Ocean turbulent heat flux responses to sea surface salinity variability during Benguela Niños and Niñas

Aroucha, L. C. ORCID: https://orcid.org/0000-0003-1279-1092, Hummels, R. ORCID: https://orcid.org/0000-0002-3746-6213 and Lübbecke, J. F. (2025) Ocean turbulent heat flux responses to sea surface salinity variability during Benguela Niños and Niñas. Geophysical Research Letters, 52 (21). e2025GL117793. ISSN 1944-8007 doi: 10.1029/2025gl117793

Abstract/Summary

Benguela Niño and Niña events are episodes of extreme warming and cooling off Angola with impacts on fisheries, ecosystems, and rainfall in southwest Africa. They are typically forced remotely or locally by variations in equatorial or alongshore winds, respectively. We use an extensive in‐situ data set to show that sea surface salinity (SSS) changes can also act as a local forcing that amplifies these extreme warm and cold events by altering the water column stratification and consequently the impact of subsurface mixing. The mixed layer turbulent heat loss during an extreme warm episode with unusually low SSS in 1995 is nearly 3× lower than during a cold event with high SSS in 1997. We also demonstrate that interannual turbulent heat flux variability in early boreal spring off Angola is strongly impacted by salt advection fluctuations, and that this turbulent mixing is significant for altering mixed layer temperatures and restoring its salinities.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/127364
Identification Number/DOI	10.1029/2025gl117793
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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