No. 13: Winter 1981
Long lines of frothing, turbulent water and transitory packets of large waves occasionally sweep across an otherwise placid sea. Usually dismissed as "rips," satellite photos reveal that these disturbances may be 125 miles long. Often several can be seen criss-crossing an ocean simultaneously from different directions. Some have a 12.5-hour period. linking them to lunar tidal action. The surface manifestations, like the tip of the iceberg, only hint at what transpires beneath the surface. The long corridors of disturbance, moving at about 5 mph, mark where "internal waves" intersect the surface. Down be-low, submarines and other objects may suddenly rise or fall as much as 600 feet. Internal waves may in fact have caused several submarine disasters.
How are internal waves created? Tid-al waters may spill over an undersea sill or ledge, creating a travelling disturbance. Some oceanographers liken the internal waves to the lee waves formed parallel to large mountain ranges. Manifestly, there is much to learn about undersea weather.
(Anonymous; "Underwater Waves Held a Possible Clue to Disappearances of U.S. Submarines," Baltimore Sun, October 5, 1980.)
Reference. We collect observations of periodic bands of waves under GHW2 in our Catalog: Earthquakes, Tides. To order, visit: here.