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Acoustic Seagliders in the Philippine Sea Lora Van Uffelen , Eva-Marie Nosal , Bruce Howe

NPAL Workshop Fallbrook, California 18-20 October 2011. Acoustic Seagliders in the Philippine Sea Lora Van Uffelen , Eva-Marie Nosal , Bruce Howe. Lora Van Uffelen , Ph.D. University of Hawaii at Manoa Ocean and Resources Engineering loravu@hawaii.edu.

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Acoustic Seagliders in the Philippine Sea Lora Van Uffelen , Eva-Marie Nosal , Bruce Howe

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  1. NPAL Workshop Fallbrook, California 18-20 October 2011 Acoustic Seagliders in the Philippine SeaLora Van Uffelen, Eva-Marie Nosal, Bruce Howe Lora Van Uffelen, Ph.D. University of Hawaii at Manoa Ocean and Resources Engineering loravu@hawaii.edu

  2. Acoustic SeagliderPhilSea10 Objectives • One component of fixed/mobile tomography array • Increase resolution of tomography system • Fundamental ambiguity between position and sound speed • Measure acoustic arrival patterns • Many ranges and depths • Complement moored instrumentation • Provide temperature/salinity profiles • Provide ambient sound data

  3. Acoustic Seaglider Hydrophone

  4. iRobotSeagliderOverview • Iridium satellite connection • Near-realtime temperature and salinity • Max depth 1000 m • Nominally ½ knot at ½ W • Deployments up to 6 months, 3000 km,600 dives

  5. Source Transmissions Transmitted sequentially at 540 sec intervals 135 sec LFM Sweep Every 3 hours on odd- numbered yeardays Glider recording 3200 seconds 4 kHz sampling rate Recorded ambient noise on alternate yeardays ARS reporting ARSlogfile Acoustic power spectral density Acoustic Recording

  6. Deploy/Recover Operations • Deployment • 4 Gliders deployed • Roger Revelle/ITOP Mooring Cruise • 6-26 November 2010 • Recovery • PhilSea10 Mooring Recovery Cruise • 24 March – 16 April 2011 • 2 Gliders recovered • 2 Gliders recovered early Photo courtesy of Kevin Hardy

  7. PhilSea10 Seaglider Tracks SG511 Low Battery Feb 16 Recovered Mar 5 SG513 Recovered April 10 SG023 Pitch Error Jan 11 Recovered Jan 26 SG500 Recovered Mar 29

  8. Seabird CT Sensor Measurements in upper 1000 m Temperature & Salinity Temperature Salinity SG023 Temperature SG500 SG511 SG513

  9. Spectrogram from ARS

  10. T6-T4 Transect SG023 Track Acoustic Path Sampling

  11. Spectrograms

  12. Doppler Effects on Glider Receptions • Glider is moving as it is recording • Nominally 40 cm/sec

  13. Rough Positioning Using Travel Times from Moored Sources

  14. Parabolic Equation Simulation

  15. T1 Reception on SG023Christmas Day, 2010

  16. T1 Reception on SG023January 2, 2011

  17. Summary • Numerous acoustic receptions • Promising arrival patterns • Improve travel time estimate using clock corrections and updated knowledge of signal characteristics • Identify acoustic ray paths • T/S profiles assimilated into NAVO ocean models and available at: http://hahana.soest.hawaii.edu/seagliders/

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