01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-02-0151 |
| Title of Abstract | Austral Autumn Surface CO2 in the Western Indian Ocean and Relationship with the Indian Ocean Dipole (IOD) |
| Authors | So-Yun Kim*, Sang-Hwa Choi, Dong-Jin Kang, Hyoun-Woo Kang |
| Organisation | Korea Institute of Ocean Science & Technology (KIOST) |
| Address | 385 Haeyang-ro Yeongdo-gu, Busan, Korea, Rep. Pincode: 49111 E-mail: soyun3369@kiost.ac.kr |
| Country | Korea, Rep. |
| Presentation | Poster |
| Abstract | The Indian Ocean plays a crucial role in global carbon cycling, yet the seasonal and climate-driven variability in air-sea CO2 exchange remains poorly understood. We investigated surface fugacity of CO2 (fCO2sea) and associated CO2 air-sea fluxes in the western Indian Ocean during austral autumn (April-June) in 2019, 2023, 2024, and 2025. The western Indian Ocean generally acted as a CO2 sink, except in the northern region (<10° S; Seychelles-Chagos Thermocline Ridge, SCTR) during negative Indian Ocean Dipole (nIOD) years, with fluxes ranging from 0.2 to 0.7 mol m-2 yr-1. Thermal effects on fCO2sea were strongest in 2025 (the warmest year), while non-thermal effects dominated in the SCTR region. During nIOD years (2023, 2025), enhanced subsurface upwelling in the SCTR region increased surface CO2 concentrations, producing positive non-thermal effect anomalies, higher fCO2sea, and weaker CO2 uptake. In contrast, during positive IOD years (2019, 2024), suppressed upwelling generated negative non-thermal anomalies, lower fCO2sea, and stronger CO2 uptake. These results highlight the relationship between IOD phases and CO2 dynamics in the SCTR region. |
| Are you part of IIOE-2 endorsed project | yes |
| Endorsed Project Number | IIOE2-EP51 |
| Keywords | surface fCO2, CO2 flux, western Indian Ocean, SCTR, IOD |
| For Awards | no |