Project groups

DM-1.4 | WEST AFRICA MODELLING (2008 - 2011)

The project E1.4 is focused on the regional climate and its variability in West Africa. The study will include the West African monsoon with respect to expected changes in vegetation such as in the Sahel region and their feedback mechanisms.

Existing studies of regional climate simulations have shown that errors in the simulated radiation budget in particular in the Sahara is a common problem of many regional climate models (Kothe et al., 2010). The study also showed that these errors were largely due to uncertainties in the surface albedo in the Sahara region. In contrast, the influence of uncertainties in the surface albedo on errors in the radiation budget was much lower for Europe (Kothe & Ahrens, 2010a). Simulations with the regional climate model system COSMO-CLM showed that in addition to the description of the land surface, the determination of sea surface temperature is another important source of uncertainty (Kothe & Ahrens, 2010b). Future developments of the model system will reduce these uncertainties.

A first projection of the future with the regional climate model COSMO-CLM shows a dramatic decrease in rainfall by 2100 over almost the whole of Africa (see figure). This first result is to be tested with improved COSMO-CLM versions and a whole ensemble of projections.

This project is supported additionally by CM-SAF and the German Meteorological Service.


Possible change in annual precipitation for the years 2071 to 2100 compared to the period 1961 to 1990, as simulated by COSMO-CLM.


Kothe, S. & B. Ahrens : Der Monsun – Segen, Fluch und Forschungsobjekt. - Natur und Museum 140 (9/10).

Kothe, S. & B. Ahrens (2010) : On the Radiation Budget in Regional Climate Simulations for West Africa. - Journal of Geophysical Research 115: D23120.

Kothe, S., Dobler, A., Beck, A. & B. Ahrens (2011) : The radiation budget in a regional climate model. - Climate Dynamics 36:1023-1036.

Kothe, S., Luethi, D. & B. Ahrens (2014) : Analysis of the West African Monsoon system in the regional climate model COSMO-CLM. International Journal of Climatology 34: 481-493.