N. Ross Chapman

Feb. 12, 2009

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Understand physics of interaction of sound with theocean bottom

• Theories of sound propagation in marine sediments• Biot; Buckingham; Chotiros et al

• Parameters of geoacoustic models• inversion methods for estimating model parameters

Research Goals

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Comprehensive geoacoustic model

• effective for use with various applications and a broad

frequency band

• Evaluate the impact of water environment variation on:• geoacoustic inversion

• propagation

• methods to mitigate its impact in predicting sonar

performance (detection & localization…)?

• Performance of inversion methods with experimental data at ground- truthed site (experimental benchmark)

SW06 Objectives

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Ground truth & Oceanographic observations:

John Goff, IG, U of Austin

• Geophysical chirp seismic reflection data

Altan Turgut, NRL

• Chirp sonar data analysis

Arthur Newhall et al., WHOI

• Environmental mooring data

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Moray• Altan Turgut• DJ Tang• Peter Dahl• Peter Gerstoft• Ross Chapman

• SWAMI 32• David Knobles • Peter Gerstoft

• DJ track• Peter Gerstoft• Ross Chapman• Kyle Becker

• SHARK• James Miller• James Lynch• Kyle Becker

• Drifting

•George

4' 3' 2' 1' 73oW 59' 1'

2'

39oN

3.00'

4'

5'

-75

-80

-80

-80

-80

-80

-80

Ballard & Becker:1610 57

Hodgkiss, Gerstoft & Huang (Track same as Chapman):1596 11

Chapman & Jiang:Long track: 1636 16

Direct measurement and geoacoustic inversion of sediment sound speed in SW06

SAMS (direct, APL-UW):1618 111598 10

Jiang, Chapman & Gerstoft:1594 11

Choi, Dahl & Goff:1630 20

Geo Probe (direct, Turgut):1550, 1605, 1640

1 km boxed area: 80 m isobath track:

1 2 31540

1560

1580

1600

1620

1640

1660

1680

So

un

d s

pe

ed

(m

/s)

Chapman & Jiang

Hodgkiss, Gerstoft & Huang

Ballard & Becker

1 2 3 41540

1560

1580

1600

1620

1640

1660

1680

So

un

d s

pe

ed

(m

/s)

SAMS: Yang, Tang & Williams

Geo Probe: Turgut

Jiang, Chapman & Gerstoft

Choi, Dahl & Goff

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Compare results of geoacoustic inversions

• How? …..TL model/data comparison

• Focus on two environments: MPL/Shark; Swami

• What are the advantages/limitations of each technique?

• which model parameters are well estimated?

• what assumptions are made in each technique?

• what type of data is required for each technique?

• What is the impact of dynamic ocean environment?• what are effective ways to mitigate effect?

Austin Meeting Objectives

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• What issues are still big problems?

• Attenuation of sound in marine sediments

• are we interpreting attenuation correctly from our inversions?

• shear wave propagation: not measured at all in SW06

• 3-D• what is the impact of the 3-D environment on the

interpretation of our data? (Water and Bottom)

• what is the azimuthal – range dependence of the model parameters? Can we measured it?

• What are the priorities in the wish list?

Austin Meeting Objectives

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• What issues are still big problems?

• Attenuation of sound in marine sediments

• are we interpreting attenuation correctly from our inversions?

• shear wave propagation: not measured at all in SW06

• 3-D• what is the impact of the 3-D environment on the

interpretation of our data? (Water and Bottom)

• what is the azimuthal – range dependence of the model parameters? Can we measured it?

• What are the priorities in the wish list?

Austin Meeting Objectives

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

Geoacoustics RESEARCH ISSUES

- Inversion performance

-Identifying the metrics for geoacoustic model comparison

- Modeling acoustic interaction with sediments

- Frequency dependence of sound speed and attenuation

- Shear wave measurements for sediment modeling

- Understanding reverberation in complex environments

- Sediment variability along track and ground truth (Sea floor and deeper)

-Roughness measurements especially for simultaneous reverberation and

propagation modeling. (Both interface and sub-bottom)

- Robust inversion in complex environments

- 3D effects in geoacoustic inversion. How to design experiments to

effectively measure geoacoustic parameters in a complex topography.

- Development of new inversion techniques (particle filters, etc.)

Austin Meeting Summary

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

- EXPERIMENTAL ISSUES

-Mitigate water column effects by conducting experiment in winter/under

thermocline.

-Location selection

-Simpler 3D environments (not canyons) where geoacoustics not

topography dominate. Transition regions between shallow and deep

water, shelf breaks, areas with 3D sub-bottoms. Shelf breaks may have

interesting sediment properties which differ from continental shelf. May

be likely to a thin soft sediment over a rough harder sediment.

-How to choose an area that offers simple 3D topography, but interesting

geoacoustics

-Identify currents/ other factors which may impact experiment

- Use of geophones/ vector sensors or novel use of existing HLA or VLAs

Austin Meeting Summary

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

-LOCATION SUGGESTIONS

-South Florida site (Well documented, well instrumented) 3D effects well

established (Kevin Heaney paper)

Synthesis/summary paper of results from SW06

--------------------

Two sites from SW 06

-- Moray, deep water, clay rich, concentrated in one area

- systematic comparison of all the data from the site

- systematic model comparison given the ground truth

- predict transmission, phase, coherence…

- Determine which parameters are important to sonar performance

prediction

- Effects of bottom roughness, sediment variability

Austin Meeting Summary

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• in situ measurements• Altan Turgut, 10 - 80 kHz

• Dajun Tang et al., 2 - 35 kHz

• Geoacoustic inversion:• David Knobles et al., 0.05 - 3.0 kHz

• James Lynch et al., 0.05 – 0.175 kHz

• James Miller et al., broadband (CSS source)

• Kyle Becker et al., 0.05 -0.175 kHz CWs

• Peter Dahl et al., 1- 20 kHz

• Peter Gerstoft et al., < 1kHz CWs and 1.5 - 4.5 kHz chirp

• Ross Chapman et al., < 1kHz CWs and 1.5 - 4.5 kHz chirp

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• More collaborators: Alex Tolstoy

Low frequency chirp at Moray

DRDC

Zoi-Heleni Michalopoulou

High frequency chirp at Moray

Ji-Xun Zhou

Subramaniam D. Rajan

SHARK

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

Peter Gerstoft et al.: • Matched field inversion ( 0.05 – 0.703 kHz, 1 km)

Ross Chapman et al.:• Matched field inversion ( 0.05 – 0.703 kHz, 1, 3 and 5 km)

• Travel time inversion(1.5 – 4.5 kHz, 0.230 km )

Kyle Becker et al.:• Simulation of water column variability on modalpropagation and transmission loss(0.175 kHz)

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Altan Turgut,

10-80 kHz, in situ probe, Moray & SWAMI 32

• Peter Dahl et al.,

1-20 kHz, matching the reflection coefficient

data with PE model, Moray site

• Ross Chapman and Yong-Min Jiang,

0.05 – 0.703 kHz, matched field inversion,

DJ track

• Ross Chapman and Yong-Min Jiang,

1.75 – 3.15 kHz, development of low frequency

sediment attenuation measurement method,

Moray site

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

• Y.-M. Jiang and N. R. Chapman, “Bayesian geoacoustic inversion in a dynamic shallow water

environment,” J. Acoust. Soc. Amer., vol. 123, EL155 - EL161, 2008.

• C.-F. Huang, P. Gerstoft and W. S. Hodgkiss, “Effect of ocean sound speed uncertainty on

matched-field geoacoustic inversion,” J. Acoust. Soc. Amer., vol. 123, EL162 - EL168, 2008.

• J. Yang, D. J. Tang, and K. L. Williams, “Direct measurement of in situ sediment sound speed at

SW06,” J. Acoust. Soc. Amer., vol. 124(3), Pt. 2 of 2, EL116 - EL121, 2008.

• A. Turgut and T. Yamamoto, “In situ measurements of velocity dispersion and attenuation in

New Jersey Shelf sediments,” J. Acoust. Soc. Amer., vol. 124(3), Pt. 2 of 2, EL122 - EL127, 2008.

• J. W. Choi, P. H. Dahl and J. A. Goff, “Observations of the R reflector and sediment interface

reflection at the Shallow Water ’06 Central Site,” J. Acoust. Soc. Amer., vol. 124, EL128 - EL134,

2008.

• Y.-M. Jiang, N. R. Chapman and P. Gerstoft, “Short range geoacoustic inversion with vertical

line array,” J. Acoust. Soc. Amer., vol. 124(3), Pt. 2 of 2, EL135 - EL140, 2008.

• M. S. Ballard and K. M. Becker, “Geoacoustic inversion on the New Jersey Margin,” J. Acoust.

Soc. Amer., vol. 124(3), Pt. 2 of 2, EL141 - EL145, 2008.

• G. R, Potty. J. H. Miller, P. S. Wilson, J. F. Lynch and A. Newhall, “Geoacoustic inversion using

combustive sound source signals,” J. Acoust. Soc. Amer., vol. 124(3), Pt. 2 of 2, EL146 - EL150,

2008.

• D. P, Knobles. P. S. Wilson, J. A. Goff, and S. E. Cho, “Seabed acoustics of a sand ridge on the

New Jersey continental shelf,” J. Acoust. Soc. Amer., vol. 124(3), Pt. 2 of 2, EL151 - EL156, 2008.

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

ASA 153 (Salt Lake City, June, 2007, 3 talks)

• Ross Chapman, Yong-Min Jiang, and Bill Hodgkiss, ‘Bayesian geoacoustic inversion in a

range-dependent environment’

• Gopu R. Potty, James H. Miller, Colin J. Lazauski, ’ Geoacoustic inversion using combustive

sound source signals’

• Ying-Tsong Lin, Arthur E. Newhall, and James F. Lynch, ‘Geoacoustic inversion using the

data nullspace projection method’

ASA 154 (New Orleans, Nov. 2007, 2 talks)• Yong-Min Jiang and Ross Chapman, ‘Analysis of the effect of water column sound speed

variation on geoacoustic inversion’

• David P. Knobles, Robert A. Koch, Preston S. Wilson, Timothy F. Duda, and Arthur E.Newhall,

‘Analyses of broadband and narrowband propagation measurements in Shallow Water 2006

(SW06)’

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

ASA 155 (Paris, June, 2008, 10 talks)• Chen-Fen Huang, ‘Effect of ocean sound speed uncertainty on matched-field geoacoustic inversion’

• Ross Chapman and Yong-Min Jiang, ‘Quantifying the uncertainty of geoacoustic parameterestimates in a dynamic environment using oceanographic data observed in the SW06 experiment’

• Yong-Min Jiang, Ross Chapman and Peter Gerstoft, ‘Short range geoacoustic inversion with a vertical line array’

• Megan S. Ballard and Kyle M. Becker, ‘Three dimensional geoacoustic inversion on the New Jersey shelf’

• YingTsong Lin, James F. Lynch and Arthur Newhall, ‘Applying the data nullspace projectionmethod to a geoacoustic Bayesian inversion in a randomly fluctuating shallow water ocean’

• Kyle M. Becker, Megan S. Ballard and Subramaniam D. Rajan, ‘Modal inversion using the acoustic field measured on a vertical array of hydrophones’

• Jee Woong Choi and Peter Dahl, ‘Mid-Frequency Bottom interaction measurements off the New Jersey continental shelf’

• D. P. Knobles, P. Wilson, J. Goff, S. Joshi, L. Collins, and S. Cho, ‘Methods of characterizationof seabed physics for a shallow water environment’

• Gopu Potty and James H. Miller, Preston S. Wilson James F. Lynch and Arthur Newhall,‘Geoacoustic inversion using combustive sound source signals’

• Jie Yang, Dajun Tang, and Kevin L. Williams, ‘An in situ sediment sound speed measurementplatform: Design, operation, and experimental results’

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

ASA 156 (Miami, Nov., 2008, 3 talks)

• Ross Chapman and Yong-Min Jiang, ‘Measurement of attenuation of sound in marine sedimentat low frequency ’

• Altan Turgut, ‘Wide-band Attenuation Measurements in New Jersey Shelf Sediments’

• Megan S. Ballard and Kyle M. Becker, ‘Variability of the water column sound speed profileand its effect on acoustic propagation during the Shallow Water 2006 Experiment (SW06)’

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

2008 (Ft. Lauderdale, 9 talks)• Jie Yang, Dajun Tang and and Kevin L. Williams, ‘Direct measurement of in situ sediment sound speed at SW06’

• Bill Hodgkiss, Peter Gerstoft, and Chen-Fen. Huang, ‘Effect of ocean geoacoustic inversion’

• Megan Ballard and Kyle Becker, ‘Range-independent inversion results from the Modal Inverse Methods Experiment (MIME)’

• Ross Chapman and Yong-Min Jiang, ‘Geoacoustic inversion results from SW06 data –long range vs. short range’

• Ying-Tsong Lin, James F. Lynch and Arthur Newhall, ‘Applying the data nullspace projectionmethod to the SW06 experiment data for bottom inversions’

• Altan Turgut, ‘Estimation of bottom attenuation and reflection coefficient by using chirp sonar’

• Jim Miller and Gopu Potty, ‘SW06 Data Analysis – URI Efforts’

• John A. Goff, Manasij Santra, ‘3-D interpolation of subsurface stratigraphic architecture in the vicinity of the SW06 region based on interpreted chirp seismic reflection data’

• D. P. Knobles, Preston Wilson, John Goff, and Bill Hodgkiss, ‘Measurements and analyses of acoustic data recorded on the New Jersey continental shelf’

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

2009 (Austin, 7 talks)

• Kyle Becker, ‘Geoacoustic characterization of the SW06 environment’

• Ross Chapman and Yong-Min Jiang, ‘Impact of Ocean Sound Speed Variability on the

Uncertainty of Geoacoustic Parameter Estimates’

• Nick Chotiros, ‘Broadband sediment acoustics models 100 Hz to 1 MHz’

• Peter Gerstoft, ‘Extracting information from noise’

• Yong-Min Jiang and Ross Chapman, ‘Estimation of sound speed and attenuation in marine

sediment using a single bounce bottom reflection geometry’

• Jim Miller and Gopu Potty, ‘Estimation of Sediment Properties, Internal Wave Characteristics,

and Surface Wave Spectra Using SW06 Data’

• Caglar Yardim, Peter Gerstoft and Bill Hodgkiss, ‘Kalman and Particle filtering for geoacoustic

parameter tracking’

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009

Chapman SW06 Workshop, Austin, Texas, 10 - 12 Feb 2009