Figure 3. Empirical probability densities of noise levels in the 125 Hz band.
Levels in the three monitoring regions during (a) 2013 (b) 2014.; Levels at individual northern North Sea monitoring sites during (c) 2013 (d) 2014. Abbreviations refer to monitoring region: Celtic Sea (CS), northern North Sea (NNS), and southern North Sea (SNS). NNS data in (a,b) are mean probability densities computed over individual sites shown in (c,d).