Ocean science news, explainers, and statistics covering marine environments, currents, climate, coasts, seafloor research, and the changing global ocean.
Ocean stratification is the arrangement of seawater into layers with different densities. Lighter water remains above denser water, reducing vertical mixing between the surface and the deep ocean. Temperature usually creates the strongest contrast across much of the planet, while salinity becomes decisive in rainy, icy or river-influenced regions. Layering is a normal feature of…
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An oceanic Rossby wave is a vast, slow-moving change in sea level and the depth of ocean layers caused by Earth’s rotation. These planetary waves usually travel westward across ocean basins. Their surface signal may be only a few centimeters high, while the boundary between warm surface water and colder deep water can move by…
A tidal bore is a steep wave front that travels upstream when a rising tide is forced into a shallow, narrowing river or estuary. Instead of the water level rising gradually, the flood tide arrives as a visible surge. Some bores resemble a low rolling step, while the largest form breaking waves that can be…
A rogue wave is an unusually large, steep wave that appears among much smaller surrounding waves. Oceanographers commonly use a threshold of more than twice the significant wave height, the average height of the highest one-third of waves in a measured record. The definition makes rogue waves relative to the sea state rather than dependent…
