Topic 18 Coasts, Beaches, and Estuaries GEOL 2503 Introduction to Oceanography.
PHYSICAL OCEANOGRAPHY Part 4: Sound in the Ocean GEOL 1033 (Lesson 29)
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Transcript of PHYSICAL OCEANOGRAPHY Part 4: Sound in the Ocean GEOL 1033 (Lesson 29)
PHYSICAL OCEANOGRAPHY
Part 4: Sound in the Ocean
GEOL 1033
(Lesson 29)
SOUND IN SEAWATER
• Sound travels – About 4 times faster in water than in air– Approximately 1 500 m/s in water
• Depth determination (study Exercise #4)– Half travel time X 1500 m/s = depth
• Echo sounder used– Record depth profiles– Detects deep scattering layers– Obtain seismic profiles
Speed of Sound in Water
• “Typical” depth profile of sound speed in seawater
Speed of Sound in Water
• Arctic & Antarctic profile
• Lower latitude profile
SOFAR & Shadow Zone
• Effects of sound speed minimum and maximum:
SOFAR Channel
• Sound velocity minimum at about 1000 m depth at low to mid latitudes
SOFAR Experiment in 1991
• Successful transmission of sound over great distance
Sound Shadow Zone
• Associated with a near-surface sound maximum speed depth
• At approximately 80 to 100 m
Ideal detection
Sound "Shadow Zone" Due to Refraction
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