(Trinidad Guardian) A huge, rarely-seen 100-mile long internal wave has been spotted near the north coast of Trinidad. A photo released two days ago by the International Space Station (ISS) shows the presence of the natural phenomenon which has largely gone undetected in T&T.
An article from the National Aeronautics and Space Administration (NASA) Earth Observatory has defined “internal waves” as “the surface manifestation of slow waves that move tens of metres beneath the sea surface.”
The NASA release states the most prominent waves can be seen at the top left of the image, where a set of waves can be seen moving from the northwest owing to the tidal flow towards the north coast of Trinidad.
“Two less prominent, younger sets can be seen further out to sea.” NASA’s Earth Observatory says the internal waves are most likely caused by a shelf break near Tobago. It defines a shelf break as the step between shallow seas and the deep ocean, “the line at which tides usually start to generate internal waves.”
A February 6 Daily Mail story described the underwater phenomenon as “colossal movements of water spanning kilometres that ripple under the surface of the Earth’s oceans.” It says these internal waves are rarely encountered or photographed but their strength can affect submarine and oil rig activities.
The T&T Guardian spoke to Legema Henry, who has an MSc in ocean engineering from the Massachusetts Institute of Technology (MIT) and is a PhD candidate in non-linear wave behaviour at the University of the West Indies, St Augustine.
Looking at the NASA images, Henry said the internal waves spotted near Trinidad were rare in how “clearly visible they were from space.” The Mail’s online article said the appearance of the waves in the pictures was enhanced because of sunlight or sunglint reflected back towards the ISS, which made the waves visible to the astronaut’s camera.
Henry explained that internal waves have a separate source of energy from surface waves. She said internal waves occur deep underwater whereas surface waves are caused by wind energy. Henry said the presence of these internal waves may be a cause for concern for some.
She said: “Oil companies see it as a concerning phenomenon, as it affects rigs and offshore technology,” she said. Violent waves can also negatively affect fishing grounds, she added. NASA’s Earth Observatory says that astronauts also have observed internal waves in other parts of the world, including off San Francisco and the Straits of Gibraltar.
