Research
Climate change in West Africa
Central Nigeria, northern Ghana, and southern Burkina Faso (Region 6)
19 December 2006
Long-term fluctuations
This area forms the southern boundary of the driest region of West Africa
extending southwards from the Sahara Desert. Interdecadal
fluctuations featured prominently in the
20th century rainfall time series. The future precipitation trends in this region are quite uncertain. The
GFDL CM2.0 and GFDL CM2.1 models project a significant downward rainfall trend
in the area, with projections by the MIUB ECHO-G model suggesting a
significant trend in the opposite direction. The other models in the set
project either an insignificant or no trend.
Region 6 precipitation differences from the 1901-1950 mean [mm/day] with a ten-year running mean in observations and selected climate models.
Annual cycle
All models in the selected set over-predict the precipitation observed in this area during the main rainy season, but still simulate a more realistic 20th century annual cycle. The GFDL CM2.0 and GFDL CM2.1 models both project a substantial reduction in observed precipitation during the peak of the rainfall season, consistent with the 21st century drying trend shown in these models' predictions. The MIUB ECHO-G model locates the peak of the rainfall season a month earlier than observed, and project more intense rainfall in the future climate. The MPI ECHAM5 model project a reduction in rainfall intensity early in the season and a slight increase in August and September, while the remainder of the models in the set showing only little or no change.
Region 6 annual cycle. The observations are shown in black, the simulations for the 20th century are dotted and around 2100 solid lines.
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