1. Reaching the Bottom Jessie Conley

2. Over 71% of the earth is covered by ocean. Average depth is 3,720 meters deep Over 71% of the earth is covered by ocean. Average depth is 3,720 meters deep

3. How do we locate the bottom?  Single Beam Sonar  Side Scan Sonar  Multibeam Sonar  Satellite Altimetry  Single Beam Sonar  Side Scan Sonar  Multibeam Sonar  Satellite Altimetry

4. Single Beam Sonar  Developed in 1920’s-30’s  Used for bathymetry mapping and determination of bottom type  Transducer sends out a signal and measures time to receive echo back  Developed in 1920’s-30’s  Used for bathymetry mapping and determination of bottom type  Transducer sends out a signal and measures time to receive echo back

5. Single Beam Sonar Mapping restricted to single line of data Dark blue represents deeper regions Mapping restricted to single line of data Dark blue represents deeper regions

6. Side Scan Sonar  Developed in 1960’s  Bottom type determination  Sends out signals 90 degrees from sonar  Images made based on strength of reverberated signal  Developed in 1960’s  Bottom type determination  Sends out signals 90 degrees from sonar  Images made based on strength of reverberated signal

7. Side Scan Sonar

8. Multibeam Sonar  Measure the depths of the ocean  Multiple transducers send out pulses simultaneously  Uses Inertial Motion Unit for more accurate bathymetry mapping  Easier to navigate and gives wider coverage  Measure the depths of the ocean  Multiple transducers send out pulses simultaneously  Uses Inertial Motion Unit for more accurate bathymetry mapping  Easier to navigate and gives wider coverage

9. Multibeam Sonar

10. Locating the Alligator  The Navy’s first submarine which sunk near Cape Hatteras  http://www.youtube.com/watch?v=QR GW99QZoeE http://www.youtube.com/watch?v=QR GW99QZoeE  The Navy’s first submarine which sunk near Cape Hatteras  http://www.youtube.com/watch?v=QR GW99QZoeE http://www.youtube.com/watch?v=QR GW99QZoeE

11. Satellite Altimetry  Quicker bathymetry mapping, but less accurate  The various bumps and ridges on the ocean surface mimic the ocean floor below them  Sends microwaves that hit the surface of the ocean and measures the patterns  Quicker bathymetry mapping, but less accurate  The various bumps and ridges on the ocean surface mimic the ocean floor below them  Sends microwaves that hit the surface of the ocean and measures the patterns

12. Satellite Altimetry