130 likes | 297 Views
Kyle M. Becker (PI) The Pennsylvania State University. Subramaniam D. Rajan (co-PI) Scientific Solutions Inc. Megan S. Ballard Graduate Program in Acoustics, Penn State. Modal Inverse Methods Experiments ( MIME ) R/V Endeavor, 04-06 August 2006. Objectives & Measurements.
E N D
Kyle M. Becker (PI) The Pennsylvania State University Subramaniam D. Rajan (co-PI) Scientific Solutions Inc Megan S. Ballard Graduate Program in Acoustics, Penn State Modal Inverse Methods Experiments (MIME) R/V Endeavor, 04-06 August 2006
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
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
Summary of Data Collected Radial CW tows – (~5 km @ 50,75,125 175 Hz) 25 hrs, 2-10 knots 3 tracks (along, across, oblique) FM sweeps (40-290 Hz) 20 Stations around circle @ 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
Synthetic Aperture CW Tracks Actual Tracks E1-E3 Sound Speed from towed CTD Day 216 2 knots (~80 min/section)
LFM Station Locations LFM data sample 40-290 Hz 0.5 sec repeat every 3 sec
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 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
Temp. (C) Analysis Plan Evidence of IW during CW tow event (6 knots) TP recorder data
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
Acknowledgements The Team: 6 STUDENTS!, 1 engineer, 2 unknown (UMich,PoliTo,URI,UW,PSU) John Camin Joy Lyons Amanda Dye me Paul Gabel Frank Inga Koszalka Jacquie Beitel Megan Ballard
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