TITLE:
Sensitivity Study of the RegCM4’s Surface Schemes in the Simulations of West Africa Climate
AUTHORS:
Adjon Anderson Kouassi, Brahima Kone, Siélé Silue, Alima Dajuma, Toure E. N’datchoh, Marcellin Adon, Arona Diedhiou, Véronique Yoboue
KEYWORDS:
Regional Climate Model, Land Surface Scheme, West Africa Climate, RegCM, Precipitation, West African Monsoon, Simulated Data
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.12 No.1,
January
4,
2022
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.