# 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), Division: Calculation of the term Δ ground(S,O)

Extent: E+W+S+N.I.

(2.5.31)
where
Aground(S,O) is the attenuation due to the ground effect between the source S and the diffraction point O. This term is calculated as indicated in the previous subsection on calculations in homogeneous conditions and in the previous subsection on calculation in favourable conditions, with the following hypotheses:
zr = zo,s ,
Gpath is calculated between S and O,
In homogeneous conditions: Ḡw = G′path in equation (2.5.17), Ḡm = G′path in equation (2.5.18),
In favourable conditions: Ḡw = Gpath in equation (2.5.17), Ḡm = G′path in equation (2.5.20),
Δ dif(S′,R) is the attenuation due to the diffraction between the image source S′ and R, calculated as in the previous subsection on pure diffraction,
Δ dif(S,R) is the attenuation due to the diffraction between S and R, calculated as in Subsection VI.4.4.b.

---
Source: https://www.legislation.gov.uk/eudr/2015/996/annex/division/ASSESSMENT/division/2/division/2.5/division/2.5.6/division/14 (the official version)
Page: https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.5/division-2.5.6/division-14
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.