Frontogenesis and estuarine circulation at the shallow sill of a tropical fjord: Insights from Ambon Bay, eastern Indonesia

Secondary estuarine circulation and the related vertical mixing at the sill of Ambon Bay, eastern Indonesia

“…While the former is common in marine systems, the latter shed light on the important of estuarine circulation, the flood/ebb-mean flow, in flushing the surface layer of IAB [1]. Furthermore, [1] indicated that the magnitude of estuarine circulation at the sill is affected by buoyant fronts established during spring flood tide.…”

“…Introduction Ambon Bay in eastern Indonesia is a shallow-silled tropical fjord due to the inner basin called inner Ambon Bay (IAB) that is separated from outer Ambon Bay (OAB, its outer waters connected to Banda Sea) by a shallow sill (i.e. 12 m; see Figure 1a) [1,2,3,4]. Due to its unique geomorphologic-topographic aspect, Ambon Bay has been of great general interest to oceanographic studies [1,2,3,4,5,6,7,8].…”

“…Due to its unique geomorphologic-topographic aspect, Ambon Bay has been of great general interest to oceanographic studies [1,2,3,4,5,6,7,8]. In particular to the sill of Ambon Bay, the location has attracted many researchers regarding its narrow, shallow aspect, behaving as a constriction of IAB and thus, the sill can create energetic hydrodynamics [6,9] and a two-layer circulation system, called estuarine circulation similarly found in partly-mixed estuaries [1,10,11]. While the former is common in marine systems, the latter shed light on the important of estuarine circulation, the flood/ebb-mean flow, in flushing the surface layer of IAB [1].…”

“…In particular to the sill of Ambon Bay, the location has attracted many researchers regarding its narrow, shallow aspect, behaving as a constriction of IAB and thus, the sill can create energetic hydrodynamics [6,9] and a two-layer circulation system, called estuarine circulation similarly found in partly-mixed estuaries [1,10,11]. While the former is common in marine systems, the latter shed light on the important of estuarine circulation, the flood/ebb-mean flow, in flushing the surface layer of IAB [1]. Furthermore, [1] indicated that the magnitude of estuarine circulation at the sill is affected by buoyant fronts established during spring flood tide.…”

“…A relevant question regarding the achievements of [1] on estuarine circulation is "is there any secondary estuarine circulation as the residual two-layer circulation prevails?". Such a question has attracted some studies in other estuaries [12,13,14].…”