Drifter (oceanography)

[8][9][10] It is designed to track the wind-driven surface currents in the upper meter of oceanic mixed layer.

The CODE drifter is slightly negatively buoyant, and small floats connected to the end of the arms to which the sails are attached provide the extra buoyancy to ensure flotation.

The surface float contains a battery, instruments that collect data like temperature, barometric pressure, wind speed and direction, and ocean salinity, and a transmitter that relays the position of the drifting buoy and data collected by the instruments on the surface float to satellites.

Because the drifter sits at this depth, its movement is influenced by processes occurring in the upper 15 meters of the ocean.

They make more accurate and frequent observations of surface current velocity than is possible from remote sensing measurements.

Modern use of solar powered GPS units allows for long term observation of surface currents.

Tracking drifters and calculating their speed and direction over several months gives a better understanding of global ocean circulation and how currents may vary between seasons.

Lagrangian drifters may be chosen over more Eulerian-type seagliders for biological research when the advective effects, or influence of mixing water, is to be minimized.

Dissolved compounds and nutrients, such as O2, NO3, and particulate organic carbon (POC), change within a bloom on various temporal and spatial scales.