About African Monsoon

The main two components of the African Monsoons are the West African Monsoon, which prevails during the Northern Hemisphere Summer (June through September), and the East African Monsoon with rains during spring (MAM) and autumn (OND). The precipitation and atmospheric circulation patterns are shown in the adjacent figure. Combined influence of the Indo-Pacific and the Atlantic Oceans drive the inter-annual and the decadal monsoon variability over these regions.

The key features of the West African Monsoon are the low level southwesterly flow from the Atlantic Ocean and the Inter-Tropical Convergence Zone (ITCZ) north of the equator. Monsoon rainfall over West Africa occurs during the June through September period (Figure left panel). The West African Sahel is well known for the severe droughts that ravaged this region during the 1970s and 1980s. The vagaries of the rainfall in Sub-Saharan Africa have a profound and often dire consequence on African society and economy.

The East African Monsoon is associated with the ITCZ moving south of the equator. The so-called long rains prevail during spring (MAM) and the short rains during autumn (OND). Thus the transition (equinox) seasons bring most rainfall to East Africa (Figure right panel). Abrupt decline in the long rains have resulted in droughts over this region.

To reduce the vulnerability of the African community to the variations in the strengths of the two monsoons, scientific community needs to improve the reliability of forecasts to unable forward planning. Understanding the monsoon systems and their predictability over Africa has highly improved through AMMA (African Monsoon Multidisciplinary Analysis), the main international program on climate and environment in Africa. AMMA is planned to continue research for a further decade focused on the integration of weather and climate science with decision making for the African society.