CT

The RBR CT sensor measures Conductivity (a proxy for salinity or salt levels of the water) and Temperature in seawater. It can be mounted at one location or onto moorings to provide temperature and salinity data at a fixed location through time. It can also be deployed like a castaway through different depths of the water column at a single time.

Data collected by this sensor provide details of the layers of fresh and salt water in the marine environment and their dynamics that are critical to understanding sea ice ecosystems. Results include graphs showing both salinity and temperature through time, or by depth (a snapshot of the water column).

The units for salinity collected by the RBR CT are mS/cm, or millisiemens per centimeter, which can be converted to the more common unit, PSU (practical salinity unit, roughly equivalent to  parts per thousand of salt). Normal winter sea water in Hudson Bay is around 30PSU. Over large parts of east-Hudson Bay, layers of freshwater from 23-26PSU can be seen from 15 m to more than 25m deep, layer on top of deeper salt water (which is closer to the typical 30PSU salinity.

The units for temperature are °C. Temperature measurements are important as freshwater and seawater layers also have different temperatures than can affect mixing as well as salinity. The freezing point of freshwater is also warmer than that of seawater, so it is important to keep track of both salinity and temperature when considering how oceanography affects sea ice formation.

Click here to read more technical information about this sensor.

This video shows how Inuit hunters deploy our sensors from RBR to capture a CT depth profile: