(a) On an outline map of Nigeria show and name: (i) one area with an annual rainfall below 100cm (ii) one area with an annual rainfall below 300cm (iii) two...

(a) As shown on the map above:

• Area with annual rainfall below 100 cm: the far northern part of Nigeria, especially the Sokoto-Rima basin/Sahelian belt. Important towns include Sokoto and Katsina.
• Area with very high annual rainfall: the southern coastal Niger Delta belt, around Port Harcourt and Calabar. This is the area conventionally shown as receiving over 300 cm of rainfall annually. The wording “below 300 cm” in the question is inconsistent with the mangrove-swamp climate required in parts (b) and (c).

(b) Four other climatic features of the very wet coastal Niger Delta area are:

• Rainfall occurs in every month of the year; there is no true dry season.
• Rainfall has a double maximum, with two periods of peak rainfall, usually around June or July and September.
• There may be a short break in rainfall around August, known as the August break.
• Temperatures are high throughout the year, with a mean annual temperature of about \(27^\circ\text{C}\).
• Relative humidity is very high because of the frequent rainfall, cloud cover and nearness to the Atlantic Ocean.
• The annual range of temperature is small because the area lies close to the Equator and is strongly influenced by the sea.

(c) The vegetation associated with this hot and very wet coastal climate is the mangrove swamp forest.

Characteristics of mangrove swamp forest include:

• It is a dense, evergreen forest because rainfall and moisture are available throughout the year.
• The trees are mainly broad-leaved and grow closely together.
• It occurs in waterlogged, muddy and saline or brackish coastal swamps, especially around river mouths and creeks.
• Mangrove trees have supporting stilt roots and breathing roots, called pneumatophores, which help them to survive in soft, oxygen-poor swamp soils.
• The vegetation consists of several species of mangrove, together with palms, reeds and other swamp plants.