Dynamic noise mapping: A map-based interpolation between noise measurements with high temporal resolution

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Author(s)
Wei, Weigang
Van Renterghem, Timothy
De Coensel, Bert
Botteldooren, Dick
Griffith University Author(s)
Year published
2016
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Since the introduction of the Environmental Noise Directive, strategic noise mapping has been used as a tool for noise policy in many European countries. Although these strategic noise maps have their merits, they also have some shortcomings: accuracy in predicted noise levels in shielded or quiet areas is not very high, the maps fail to capture sounds that are less easy to predict, and above all the dynamics of the sound environment are not included. However, these dynamics might be important to evaluate sleep disturbance and noise annoyance. In this paper, a model to dynamically (every 15 min) update a noise map based on ...
View more >Since the introduction of the Environmental Noise Directive, strategic noise mapping has been used as a tool for noise policy in many European countries. Although these strategic noise maps have their merits, they also have some shortcomings: accuracy in predicted noise levels in shielded or quiet areas is not very high, the maps fail to capture sounds that are less easy to predict, and above all the dynamics of the sound environment are not included. However, these dynamics might be important to evaluate sleep disturbance and noise annoyance. In this paper, a model to dynamically (every 15 min) update a noise map based on measurements is proposed. This model relies on reasonable good source and propagation models and a not-very-dense measurement network. The least mean squares method (LMS) is used for tuning model parameters. To avoid an under-determined system, the number of degrees of freedom is reduced by grouping the sources and propagation paths into different categories. Source strengths and propagation path attenuations in the same category are corrected by offsetting the same small values from their base levels. The map-based interpolation is performed jointly on <sup>LAeq</sup>,<sup>L10</sup> and <sup>L90</sup>, and takes into account 1/3-octave band spectra. The efficiency of the proposed method was validated in a case study in the Katendrecht district of Rotterdam, the Netherlands. The results showed that more than 75% of the <sup>LAeq</sup> predictions are closer to the measurement than the ab initio calculations based on traffic data. Values for <sup>L10</sup> and <sup>L90</sup> are closer to measurements for 55% and 90% of the observations, respectively.
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View more >Since the introduction of the Environmental Noise Directive, strategic noise mapping has been used as a tool for noise policy in many European countries. Although these strategic noise maps have their merits, they also have some shortcomings: accuracy in predicted noise levels in shielded or quiet areas is not very high, the maps fail to capture sounds that are less easy to predict, and above all the dynamics of the sound environment are not included. However, these dynamics might be important to evaluate sleep disturbance and noise annoyance. In this paper, a model to dynamically (every 15 min) update a noise map based on measurements is proposed. This model relies on reasonable good source and propagation models and a not-very-dense measurement network. The least mean squares method (LMS) is used for tuning model parameters. To avoid an under-determined system, the number of degrees of freedom is reduced by grouping the sources and propagation paths into different categories. Source strengths and propagation path attenuations in the same category are corrected by offsetting the same small values from their base levels. The map-based interpolation is performed jointly on <sup>LAeq</sup>,<sup>L10</sup> and <sup>L90</sup>, and takes into account 1/3-octave band spectra. The efficiency of the proposed method was validated in a case study in the Katendrecht district of Rotterdam, the Netherlands. The results showed that more than 75% of the <sup>LAeq</sup> predictions are closer to the measurement than the ab initio calculations based on traffic data. Values for <sup>L10</sup> and <sup>L90</sup> are closer to measurements for 55% and 90% of the observations, respectively.
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Journal Title
Applied Acoustics
Volume
101
Copyright Statement
© 2016 Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (http://creativecommons.org/licenses/by-nc-nd/4.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, providing that the work is properly cited.
Subject
Classical Physics
Mechanical Engineering
Architecture
Science & Technology
Acoustics
Dynamic noise map
Environmental noise monitoring