One of NASA’s newest Big Sci machines has generated a high quality map of ocean salinity. It is still preliminary and a few months of calibration is needed, but soon enough Aquarius will start monitoring ocean salinity on an ongoing basis.
Ocean salinity is important because it is linked to the overall climate system. For instance, where evaporation is high, owing to atmospheric conditions, salinity goes up. Salinity is related to ocean currents … saline water sinks, drawing nearby water to itself. This can drive major ocean currents.
You can see the map and get various downloads here.