CTD casts

A CTD cast involves lowering an instrument package—called a CTD (Conductivity, Temperature, Depth)—into the ocean to collect detailed data about water conditions. As it descends and ascends, the CTD measures how salty (conductivity), how warm (temperature), and how deep (pressure) the water is at different layers. These measurements help scientists understand water properties, currents, and mixing in the ocean, which are essential for climate studies, marine research, and environmental monitoring. The process provides a snapshot of the ocean’s vertical structure at a specific location and time.