Sea Level Trend and Fronts in the South Atlantic Ocean
Event: 2020 Ocean Surface Topography Science Team Meeting (virtual)
Session: Science I: Climate data records for understanding the causes of global and regional sea level variability and change
Presentation type: Type Forum
The understanding of the physical drivers of sea level trend is crucial on global and regional scales. In particular, little is known about the sea level trend in the South Atlantic Ocean in comparison with other parts of the world. The South Atlantic presents a very complex circulation: the encounter of two large western boundary currents, the presence of several fronts and eddies. These main processes can impact on the sea level trend. Thus, in this work, we compute the South Atlantic mean sea level (SAMSL) trend from 25 years of satellite altimetry data, and we analyze the contributions of steric height (thermosteric and halosteric components) and ocean mass changes for the period 2005–2016 when all the source data used (Argo, GRACE and satellite altimetry) overlap. The results show that the SAMSL trend is 2.65 ± 0.24 mm/yr and is mostly explained by ocean mass trend, which is 2.22 ± 0.21 mm/yr. However, between 50° S–33° S, the steric height component constitutes the main contribution in comparison with the ocean mass component. Within that latitudinal band, three regions with trend values higher than the SAMSL trend are observed when considering 25 years of satellite SLA. In the three regions, a southward displacement of the Subtropical, Subantarctic, and Polar Fronts is observed. The impact of the southward shift of the fronts in the SLA trend is discussed.