Abstract:
Two simulations of five years (2003-2007) were conducted with the Regional
Climate models RegCM4, one coupled with Land surface models BATS and
the other with CLM4.5 over West Africa, where simulated air temperature
and precipitation were analyzed. The purpose of this study is to assess the
performance of RegCM4 coupled with the new CLM4.5 Land surface scheme
and the standard one named BATS in order to find the best configuration of
RegCM4 over West African. This study could improve our understanding of
the sensitivity of land surface model in West Africa climate simulation, and
provide relevant information to RegCM4 users. The results show fairly realistic
restitution of West Africa’s climatology and indicate correlations of 0.60 to
0.82 between the simulated fields (BATS and CLM4.5) for precipitation. The
substitution of BATS surface scheme by CLM4.5 in the model configuration,
leads mainly to an improvement of precipitation over the Atlantic Ocean,
however, the impact is not sufficiently noticeable over the continent. While
the CLM4.5 experiment restores the seasonal cycles and spatial distribution,
the biases increase for precipitation and temperature. Positive biases already
existing with BATS are amplified over some sub-regions. This study concludes
that temporal localization (seasonal effect), spatial distribution (grid
points) and magnitude of precipitation and temperature (bias) are not simultaneously
improved by CLM4.5. The introduction of the new land surface
scheme CLM4.5, therefore, leads to a performance of the same order as that
of BATS, albeit with a more detailed formulation.
