State of the Ocean Observing System

Data Used

Data Used

Data used for identifying empirical relationships between salinity and temperature for the South Atlantic between 25S and 45S

Empirical models capturing the co-variability of salinity with temperature in the South Atlantic are based on CTD data from the World Ocean Database and from the ARGO profiling floats. Both data sets come with flags indicating quality and only the most reliable data have been used for determining the empirical relationships. A few of these data, which appeared as outliers when plotted, were discarded.

CTD Station Map

Near the ocean's surface temperature can offer relatively little information about salinity, making accurate estimates difficult. Improved accuracy might be obtained by exploiting a possible dependence of near-surface salinity on the time of year, but unfortunately the available data are not sufficient to extract seasonality.

Each profile was linearly interpolated to pressure levels at 25 dbar intervals. The nature of the temperature-salinity relationships can be seen by examining TS plots at each level for 20-degree-longitude by 5-degree-latitude subregions. Best-fit linear and quadratic relationships have been overlaid.

Using colors to group the data by longitude and latitude reveals systematic spatial variations within the 20x5 degree sub-regions.