Roger Revelle
R/V Roger Revelle

Conductivity, Temperature, and Depth (CTD) sensors are in situ instrument packages that are used to measure water depth, pressure, salinity, temperature, and density in the ocean. CTD sensors can be deployed on various water-based platforms such as autonomous underwater vehicles (AUVs), buoys, gliders, or research vessels. When deployed on a vessel, CTD sensors are typically attached to a rosette and then lowered to the seafloor to measure water properties. CTD sensors have a typical sampling rate of 30 Hz and can collect precise measurements for a specific water depth depending on the researcher's needs.

Generic-Atmospheric State (Gen-AtmsState) refers to non-specific instruments on a platform used for measurements of atmospheric state parameters. These are typically in situ sensors that measure temperature, pressure, humidity, and wind speed/direction. Types of atmospheric state instruments include thermometers, hygrometers, barometers, and anemometers.

The Acoustic Doppler Current Profiler (ADCP) is an in situ acoustic sensor used to measure ocean currents. ADCP uses the Doppler effect to detect sound waves to provide measurements of the speed and direction of currents throughout the water column. ADCP can easily be mounted on different water platforms such as ships, buoys, and autonomous underwater vehicles (AUVs). It also can be deployed on the seafloor to provide profile measurements of ocean currents.

Gravimeters are passive sensors that measure the strength of Earth’s gravitational field. These measurements are used for determining density variations in rocks, oil and mineral prospecting, the monitoring of glacier changes, and the study of volcanic activity. Gravimeters can be used for airborne and ground-based operations.