Describe and explain the seasonal variations in climate in a tropical region (10 marks)
The seasonal variations in climate, in a tropical region, which includes temperature, precipitation and wind direction, are due to a number of factors. The tropical continental climate in Africa, north of the equator, can be described as transitional, as it is between the rainforest margins of the central African rainforest and also the desert margins of the Saharan desert. This results in a continual, gradual change to the climate, so that as the latitude increases, there are recognisable changes to the climate. All areas have a wet season (June to August), when up to 95% of the total annual rainfall will fall, and a dry season (December to February), where there is either no rain or only very small quantities of rain. All areas are also hot throughout the year, often over 25°C, due to the fact that the sun is always directly over head or at a high angle in the sky, leading to a high concentration of insolation. Nigeria, Mali and Chad, in West Africa, are located between the equatorial rainforest on the equator and the Sahara desert, and are examples of countries which experience a tropical wet dry climate.
Features of a tropical wet dry climate includes seasonal characteristics, which are linked with the seasonal migration of the Intertropical Convergence Zone (ITCZ). This is due to the fact that as the ITCZ moves so does the location of the rising limb of the Hadley cell, which is associated with low pressure, clouds, and precipitation. Also, the location of the descending limb of the Hadley and Ferrel cells also move with the ITCZ, and are associated with high pressure, cloudless skies, and stable, dry conditions.
In areas on the rainforest margins, there is more total annual rainfall (over 1000mm per year), and a longer wet season which lasts for 10 or 11 months (and therefore a...
Please join StudyMode to read the full document