Added value in dynamically downscaling seasonal mean temperature simulations over West Africa

The present study proposes an assessment of the Added Value (AV) in seasonal mean temperature regional simulations by the Rossby Centre Regional Climate Atmospheric Model version 4 (RCA4) over West Africa, with emphasize on the contribution the driving Global Climate Models (GCMs) and the downscaling experiment. The results show that the AV by RCA4 varies depending on the driven GCMs, the season, and subareas of the study domain, while consistent performances are observed for specific GCMs. These results suggest that the key influencing factor of the quality of GCM driven RCA4 simulations is the consistencies between the GCMs and the RCA4 model physics. Our findings also point out that the RCA4's contribution to the AV results is influential, as it highly compensates the driven GCMs biases, although positive AV results are typically GCM dependent.

Automated summary

The study suggests that the AV by RCA4 varies depending on the driven GCMs, the season, and subareas of the study domain, while consistent performances are observed for specific GCMs. The key influencing factor is the consistencies between the GCMs and the RCA4 model physics. RCA4's contribution to the AV results is influential, as it highly compensates the driven GCMs biases, although positive AV results are typically GCM dependent.