Ocean Turbulent Heat Flux Responses to Sea Surface Salinity Variability During Benguela Niños and Niñas

Abstract 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.