The CTD is perhaps the most commonly used tool in an oceanographer's armoury, providing detailed profile and time series data on the measured parameters Conductivity, Temperature and Pressure, but more particularly the calculated values of Salinity, Density and Sound Velocity.
Digital sampling techniques ensure high accuracy, and the unique construction gives sensor stability at any depth. Temperature is always measured with a fast response PRT (Platinum Resistance Thermometer), and instruments also use industry standard strain gauge or resonant quartz pressure sensors.