Meetings: Documents

Sea Surface Salinity Variability in the South Atlantic from Satellite and Model Data
[10-Dec-18] De Morais Chiossi, P. and Sato, O.T.
Presented at the 2018 AGU Fall Meeting
Observations of the temporal and spatial variability of the South Atlantic Ocean are of great scientific interest due to its influence on the regional weather and global climate through the Meridional Overturning Circulation (MOC). These changes directly affect society through variations in the pattern of rain, humidity, heat flux, and wind patterns. Despite this, there are still many gaps in understanding the full implications and impacts of ocean variability. The salinity is one of the least understood, mainly due to the absence of broad and long-term sustainable in situ data in the South Atlantic. Although, this has been changing lately with the surge of satellite missions designed to measure surface salinity, along with the increase of active Argo profilers.
Salinity influences the formation of water masses and the elevation of the sea surface, affecting circulation patterns, as well as serving as indicators of the marine hydrological cycle. In this study, sea surface salinity data obtained from two satellites (SMOS, Aquarius) and model (ECCO) were processed and evaluated in order to quantify the spatial and temporal variability of the surface salinity of the South Atlantic Ocean. Persistent surface salinity gradients were identified in the form of oceanic fronts, present along the limits of the subtropical gyre, in regions of intense river discharge and precipitation. In addition to the analysis of the satellite data, an estimation of the dominant terms of the surface salinity budget was calculated using the solutions of the ECCO model. Results indicated that the advective terms are dominant in the regions of the salinity fronts, and that the effect of the surface forcing on the surface salinity is mostly counterbalanced by diffusive mixing, resulting in a tendency of the salinity variability to follow the variation of the advective terms.