Studying Massive Underwater Waves

The world's oceans are still very mysterious places, in spite of the many study hours that were dedicated to discovering their secrets. Coastal areas are even more difficult to analyze, on account of the massive volume of interactions between the water, atmosphere and land. One of the phenomena that rose scientists’ interest is the one which promotes the formation of steep, underwater waves. They form between layers of warm and cold water, but appear exclusively in coastal regions. The exact mechanisms that generate them were the target of a new investigation by researchers at the University of Rhode Island, which managed to gain more thorough insight into the forces at work in these cases.

Underwater waves are so massive, that they create effects on surface waves. These patterns can readily be viewed from satellites, says URI Graduate School of Oceanography dean and physical oceanographer David Farmer, the leader of the study. He worked together with student Qiang Li to determine the height that these waves can reach. The two discovered that the South China Sea is at times home to nonlinear internal waves of very high amplitude that reach as much as 150 meters in height. The team presented their report in Portland, Oregon, at the 2010 Ocean Sciences Meeting of the American Geophysical Union (AGU).

“The large waves in the South China Sea have attracted a fair bit of attention in recent years, but much of this has been directed at the interaction of the waves with the sloping continental shelf of mainland China where they break, overturn and produce intense mixing. Our focus is on the way in which they are generated in Luzon Strait, between Taiwan and the Philippines, and the way they evolve as they propagate westwards across the deep ocean basin of the South China Sea,” Farmer said at the scientific gathering, ScienceDaily reports.

Understanding these waves is critical to many areas of ocean studies. The phenomena are very hazardous to structures engineered at sea, such as drilling rigs, and they can fatally interfere with submarine navigation. The way in which sound is propagated underwater is also disturbed, which influences both the dispersion of sonar waves and the click of whales. Many marine animals communicate using either low- or high-pitched sounds, and so their ability to understand each other may be hampered if they navigate into a region experiencing underwater waves.