CLIMATIC CLASSIFICATION

WEEK 9 & 10

SUBJECT: GEOGRAPHY

CLASS:    SS2                 

DATE: ……………………………….

TOPIC:

CLIMATIC CLASSIFICATION

CONTENT:

(i) Greek climatic classification 

(ii) Koppen’s climatic classification

SUB-TOPIC I:

GREEK CLIMATIC CLASSIFICATION

Climatic classification is a conscious attempt at grouping different climates with similar characteristics together. This is because climate is not the same in every place.

The most common classification of climates are:

1. Greek classification
2. Koppen’s classification

GREEK SYSTEM OF CLASSIFICATION OF CLIMATE

This is the earliest, simple and rough climate classification put forward by the Greek people. The Greek made their classification on the basis of Temperature. On this basis, the world is divided into climatic zones namely (i) Torrid zone (ii) Temperate zone and (iii) Frigid zone

1. TORRID ZONE: This zone is found within the tropics (i.e. tropic of Cancer and Capricorn). It is very hot because of its nearness to the equator and the temperature is high throughout the year.
2. TEMPERATE ZONE: This zone is found between the torrid and frigid zone. It has moderate temperature and has seasonal differences in temperature.
3. FRIGID ZONE: This zone is found within the Polar Regions (Arctic and Antarctic). The zone is generally cold and has lots of ice-caps.

CRITICISMS OF GREEK CLASSIFICATION

1. The problem with this classification is that it emphasises temperature leaving out other climatic factors.
2. It is too simple.
3. It ignores the influence of latitude and altitude, presence of vegetation and wind.
4. It fails to recognise climates such as the humid and the desert regions.

EVALUATION

1. Define climatic classification.
2. What are the 3 zones of Greek classification of climate?

iii. Mention four disadvantage of Greek classification of climate.

SUB-TOPIC 2:

KOPPEN’S SYSTEM OF CLASSIFICATION

Dr. Vladimir Koppen devised the best climatic classification in 1918. The basis of Koppen’s classification was Temperature and Rainfall (precipitation). He identified 5 major climatic groups which correspond with the five main vegetation groups. They are represented by capital letters as follows:

A= TROPICAL RAINY CLIMATE

This climate is moist and hot with average monthly temperature above 180C. It has heavy rainfall throughout the year which is more than evaporation.

B= DRY CLIMATE

This climate lacks surplus water. Evaporation exceeds annual rainfall. No river flows permanently in this region. This is a really arid (dry) region.

C= WARM TEMPERATE RAINY CLIMATE (Humid Mesothermal Climates)

Here, the average temperature of the coldest month is below 180C but above – 30C. The average temperature of the warmest month is 100C. It has both summer and winter season.

D= SNOWY AND COLD CLIMATE (Cold snow forest climate)

This zone’s average temperature of the coldest month is – 30C and that of the warmest month is 100C. It is characterised by frozen and snow cover for several months.

E= POLAR CLIMATE (Ice climate)

The average temperature of the warmest month is below 100C. There is lack of warm season and precipitation is in the form of snow.

OTHER SUB-DIVISIONS OF KOPPEN’S CLIMATIC CLASSIFICATION

The five major climatic groups already described are sub-divided into different sub-groups for each of the climates as follows:

A has Af, Am and Aw sub groups.

B has Bs and Bw sub groups.

C has Cw, and Cf sub groups.

D has Dfand Dw sub groups.

E has Et and Ef sub groups.

HOW TO UNDERSTAND THE CLIMATIC SUB GROUPS

The small letters f, s, w andm show how seasonal precipitation is and they mean the followings:

f = no dry season generally

s= no dry season in summer

w= no dry season in winter

m=moderate dry season in winter and summer

The capital letters of S and W show the two subdivisions of dry climates

S= means steppe or semi desert

W= means desert or arid

In polar climates

T= means Tundra

F= means Ice cap

BRIEF DESCRIPTION OF THE SUB GROUPS

A-Climates (Tropical rainy climates): There are three sub groups of A – climates. These are Af, Am, and Aw.

1. Af = TROPICAL RAIN FOREST CLIMATE: This climate is located within 50 North and South of the equator.

Location

(a) Amazon basin of South America

(b) The Zaire basin of Central Africa

(c) The coasts of West Africa

FEATURES OF THE Af CLIMATE

1. Temperatures are high and uniform throughout the year
2. Mean monthly temperature is 270C

iii. Diurnal range is between 60C to 80C

1. There is rainfall throughout the year
2. Amount of rainfall is 1500mm to 2000mm
3. There is a double maxima (two highest rainfall periods)

vii. Humidity is 70% to 80% throughout the year.

2. Am= TROPICAL MONSOON CLIMATE

Distribution: This climate is located within latitude 100 and 350 north and south of the equator.

Areas covered by the Am zone include:

1. Monsoon Asia, including India, Pakistan, Bangladesh, Burma, Thailand, South East and Eastern Asia.
2. North Australia

iii. Central America, West Indies and parts of the coast of Brazil

1. Parts of the coast of East Africa and West Africa.

FEATURES OF Am ZONE

1. High temperature of about 270C
2. Temperature range is 60C

iii. High annual rainfall of 1500mm

1. There is concentration of rain in rainy season
2. There is alternating wet and dry seasons 
3. Aw = TROPICAL GRASSLAND OF SAVANNA

Distribution: This is located within 50 – 250 north and 50 – 200 south of the equator.

Areas covered include:

1. Central America
2. North West of South America

iii. Interior uplands of Brazil, Bolivia and Paraguay

1. South Central and Eastern Africa
2. West Africa
3. West Malaysia

vii. Parts of India and South East Asia

viiiNorthern Australia

FEATURES OF Aw ZONE

1. Temperatures are more extreme 200C – 300C
2. High range of temperature of 90C

iii. Rainfall between 250mm – 1500mm

1. Rainfall is seasonal, mainly in summer
2. Rainfall is mainly convectional (single maxima)

B- CLIMATE (DRY CLIMATE)

There are 2 sub-groups of B – climate namely Bs and Bw

1. Bs = Steppe (semi – arid) climate

Distribution: This climate is located within 300 – 400 north and south of the equator. Area covered is Italy, Argentina, Uruguay, South Africa and Australia.

FEATURES

1. There are extremes of temperature cold winter and hot summer
2. It has temperature of 190C – 420C

iii. Annual range of temperature is 400C

1. Annual rainfall is 508mm in summer
2. The relative humidity is very low.
3. Bw = Desert (Arid) Climate

Distribution: This climate is located in the western coast of the continents 150 – 300 north of the equator. It is found in the areas of West Africa, South Africa, Namibia and Iran.

Features 

1. High temperature between 300C– 580C
2. Humidity is relatively low

iii. Low annual rainfall of 150mm

1. Temperature range is 110C

C= CLIMATES (warm temperate rainy climate) 

There are 3 sub-groups of the climate these are Cf, Cw and Cs

1. Cf = Mild humid climate:It has no dry season with the least month of rainfall having 30mm
2. Cw = Mild humid climate:  it has a dry winter with heavy rainfall in summer

iii. Cs = Mild humid climate:  it has dry summer with heavy rainfall in winter

D= CLIMATES (Snowy and cold climate)

There are 2 groups in D climates

Df = Snowy forest climate: it has moist winter, no dry season with cold climate.

Dw= Snowy forest climate: it has dry winter with cold climate.

E= CLIMATES (Polar climates)

The E – climate has 2 sub-groups namely:

ET = Tundra climate; average temperature is less than 100C

EF= Continuous forest climate; average temperature of all months is less than 00C. It has ice caps. It is found in extremes of north and south poles.

ADVANTAGES OF KOPPEN’S CLASSIFICATION

1. It is very simple to understand
2. It is objective
3. It is quantitative because numerical values are used for defining boundaries of climatic groups.
4. It is commonly used in teaching at various levels of educational institutions

DISADVANTAGES OF KOPPEN’S CLASSIFICATION

1. It did not consider the climate of highland
2. Letters used are many and confusing
3. There is no clear boundary of one climate from another.

DIFFERENCES BETWEEN GREEK AND KOPPEN’S SYSTEM OF CLIMATIC CLASSIFICATION

1. Greek’s climatic has three major belt while Koppen’s has five major climatic types
2. Koppen’s applied quantitative approach in the classification while Greek’s employs descriptive approach
3. Greek’s classification does not recognise sub-groups, whereas Koppen’s recognises various sub-group 
4. Greek’s climatic classification is based on temperature while Koppen’s is based on climate and vegetation  

EVALUATION:

1. State Koppen’s fivemajor climatic groups.
2. Outline three advantages and disadvantages of Koppen’s classification. 

GENERAL EVALUATION

1. With the aid of a diagram, describe the Greek climatic classification.
2. Differentiate between Greek and Koppen’s System of Climatic Classification 
3. Identify and make a list of major and sub-groups of Koppen’s climatic classification.
4. What three advantages has the Koppen’s classification over the Greek system (SSCE June 1995)

WEEKEND ASSIGNMENT

Objective Test

1. The basis for Koppen’s climatic classification is (A) rainfall and temperature (B) rainfall and pressure (C) temperature and pressure (D) rainfall and humidity.
2. Aw in Koppen’s classification of climate refers to (A) Steppe (B) Tropical (C) Mediterranean                     (D) Polar.
3. Which of the following towns is located in Koppen’s Aw climate? (A) Lagos (B) Tamale C) Algiers  (D) Lome.
4. The climatic element used by the Greek to classify climate is (a) Humidity (b) Rainfall (c) Wind(d) Pressure (e) Temperature.
5. The zone similar to the Frigid zone in Koppen’s classification is (a) E-climate (polar climate) (b) A-climate (tropical rainy climate) (c) D-climate (snowy and cold climate) (d) C-climate (worm temperature (e) B-climate (dry climate).
6. One of the disadvantages of the Koppen’s classification is that (a) it is objective (b) it is quantitative (c) it did not consider the climate of highlands (d) it uses rainfall as well as temperature (e) the polar region is considered.

ESSAY QUESTIONS

1. State three climatic zones of the Greek classification.
2. Explain one of the zones mentioned in 1 above.

READING ASSIGNMENT

Read your textbooks for your examinations.

REFERENCE TEXTS

1. Essential Geography for Senior Secondary Schools by O.A, Iwena.
2. Comprehensive Geography for Senior Secondary Schools by Peter Oluwasfemi S.A.