Development and application of seven-electrode temperature and salinity sensor

The temperature and salinity of seawater are essential physical parameters for marine science. The measurement of conductivity is an important means of salinity measurement. In this article, seven electrodes are used to design a temperature and salinity sensor. The sensor detects voltage signal and current signal in strong marine noise environments using lock-in amplifier technology to improve the measurement accuracy of seawater conductivity. A seven-electrode temperature and salinity sensor and a Seabird SBE37-SI temperature and salinity sensor are used for laboratory comparison, the temperature measurement error and the conductivity measurement error are within ±0.005°C and ±0.0003s/m. The temperature and salinity sensor is installed on an ocean buoy, and offshore testing is carried out. The test data shows that the sensor's measurement data is accurate and reliable, and can be used to measure the temperature, conductivity, and salinity of seawater.