Argo floats are free-moving floats that report vertical profiles of salinity

temperature and pressure at regular time intervals. These floats give good measurements of temperature and pressure

but salinity measurements may show significant sensor drifting with time. It is found that sensor drifting with time is not purely linear as presupposed by Wong (2003). A new method is developed to calibrate conductivity data measured by Argo floats. In this method

Wong’s objective analysis method was adopted to estimate the background climatological salinity field on potential temperature surfaces from nearby historical data in WOD01. Furthermore

temperature and time factors are taken into account

and stepwise regression was used for a time-varying or temperature-varying slope in potential conductivity space to correct the drifting in these profiling float salinity data. The result shows salinity errors using this method are smaller than that of Wong’s method

the quantitative and qualitative analysis of the conductivity sensor can be carried out with our method.