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Acoustics Bottom Characterization/Inversion SW06 Workshop 1 February 2007. Objectives Develop geoacoustic models for the SW06 site
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Acoustics Bottom Characterization/Inversion SW06 Workshop 1 February 2007
Objectives • Develop geoacoustic models for the SW06 site • Synthesize regional geoacoustic information to develop comprehensive models across 50 Hz - 20 kHz incorporating known geoacoustic variability over the SW06 area • Estimate geoacoustic model parameters using different inversion methods and characterize their uncertainty • Assess performance of different geoacoustic inversion methods and quantify impact of water column and sea surface variability
Geographic Areas of (Near-Term) Primary Interest • Vicinity of APL/UW Mooray and MPL VLA1 deployment site and quasi-range-independent radial track to NE • Vicinity of WHOI Shark array and radial tracks in sector from NE through NW • Sand ridge between ARL/UT SWAMI-32 and SWAMI-52 arrays • Region with sub-seafloor channels to NE of SW06 site
Information Needed to Proceed • Regional sound speed structure and temporal variability • Deterministic sound speed fields where possible but EOFs, correlation scales, and statistics are of particular interest • Regional seafloor information • Subbottom structure (e.g. “R” reflector depth) from chirp profiler and direct in-situ measurements in upper 2 m (cone penetrometer, SAMS, geoprobe)
Individual Objectives and Collaborations Dahl / Tang MF (1-20 kHz) data analysis and inversions Bottom loss as a function of angle/frequency/orientation and comparison with in-situ seafloor measurements Inversion for geoacoustic properties over NE radial track (1-10 kHz) Badiey Chirp data over same track as SWARM-95 air gun data Radial tracks to Shark array
Turgut Chirp sonar data analysis for seafloor structure and correlation scales Knobles SWAMI-32 short-range circular track data 20 km sand ridge track between SWAMI arrays Hodgkiss / Gerstoft Inversions along MPL VLA1 NE track line (LF/MF tonals, lightbulb data) MPL VLA1 circular track and vertical source deployment reflection coeff analysis Estimating Greens functions between hydrophone pairs using active source data
Becker Inversions using LF (50-300 Hz) data from Shark out to 6 km Towed CTD chain with J-15 Heaney Inversions using OMAS mobile source (600 and 900 Hz) and sonobuoy receivers Pecknold 1.2 and 3.5 kHz TL run along NE track line Frisk Inversions NE area with subbottom channels using 50-175 Hz drifting J-15 source and 4 drifting buoys
Miller/Potty LF inversions using CSS data Williams Impact of IWs in modest range (~1 km) inversions Lynch Amplitude dependent inversions Data null space projection method (minimize impact of fluctuating modes)
Chapman MF Inversions of CW tones from experiments on ‘DJ’ track MF Inversions of LF and MF chirp data from circle at Moray/MPL-VLA1 site Reflection coefficient inversion at circle at Moray/MPL-VLA1 site
Interactions • Mailing list for updates of common interest • Workshop ~Jan/Feb 2008 (San Diego)