01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-04-0081 |
| Title of Abstract | Subsurface Cooling and Freshening in the South Indian Ocean: Distribution, Variability, and Climate Implications |
| Authors | Meng Han*, Helen E. Phillips, Nathan L. Bindoff, Ming Feng, Ramkrushnbhai Patel |
| Organisation | University of Tasmania |
| Address | unit21, 1 Creswells Row Hobart, TAS, Australia Pincode: 7000 E-mail: meng.han@utas.edu.au |
| Country | Australia |
| Presentation | Oral |
| Abstract | The Indian Ocean has experienced rapid surface warming in recent decades, yet the subsurface shows significant basin-scale cooling and freshening during the Argo era. These anomalies display strong spatial contrasts across the South Indian Ocean (SIO), differing between the eastern and western regions of the SIO, suggesting distinct formation mechanisms and propagation pathways. Analysis of Argo observations indicates that long-term cooling and freshening in both regions are primarily driven by spice (along-isopycnal) changes, while heave (vertical displacement of isopycnals) contributes mainly to smaller-scale variability linked to ENSO and the Indian Ocean Dipole. Freshening accounts for much of the cooling along isopycnals, underscoring the dominant role of salinity in shaping subsurface thermal trends. Both eastern and western SIO anomalies likely originate from multiple source regions, reflecting complex interactions between water mass formation and climate variability. We discuss possible mechanisms underlying spice- and heave-driven changes and propose potential pathways for anomaly propagation across the SIO. These findings highlight the importance of understanding multiple sources and pathways of subsurface changes and their connections to climate variability. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | South Indian Ocean, spice and heave, water mass |
| For Awards | no |