Bølgestrømmen

Bølgestrømmen refers to the movement of water within the ocean that is caused by the propagation of waves. While waves themselves are a surface phenomenon transferring energy, bølgestrømmen describes the net displacement of water particles that occurs as a consequence of this wave action. This phenomenon is distinct from the wind-driven currents that move large volumes of water over long distances.

The primary driver of bølgestrømmen is the interaction between wind and the ocean surface. As wind blows, it imparts energy to the water, creating ripples that grow into larger waves. These waves are characterized by orbital motion of water particles. In deep water, particles move in near-circular paths, returning to their original position after the wave passes. However, as waves approach shallower water, this orbital motion is altered, leading to a net forward movement of water.

This net forward movement is particularly noticeable near the shore. As waves break, they create a strong onshore current, often referred to as the swash. This current carries water and sediment up the beach. Conversely, water then returns seaward, often through rip currents, which are powerful, narrow channels of water moving directly away from the shore. Bølgestrømmen plays a significant role in sediment transport, shaping coastlines, and influencing marine ecosystems.