Natural temporal variability of atmospheric acoustic absorption coefficients

✍ Scribed by D.Keith Wilson; Dennis W. Thomson

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 518 KB
• Volume: 34
• Category: Article
• ISSN: 0003-682X
• DOI: 10.1016/0003-682x(91)90026-b

✦ Synopsis

A BSTRA CT Since acoustic absorption coefficients depend upon environmental temperature and humidity, they vary in response to changing atmospheric conditions on a variety of time scales. This natural temporal variability is often neglected in outdoor noise assessment work, where averaged meteorological data are used to estimate absorption. In this stud)" the authors assess the validio' of calculating absorption coefficients from meteorological data which have been averaged on various time scales. The results indicate that the use of annual mean meteorological data can result in frequency-dependent r.m.s. errors ranging from 20 to 50%. Seasonal averaging can result in r.m.s, errors of 20 to 30%. Even daily averages may be unsatisfactory: for some of the cases presented absorption changes by 200% during the course of a single day.