Modal%20Inverse%20Methods%20Experiments

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Modal Inverse Methods Experiments (MIME) R/V
Endeavor, 04-06 August 2006
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Objectives Measurements
Range-Dependent Geoacoustic Inversion Modal
Arrival Times - VLA/airgun LFM Modal Wavenumbers
- SA(VLA)/J-15 Doppler Wavenumber Shifts -
SA(VLA)/J-15 Impact of Oceanic Variability on
GI Spatial Measure of SVF - CTD chain
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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 _at_ 50,75,125 175 Hz) 25
hrs, 2-10 knots 3 tracks (along, across,
oblique) FM sweeps (40-290 Hz) 20 Stations
around circle _at_ 15 km 120 pings per
station Towed CTD chain Deployed concurrently
with J-15 Endeavor FastNav 3 types GPS at 1
sec Endeavor CTD Casts before/after
deploy/recovery of source/chain TPpod Temp/Depth
recorder mounted on J-15
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(No Transcript)
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Synthetic Aperture CW Tracks
Actual Tracks E1-E3
Sound Speed from towed CTD Day 216 2 knots (80
min/section)
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Sample CW Data
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LFM Station Locations
LFM data sample 40-290 Hz 0.5 sec repeat 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(fr) ? wave number estimation for
geoacoustic inversion perturbative and ASSA
for discrete wave numbers at multiple
frequencies (PhD Thesis, JASA) ? look for
range-dependence in wave number
along different 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)
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 data collected during some of the
larger internal wave events. Mohsen Badiey, Jim
Lynch
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Acknowledgements
The Team 6 STUDENTS!, 1 engineer, 2
unknown (UMich,PoliTo,URI,UW,PSU)
John Camin
Joy Lyons
Amanda Dye
me
Frank
Paul Gabel
Inga Koszalka
Jacquie Beitel
Megan Ballard
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Acknowledgements
WHOI (SHARK VLA and J-15-3) Jim Lynch, Art
Newhall, Keith von der Heydt John Kemp (et.
al.), Cal Eck, Neil McPhee Cynthia Sellers URI
(R/V Endeavor) Capt. McMunn, Jay StGermain,
William Fanning Mary-Lynn Dickson FAU
(J-15) George Frisk DRDC Paul
Hines Organization ONR, Ellen Livingston, Jim
Lynch, Dajun Tang