Long-term stability of salinity measurements by autonomous observing systems with RBR inductive conductivity sensors
In this study, we assess the long-term salinity stability from multiple RBR CTDs. The data were collected by CTDs on Argo floats and long-term moorings, and by CTDs returned to RBR for factory calibration. The quantitative assessment of salinity drift is performed by comparing data with other sensors and climatological data products. All methods of assessment are subject to errors associated with delineating sensor problems from the changes in ocean water measured by different instruments. Nevertheless, the results of this study demonstrate high level of stability of the salinity measurements collected by RBR inductive conductivity sensors. For example, salinity measured by the Argo floats with RBR CTDs working in different regions of the Pacific Ocean have drifted at a rate of <0.005 psu/year over two- to four-years of deployment.