The Structure and Dynamics of Stationary Fronts in an Angled River Plume
- Keyan Liu,
- Jiaxue Wu,
- Huan Liu,
- Xiangyu Li,
- Zhenkun Lin
Xiangyu Li
Leibniz Institute for Baltic Sea Research Warnemuende
Author ProfileAbstract
In angled river plumes, the river flow is oriented obliquely to the
coast, resulting in a lateral expansion into the sea rather than a
radial one. However, the frontal structure and dynamics in these systems
are not straightforward, especially under the influence of coastal
currents. Here, we present detailed observations of an angled river
plume and its fronts in the Macao waters. During the ebb tide, the river
plume transitions from subcritical to supercritical due to the
acceleration caused by lateral contraction. Despite these changes, the
plume front remains nearly stationary, forming a steady gravity current
that meets the critical conditions in a coordinate system normal to the
front. Furthermore, the adjustment of the cross-flow changes the Froude
angle, leading the frontal shape to a parabolic planform. Beneath the
surface front, internal bores have observed, predominantly driving
frontogenesis processes via vertical straining rather than horizontal
advection. These findings offer novel understanding of stationary
surface fronts, which may trap the river-borne materials and pose
significant challenges to coastal environments and ecosystems.02 Aug 2024Submitted to ESS Open Archive 05 Aug 2024Published in ESS Open Archive