This study aimed to observe and simulate a process that releases heat from shallow and deep waters in the Aceh Waters. The simulations modeled vertical slice cases with varying seawater densities based on stability frequency. One transect was taken in shallow waters in Krueng Raba Bay, while the other two were taken in deep waters in Sabang Bay. This study used a 2D non-hydrostatic model with stratified densities from the sea surface to the specified depth. Seawater density changes increase in areas with shallow depth and leave low-density in the high depth area. The vertical current velocity or upwelling starts to strengthen in the sill area at two hours, in the simulation. The lighter fluid moves upwards, looking for a gap in the denser fluid on the surface, at a speed of 0.0042 m/s to 0.03 m/s. Areas with high depth have these speeds falling after about 3 hours in the simulation, but the surface layer shows seawater density stability. In general, the deep sea area is not affected by the convection process, and the sea surface area is well-mixed after 3 hours of simulation.
