A research vessel sailing in SOME Sea suddenly began to shake violently, its speed plummeting from 15 knots to 5 knots, despite calm seas. The crew encountered the ocean’s most mysterious “invisible player”: internal waves.
What are internal waves? First, let’s understand the “seawater sandwich.”
The waves we normally see are “surface waves” bouncing around on the surface; internal waves, on the other hand, are hidden within the ocean’s inner densities—the densities formed by layers of water. Think of the seawater as being divided into a “sandwich”: the upper layer is light (higher temperature, lower salinity), while the lower layer is heavier (lower temperature, higher salinity). The junction between the two layers is the densities. When ocean currents collide with underwater mountains or islands, or when winds stir the surface waters, the densities act like a plucked string, generating internal waves that rise and fall.
How powerful are internal waves? You’re definitely concerned about these impacts.
Don’t assume that internal waves pose no threat just because they’re hidden deep. Their energy can easily “manipulate” marine activities:
✅ “Invisible Trap” for Submarines: During World War II, submarines that entered internal wave zones were thrown to the surface by the turbulent currents, exposing their targets. Today, submarines check “internal wave forecasts” before sailing to avoid dangerous areas.
✅ “Nutrient Delivery” for Fishing Grounds: When internal waves surge, they pull nutrients (such as phosphates and nitrates) from the seabed to the surface, nourishing plankton. Many fisheries in my country’s South China Sea rely on internal waves to “feed” the fish!
✅ “Invisible Test” for Marine Engineering: Submarine cables and oil drilling platforms can be damaged by the currents if they encounter strong internal waves. After the 2010 Gulf of Mexico oil spill, scientists specifically monitored the impact of internal waves on the spread of oil spills.
How can “internal waves” be observed?
In the past, crew members relied on “feeling” for internal waves, but now high-tech technologies are available:
● Satellite remote sensing: By monitoring subtle changes in sea surface temperature and altitude, we can “infer” the internal waves beneath the surface (much like finding an object by its shadow);
● Submarine buoys: Submerge monitoring equipment near the thermocline to record the amplitude and velocity of internal waves in real time;
● Underwater robots: They have captured high-definition images of internal waves driving seawater movement in SOME Sea.
Frankstar specializes in ocean wave monitoring, creating professional sensor and buoy solutions.
With the development of marine environmental monitoring, marine engineering, and renewable ocean energy, accurate and reliable wave data acquisition equipment is becoming critical infrastructure. As a professional developer of wave sensors and buoys, Frankstar is committed to developing high-performance, easy-to-deploy products that can adapt to complex sea conditions, and actively promotes their application in scientific research, engineering, energy, and other fields.
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Post time: Oct-10-2025