In the past decade, with the successful launch of the soil moisture and ocean salinity (SMOS) satellite by the European Space Agency (ESA) [3], the Aquarius / SAC-D satellite [4], and the soil moisture active passive (SMAP) satellite [5, 6] by the National Aeronautics and Space Administration (NASA), global sea surface salinity (SSS) observations from space have become possible and a significant improvement has been made to understand the ocean dynamics and climate change.