Massachusetts Bay - Internal wave packets digitized from SAR imagery

Internal waves are nonsinusoidal waves that occur at the interface between two layers of ocean water of differing densities (Brown et al., 1989 p.9). They occur when seasonally stratified water is forced by diurnal tides over abrupt topographic features, such as banks or ledges.

These processes often produce several internal waves at once and as a result, internal waves usually propagate horizontally in groups or packets. As these packets approach shallow water (typically 25 to 40 m in depth), they gradually disappear due to increasing bottom attenuation, disrupting the pycnocline and vertically mixing water of differing densities (Jackson and Apel, 2004 p.198).