On the use of the intermittency ratio for the assessment of aircraft noise during the night

Abstract

This paper explores the possibility of using the intermittency ratio as a novel metric for evaluating aircraft noise during nighttime periods. Using Dublin airport as a test case, the paper presents an analysis of nighttime flight patterns and corresponding noise data. It outlines the limitations of using a simple Lnight indicator to capture the temporal variation of noise. Similar limitations are observed with the use of a Noise Quota System. It is proposed that such assessments should be complemented with additional indicators that consider how many noise events (and noise induced awakenings) occur throughout the nighttime period. One indicator that has been suggested may be appropriate for use is the 'Intermittency Ratio', and as such this study investigates how the intermittency ratio might capture the temporal variations in noise emissions around Dublin Airport. Results suggest that while the metric offers some additional insight into the acoustic climate in the environs of an airport, it is not (yet) suitable for distinguishing between scenarios that can yield similar Lnight values, but significantly different temporal changes. The findings underscore the need to use additional indicators in the assessment of nighttime noise from aircraft.