Adding Decibels

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Adding Decibels
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Speed of Sound Factors

• Temperature
• Pressure or Depth
• Salinity

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Temperature, Pressure, and Salinity
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Class Sound Speed Data
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More Curve Fitting
Chen and Millero
Leroy
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Expendable Bathythermograph
Canister Loading Breech
Canister Loading Breech
Launcher Recorder Cable (4-wire shielded)
Stantion
LAUNCHER
Optional Equipment
Alternating Current PowerCable (3-wire)
Terminal Board
Depth/Temperature Chart
RECORDER
Wire Spool
Thermistor
PROBE (XBT)
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Typical Deep Ocean Sound Velocity Profile (SVP)
Sonic Layer Depth (LD)
P
T
C
Deep Sound Channel Axis
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Refraction
High c1
B
A
D
E
Low c2
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Multiple Boundary Layers
where c1 lt c2 lt c3 lt c4 and ?1 gt ?2 gt ?3 gt
?4
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Simple Ray Theory
c
(c1,z1)
(c,z)
Snells Law
z
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Ray Theory Geometry
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The z (Depth) and x (Range) Directions
csurface1500 m/s
z
?I20?
x
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The z (Depth) and x (Range) Directions
csurface1500 m/s
z
?I20?
x
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Why is R Radius?
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Summary
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Negative Gradient
x1
x2
c2
z2
q2
q1
z1
c1
R
Negative gradient, g
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Example 1

• Given c1 964 m/s, c2 1299 m/s, q2 30o
• Dz(between 1 and 0) 3000m
• Find q1, co, g (between pt 1 and 0), R

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Example 2

• Find gradient, g
• Find Radius of Curvature, R, for each ray.
• Skip distance i.e. the distance until the ray
  hits the surface again
• Max depth reached by each ray

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Backups
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Slope tanq
x1
x2
z1
z2