Articles | Volume 10, issue 3
05 Jul 2018
 | 05 Jul 2018

Sea surface salinity and temperature in the southern Atlantic Ocean from South African icebreakers, 2010–2017

Giuseppe Aulicino, Yuri Cotroneo, Isabelle Ansorge, Marcel van den Berg, Cinzia Cesarano, Maria Belmonte Rivas, and Estrella Olmedo Casal

Abstract. We present here sea surface salinity (SSS) and temperature (SST) data collected on board the S.A. Agulhas-I and S.A. Agulhas-II research vessels, in the framework of the South African National Antarctic Programme (SANAP). Onboard Sea-Bird thermosalinographs were regularly calibrated and continuously monitored in-between cruises, and no appreciable sensor drift emerged. Water samples were taken on a daily basis and later analyzed with a Portasal salinometer; some CTD measurements collected along the cruises were used to validate the data. No systematic differences appeared after a rigorous quality control on continuous data. Results show that salinity measurement error was a few hundredths of a unit on the practical salinity scale. Quality control included several steps, among which an automatic detection of unreliable values through selected threshold criteria and an attribution of quality flags based on multiple criteria, i.e., analysis of information included in the cruise reports, detection of insufficient flow and/or presence of air bubbles and ice crystals in the seawater pipe, visual inspection of individual campaigns, and ex post check of sea ice maps for confirming ice field locations. This data processing led us to discard about 36 % of acquired observations, while reliable data showed an excellent agreement with several independent SSS products. Nevertheless, a sea ice flag has been included for identifying valid data which could have been affected by scattered sea ice contamination. In our opinion, this dataset, available through an unrestricted repository at, contributes to improving the knowledge of surface water features in one of the most important regions for global climate. The dataset will be highly valuable for studies focusing on climate variability in the Atlantic sector of the Southern Ocean, especially across the Antarctic Circumpolar Current and its fronts. Furthermore, we expect that the collected SSS data will represent a valuable tool for the calibration and validation of recent satellite observations provided by SMOS and Aquarius missions.

Short summary
We present sea surface salinity and temperature data collected across the Atlantic sector of the Southern Ocean by thermosalinographs on board Agulhas-I and Agulhas-II research vessels. After a rigorous quality control, data have been validated through comparison with water samples and independent products. Hence this dataset represents a valuable tool for validating salinity observations provided by SMOS and Aquarius missions and improving the study of climate variability over this region.