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.