Validating salinity from SMAP with Saildrones and research vessel data during ATOMIC-EUREC4A

During the EUREC4A-OA/ATOMIC campaign, saildrones and research vessels were deployed in the North Equatorial Current and the Boulevard des Tourbillons in order to investigate mesoscale eddies and submesoscale fronts and their role in ocean-atmosphere interactions. In this study, Saildrone salinity observations recorded during the campaign were compared with four different SSS products SMAP JPL, SMAP RSS 40 km, SMAP RSS 70 km and HYCOM, with the aim of highlighting the strengths and weaknesses of each product. This study represents the first validation of SMAP satellite derived SSS using the Saildrone in the river influenced Western Tropical Atlantic, this information can allow researchers to make informed decisions regarding the most ideal product for their application as well as highlight issues to algorithm developers. Overall, it was found that SMAP RSS70 outperformed its counterparts in areas with no submesoscale irregularities. However, RSS40 was better at identifying small irregularities in salinity such as a fresh tongue, with HYCOM being on the opposite spectrum, failing to identify the tongue. Akin to the RSS70, JPL and HYCOM performed well in areas where the large scale salinity conditions were constant. Finally, the results of this study can aid in the improvement of mesoscale and submesoscale SSS products, which can lead to the refinement of NWP and climate models and therefore to improved weather, ocean and climate forecasts, especially for tropical regions.