Chi-Tsong Chen-Analog and Digital Control System Design-Oxford University Press, USA (2006)
Georges Dossot, James H. Miller, Gopu R. Potty, Dept. of Ocean Engineering, URI James F. Lynch,...
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Georges Dossot, James H. Miller, Gopu R. Potty, Dept. of Ocean Engineering, URI James F. Lynch, Arthur E. Newhall, Ying Tsong Lin, WHOI Mohsen Badiey, University of Delaware Kevin Smith, D. Benjamin Reeder, Naval Postgraduate School 158 th Acoustical Society of America meeting San Antonio, Texas, October 2009 Modeling intensity fluctuations of acoustic transmissions from the R/V Sharp during SW06
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Transcript of Georges Dossot, James H. Miller, Gopu R. Potty, Dept. of Ocean Engineering, URI James F. Lynch,...
Georges Dossot, James H. Miller, Gopu R. Potty, Dept. of Ocean Engineering, URIJames F. Lynch, Arthur E. Newhall, Ying Tsong Lin, WHOIMohsen Badiey, University of DelawareKevin Smith, D. Benjamin Reeder, Naval Postgraduate School
158th Acoustical Society of America meetingSan Antonio, Texas, October 2009
Modeling intensity fluctuations of acoustic transmissions from the R/V Sharp during SW06
Outline
SW06 & R/V Sharp• 50+ events• Different locations
Specific internal wave events• Event 44 (past work)• Similar events (new work)
Modeling• Simplified model• Looking forward → Modeling real environment
SW06 Test Site & R/V Sharp Locations
-73.35 -73.3 -73.25 -73.2 -73.15 -73.1 -73.05 -73 -72.95 -72.9 -72.85
39.05
39.1
39.15
39.2
39.25
SHARK
5 km
Longitude (degrees)
Lat
itu
de
(deg
rees
)SW06 Test Site & R/V Sharp Locations
A1A (4)
B1 (9)B1A (5)
B1B (5)
B5A (2)
C1A (3)C1B (4)
C3 (3)
C5A (4)
C1D (3)60
60
70
70
70
80
80
SW29
SW30
SW31
SW32
SW33
SW34
Acoustic Transmission Paths
SW06 Acoustic Sources
SHRUsShip Positions
Environmental Moorings
R/V Sharp & SW06: • 180 hours of acoustic
transmissions• Various ranges and bearings• 50+ internal wave events
witnessed
Interested in source-receiver path near parallel to approaching internal waves
M. Badiey, B. G. Katsnel’son, J. Lynch, S. Pereselkov, “Frequency dependence and intensity fluctuations due to shallowwater internal waves,” J. Acoust. Soc. Am. 122, 747-760 (2007)
Objectives
SHARK Array
Research Vessel
Propagating Internal Wave
B. G. Katsnel’son, J. Lynch, A. V. Tshoidze, “Space-Frequency Distribution of Sound Field Intensity in the Vicinity of the Temperature Front in Shallow Water,” Acoustical Physics 53(5), 611-617 (2007)
Examine intensity fluctuations over time…→ before, during, and after internal wave events
Examine intensity fluctuations over space…→ depth and modal dependence
Statistically characterize intensity fluctuations…
FrequencyfTimetnumberarrivalChirpk
NumberModeNorDepthz
),(
),,),||(( ftkNzI
Intensity Measurements
Integrated Energy:
Temporally Integrated Energy:
Point Observations of Broadband Intensity:
Observations of Point Scintillations:
Point Observations of Peak Intensity:
Observations of Modal Amplitudes:
),,()( kzIddzkI z
),,(),( kzIdkzI
),,( kzI
12
2
I
ISI
)],,([max),( kzIkzIP
A. Fredericks, J. A. Colosi, J. Lynch, C. Chiu, and P. Abbot, “Analysis of multipath scintillation from long range acoustic transmissions on the New England continental slope and shelf,” J. Acoust. Soc. Am. 117, 1038–1057 (2005)
Duda, T.F., Lynch, J.F., Newhall, A.E., Lixin Wu, Ching-Sang Chiu, “Fluctuation of 400-Hz sound intensity in the 2001 ASIAEX South China Sea experiment,” Oceanic Engineering, IEEE Journal of, 29(4), 1264 – 1279 (2004)
),,( fkNI
Outline
SW06 & R/V Sharp• 50+ events• Different locations
Specific events• Event 44 (past work)• Similar events (new work)
Modeling• Simplified model• Looking forward → Modeling real environment
Event 44 “Point” Observations
‘ramping’ before arrival of internal wave
Note warm water bottom intrusion
0
5
10
I (z,k)
Temporally Integrated Energy - Phone 1, z = 13.5 m
0
100
200
300Phone 1 Distribution
0
5
10
I (z,k)
Temporally Integrated Energy - Phone 4, z = 24.75 m
0
100
200
300Phone 4 Distribution
0
5
10
I (z,k)
Temporally Integrated Energy - Phone 10, z = 47.25 m
0
200
400
600Phone 10 Distribution
03:00 06:00 09:00 12:000
5
10
I (z,k)
Time Transmitted
Temporally Integrated Energy - Phone 14, z = 77.25 m
0
100
200Phone 14 Distribution
Event 44 depth dependance
Depth dependant variability
Event 46 (new)Trapped sound between solitons?
Event 47 (new)
Notice quiet conditions both before & after internal wave activity
200 400 600 8000
2
4
6
8
10
I( ,z,k)
Transmission number
Intensity "Point" Observations
0 2 4 6 80
500
1000
1500Intensity "Point" Observations Distribution
I(,z,k)
Nu
mb
er o
f ar
riva
ls
Event 47 (new)Slight ‘ramping’ before arrival of internal wave
Event 47 (new)
0
5
10
15
I (z,k)
Temporally Integrated Energy - Phone 1, z = 13.5 m
0
100
200
300Phone 1 Distribution
0
5
10
15
I (z,k)
Temporally Integrated Energy - Phone 4, z = 24.75 m
0
100
200
300Phone 4 Distribution
0
5
10
15
I (z,k)
Temporally Integrated Energy - Phone 10, z = 47.25 m
0
100
200
300Phone 10 Distribution
21:00 22:00 23:00 00:000
5
10
15
I (z,k)
Time Transmitted
Temporally Integrated Energy - Phone 14, z = 77.25 m
0
100
200
300Phone 14 Distribution
Lack of warm water intrusion near bottom → less depth dependant variability
Outline
SW06 & R/V Sharp• 50+ events• Different locations
Specific events• Event 44 (past work)• Similar events (new work)
Modeling• Simplified model• Looking forward → Modeling real environment
Assumptions: • 5km × 5km × 100m water
column• Flat bottom• Single layer soundspeed
properties for sediment• Source at 75 m depth• Single soliton marches
eastward• Same source-receiver angle
as in Event 44• Virtual VLA 4 km away from
source
Modeling
Using 3D PE model provided by NPS, start with a simple scenario
4 km range slice50 m depth slice
Modeling
Cross-Range (km)
de
pth
(m
) a
t 4
km
Ra
ng
e
TL (dB re 1m), soliton 2500 m away
-2 0 2
0
20
40
60
80
100
50
60
70
80
90
100
Cross-Range (km)R
an
ge
(k
m)
TL (dB re 1m), soliton 2500 m away
-2 0 20
1
2
3
4
5 50
60
70
80
90
100
Modeling
0 5 10 150.5
1
1.5
2
2.5
I( ,z,k)
Transmission number
Intensity "Point" Observations
0.5 1 1.5 2 2.50
20
40
60
80
100Intensity "Point" Observations Distribution
I(,z,k)
Nu
mb
er o
f ar
riv
als
Although not quite as dramatic, the same ramping trend is evident as soliton moves closer. Modeled distribution similar to that of measured data.
Modeling: Next steps
G. R. Potty, J. H. Miller, P. S. Wilson, J. F. Lynch, A. Newhall, “Geoacoustic inversion using combustive sound source signals,” J. Acoust. Soc. Am. 124, EL150 (2008)
Y-M Jiang, N. R. Chapman, M. Badiey, “ Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data,” J. Acoust. Soc. Am. 121, 1879-1894 (2007)
→ Modeling inputs for bathymetry and sediment properties to be taken from data and literature
Modeling: Next steps→ Creating 3D soundspeed profile requires interpolation from various moorings and sensors and code modification
Conclusions & Future Work
• Wealth of data from over 50 events across different bearings and ranges
R/V Sharp datasets
• Provide evidence of refraction – and ‘ramping’ of intensity measurements before arrival of IW
• Provide insight into depth dependence of intensity fluctuations associated with (or lack of) warm water bottom intrusions
Events 44, 46, 47
• Simple 3D model shows similar trends to measured data• Next steps to include measured data to better portray actual
environment
Modeling
Thank you
