Applying ΔL to adjust both Lmax and LE NPDs effectively assumes that different atmospheric conditions affect the reference spectrum only and have no effect on the shape of the level-time-history This may be considered valid for typical propagation ranges and typical atmospheric conditions.
Commission Directive (EU) 2015/996Show full title
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)