1:45 PM - 2:00 PM
[AOS14-01] The cooling of sea surface temperature in the southern Indonesian Seas due to a combination of the Ekman transport and tidal mixing in narrow straits
Keywords:SST in the Indonesian Seas, Tidal mixing in narrow straits, Ekman transport
In this study, to investigate the mechanisms of SST cooling around the NTIs, we carry out a numerical simulation using a regional ocean model where the realistic distribution of vertical diffusivity estimated from a high resolution baroclinic tide model is incorporated. The simulated results show that significant mixing in the narrow tidal straits between the NTIs creates well-mixed waters, which spread out northward (southward) during Austral summer (winter) and finally causes significant SST cooling over a large area of southern Indonesian Seas.
We therefore carry out numerical experiments where either of the monsoonal wind or localized tidal mixing in the narrow straits is switched off. These numerical experiments show that well-mixed waters in the narrow straits are continuously advected by the northward (southward) flow driven by the western (eastern) monsoonal wind during Austral summer (winter) until the Indonesian Throughflow spreads them out over a large area of southern Indonesian Seas, demonstrating the importance of the combined effect of the Ekman transport and tidal mixing.