Journal of Waterway, Port, Coastal, and Ocean Engineering
L2. Amenazas por procesos de aguas superficiales
Universidad Técnica Federico Santa María
New remote sensing observations that demonstrate the presence of rip current plumes in X-band radar images are presented. The observations collected on the Outer Banks (Duck, North Carolina) show a regular sequence of low-tide, low-energy, morphologically driven rip currents over a 10-day period. The remote sensing data were corroborated by in situ current measurements that showed depth-averaged rip current velocities were 20–40 cm/s20–40 cm/s whereas significant wave heights were Hs=0.5–1 mHs=0.5–1 m. Somewhat surprisingly, these low-energy rips have a surface signature that sometimes extends several surf zone widths from shore and persists for periods of several hours, which is in contrast with recent rip current observations obtained with Lagrangian drifters. These remote sensing observations provide a more synoptic picture of the rip current flow field and allow the identification of several rip events that were not captured by the in situ sensors and times of alongshore deflection of the rip flow outside the surf zone. These data also contain a rip outbreak event where four separate rips were imaged over a 1-km stretch of coast. For potential comparisons of the rip current signature across other radar platforms, an example of a simply calibrated radar image is also given. Finally, in situ observations of the vertical structure of the rip current flow are given, and a threshold offshore wind stress (>0.02 m/s2>0.02 m/s2) is found to preclude the rip current imaging.
- Merrick C. Haller, M.ASCE, email@example.com, Associate Professor, School of Civil and Construction Engineering, Oregon State Univ., 220 Owen Hall, Corvallis, OR 97331 (corresponding author).
- David Honegger, Graduate Research Assistant, School of Civil and Construction Engineering, Oregon State Univ., 220 Owen Hall, Corvallis, OR 97331.
- Patricio A. Catalan, Assistant Professor, Departamento de Obras Civiles, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390206, Chile. Associate Researcher, Centro Nacional de Investigación para la Gestión Integrada de Desastres Naturales, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390206, Chile. Associate Researcher, Centro Científico Tecnológico de Valparaíso, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390206, Chile.