Persistent transport barrier on the West Florida Shelf

Area of Science:

• Oceanography
• Physical Oceanography
• Coastal Dynamics

Background:

• Drifter trajectory analysis identified a "forbidden zone" (FZ) on the southern West Florida Shelf (WFS).
• The FZ suggests a persistent cross-shelf transport barrier limiting water mass exchange.
• Understanding these barriers is crucial for coastal processes, including harmful algal bloom dynamics.

Purpose of the Study:

• To identify and characterize the persistent cross-shelf transport barrier on the southern WFS.
• To investigate the seasonal variability of this transport barrier.
• To assess the feasibility of using high-frequency (HF) radar for monitoring such barriers.

Main Methods:

• Utilized a year-long surface current record from a Hybrid-Coordinate Ocean Model simulation.
• Computed Lagrangian Coherent Structures (LCSs) to identify transport barriers.
• Analyzed a month-long surface current record from HF radar measurements.

Main Results:

• Lagrangian coherent structures (LCSs) confirmed a persistent cross-shelf transport barrier co-located with the FZ.
• The barrier's position exhibited seasonal oscillation, shifting shoreward in summer and seaward in winter.
• HF radar data revealed transient transport barriers, demonstrating potential for monitoring.

Conclusions:

• A persistent cross-shelf transport barrier exists on the southern WFS, influencing water mass movement.
• The barrier's seasonal variability suggests dynamic oceanographic conditions.
• HF radar systems show promise for monitoring ocean transport barriers on the WFS, with implications for harmful algal bloom prediction.