[A-OS16] Physical, biogeochemical, and ecological processes and variability in the Indian Ocean

[AOS16-05] What drives the Seasonal Variability of the Indian Ocean Meridional Overturning Circulation and Deep Inflow?

*Lei HAN¹ (1.Xiamen University Malaysia)

Keywords:Indian Ocean, Meridional Overturning Circulations, Sloshing, Deep inflow

The seasonal variability of the Indian Ocean Meridional Overturning Circulation (IMOC) has long been attributed to Ekman flow and its barotropic compensation (Lee and Marotzke, 1998). However, my analysis suggests that its seasonality is primarily governed by a sloshing mode associated with basinwide adiabatic water redistribution, rather than a purely Ekman-driven mechanism. Furthermore, the deep inflow into the Indian Ocean exhibits seasonal variations linked to this sloshing overturning mode, a pattern partially supported by cross-basin field campaigns along 32°S, which have been fully occupied three times in history. Additionally, this perspective also provides a new explanation for the diffusivity dichotomy problem. By reframing the IMOC in this context, the traditional view of its role in the global conveyor belt is challenged.