West African Monsoon in State-of-the-Science Regional Climate Models

摘要: The western Sahel (e.g. rectangle in Figure 1) climate is dominated by the West African Monsoon (WAM), a large-scale circulation characterized reversal direction of winds lower levels atmosphere from Atlantic Ocean transporting moisture into land. Although it occurs only during small portion annual cycle between May and Sep‐ tember, WAM climatological feature major social importance to local populations over Africa whose economy relies primarily on agriculture. In response several dec‐ ades below normal rainfall experienced since late 1960s, numerous studies have iden‐ tified various factors that control monsoon variability. Among them are variability ocean Sea Surface Temperatures (SSTs) Fontaine et al. 1998), continental land surface conditions Wang Eltahir 2000) atmospheric Nicholson Grist 2001; Jenkins 2005).