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CTD stands for Conductivity, Temperature, Depth. These three parameters are among the most fundamental sets of observations in ocean science because they are used to calculate salinity and density of the water, and identify bodies of water from known oceans or areas. Measuring temperature and conductivity allows calculation of salinity, and then from salinity and temperature it is possible to calculate density.

OceanLab has several CTD instruments (click here for equipment overview). They are installed on the profiling frame at the Munkholmen site, and at Ingdalen there is a CTD in the inside of the buoy (ca. 1m depth) and several attached at different depths on the mooring line (at 10m, 25m, 50m, 100m, 250m and 500m depths). The instruments on the mooring line at Ingdalen are battery powered, and communicate their data to the surface through the mooring line using an inductive modem.

Instrument locations and types

surface water temperature


Munkholmen profiling frame.

Ingdalen CTD mount before deployment.

Ingdalen inductive modem connection before deployment.

Ingdalen MicroCAT CTD on the mooring cable before deployment.

External links

 CTD (instrument)
 Water mass
 The oceanic mixed layer
 NOAA Ocean Facts

Page updated: 18.07.22