Transmission Loss method

Fast TL

Explore the project’s range-and-depth approximation and compare it with spherical spreading.

Selected range 28.0 kmRepresentative depth 1382 m

Absorption

Critical angle ψ 0.50 radReflection gradient η 0.30 Np/rad

77.4 dB fast TL89.1 dB sphericalMode-stripping regime · 28.0 km

fast TLspherical spreading

How the equation changes

Three spreading regimes

The two break ranges move when depth, critical angle, or reflection gradient changes. Absorption is added in every regime.

r < 1.38 km20 log₁₀(r) + αr

fast TL and the spherical reference coincide.

1.38 km ≤ r < 14.5 km10 log₁₀(r) + 10 log₁₀(d / 2ψ) + αr

The curve grows more slowly after the first break.

r ≥ 14.5 km15 log₁₀(r) + 5 log₁₀(ηd / π) + αr

The final regime lies between cylindrical and spherical spreading.