Researchers find explanation for interacting giant, hidden ocean waves
In certain parts of the ocean, towering, slow-motion rollercoasters called internal tides trundle along for miles, rising and falling for hundreds of feet in the ocean’s interior while making barely a ripple at the surface. These giant, hidden swells are responsible for alternately drawing warm surface waters down to the deep ocean and pulling marine nutrients up from the abyss. Internal tides are generated in part by differences in water density, and created along continental shelf breaks, where a shallow seafloor suddenly drops off like a cliff, creating a setting where lighter water meets denser seas. In such regions, tides on the surface produce oscillating, vertical currents, which in turn generate waves below the surface, at the interface between warmer, shallow water, and colder, deeper water. These subsurface waves are called “internal tides,” as they are “internal” to the ocean and travel at the same frequency as surface tides. Internal tides...