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