What type of acoustic signal would be most likely measured in shallow water?

In shallow water environments, the characteristics of sound propagation are influenced significantly by the water depth and the interaction of sound waves with the ocean surface and the bottom. Surface reflections are particularly prominent in shallow water because sound waves can reflect off the surface and create complex paths as they interact with both the water's surface and the seafloor.

When sound is emitted in shallow waters, a notable portion of that sound energy can bounce back from the surface, which can be measured. This reflection can provide useful information about both the acoustic environment and the characteristics of the water column.

High-frequency signals also play a role in shallow waters as they are subject to rapid attenuation, but they do not capture the broader scope of signal behavior that includes reflections from the surface. Deep scattering and long-range signals are generally more relevant in deeper waters where the environment and signal propagation are different due to the larger vertical scale and less interaction with the surface. Thus, surface reflections provide a more relevant and measurable acoustic signal in shallow water contexts.