Satellites can measure sea surface salinity (SSS) alone, but they take these measurements across large areas. In-situ instruments collect data throughout the water column, but have more limited coverage, taking measurements on a much smaller scale.

In-situ instruments are more traditional, while salinity measurements obtained from space still need a certain level of validation and calibration before they can be fully "stand-alone" to the same degree of reliability. In order to understand all of the processes affecting ocean salinity (3-D and 4-D) you need both types of measurements to get a more detailed picture.

Featured Video: Salinity From Space is Awesome

Resources

• Measuring Salinity from Space
  [NASA Earth Observatory]
  Salinity is a challenging but critically important measurement for oceanographers
• Ocean Salinity Viewed from Sea and Space
  [NASA Earth Observatory]
  NASA Program Scientist Eric Lindstrom describes why scientists want to spend six weeks at sea measuring ocean saltiness
• Salt of the Earth: Aquarius Will Reveal Salinity Ties to Climate
  [NASA Salinity]
  People have been measuring salinity for centuries, but ships and buoys alone cannot match the perspective from space
• How Do We Cover the Globe with Aquarius Data?
  [COSEE-Ocean Systems]
  The Aquarius/SAC-D satellite has begun collecting global salinity data - but it is not without challenges