Implications of satellite sea-surface salinity observations for operational microwave radiometry

Global satellite sea-surface salinity (SSS) observations are now a reality; consequently, the influences of SSS on operational microwave radiometry need to be considered. At the same time, the in-progress transition of operational agencies from salinity-independent radiative transfer modeling (RTM) to a salinity-dependent RTM exposes non-negligible sources of error and uncertainty in past operational passive microwave retrievals; consequently, the impact of improved modeling of SSS influences on ocean surface permittivity, as a principal component of ocean surface emissivity, is examined. Both reductions and continuing elements of uncertainty due to SSS are explored. Ocean surface emissivity´s interwoven dependencies on salinity, temperature, and frequency are highly nonlinear; consequently, impacts due to salinity will depend on the instrument, application, and situation.