Division: Calculation of the attenuation Adif - Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance)

The attenuation due to diffraction, taking the ground effects on the source side and receiver side into account, is calculated according to the following general equations:

A_{dif} = Δ_{dif (S,R)} + Δ_{ground (S,O)} + Δ_{ground (O_{n}, R)}

(2.5.30)

where

Δ _{dif (S,R)} is the attenuation due to the diffraction between the source S and the receiver R
Δ _ground(S,O) is the attenuation due to the ground effect on the source side, weighted by the diffraction on the source side; where it is understood that O = O₁ in case of multiple diffractions as in Figure 2.5.f
Δ _ground(O,R) is the attenuation due to the ground effect on the receiver side, weighted by the diffraction on the receiver side (see the following subsection on calculation of the term Δ _ground(O,R) ).

Division Calculation of the attenuation Adif