What controls the formation of nocturnal low-level stratus clouds over southern West Africa during the monsoon season?

Babić, Karmen; Kalthoff, Norbert; Adler, Bianca; Quinting, Julian F.; Lohou, Fabienne; Dione, Cheikh; Lothon, Marie

doi:https://doi.org/10.5194/acp-19-13489-2019

Articles | Volume 19, issue 21

https://doi.org/10.5194/acp-19-13489-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Results of the project "Dynamics–aerosol–chemistry–cloud...

https://doi.org/10.5194/acp-19-13489-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 21

Research article

|

05 Nov 2019

Research article |

| 05 Nov 2019

What controls the formation of nocturnal low-level stratus clouds over southern West Africa during the monsoon season?

Karmen Babić, Norbert Kalthoff, Bianca Adler, Julian F. Quinting, Fabienne Lohou, Cheikh Dione, and Marie Lothon

Data sets

DACCIWA field campaign, Savè super-site, UPS instrumentation S. Derrien, Y. Bezombes, B. Bret, O. Gabella, C. Jarnot, P. Medina, E. Piques, C. Delon, C. Dione, B. Campistron, P. Durand, C. Jambert, F. Lohou, M. Lothon, F. Pacifico, and Y. Meyerfeld https://doi.org/10.6096/dacciwa.1618

DACCIWA field campaign, Savè super-site, Cloud and precipitation J. Handwerker, S. Scheer, and T. Gamer https://doi.org/10.6096/dacciwa.1686

Radiosonde - All sites M. Maranan and A. Fink https://doi.org/10.6096/baobab-dacciwa.1656

DACCIWA field campaign, Savè super-site, Thermodynamic data sets A. Wieser, B. Adler, and B. Deny https://doi.org/10.6096/dacciwa.1659

DACCIWA field campaign, Savè super-site, Surface measurements M. Kohler, N. Kalthoff, J. Seringer, and S. Kraut https://doi.org/10.6096/dacciwa.1690

Short summary

This study investigates differences in atmospheric conditions between nights with and without low-level stratus clouds (LLCs) over southern West Africa. We use high-quality observations collected during 2016 summer monsoon season and the ERA5 reanalysis data set. Our results show that the formation of LLCs depends on the interplay between the onset time and strength of the nocturnal low-level jet, horizontal cold-air advection, and the overall moisture level in the whole region.