Observations of Observations of Barrier Layer Seasonal Variation in the Banda Sea

– Furqon Azis Ismail, Scientist, BRIN –

Résumé :

The Banda Sea is crucial to the circulation of the world’s oceans and atmosphere due to its location within the equatorial regions of the Indonesian Maritime Continent. It links the Pacific and Indian Oceans’ circulation via the Indonesian Throughflow and contributes to driving atmospheric conditions via heat and moisture fluxes. Strong salinity-stratified barrier layers insulate the water exchange between the surface and subsurface. The formation and seasonal variation of barrier layer thickness (BLT) in the Banda Sea are analyzed based on all available observations and ocean reanalysis outputs. Observations show that the Banda Sea has a barrier layer for the most part of the season. The BLT maximum appears during austral winter (June to August) months. The seasonal BLT maximum is attributed to the near-surface water freshening, which shoals the mixed layer depth (MLD) and deep isothermal layer depth (ILD) maintained by a steady anticyclonic gyre. Other processes, such as wind stress curl-induced Ekman pumping associated convergence, also modulate its seasonal variability.