Modeling of sound propagation in the atmospheric boundary layer: Application of the MIUU mesoscale model

A mesoscale atmospheric model, the Meteorological Institute of Uppsala Univ ersity model, has been used to simulate local wind and temperature profiles in an area with hilly terrain in eastern Norway. Simulated wind and temper ature profiles (up to 250 m height above ground) have been used as input to an acoustical model, called Gases. In this way, sound propagation out to 1 .4 km distance along ground has been determined for a site situated in a va lley bottom in the center of the model domain. Measured ground conditions a re also included in the acoustical model. During the investigated period, m eteorological measurements were carried out in conjunction with measurement s of low-frequency (less than or similar to 100 Hz) impulse sound propagati on out to a range of 1400 m along a flat, uniform, and snow-covered ground. For a case with geostrophic winds of the order of 25 m s(-1) the predicted profiles are compared with profiles measured by meteorological towers and a tethered balloon launched at the site. Acoustic predictions based on both measured and simulated atmospheric profiles agree well with measured singl e-frequency sound levels in most cases. This suggests that forecasts of sou nd propagation using both a nested mesoscale atmospheric model and an acous tical model should be possible in future.