The impact of lateral advection on SST and SSS in the northern Bay of Bengal during 2015

Abstract

The Bay of Bengal is subject to strong lateral advection of low-salinity water. This advection leads to the development of strong upper-ocean stratification (salinity stratification), which can have a significant impact on the evolution of SST and SSS by modifying mixing near the surface. In this study, we use a 1-dimensional (1-D) ocean mixing model (PWP) forced with in-situ air–sea fluxes from a surface mooring, along with estimates of horizontal surface freshwater and heat advection from a satellite ocean current product. We develop an ensemble of 1-D simulations by varying estimates of the advection used to force the model and analyze how the advection of temperature and salinity influences the evolution of SST and SSS. The use of an ensemble of solutions, rather than any single solution, compensates for uncertainty in our satellite estimates and significantly improves confidence in our results. Our results indicate that air–sea fluxes are not sufficient to properly simulate the evolution of SST in the northern Bay of Bengal, and that accounting for freshwater advection is required in order to reduce error in SST.