Numerous physical parameters are measured in the oceans, in order to study the characteristics of the water (temperature, salinity, etc.) but also its movements (currents) and the presence of chemicals or microfauna and microalgae.

Analyse d'eau de mer
Analyse d'eau de mer

What is measured?

The most common parameters measures are seawater temperature and salinity. These two variables provide information on the density of the water masses, a key parameter in ocean circulation. Salinity measurements also supply information on the freezing point and biodiversity present.

Other physico-chemical parameters can also be measured such as:

  • dissolved oxygen
  • chlorophyll
  • nitrates
  • turbidity (presence of matter in suspension in the water)
  • current speed and direction
  • presence of rare gases
  • pressure, etc.

Find all the parameters available in certain information systems:

How are these parameters measured?

These physical parameters are measured using different equipment and different methods.

Vertical profiles

A vertical profile concerns the measurements at a specific geographical point, taken throughout the water column.

Hydrology data for instance is obtained with bathysounders or bottles.

Bathysounders take water samples at different depths in the water column and analyse different parameters (mainly temperature, salinity, pressure and conductivity).

Example: hydrology data obtained with bathysounders or bottles.

Mise à l’eau d’une bathysonde
Mise à l’eau d’une bathysonde


Trajectories concern the measurements recorded along the route taken by the ship or currents: they are measured using drifter buoys or floats.

Example: data from a hull-mounted ADCP (Acoustic Doppler Current Profiler).

Time series

Time series are measurements recorded at a fixed point over a specific time period. They are taken by moorings, anchored buoys, tide gauges and semaphore towers. They are used for instance to collect current meter data, i.e. current measurements: direction, speed and possibly pressure and temperature, etc.

Example: current meter data (current measurements: direction, speed and possibly pressure and temperature, etc.)