| SeaBASS - Active Acoustics
from the course.
If you have any questions, feel free to email me: joe 'dot' warren 'at'
stonybrook 'dot' edu or visit my lab page.
Scattering (.pdf) [5.4MB]. For more information see: Warren et al., 2002, IEEE
J. Ocean Engineering or Warren et al., 2001,
ICES J. Mar. Sci.
(.pdf) [1.7MB]. For more information, see Forman
and Warren, 2009, ICES J. Mar. Sci. and Smith, Ressler, and Warren,
in press, JASA.
Inverse Problem (.pdf) [1.4MB]. For more information see: Warren et
al., 2003, ICES J. Mar. Sci. and Warren and Wiebe, 2008, CJFAS.
Equipment (.pdf)[6.1MB]. For more information see: Warren
and Demer, 2010, CJFAS; Cox et al., 2009,
DSR2, or Cox et
al., 2009, MEPS.
Using the data provided in the following figures, answer these
questions. Show your work!
1a. What is the numerical density (# of animals / m^3) of
siphonophores in the middle of the "siphonophore patch" [10-15 m
1b. Do you think your estimate in (a) would be an over or underestimate
1c. The TS histograms show a shift with larger TS values occurring in
deeper waters. Provide a possible, logical explanation for why
this would occur.
Figure 1. Volume backscatter strength ["big" Sv] (120 kHz) recorded by
the Greene Bomber in Cape Cod Bay. Colorscale is "big" Sv.
Fig. 2. Target strength of a 1 mm gas bubble according to theory (red
line), in situ measurements from an ROV (blue circles), and tank-based
measurements (blue crosses).
Fig 3. TS histograms for different depth bins for two different days
collected by the Greene Bomber. The number of targets for each
histogram is given in the upper right hand corner of the subplot.
This transect was collected less than a month ago from an area in
Flandres Bay, Antarctica. This site was promptly named (by myself)
2a. Calculate what the mean numerical density (# of animals /
m^3) of krill are in Krill City.
Fig 4. Acoustic echogram showing a transect through Krill City.
Colorscale is "big" Sv.
Fig 5. Length distributions from krill caught in nearby
Wilhelmina Bay (assume that the data from 100 - 200 m are
representative of Flandres Bay as well).
Fig 6. A plot of RTS vs. kL using the SDWBA model for krill. The purple
line is the current standard used by CCAMLR in estimating krill
abundance in the Southern Ocean and regulating the krill fishery.
However, not every researcher working on krill in this area uses this
model. RTS = TS - 20log (L / Lo) where Lo = 38.35 mm
3a. Think of an experiment that you would like to conduct using active
acoustics. You have complete freedom to select your target
species. study location, length/duration of study, etc. Using the
following guidelines, please develop an active acoustic system and
measurement plan (duty cycle, ping rate, survey speeds, etc) that would
allow you to achieve your goals. Your average budget must be less
than $120,000 / year. Each group will give a brief presentation of
their project scope and methodology. Feel free to use the easel,
Single Beam Echosounders [$cost] are available at 18 [30k], 38 [20k],
70 [25k], 120 [20k], 200 [20k], 333 [25k], 465 [20k], 710 [28k], and
1000 [18k] kHz
Split Beam Echosounders are available at 38 [35k], 70 [35k], 120
[35k], 333 [35k] kHz
Acoustic Doppler Current Profilers are available at 38, 150, 300, 600,
and 1200 kHz [each 25k]
A multibeam echosounder is available at 200 [150k] kHz.
A broadband echosounder is not available.
Ship time is available: on a large vessel (operating 24 hrs a day, can
go offshore) at 5k / day or on a small vessel (10 hrs a day,
can't go further than 10 n.mi. from land) at 0.5k / day.
Echosounders can be deployed from a mooring: add 5k for each
echosounder for mooring deployment + 1k / month for batteries. For
real-time data transmission to shore, add 10k per echosounder.
AUVs: REMUS vehicle 125k [limited to one-day surveys
before having to return to base and recharge batteries]
Gliders: Are available [125k], however they can only use a 200 kHz
Grad student: 40k / year. Capable of analyzing one month of data from
Technician: 60k / year. Capable of analyzing 6 months of data from 4
PI/Advisor: free. Capable of making grad student's life miserable
Echoview License: 15k
Matlab license: 2k + 6 months of grad student's time