#stokesdrift — Public Fediverse posts

Where Waves Carry Plastics

The classic theory of steady wave motion predicts a phenomenon called Stokes drift, in which particles spread horizontally in the direction of wave travel. That means that something like microplastics will drift in the direction that waves are traveling. But in the real world, ocean waves aren’t quite so neat and unchanging. A new study looks at what happens when waves are decaying in strength–in other words, what happens in our world when the wind dies down.

In those circumstances, the researchers found that particles did not just drift horizontally–they drifted vertically, too. Further, how much a particle drifts vertically depends on its initial depth. Since plastics vary in their buoyancy–and can be found in varying numbers and sizes throughout the upper layer of the ocean–this mechanism could significantly affect how waves mix and transport pollution. (Image credit: N. Jensen; research credit: T. Izawa et al.; via Physics World)

Where Waves Carry Plastics

The classic theory of steady wave motion predicts a phenomenon called Stokes drift, in which particles spread horizontally in the direction of wave travel. That means that something like microplastics will drift in the direction that waves are traveling. But in the real world, ocean waves aren’t quite so neat and unchanging. A new study looks at what happens when waves are decaying in strength–in other words, what happens in our world when the wind dies down.

In those circumstances, the researchers found that particles did not just drift horizontally–they drifted vertically, too. Further, how much a particle drifts vertically depends on its initial depth. Since plastics vary in their buoyancy–and can be found in varying numbers and sizes throughout the upper layer of the ocean–this mechanism could significantly affect how waves mix and transport pollution. (Image credit: N. Jensen; research credit: T. Izawa et al.; via Physics World)