole from the Southern Hemisphere, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3655,, 2021.