Coastal upwelling and tropical warm water intrusions are key drivers of interannual fog variability along the southwestern African coast

Mass, Alexandre; Cermak, Jan; Andersen, Hendrik

doi:10.5194/acp-26-12565-2026

Articles | Volume 26, issue 17

https://doi.org/10.5194/acp-26-12565-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Aerosol, fog, climate, and biogeochemistry in southern Africa...

https://doi.org/10.5194/acp-26-12565-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 17

Research article

|

04 Sep 2026

Research article |

| 04 Sep 2026

Coastal upwelling and tropical warm water intrusions are key drivers of interannual fog variability along the southwestern African coast

Alexandre Mass, Jan Cermak, and Hendrik Andersen

Data sets

Satellite-based fog and low stratus monthly cover in the Angolan Namib and Central Namib Alexandre Mass et al. https://doi.org/10.35097/pebssmnzn7n8czg5

ERA5 monthly averaged data on single levels from 1940 to present H. Hersbach et al. https://doi.org/10.24381/cds.f17050d7

ERA5 monthly averaged data on pressure levels from 1940 to present H. Hersbach et al. https://doi.org/10.24381/cds.6860a573

Model code and software

Code for: "Coastal upwelling and tropical warm water intrusions are key drivers of interannual fog variability along the southwestern African coast" Alexandre Mass et al. https://doi.org/10.5281/zenodo.21630065

Short summary

Fog is a vital water source in the Namib Desert, but its year-to-year variability is poorly understood. Using satellite observations and reanalysis data, we show that fog and low-cloud variability is closely tied to sea surface temperatures in the Benguela upwelling system. Warm events driven by tropical water intrusions are followed by reduced fog in the northern Namib, indicating that ocean state carries predictive information for fog in this hyper-arid ecosystem.