Measurement of rain-induced oceanic surface salinity stratification using L-band satellite radiometers

This paper presents recent results of an investigation into the transient effects of oceanic rainfall on the profile of near-surface salinity. Based upon research conducted with the NASA/CONAE Aquarius/SAC-D mission, it was determined that the primary rain impact was to dilute the sea surface salinity (SSS), which was accurately captured by the Aquarius (AQ) microwave radiometer/scatterometer observations. As a result, CFRSL has developed a rain impact model (RIM) to provide a quality flag for AQ SSS measurements, which alerts the users of the possibility of salinity stratification. RIM uses the ocean community salinity model HYCOM and a NOAA global rainfall product CMORPH to estimate the change in SSS at the time of the satellite observation. While this paper is applicable to all L-band radiometer missions namely, Aquarius, SMOS and SMAP, only results from AQ will be presented herein. An example of near-surface salinity profiles derived from AQ RIM is presented with associated rain events captured by CMORPH.