Nigeria: Climate

Climate is the average weather condition of the atmosphere over a long period of time usually about 30-35years.

FACTORS AFFECTING CLIMATE

1.  Latitude

2.  Altitude

3.  Distance from the sea

4.  Ocean currents etc.

Elements of climate

1. Temperature
2.  Rainfall
3.  Wind
4.  Relative humidity
5.  Pressure
6.  Cloud cover
7.  Sunshine

EVALUATION

1. What is climate?
2. State the elements of climate.

(i) Temperature: It is the degree of hotness and coldness of a place. Temperature in Nigeria is not uniform and has the following characteristics:

a). It varies from place to place: Temperature is low in the south with an average temp. of about 24^oC because of the cooling effects of the Atlantic ocean, while it is high in the north due to the effects of the Sahara desert or distance from the sea.

b) It varies with altitude(height): places in Nigeria with high altitude like Jos plateau, obudu etc have lower temperature(20^oC) while the surrounding lowlands experience high temprature(of over 27^oC).

c) It varies with seasons: During raining seasons, temperature are usually higher in the north but lower in the south during dry season due to the effects of harmatan.

d) Variation in annual range: The annual range of temperature in the south varies from 2-3^oC while that of the north is about 9^oC.

(ii) Wind: Wind is defined as air in motion. Nigeria is characterised with four types of wind which are:

a) The Tropical Maritime Airmass (south-west trade wind): This wind comes from the Atlantic Ocean and it brings about raining season to southern parts of Nigeria, especially around Warri and Port-Harcourt with twelve months of continuous rainfall. Raining season in the south starts from March- October, with a short dry season at August called AUGUST BREAK.

b) Tropical Continental Airmass (north – east trade wind): This trade wind is responsible for dry season in northern parts of Nigeria. It comes from the Sahara desert. It is cold, dusty and dry hence, it does not bring rain but it brings a very cold, dusty and dry weather called harmattan. It starts from November and ends around February.

c) Equatorial Easterlies: This wind blows around the equator from the east. It has some influence on the N.E AND S.W trade winds when they meet.

d) Land and sea breeze: these local winds are restricted to the coast of Lagos, Warri, Port Harcourt, e.t.c. These are local winds which blows alternately between land and sea on daily basis

SEASON

There are two types of seasons in Nigeria. The two seasons are wet and the dry season. During dry season, the tropical continental air mass and the south westerly wind influence the whole of Nigeria.

During the dry season, most parts of the country is influenced by the tropical continental air mass.

Rainfall :- Rainfall in Nigeria is unevenly distributed. It generally increases from the coast inland. Along the coast, rain falls for about 8 to 12 months of the year. Further inland, the period of rainfall decreases to less than six months. The shortest periods of rainfall are to the northwest and northeast, where rain falls for less than four months of the year.

The mean annual rainfall varies from about 2000mm along the coast to less than 600mm in the northern part of the country.

Insolation and Sunshine

Insolation is generally high throughout the year in Nigeria. Relatively less amount of insolation is received in the south where cloud cover is thicker than in the north where clouds are less. The highest amount of insolation is received in the north. Sunshine hour are less in the raining season than in the dry season.

Relative Humidity

Relative Humidity decreases towards the North, Humidity is higher in the south than in the north. Humidity is also higher in the raining season than in dry season.

EVALUATION

1. Explain factors affecting temperature.

2. Describe the temperature of Nigeria.

GENERAL EVALUATION QUESTIONS

1. What is weather?
2. What is climate?
3. Differentiate between weather and climate.
4. State the elements of weather and climate.
5. State factors that can affect the weather and climate of a place.

READING ASSIGNMENT

Essential Geography, O.A. Iwena Pages 238-242.

WEEKEND ASSIGNMENT

1.         The largest river in Nigeria is    (a) Nile (b) Benue (c) Niger (d) Ogun

2.         Which if these towns is a popular confluence town in Nigeria (a) Jos (b) Lokoja (c) Osun

(d) Udi

3.         Which of these rivers flow into Lake Chad (a) Ogun (b) Gana (c) Cross River (d) Osse

4.         Which of these is a natural lake in Nigeria (a) Shiroro lake (b) Lake Chad (c) Lake Kanji

(d) Lake Tanganyika

5.         River Niger has its source from (a) Niger State (b) Adamawa Highlands (c) Guinea Highlands (d) Sokoto State

THEORY

1. List four effects of climate.
2. Nigeria experiences which type of season?