|
|
 |
|
|
|
|
|
SeaBASS - Active Acoustics  Lectures 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. Basics of Acoustic 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. TS Modelling (.pdf) [1.7MB]. For more information, see Forman and Warren, 2009, ICES J. Mar. Sci. and Smith, Ressler, and Warren, in press, JASA. Forward and Inverse Problem (.pdf) [1.4MB]. For more information see: Warren et al., 2003, ICES J. Mar. Sci. and Warren and Wiebe, 2008, CJFAS. Survey Design and Equipment (.pdf)[6.1MB]. For more information see: Warren and Demer, 2010, CJFAS; Cox et al., 2009, DSR2, or Cox et al., 2009, MEPS. In Class Problems Question #1 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 depth, 8-9pm]. 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. Question #2 This transect was collected less than a month ago from an area in Flandres Bay, Antarctica. This site was promptly named (by myself) "Krill City". 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 Question #3 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 $120,000 / year. Each group will give a brief presentation of their project scope and methodology. Feel free to use the easel, whiteboard, etc. Equipment: Single Beam Echosounders [$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. Platforms: 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 single-beam echosounder. Data Analysis: Grad student: 40k / year. Capable of analyzing one month of data from two echosounders Technician: 60k / year. Capable of analyzing 6 months of data from 4 echosounders PI/Advisor: free. Capable of making grad student's life miserable Echoview License: 15k Matlab license: 2k + 6 months of grad student's time www.stonybrook.edu |