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winter. Speed of Sound. 4850ft/s 4900 ft/s 4950 ft/s 5000ft/s. Surface Layer. 300 600 3000 6000 9000. Seasonal Thermocline. Main Thermocline. Deep Isothermal Layer. Nominal SVP (Sound Velocity Profile). “Layer”.
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winter Speed of Sound 4850ft/s 4900 ft/s 4950 ft/s 5000ft/s Surface Layer 300 600 3000 6000 9000 Seasonal Thermocline Main Thermocline Deep Isothermal Layer Nominal SVP (Sound Velocity Profile) “Layer”
c z c z c z Gradients and Bending Iso-speed positive negative
Surface Duct – Surface Shadow Zone SVP positive SVP negative
Surface Shadow Zone Implications Originally called the “afternoon effect”
Convergence Zone Depth Excess > 300 fathoms
Deep Shadow Zones • BD = 17(LD)1/2 if LD < 60m. • BD = LD + 60m if LD > 60m.
Deep sound channel range Sound speed depth
Mixed Layer Example D = 40 m L = 100 m C1 = 1500 m/s g = 0.017 s-1 • Find sound speed at S and at bottom of layer • Angle of the rays at the source • Angle of the rays at the surface • Radius of curvature of the ray • Skip distance , X S
x2 x1 R c1 z1 q1 z2 c2 q2 Positive gradient, g Summary