6. Stromen vanuit de ruimte (in het Engels)

Measuring ocean currents

schematic showing different methods for measuring ocean currents Jason satellites Jason float Jason float Research ship Bottom pressure recorder Current meter mooring Coloured dye Coloured dye Drift cards Moored buoy ADCP Cable Trainer and duck

Click on the image to learn more about the different methods used to measure ocean currents

Satellite and in situ measurements

Satellite measurements give us a broad overview, and tell us how currents vary in time and space. However, we also need data from other Brons: instruments anchored to the sea floor (moorings), drifting with the currents (floats), or mounted on buoys, platforms and ships.

Together these different measurements can help us understand what controls the flow of water in the ocean and along our coasts.

The measurements may be combined with numerical models used to forecast the transport of sediment or pollutants or to investigate how the ocean system might react to external changes such as global climate change.

Staying put or going with the flow?

Traditionally there are two direct ways to measure currents: you can add something to the water and follow it as it moves (Lagrangian measurements), or you can place an instrument in a fixed position and measure how fast the current flows past it (Eulerian measurements). Currents may also be measured indirectly: by measuring other parameters and using these to calculate the current speed and direction. Oceanographers use all these methods to learn about flow in the ocean.

The illustration above shows different ways to obtain data on current speed and direction. Follow the links in the image to find out more about each method, and decide if it is Lagrangian, Eulerian, indirect (derived from other parameters), or perhaps a mixture of these.