Some additional information on measuring sea surface salinity.

• The Salinity Sea Ice Working Group A working group focusing on the remote sensing of salinity.
• Remote Sensing of Open Ocean Sea Surface Salinity Looks like the beginning of a proposal to compare SLFMR and ESTAR.
• Airborne sensors The second table is especially interesting for SSS.
• SMOS A proposal for a test satellite for measuring soil moisture and SSS (apparently same microwave bands).
• SOIL MOISTURE EXPERIMENTS IN 2001 Observation plans, including updates on SMOS.
• Report of the Workshop on NASA Earth Science Enterprise Post-2002 Missions Briefly states some of the problems with remote sensing of sea surface salinity, including:
  • ... soil moisture is the "easy" measurement because it produces a very large signal in brightness temperature, whereas ocean salinity is the "difficult" measurement because it first requires separating thermometric temperature from emissivity, with the latter representing the signature for salt concentration only after other sources of emissivity variation are removed (temperature, roughness, phytoplankton concentration, effluent concentration).
  • Measuring continental soil moisture ... offers the opportunity of synergism with an ocean salinity measurement. The same instrument, an L-band microwave radiometer, can be used for ocean salinity measurements although it is not optimal (an S-band instrument is preferred if salinity is an objective.)