Modeling the influence of weather to acoustic absorption of ground surface: an in-situ study by long-term measurements

摘要

It has been known that the moisture content of soil significantly affects the acousticproperties of the ground surface. For better prediction of outdoor sound propagation,studies have been conducted for quantifying the effect through in-situ and laboratorymeasurements. However, no study has investigated meteorological influence on thevariation of the acoustic properties of the ground. In this study, an in-situ measurementcampaign was run from July 2014 to January 2015 at a site in Niigata, Japan. Anautomatic weather station observed temperature and rainfall with one-minute interval. Aburied soil moisture sensor measured the volumetric water content (VWC) of the groundnear the station with five-minute interval. The acoustic absorption coefficient of the sameground position was measured with an in-situ measurement technique once a day. Fromthe results, a two-stage model was derived. The first stage models the effects of the rainfalland the temperature as short and long-term factors to the VWC. The second stage modelsthe effects of the VWC to the acoustic properties. The derived model was found to explainthe long-term and approximately half of the short-term variations of the acousticabsorption.