The SBE19 CTD is a measuring instrument for physical oceanography, operated by cable between the surface and the sea floor. It is designed to measure in real time water temperature, conductivity and depth down to 7000 m, at a frequency of 4 Hz.

The CTD is generally mounted on a “rosette” or frame which also carries the water-sampling bottles (triggered by the operator at the desired depth) and perhaps other measuring instruments, such as current meters.

Measuring ranges:

• Temperature: -5 to +35 °C
• Conductivity: 0–9 S/m
• Depth: 0–7000 m 

 

	Temperature (°C)	Conductivity (S/m)	Depth
Measuring range	-5 to +35	0–9	0 to the maximum of the selected range (20, 100, 350, 1000, 2000, 3500, 7000 m)
Accuracy	0.005	0.0005	0.1% of the selected range
Resolution	0.0001	0.00001–0.00007 depending on water salinity	0.002% of the selected range

 

The CTD is controlled using a SBE36 deck unit installed on the ship.