Helicopter CTD – transportable CTD with autonomous winch
High resolution profiles of typical physical parameter of seawater such as temperature, conductivity/salinity, and pressure can only be measured in the water column, including the bottom boundary layer, by means of a single wire cable.
In ice covered regions this is only possible aboard a ship or from an ice floe.
The latter requires autonomous instrumentation able to handle long cable lengths to reach the bottom. In shelf areas of less than 500 m deep water but also for greater depth along the continental shelf break full-depth data acquisition needs a cable length of more than 1500 m.
Such self-sustaining system has the advantage of being independent from ship operations and gives a wider range for data collection not consuming expensive and rare ship time. This is even more important, when the ship is immoveable due to heavy ice conditions.