Question 4
(a) Draw an outline map of Nigeria.
On the map, show and name:
- the position of the Tropical Maritime air mass(S. W. winds) in July;
- the position of Inter Tropical Convergence Zone (I.T.C.Z.) in July;
- the relative position of Tropical Continental air mass (N.E. winds) in July;
- three towns located in 4 (a)1 above.
(b) State four characteristics of wet season in Nigeria.
- List two cash crops grown during the wet season in Nigeria.
Observation
This question was not popular among the candidates and the performance of the candidates who attempted it was just fair. Most of the candidates who attempted it could not draw good sketch maps showing the I.T.C.Z. , the S.W. winds and the N.E. winds. The (b) and (c) aspects of the question were better attempted by the candidates. Some of the candidates could not state the characteristics of the wet season in Nigeria. The expected answers were:
- temperature is high, 27o c to 33oc;
- the prevailing wind is the Tropical Maritime Air Mass;
- there is low pressure in the north due to high temperature;
- there is high pressure in the south due to low temperature;
- heavy rainfall occurs in Nigeria during the wet season( over 1500 mm);
- the south experiences double maxima of rainfall;
- the north experiences single maximum of rainfall;
- rainfall amount decreases from the south towards the north;
- rainfall duration decreases from the south towards the north;
- short dry season in August in the South( August break);
- relative humidity (80% to 100%) decreases northwards;
- rainy season starts from April and ends in October;
- heavy rainfall in July and September in the south;
- heavy rainfall in the north in July;
- diurnal range of temperature increases northwards (2oC - 11o C) rain accompanied with thunderstorms/line squalls.