SeaSonde and Tide Gauge Tsunami Observations New Jersey June 13, 2013
Belinda Lipa, Hardik Parikh, Don Barrick Codar Ocean Sensors
Scott Glenn, Hugh Roarty Rutgers University
Synopsis
• SeaSonde coastal HF radars see tsunami's orbital velocity
• Single radar observes velocity pattern vs. distance offshore
• Flow was observed perpendicular to isobaths
• Arrival-time was obtained vs. distance from shore
SeaSonde onshore velocity vs time Tide gauge water level vs time
Arrival time vs. distance from shore Tsunami observations June 13, 2013 1700-1900 • First observations were offshore - velocity 'minimum' (wave trough)
• Observed 23 km out, 30 minutes before coastal arrival
• Velocity weakens at coast because semi-hard boundary stops flow
• Tide gauge (height) and radar (velocity) arrival times at coast agree
Distance from shore :Blue -7km Red -9km Black-11kmGreen-13km
Blue: SeaSondeRed: Tide Gauge
SeaSonde onshore velocity Tide gauge water level
Tsunami observations June 13, 2013 2100-2400
Distance from shore :Blue -7km Red -9km Black-11km Green-13km
• Velocity is first onshore 'maximum' (wave peak), then offshore 'minimum' (wave trough)• Radar peak/trough times precede tide-gauge’s by 30 minutes
Future Work: Multiple Radar Sites
• Detrend velocities• Generate tsunami 2D current maps from adjacent sites in area
• Interpret patterns in terms of bathymetry and tsunami height
IOOS MARACOOS RegionalAssociation SeaSonde radar
network managed by Rutgers
Example of current maps from the 2011 Japan tsunami