ABSTRACT
The way in which sound travels outdoors has been of interest for several centuries. Initial experiments were concerned with the speed of sound [1]. The Francisan (Minimite) friar, Marin Mersenne (1588-1648), suggested timing the interval between seeing the flash and hearing the report of guns fired at a known distance. William Derham (1657-1735), the rector of a small church near London, was first to observe the influence ofwind and temperature on sound speed and the difference in the sound of church bells at the same distance over newly fallen snow and over a hard frozen surface. Many records of the strange effects of the atmosphere on the propagation of sound waves have been associated with war [2, 3]. In June 1666, Samuel Pepyswrote that the sounds of a naval engagement between the British and Dutch fleets were heard clearly at some spots but not at others a similar distance away or closer. Pepys spoke to the captain of a yacht that had been positioned between the battle and the English coast. The captain said that he had seen the fleets and run from them, ‘. . . but from that hour to this hath not heard one gun . . .’. The effects of the atmosphere on battle sounds were not studied in a scientific way until after the First World War. During that war, acoustic shadow zones, similar to those observed by Pepys, were observed during the battle of Antwerp. Observers also noted that battle sounds from France only reached England during the summer months and were best heard in Germany during the winter. After the war there was great interest in these observations among the scientific community. Large amounts of ammunition were detonated throughout England and the public was asked to listen for sounds of explosions. Although there was considerable interest in atmospheric acoustics after the First World War, the advent of the submarine encouraged the greatest efforts in underwater acoustics research during and after the Second World War. The theoretical and numerical methods widely deployed in predicting sound propagation in the oceans have been adapted subsequently for use in atmospheric acoustics. A meeting organized by the University of Mississippi and held on the Mississippi Gulf Coast in 1981 was the first in which researchers in underwater acoustics met with scientists interested in atmospheric acoustics
and stimulated the adoption and adaptation of the numerical methods, used for underwater acoustics, in the atmosphere [4].
