What phenomenon is described as sound bending towards the earth?

The phenomenon where sound bends towards the Earth's surface is known as super-refraction. This occurs under specific atmospheric conditions where a temperature inversion exists, causing sound waves to travel along paths that are much closer to the ground than they typically would under normal conditions.

In super-refraction, the sound waves are affected by the gradient of temperature and humidity, resulting in energy being focused downwards. This causes the sound to be heard at distances that would normally be beyond the range at which it could be detected. Therefore, in situations of super-refraction, sound can effectively "bend" and travel farther than expected, making it a critical concept in understanding acoustic propagation in various environmental conditions.

Understanding this concept is essential for applications in naval operations and environmental assessments where sound may behave unusually based on atmospheric layers. The other options represent different sound propagation behaviors that do not specifically involve the bending of sound toward the Earth in the same manner.