Modal Inverse Methods Experiments ( MIME ) R/V Endeavor, 04-06 August 2006
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Transcript of Modal Inverse Methods Experiments ( MIME ) R/V Endeavor, 04-06 August 2006
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Modal Inverse Methods Experiments(MIME)
R/V Endeavor, 04-06 August 2006
Kyle M. Becker (PI)The Pennsylvania State University
Subramaniam D. Rajan (co-PI)Scientific Solutions Inc
Megan S. BallardGraduate Program in Acoustics, Penn State
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Range-Dependent Geoacoustic Inversion
Modal Arrival Times - VLA/airgun LFMModal Wavenumbers - SA(VLA)/J-15
Doppler Wavenumber Shifts - SA(VLA)/J-15
Impact of Oceanic Variability on GI
Spatial Measure of SVF - CTD chain
Objectives & Measurements
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Primary Measurement Assets
J-15-3 LF source – Starboard J-Frame (z = 30 m)CW comb (50,75,125, 175 Hz)radial tows ~5 km out/back on VLA
FM sweep (40-290 Hz) 15 km standoff, 0.5s on/2.5s off
~173 dB re 1uPa/1m SL
Towed CTD chain temporal/spatial measure of C,T,P.48 sensors 141 m vertical aperture (3* meter spacing)NOT fully deployed during MIME
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Summary of Data Collected
Radial CW tows – (~5 km @ 50,75,125 175 Hz)25 hrs, 2-10 knots3 tracks (along, across, oblique)
FM sweeps (40-290 Hz)20 Stations around circle @ 15 km120 pings per station
Towed CTD chain Deployed concurrently with J-15
Endeavor FastNav 3 types GPS at 1 sec
Endeavor CTDCasts before/after deploy/recovery of source/chain
TPpodTemp/Depth recorder mounted on J-15
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Synthetic Aperture CW Tracks
Actual Tracks E1-E3
Sound Speedfrom towed CTDDay 216 2 knots(~80 min/section)
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LFM Station Locations
LFM data sample40-290 Hz 0.5 secrepeat every 3 sec
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Analysis & Publication Plan
Associate temporal and spatial acoustic and environmental data
Reduction of data p(t) to p(f;r) wave number estimation for geoacoustic inversion
perturbative and ASSA for discrete wave numbersat multiple frequencies (PhD Thesis, JASA)
look for range-dependence in wave number alongdifferent tracks – STFT and TFD approaches(PhD Thesis, JASA)
Impact of variability on GI and kr estimation(PhD Thesis, JASA)
Doppler wave number shift and estimation of modal group velocity for moving source (JOE)
Temporally locate LFM pings Range dependent inversions based on modal
travel time differences Scintillation due to source motion or variability
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Analysis Plan
Evidence of IW during CW tow event (6 knots)
Tem
p. (C)
TP recorder data
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Collaborations
G.V. Frisk and MOMAX
David Knobles – CW and light bulb data
Any propagation concurrent with towed CTD datacollected during some of the larger internal wave events. Mohsen Badiey, Jim Lynch
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Acknowledgements
John Camin Frank
JacquieBeitel
Joy Lyons
AmandaDye Paul
Gabel
Megan Ballard
Inga Koszalka
me
The Team: 6 STUDENTS!, 1 engineer, 2 unknown(UMich,PoliTo,URI,UW,PSU)
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WHOI (SHARK VLA and J-15-3)Jim Lynch, Art Newhall, Keith von der HeydtJohn Kemp (et. al.), Cal Eck, Neil McPheeCynthia Sellers
URI (R/V Endeavor)Capt. McMunn, Jay StGermain, William FanningMary-Lynn Dickson
FAU (J-15)George Frisk
DRDCPaul Hines
OrganizationONR, Ellen Livingston, Jim Lynch, Dajun Tang
Acknowledgements