uCTD - Oceanscience

The underway Conductivity Temperature Depth (uCTD) is a profiler device, with a torpedo-like shape, to measure salinity, through conductivity, temperature, through a thermistor and depth, through pressure. It differs from the conventional CTD because it can be deployed over a moving vessel up to 20kt (OCEANSCIENCE, 2016). It has the convenience of an expendable device like the XBT, but it’s recoverable and reusable (OCEANSCIENCE, 2016; RUDNICK & KLINKE, 2007; TELEDYNE OCEANSCIENCE, 2016). The uCTD affords to make profiles at up 1000m and the data is transmitted through Bluetooth (TELEDYNE OCEANSCIENCE, 2016). As it goes under, the uCTD profiles the water column obtaining and transmitting temperature, salinity and depth data. As occurs with the XBT, the cable drag is negligible and the velocity of the cable through the water is zero (RUDNICK & KLINKE, 2007).

The device is tethered to the ship by up to 2000m line and has a re-spooling mechanism allowing the probe to be recovered and re-launched without stopping or slowing down the ship (OCEANSCIENCE, 2016; TELEDYNE OCEANSCIENCE, 2016).       The advantages of the uCTD include lower cost per profile with increasing use, no hazardous materials are left behind, once it’s recoverable and the sensors can be calibrated postdeployment, assuring the quality of observations (RUDNICK & KLINKE, 2007).


OCEANSCIENCE UnderwayCTD: CTD Profiling from a moving vessel Acquired from http://oceanscience.com/Products/UnderwayCTD/Underway-CTD.aspx on February, 20th 2016.

RUDNICK, D.L.; KLINKE, J. The Underway Conductivity–Temperature–Depth Instrument Journal of Atmospheric and Oceanic Technology v. 24, p. 1910-1923. 2007. DOI: 10.1175/JTECH2100.1.


ULLMAN, D.S.; HEBERT, D. Processing of Underway CTD Data Journal of Atmospheric and Oceanic Technology v. 31, p.984-998. 2014. DOI: 10.1175/JTECH-D-13-00200.1.