Measurements for Oceanography

This chapter describes the instruments and platforms used to measure the physical properties of seawater to study the density field and dynamics of the ocean. Firstly, instruments used to measure temperature and salinity from ships are introduced: CTD system, XBT/XCTD, and underway probes. Lagrangian (drifters and floats) and Eulerian (single point current meters, ADCP) instruments used to obtain surface and deep ocean current measurements are then described. These instruments are considered the classical tools used to collect observations in the oceans. In the last section, autonomous and/or unmanned vehicles that have had a significant development in the last decade are described. The use of unmanned vehicle has now become more and more widespread. Floats represent the precursor to a new generation of marine drones which include gliders and wave gliders.