A shipboard profiling CTD measures water parameters as it is lowered over the side of a ship with a winch to take measurements of a vertical column of water. Sea-Bird shipboard profiling CTDs are built to perform under the unique dynamic conditions found when profiling. Features include pumped and ducted constant flow for matched temperature and conductivity response, measurements made on the same sample of water with a predictable delay and predictable flow effects, and aligning and coordinating measurements done with software or (for some models) automatically.
Shipboard profiling CTDs can be integrated with a water sampler, to collect 1 or more actual samples of water for analysis in the lab after recovery of the package. The water samples can be used to verify the accuracy of data measured by the instruments on the package, and/or to provide additional information that cannot be measured with an instrument in the field.
Application Note 82 provides guidelines on specifying a profiling CTD.