Which type of wave is described as better over water than dry terrain?

Sky waves are radio waves that can be reflected off the ionosphere and are particularly effective for long-distance communication. These waves can travel significant distances by bouncing off the ionosphere, which is especially beneficial when transmitting over water due to the reduced interference from obstacles found on dry terrain. Water provides a more uniform surface for the radio waves, which can enhance their propagation compared to land where interference from buildings, trees, and other structures can hinder transmission.

In contrast, ground waves tend to follow the contour of the earth and may struggle to maintain strength over large bodies of water. Surface waves are very similar to ground waves but are more affected by the curvature and surface conditions of the terrain. Direct waves travel in a straight line between the transmitter and receiver and may not have the same range as sky waves, particularly in long-distance scenarios. Sky waves offer more effective propagation under the right atmospheric conditions, making them more advantageous for communication over water.