Meetings: Documents

Sea Surface Salinity Distribution in the Southern Ocean as Observed from Space
[12-Dec-18] Garcia-Eidell, C., Comiso, J.C., Dinnat, E., and Brucker, L.
Presented at the 2018 AGU Fall Meeting
Sea surface salinity (SSS) retrieved from the Aquarius and Soil Moisture and Ocean Salinity (SMOS) satellites were compared with quality-controlled measurements from ship, floats, moored buoys and others to evaluate the accuracy of satellite-derived SSS data in the Southern Ocean. Latest versions of the Aquarius official release, Combined Active-Passive product, weekly polar-gridded product, as well as the SMOS BEC Objectively-Analyzed L3 product were used and results show root-mean-square error values with respect to in-situ measurement ranging from 0.25 to 0.58 psu. Observed differences in the Aquarius products is a result of varying salinity retrieval algorithm, smoothing, and masking of sea ice. The SMOS product showed the highest SSS deviation when compared with in-situ measurements perhaps due to the bias-adjustment done on the dataset as well as uncertainty associated with decrease in sensitivity to SSS in colder waters. The different SSS products consistently showed freshening close to the sea ice edge at the end of the summer melt seasons followed by a slight increase in SSS late autumn to winter due to brine rejection during sea ice formation. Lowest SSS values are observed during spring time near the ice edges when the melt process begins but are generally higher in warmer waters away from the pack due to evaporation. Furthermore, an initial assessment of SSS retrieved by the Soil Moisture Active Passive (SMAP) instrument using the Remote Sensing Systems (RSS) L2C version 2.0 shows that the SMAP dataset deviates from the observed SSS seasonality captured every year by Aquarius. This may indicate that currently available SMAP data in the polar regions are not mature enough for use in scientific studies.