Seafloor Characterization

Intro
Single Beam Sonar
Multibeam Sonars
ARA Analysis
Ground-Truth Studies
New Projects

We have a number of inter-connected research programs underway aimed at exploring the ability of our mapping systems to provide quantitative information on the make-up and character of the seafloor as well as its depth.

These programs deal with a range of sensors (single beam, multibeam and sidescan sonars, lidar, video, etc.) and involve theoretical studies, the collection of remotely sensed data, and "ground-truth" samples. These efforts are particularly relevant for the increasingly important topic of essential fisheries habitat characterization.

Single Beam Sonar and Mapping and Characterization
Multibeam and Interferometric Sonars
ARA (formerly AVO) Analysis
Ground-Truth Studies
lidar
Optical Imagery
Two new projects (funded separately, but complementary to our ongoing work) began 2007

Related Publications for Seafloor Characterization

2008

1. Hatch, L. , Clark, C. , Merrick, R. , Van Parijs, S. , Ponirakis, D. , Schwehr, K. , Thompson, M. , Wiley, D. N., 2008, "Characterizing the Relative Contributions of Large Vessels to Total Ocean Noise Fields: A Case Study Using the Gerry E. Studds Stellwagen Bank National Marine Sanctuary", Environmental Management, Vol. 42, No. 5, pp. 735 - 752. Journal Article.

2007

2. Lyons, A. P., Weber, T. C., 2007, "A multibeam sonar survey for benthic lake habitat: Assessing the impact of invasive mussels in Seneka Lake, New York", 2nd International Conference Underwater Acoustic Measurements: Technologies & Results, Heraklion, Crete, Greece, 25 - 29 June. Conference Proceeding.

3. Vorosmarty, C. J., Ericson, J. P., Dingman, S. L., Ward, L. G., 2007, "Future impacts of fresh water resource management: sensitivity of coastal deltas", Symposium at IUGG International Association of Hydrological Sciences, Copenhagen, Denmark, Vol. 314, 30 November, pp. 231 - 238. Conference Proceeding.

2006

4. Weber, T. C., Lyons, A. P., 2006, "A multibeam survey of mid-Seneca Lake: bathymetry, backscatter, and invasive species", 2nd Annual Finger Lakes Research Conference, Geneva, NY, USA, 1 October, pp. 1 - 17. Conference Proceeding.

5. Fonseca, L. , 2006, "Acoustic Backscatter and Remote Seafloor Characterization", International Marine Technicians Symposium, Woods Hole, MA, USA, 17 - 19 October. Conference Proceeding.

6. Conrad, R. , 2006, "Development and Characterization of a Side Scan Sonar Towfish Stabilization Device", Master of Science, pp. 1 - 167. Thesis.

2005

7. Cutter Jr., R. G., 2005, "Benthic Habitat Classification and Characterization Using Multibeam Sonar Data: the Provisional Truth of Ground-truth", Technologies and Results International Conference for Underwater Acoustic Measurements, Heraklion, Crete, Greece, 28 - 1 June. Conference Proceeding.

8. Holland, C. W., Weber, T. C., Etiope, G. , 2005, "Close-range acoustic scattering from mud volcanoes", 149th Meeting Held Jointly with the Canadian Acoustical Association Acoustical Society of America, St. Andrews, New Brunswick, Canada, 16 - 20 May. Conference Proceeding.

9. Cutter Jr., R. G., Rzhanov, Y. , Mayer, L. A., Grizzle, R. E., 2005, "Ground-truthing benthic habitat characteristics using video mosaic images: Benthic Habitats and the Effects of Fishing", American Fisheries Society Symposium, Vol. 41, pp. 171 - 179. Journal Article.

10. Grizzle, R. E., Ward, L. G., Adams, J. R., Dijkstra, S. J., Smith, B. , 2005, "Mapping and characterizing oyster reefs using acoustic techniques, underwater videography, and quadrat sampling", in Benthic Habitats and the Effects of Fishing, P.W. Barnes & J.P. Thomas (ed.): American Fisheries Society, pp. 153 - 159. Book Section.

11. Fonseca, L. , Mayer, L. A., Kraft, B. J., 2005, "Seafloor Characterization through the Application of AVO Analysis to Multibeam Sonar Data", University of Bath Boundary Influences in High Frequency Shallow Water Acoustics, Bath, UK. Conference Proceeding.

12. Cutter Jr., R. G., 2005, "Seafloor Habitat Characterization, Classification and Maps for the Lower Piscataqua River Estuary", Doctor of Philosophy. Thesis.

13. Ward, L. G., Bub, F. L., 2005, "Temporal variability in salinity, temperature and suspended sediments in a Gulf of Maine Estuary (Great Bay Estuary, New Hampshire)", in High Resolution Morphodynamics and Sedimentary Evolution of Estuaries, D.M FitzGerald, J. Knight (ed.): Springer Publisher, pp. 115 - 142. Book Section.

2004

14. Cutter Jr., R. G., 2004, "Benthic Habitat Characterization of the Lower Piscataqua River Estuary", Capacity Development Workshop on Acoustic Techniques in Seabed Assessment, St. Andrews, New Brunswick, Canada. Conference Proceeding.

15. Dijkstra, S. J., Elston, G. R., 2004, "Quantitative Inter-Channel Calibration of SHOALS Signals for Consistent Bottom Segmentation and Characterization", American Society for Photogrammetry and Remote Sensing, Denver, CO, USA, 23 - 28 May. Conference Presentation Only.

16. Goff, J. A., Kraft, B. J., Mayer, L. A., Schock, S. G., Sommerfield, C. K., Olson, H. C., Gulick, S. P., Nordfjord, S. , 2004, "Seabed characterization on the New Jersey middle and outer shelf: Correlability and spatial variably of seafloor sediment properties", Marine Geology, Vol. 209, pp. 147 - 172. Journal Article.

17. Hou, T. , Huff, L. C., 2004, "Seabed Characterization Using Normalized Backscatter Data by Best Estimated Grazing Angles", International Symposium on Underwater Technology, St. Andrews, New Brunswick, Canada, 20 - 23 April, pp. 153 - 160. Conference Proceeding.

18. Zoksimovski, A. , 2004, "Underwater Communication Channel Characterization in the Southern California Off-Shore Range", Master of Science, 174 pages. Thesis.

19. Ward, L. G., 2004, "Variations in physical properties and water quality in the Webhannet River Estuary (Wells National Estuarine Research Reserve, Maine)", Journal of Coastal Research, Vol. 45, pp. 39 - 58. Journal Article.

20. Elston, G. R., Dijkstra, S. J., 2004, "Waveform characterization, clustering and segmentation of SHOALS", 5th Annual Joint Airborne LIDAR Bathymetry Technical Center of Expertise Coastal Mapping and Charting Workshop, St. Andrews, New Brunswick, Canada. Conference Proceeding.

2003

21. Lee, H. J., Kayen, R. E., Gardner, J. V., Locat, J. , 2003, "Characteristics of Several Tsunamigenic Submarine Landslides", in Submarine Mass Movements and Their Consequences: First International Symposium, J. Locat & J. Mienert (ed.): Kluwer Academic, pp. 357 - 366. Book Section.

22. Schmal, G. P., Hickerson, E. L., Weaver, D. C., Gardner, J. V., 2003, "High-Resolution Multibeam mapping and habitat characterization of topographic features in the northwest Gulf of Mexico", U.S. Hydrographic Conference, Biloxi, MS, USA, 24 - 27 March. Conference Proceeding.

23. Grizzle, R. E., Adams, J. R., Dijkstra, S. J., Smith, B. , Ward, R. W., 2003, "Mapping and Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography and Quadrat Counts", P.W. Barnes & J.P. Thomas (ed.): American Fisheries Society. Book.

24. Ward, L. G., Burdicki, D. M., Adams, J. R., 2003, "Preliminary Studies of the Impact of Sea Level Rise on Coastal Environments (New Hampshire, USA)", Fifth International Conference on Coastal Sediments, Clearwater Beach, FL, USA, 18 - 23 May, 13 pages. Conference Proceeding.

25. Sternlicht, D. S., de Moustier, C. , 2003, "Remote sensing of sediment characteristics by optimized echo-envelope matching", Journal of the Acoustical Society of America, Vol. 114, No. 5, pp. 2727 - 2743. Journal Article.

2002

26. Hou, T. , Mayer, L. A., Rzhanov, Y. , 2002, "Application of Wavelet Multi-resolution to Multibeam Backscatter for the Seabed Characterization", Oceanology International, London, UK, 5 - 8 March. Conference Proceeding.

27. Dijkstra, S. J., Grizzle, R. E., 2002, "Automated Interpretation of Sidescan and Single- Beam Sonar for Characterization and Mapping the Extent of Subtidal Oyster Reefs", 94th Annual National Shellfisheries Association Meeting, Mystic, CT, USA, 14 - 18 April. Conference Proceeding.

28. Kent, G. M., Driscoll, N. W., Gardner, J. V., 2002, "Lake Tahoe's submerged record of active faulting is characteristic of the Basin and Range", 54th Annual Meeting Rocky Mountain Geological Society of America, Cedar City, UT, USA, Vol. 33, No. 4, 7 - 9 May. Conference Abstract.

29. Sternlicht, D. S., de Moustier, C. , 2002, "Near bottom sediment characterization offshore SW San Clemente Island", IEEE Oceans, Biloxi, MS, USA, 29 - 31 October, pp. 2086 - 2092. Conference Proceeding.

30. Cutter Jr., R. G., Rzhanov, Y. , Mayer, L. A., 2002, "Quantitative Ground-Truthing of Habitat Characteristics Using Video Mosaic Images". Poster.

2001

31. Adams, J. R., Dijkstra, S. J., Grizzle, R. E., Nelson, J. , Ward, L. G., 2001, "Comparison of Acoustic Techniques, Videography, and quadrant sampling for Characterizing Subtidal Oyster Reefs", 94th Annual National Shellfisheries Association Meeting, Mystic, CT, USA, 14 - 18 April. Conference Proceeding.

32. Hou, T. , Huff, L. C., Rzhanov, Y. , Mayer, L. A., 2001, "Seafloor Characterization from Spatial Variation of Multibeam Backscatter vs. Grazing Angle", Fall Meeting Eos Transactions, American Geophysical Union (Abs.), San Fransisco, CA, USA, Vol. 83, No. 47, 10 - 14 December. Conference Presentation Only.

33. Dijkstra, S. J., 2001, "Seafloor Characterization using Vertical Incidence Echosounders: A Study in Portsmouth Harbor and the Great Bay Estuary, New Hampshire", 2nd International Conference on High-Resolution Survey in Shallow Water, Portsmouth, NH, USA, 24 September. Conference Proceeding.

34. Ward, L. G., Bub, F. L., 2001, "Suspended sediment dynamics in the Great Bay Estuary, NH: Patterns and controlling processes", Annual Meeting Geological Society of America, Boston, MA, USA, Vol. 33, No. 6, 5 - 8 November, pp. 273 - . Conference Abstract.

2000

35. Dijkstra, S. J., Mayer, L. A., 2000, "TracEd: A remote acoustic Seafloor characterization system for use with vertical incidence echosounders", IEEE Oceans, pp. 1211 - 1217. Journal Article.

1999

36. Ward, L. G., Birch, F. S., 1999, "Sedimentology of the New Hampshire inner continental shelf based on subbottom seismics, side scan sonar, bathymetry, and bottom samples", Marine Georesources and Geotechnology, Vol. 17, pp. 165 - 172. Journal Article.

1998

37. Ward, L. G., Kearney, M. S., Stevenson, J. C., 1998, "Variations in sedimentary environments and accretionary processes in estuarine marshes undergoing rapid sea level rise, Chesapeake Bay", Marine Geology, Vol. 151, pp. 111 - 134. Journal Article.

PRIMARY CONTACT: Semme Dijkstra

In general support of our seafloor characterization efforts, Semme Dijkstra has continued the development of several software tools. The TracEd tool provides a robust means of tracking, editing and parsing returns from single beam echosounders. This tool, which has the potential to be a very useful aid to single-beam hydrographic data processing, has now been ported to the Windows environment. Upgrades to TracEd this year include the extended ability to display of LIDAR data, as well as interfaces for the ODOM Echotrac MKIII, cvc2 and cv3 systems, and revised snippet editing. The Lassoo tool which is used for comparing multivariate data sets to imagery data sets in both geographic and multivariate feature space has also undergone a number of upgrades including the development of a generalized AI classification scheme that is designed to automatically identify benthic organism grazing haloes that have been shown to be associated with the location of underwater ordinance in certain locations (e.g. Vieques).

Related Publications for Single Beam Sonar

2008

1. Lippmann, T. C., Smith, G. M., 2008, "Shallow Surveying in Hazardous Water", 5th International Shallow Water Survey Conference, Durham, NH, USA, 21 - 24 October, pp. 118 - 118. Conference Abstract.

We have made substantial progress in developing approaches to multibeam seafloor characterization on a number of fronts. These developments have been made using EM 120, 121, 300, 1000, 1002, 3000, 3002, and Reson 8101, 8111, 8160, 8125 and 7125, as well as GeoAcoustics GeoSwath, Klein 5000 and 5410 data collected in support of the ONR, NSF, USGS, and Icelandic-sponsored programs, along with multibeam sonar data collected by NOAA and others in Portsmouth Harbor as part of the Shallow Water Survey 2001 "Common Data Set", and data collected on the NOAA vessels, Thomas Jefferson, Nancy Foster, Rainier, Rude, Fairweather, Dyson and Bigelow. This year we have also begun the collection of a new "Common Data Set" in support of the upcoming Shallow Survey 2008 Conference. With the availability of these data sets, much of our recent effort in terms of seafloor characterization has focused on enhancing our ability to extract quantitative information from our sonars (through better processing and modeling) and improving our ground-truthing abilities.

If we are to use sonar backscatter data to correctly characterize seafloor properties, we want the backscatter that we measure to represent changes in the seafloor rather than instrumental changes or changes in the geometry of ensonification. While many system and geometric corrections are applied by the manufacturers in their data collection process, some are not (e.g. local slope), and for others, many questions remain about how and where they were applied (see discussion of Backscatter Processing above). As described in the Backscatter Processing section, we have been working closely with NOAA and the manufacturers to fully and quantitatively understand the nature of the backscatter data collected and to develop tools (GeoCoder) that can properly make the needed adjustments to the data. Once such corrections are made the resulting backscatter should be much more representative of true sea floor variability and thus be an important contributor to efforts to remotely characterize the seafloor.

Related Publications for Multibeam Sonars

2008

1. Malik, M. A., Mayer, L. A., Fonseca, L. , Ward, L. G., Huff, L. C., Calder, B. R., 2008, "Approaches and requirements of quantitative comparison of the multibeam sonar benthic acoustic backscatter", 5th International Shallow Water Survey Conference, Durham, NH, USA, 21 - 24 October. Conference Abstract.

2. Felzenberg, J. , Ward, L. G., Rzhanov, Y. , Mayer, L. A., 2008, "Detecting bedform migration in Portsmouth Harbor on relatively short time-scales from high-resolution multibeam bathymetry", 5th International Shallow Water Survey Conference, Durham, NH, USA, 21 - 24 October. Conference Abstract.

3. Felzenberg, J. , Ward, L. G., Rzhanov, Y. , Irish, J. D., Mayer, L. A., 2008, "Detecting bedform migration in Portsmouth Harbor, New Hampshire, USA, on relatively short spatial and temporal scales", American Geophysical Union, San Fransisco, CA, USA, 15 - 19 December. Conference Abstract.

4. Malik, M. A., 2008, "Tools, methods and applications of ocean floor mapping: Examples from Western Gulf of Maine", Maine Fisherman Forum, Rockport, ME, USA, 28 - 1 February. Conference Presentation Only.

2006

5. Ward, L. G., Malik, M. A., Cutter Jr., R. G., Brouder, M. A., Grizzle, R. E., Mayer, L. A., Huff, L. C., 2006, "High resolution benthic mapping using multibeam sonar, videography, and sediment sampling in the Gulf of Maine: Application to geologic and fisheries research.", Annual Meeting Geological Society of America, Boston, MA, USA, Vol. 38, No. 7, 5 - 8 November, 377 pages. Conference Abstract.

PRIMARY CONTACT: Luciano Fonseca

The GeoCoder software (which is designed to make fully corrected backscatter mosaics and calculate a number of backscatter statistics) has now been integrated with the ARA software package - also developed by Luciano Fonseca - which is designed to analyze the angular response of the backscatter as an approach to remote seafloor characterization. The ARA software has now implemented a fully constrained iterative inversion model that is based on both empirical data sets (Hamilton) and theoretical approaches (Jackson and Biot). There are many advantages derived from this integration, for instance, the prediction of the bottom type provided by the ARA can help remove the backscatter angular response, which is sediment specific, making it possible to assemble backscatter mosaics with fewer angular artifacts. Additionally, the enhanced backscatter mosaics can be segmented based on texture and statistics, so that it should be possible to calculate an average angular response not just for a stack of consecutive pings(a patch), but also for a segmented region in the backscatter mosaic. Another benefit is that, with a certain number of assumptions mainly relating to backscatter offsets and beam pattern, the same ARA seafloor characterization can be applied to different sonar systems.

In 2006, the concept of "theme analysis" was added to GeoCoder and the ARA software. With that, average backscatter angular responses can now be calculated for specified areas of the seafloor, referred to as themes, rather than for fixed patches of stacked pings in the along-track direction. The average angular response of the theme, and not of the patch, can now be analyzed with the ARA tools, so that an estimate of the seafloor properties of an area can be calculated. Similarly, the average angular response of the theme, and not one along-track moving average, can now be used to calculate the angle vs. gain (AVG) tables necessary to build an enhanced backscatter mosaic. With these new AVG tables, the mosaics show fewer artifacts in the along-track direction. The themes can be generated manually with image processing editing tools or can be generated automatically. For that, the theme areas are segmented and clustered directly in the angular response space, and not in the image textural space.

This past year, the "theme analysis" has been enhanced significantly. Theme segmentation can now be done visually by an interpreter or automatically with the aid of image processing algorithms. Fonseca and Yuri Rzhanov are working together to develop segmentation algorithms that take into account the acquisition geometry of the sidescan or multibeam sonar and analyze, simultaneously, parameters extracted from the backscatter mosaic (image-distribution space) and from the angular response (angular-response space). In addition a tool has been added this year that allows the editing and interpretation of the ARA parameters that describe the angular response curve in slope-intercept space. The results of this editing can then be used directly in the model inversion. Finally a capability has been added that allows the simultaneous adjustment of the inversion parameters when information is available at multiple frequencies from the same piece of seafloor. While these situations are rare, the potential for obtaining a more robust solution of seafloor character is quite exciting.

A "blind" test of the ARA technique was done this year as part of a symposium on seafloor characterization held in Northern Ireland. Acoustic backscatter from a Simrad EM1002 survey of the Stanton Bank, Northern Ireland was analyzed using the ARA tools with no knowledge of the actual bottom type. The results were then compared to bottom photographs acquired in the same area last summer. The results were compiled in a GIS and showed very good correlation between the bottom type predicted by the ARA and that shown in photos and by other analyses. The organizer of the symposium, Professor Craig Brown at the University of Ulster wrote to Fonseca:

"I personally think that your approach is one of the most exciting developments in the field of seabed habitat mapping. Your approach is unique and I think (with further development) could be just the thing to map seafloor features such as habitats. The combined methods of ARA and theme discrimination from the mosaic offer all the ingredients for accurate and vastly improved delineation of more subtle biological traits (i.e. bioturbation, animal biomass etc.)."

Related Publications for ARA Analysis

2008

1. Fonseca, L. , Rzhanov, Y. , 2008, "Automatic Construction of Acoustic Themes from Multibeam Backscatter Data", 5th International Shallow Water Survey Conference, Durham, NH, USA, 21 - 24 October. Conference Abstract.

PRIMARY CONTACT: Barbara Kraft

In order to better understand the relationship between remotely measured sonar backscatter and the physical properties of the seafloor, we have also developed (with ONR funding) an instrument system designed to make in situ measurements of sound-speed, sound attenuation, and resistivity (along with video of the seafloor -- ISSAP). In the past year, Barbara Kraft and Glenn McGillicuddy have calibrated the ISSAP transducers (to better understand the measurements made with them). In the case of the Geoclutter work, ISSAP measurements have been compared with the ARA model predictions of Fonseca with very encouraging results (reported in previous annual reports).

The most recent ground-truthing study involves the Master's thesis work of graduate student Luis Soares-Rosa. Luis focused his research on the Historic Area Remediation Site (HARS), a well-studied region of controlled disposal of hazardous waste and capping. This dataset is important because it provides a wide variety of sediment types ranging from clays to gravel in a relatively small area along with a large amount of ground-truth and sonar (single beam, multibeam, side scan sonar, sub-bottom profiling, grab samples, corers, plan view and profile images) collected over an eight year period. This extended dataset allows understanding the sedimentary dynamics of this area and its evolution, which in turn influences the strategy for determining the need for new sediment sampling to fill existing gaps.

Comparisons of the ARA results with ground-truth measurements (Sediment Profile Imaging (SPI) camera, grain size analyses on grab samples and bottom photos) proved very encouraging. When the sediment sampled was both laterally and vertically homogeneous (within the uncertainty of the relative positioning of the sample and the acoustic data), the ARA used in the "patch" (averaging over a swath width) mode proved to be a very effective predictor of the mean grain size of the sediment (R2 = 0.90); when there was substantial lateral variability, the "theme" mode of the ARA proved to be a better approach. The difference in the ARA predicted mean grain size and the measured mean grain size was ±0.4 phi at 1 sigma.

Two new projects (funded separately, but complementary to our ongoing work) began in 2007.

The first project is aimed at using stereo cameras to improve the accuracy of optically-assisted acoustic rockfish abundance measurements and habitat surveys. This project is funded by NOAA's Southwest Fisheries Science Center, with J. Butler, G. Cutter, D. Pinkard, D., Demer collaborating with Rzhanov at the Center.

The second project, funded through IOOS, is for the development in cooperation with Scott Gallager and others at Woods Hole Oceanographic Institution, of a mobile bentho-pelagic observatory to support fisheries and ecosystem management (NEBO). Our role in this effort will be to create video mosaics from the high-resolution photographic and video data collected by the WHOI benthic sled and to compare the habitat-relevant analyses of this imagery to acoustic data collected by multibeam and sidescan sonar.