How does salinity and density affects sea surface temperature? I was reading Planning Commission report of Five Year plan (2012-2017) of India, and in the context of Inter-linking of rivers it is mentioned that :


  The presence of a low salinity layer of water with low density is a reason for maintenance of high sea-surface temperatures (greater than
  28 degrees C) in the Bay of Bengal, creating low-pressure areas and
  intensification of monsoon activity.


So how does salinity and density affects SST?
A low salinity layer that is associated with low density (assuming the same temperature) will remain on top of the water column. As such the water will be able to get warmer and the difference in salinity and temperature will make it even more difficult to mix it down with the rest of the water column. So the combination of high temperature and low salinity results in even lower densities. You can play with the relationship using http://www.mt-oceanography.info/Utilities/density.html