Intensity changes of Indian Ocean dipole mode in a carbon dioxide removal scenario

Soon Il An, Hyo Jin Park, Soong Ki Kim, Jongsoo Shin, Sang Wook Yeh, Jong Seong Kug

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15 Citations (Scopus)


The Indian Ocean Dipole/Zonal mode (IOD) is an interannual phenomenon over the tropical Indian Ocean, causing a pronounced impact worldwide. Here, we investigate the mechanism of the change in IOD characteristics in a CO2 removal simulation for an earth system model (ESM). As the CO2 concentration increases, the intensity of IOD tends to increase, but at high CO2 concentrations, further increases decrease the IOD intensity. The minimum IOD amplitude was recorded during the early decrease in CO2. First, we developed a conceptual model for IOD that is composed of local air-sea coupled feedback, delayed ocean dynamics, El Niño impact, and noise forcing. Then, by adopting ESM results into this simple IOD model, we revealed that the local air–sea coupled feedback is a major factor for changing IOD amplitude, while El Niño does not exert a change in IOD amplitude. The local air–sea coupled feedback including thermocline feedback, wind-evaporation feedback, and Ekman feedback is strongly modified by the air–sea coupling strength during progression of a global warming. Consequently, under the higher CO2 concentrations, IOD amplitude is reduced due to the weakening of air-sea coupling over tropical Indian Ocean.

Original languageEnglish
Article number20
Journalnpj Climate and Atmospheric Science
Issue number1
Publication statusPublished - 2022 Dec

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© 2022, The Author(s).

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Environmental Chemistry
  • Atmospheric Science


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