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IT and Computing Science

Publications

Rip Current Observations via Marine Radar

Publicaciones

Rip Current Observations via Marine Radar

Research areas:

Informática y Computación

Year:

2013

Type of Publication:

In Proceeding

Authors:

Abstract:

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, NC) 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/s, while significant wave heights were Hs ~ 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 to 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, as well as 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 (>0.02m/s2) is found to preclude the rip current imaging.

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