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Outline Glider acoustics Combustive sound source inversions 3D effects of front and internal waves Papers in progress Preliminary Results James H. Miller.

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Presentation on theme: "Outline Glider acoustics Combustive sound source inversions 3D effects of front and internal waves Papers in progress Preliminary Results James H. Miller."— Presentation transcript:

1 Outline Glider acoustics Combustive sound source inversions 3D effects of front and internal waves Papers in progress Preliminary Results James H. Miller and Gopu R. Potty

2 Hydrophone Mounted on Slocum Glider Results –Initial test worked well ~1/2 hour of data –Full test glider flew 200km over 14 days! –Undocumented software feature in Bioprobe caused early termination –Another test planned for this winter Towed configuration

3 Single Phone Data from Glider 400 Hz WHOI tomo source 224 Hz WHOI tomo source 200 Hz Miami source 300 Hz NRL FM chirps Glider ‘Clicks’ Glider whine Collaborators: Jason Holmes, Jim Lynch, Scott Glenn, Josh Kohut, Hugh Roarty

4 Glider Location Acoustic glider location

5 Measured Phase Stability Phase of 224 Hz source stable and linear over time Glider click Miami sound machine 224 Hz WHOI source Glider click Miami sound machine on

6 Synthetic Aperture Output 224 Hz tomography signal carrier Beamformer turned on at 50 seconds Glider click

7 Synthetic Aperture Beamformer 224 Hz carrier MSM 200 Hz tomo sideband?

8 Pulse compressed MSM Interference Glider click Mode 1 Mode 2

9 Combustive Sound Source (CSS) Data on the SHRUs Shru 1; 15.27 km Source deployed from R/V Knorr by Preston Wilson/ David Knobles Source waveform monitored Source depth ~ 26 m Inversions using CSS data (using mode travel times) Collaborators: Lynch, Newhall, Wilson, Knobles, Hodgkiss, Chapman Mode 1 Mode 2

10 Frontal Reflection Effects on CW TL 10 o C 15 o C SourceReceiver Range 1 km Front Fixed frequency= 200 Hz Varying range Lynch, J.F.; Colosi, J.A.; Gawarkiewicz, G.; Duda, T.F.; Pierce, A.D.; Badiey, M.; Katsnelson, B.G.; Miller, J.H.; Siegmann, W.; Chiu, C.-S.; Newhall, A.,“Consideration of Fine-Scale Coastal Oceanography and 3-D Acoustics Effects for the ESME Sound Exposure Model,” IEEE J. Ocean. Eng., 31, (1), 33 – 48, (2006).

11 28.2 km 30.3 km 34.7 km Frequency – 93 Hz Source depth ~ 50 m Source Level – 165 – 168 dB Collaborators: Lynch, Newhall, Badiey, Duda, Gawarkiewicz J-15 Tow Parallel to the Shelf Break Front

12 This image 16 hours later than transect, Internal wave seen on ship’s radar inshore of Knorr at 11 PM Local (0400 GMT 9/5/06) Shark Knorr 3D J-15 Run Track

13 J-15 Tow Parallel to the Front: Model Front Internal wave packet WHOI HLA/VLA (Shark) Frequency – 93 Hz Source depth ~ 50 m Source Level – 165 – 168 dB Collaborators: Lynch, Newhall 2 modes Ship track

14 28.2 km 34.7 km Frequency – 93 Hz Source depth ~ 50 m Source Level – 165 – 168 dB Collaborators: Lynch, Newhall J-15 Tow Parallel to the Front: Data J-15 on Front Internal wave packet Knorr track Range km 25 30 35 40 45 50 Data shows 20 dB increase, model only 10 dB. Where is the other 10 dB coming from? Curvature of front? Internal wave structure?

15 ASA Meeting - Abstracts 1.The effect of a rough sea surface on acoustic normal modes (Miller and Lynch - Medwin session, invited) 2.Observations of phase and travel time variations of normal modes during Tropical Storms Ernesto and Florence (Langer, Miller, Potty, Lynch, Newhall) 3.Geoacoustic inversion using combustive sound source signals (Potty, Miller, Wilson, Lynch, Newhall) 4.Acoustic measurements in shallow water using an ocean glider (Georges A. Dossot, James H. Miller, Gopu R. Potty, Kristy A. Moore, Jason D. Holmes, Scott Glenn, and Jim Lynch) 5.Investigation of 3D propagation effects at the New Jersey shelf break front (Kristy A. Moore, James H. Miller, Gopu R. Potty, Georges Dossot, James Lynch, Arthur Newhall, and Glen Gawarkiewicz)


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