Measurement
The SBE 16plus CTD measures conductivity (S/m), temperature (ºC), depth via pressure (dBar) , and provides calculated values for salinity (psu) and sound velocity (m/s).
Description
The SBE 16plus is a Temperature, Conductivity, and Pressure recorder intended for long-duration, fixed-site deployments. The 16plus also provides calculated values for salinity and sound velocity (salinity is determined from conductivity, and then further adjusted using the temperature and depth measurements).
Seawater is drawn through an inlet using a downstream pump. The water passes by a thermistor, which measures temperature, and then moves through a cell containing electrodes, which measure conductivity. Small tributyl tin (TBT) inserts at the inlet and outlet of the conductivity cell create a toxic environment within the cell, thus reducing bio-fouling of the electrodes. Bio-fouling can cause undesirable changes to instrument calibrations.
The SBE 16plus in Saanich Inlet has four differentially-amplified input channels that can be populated by a number of off the shelf analog and serial instruments such as:
- PSI Gas Tension Device (serial)
- Aanderaa Oxygen Optode 4175 (analog)
- SeaTech Transmissometer (analog)
Technical Specifications
| T | C | P | |
|---|---|---|---|
| Units | deg. C | S/m | dBar |
| Range | -5 – +35 | 0 – 9 | 0 – 350 |
| Accuracy | 0.005 | 0.0005 | 0.35 |
| Resolution | 0.0001 | 0.00005 | 0.007 |
| Stability/month | 0.0002/mo | 0.0003 | 0.014 |
