Climate
- The tropical wet and dry climate of Africa shows seasonal variation in wind direction, precipitation and temperature.
- Variations occur with increasing latitude from the equator.
Precipitation Varies
- Equatorial rainforest margins more than 1,000mm per year, rain season lasts 10-11months.
- Desert/semi-arid margins are less than 500mm per year, away from the equator the reliability of the rainfall decreases, only 1-2 months rainy season.
Temperature Varies
- The equatorial rainforest margin temperature range is 22°C in the wet season and 28°C in the dry season.
- On the desert margins the temperature ranges from 18°C in the wet season to 34°C in the dry season.
- During the dry season, the subtropical anticyclone moves over the desert margins, the subsiding air of the high pressure suppresses convection, giving rise to clear skies and high daytime temperatures.
- The trade winds blow from the high pressure towards the ITCZ, moves towards the coast. The air has a low moisture content, known as harmattan.
- In the wet season, the ITCZ migrates polewards, it brings rainfall because uplift and convection are fed by moist, unstable, tropical maritime air, the poles have a short rainy season so have low annual rainfall.