Abstract :
The way the medium controls sound reception in shallow water is discussed generally, and illustrated by some North Sea experiments with explosion sources. The ray and mode theories are introduced, and it is shown where it is convenient to change from one to the other. Transmission loss is the most important parameter, and is least around 200 c/s. Time dispersion is mainly due to the dispersion in the vertical arrival angle. Large fluctuations are observed when using a continuous wave source. The propagation is dominated by the characteristics of the two boundaries.
