Exploring steric sea level variability in the Eastern Tropical Atlantic Ocean: a three-decade study (1993–2022)

Ghomsi, FEK, Mohamed, B, Raj, RP, Bonaduce, A, Abiodun, BJ, Nagy, H, Quartly, GD and Johannessen, OM 2024 Exploring steric sea level variability in the Eastern Tropical Atlantic Ocean: a three-decade study (1993–2022). Scientific Reports, 14 (1). https://doi.org/10.1038/s41598-024-70862-0

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Abstract/Summary

Sea level rise (SLR) poses a signifcant threat to coastal regions worldwide, particularly afecting over 60 million people living below 10 m above sea level along the African coast. This study analyzes the spatio-temporal trends of sea level anomaly (SLA) and its components (thermosteric, halosteric and ocean mass) in the Eastern Tropical Atlantic Ocean (ETAO) from 1993 to 2022. The SLA trend for the ETAO, derived from satellite altimetry, is 3.52 ± 0.47 mm/year, similar to the global average of 3.56 ± 0.67 mm/year. Of the three upwelling regions, the Gulf of Guinea (GoG) shows the highest regional trend of 3.42 ± 0.12 mm/year. Using the ARMORD3D dataset, a positive thermosteric sea level trend of 0.88 ± 0.04 mm/year is observed, particularly in the equatorial and southern Atlantic regions. The steric component drives the interannual SLA variability, while the ocean mass component dominates the long-term trends, as confrmed by the GRACE and GRACE-FO missions for 2002–2022. For those two decades, the total SLR from altimetry amounts to 3.80 ± 0.8 mm/year, whilst the steric component is reduced to only 0.19± 0.05 mm/year, leaving a residual increase in the ETAO of 3.69 ± 0.5 mm/year. The independent mass change from GRACE amounts to 2.78 ± 0.6 mm/year for this region, which just closes the sea level budget within present uncertainty levels. Spatial analysis of the steric components indicates a warming along the equatorial African coast including the GoG and a freshening near Angola. Strong correlations with regional climate factors, particularly the Tropical South Atlantic Index, highlight the infuence of persistent climate modes. These fndings underscore the urgent need for mitigation and adaptation strategies to SLR in the ETAO, especially for densely populated coastal communities

Item Type:	Publication - Article
Additional Keywords:	Eastern Tropical Atlantic Ocean, Altimetry, Reanalysis, Sea level rise, Climate indices
Divisions:	Plymouth Marine Laboratory > Science Areas > Earth Observation Science and Applications
Depositing User:	S Hawkins
Date made live:	14 Oct 2024 14:36
Last Modified:	14 Oct 2024 14:36
URI:	https://plymsea.ac.uk/id/eprint/10305

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