Natural Regions of the World

The average weather conditions of temperature and rainfall at a specific place or a region over a period of several decades (around 30 years) is known as climate.

The world climate types have been classified on the basis of world's climate/temperature zones based on latitudes. It is observed that all the places located on a particular latitude would experience similar type of climate, although the local factors may play a certain role.

The different climatic regions of the world are:

1. Equatorial region
2. Tropical grasslands
3. Tropical desert
4. Tropical monsoon
5. Mediterranean
6. Temperate grasslands
7. Taiga
8. Tundra

The Equatorial type of climatic regions are found along the Equator at 5°N to 5° on either side. The typical Equatorial climatic features are experienced between 2° and 8°N while swinging of Pressure Belt affects the Rain Belt between 10°N to 10°S.

Equatorial regions are also known as Tropical Wet Climate or Tropical Rainforest Climate.

The Equatorial Region receives maximum amount of incoming radiation (insolation). Therefore, the Equatorial Region has the hottest climate.

The equatorial areas are known for heavy convectional rainfall. Torrential rain is experienced in the afternoon at 4 o'clock and is generally accompanied by lightning and thunder. Many areas receive about 200 cm rainfall annually.

The equatorial region receives this kind of rainfall because of intense heating of the surface and abundant supply of moisture.

The characteristic features of the Equatorial Type of Climate are:

1. Equatorial type regions do not experience any season as there is very little change in range of temperature.
2. These regions experience average temperature of 26°C throughout the year with a belt of low pressure. Extensive cloud cover and heavy rainfall prevent any rise in temperature.
3. The annual range of temperature is about 3°C and diurnal temperature range is about 6°C to 8°C.
4. These areas experience heavy torrential rainfall accompanied by lightning and thunder often in the afternoons.
5. Humidity is always high.

A few important trees found in the equatorial region are mahagony, ebony, rosewood and greenheart. They are used for expensive furniture. Beside this cinchona, banana, bam leaves, coconut and palm trees are also found there. They are of great commercial value

Diurnal range of temperature is low in the equatorial region because this region receives 12 hours insolation causing equal daylight and darkness. It results in little temperature variation.

The tropical monsoon type of climate is found in the tropical regions where due to differential heating of land and water, a complete seasonal reversal of winds takes place. The location lies between 10° and 30° on either side of the equator.

The most clearly defined monsoon climates are located in the coastal areas of the South-East Asia, India, Myanmar, Bangladesh, Indonesia, South China and Philippines. Other areas outside Asia which experience seasonal reversal of winds are said to have only monsoonal tendencies. Such areas exist in the tropical Africa along the South-west coast. Equatorial East Africa including areas of Malaysia are found to have monsoonal character. Part of North-East Latin America, north coast of Puerto Rico and the Dominican Republic in the Caribbean Islands have a mild monsoonal effect.

The monsoon lands are greatly affected by the differential heating of land and water. During summer, the landmass of Asia is heated and low pressure is created. Winds from surrounding seas and oceans start blowing from sea to land carrying a lot of moisture, as they cross the water bodies. This is how South-West monsoon winds originate.

A few important features of the Tropical Monsoon Climate are:

1. Seasonal reversal of winds is the chief feature.
2. Temperature ranges from 15°C in the cool season to 32°C in hot season.
3. Three distinct seasons can be identified
   1. Cool dry season (Nov to Feb)
   2. Hot dry season (March to May)
   3. Hot wet season (June to Oct)
4. Great variation in rain takes place from 12 cm in the deserts to 200 cm in coastal regions

The characteristics of the climate of hot deserts are:

1. Rain rarely falls and average rainfall is usually below 12 cm. Sometimes there may be a sudden torrential downpour due to depression which may cause temporary floods.
2. The average temperature varies from 29°C in hot season to 10°C in cool season.
3. Absence of clouds causes temperature to rise upto 49°C at times. At night, because of clear skies, radiation is rapid and temperature may fall to 15°C to 5°C. Thus diurnal range of temperature is very high.

The natural vegetation found in hot deserts are mostly xerophytic plants. These are cacti, thorny bushes and coarse grasses. These plants have long roots to absorb water deep from ground and needle shaped leaves to reduce transpiration. Leaves are modified into spines.

The major hot deserts of the world are found on the Western margins of the continents because the trade winds blowing from North-East to South-West shed their moisture on the Eastern side.

The important features of the Tropical Deserts are:

1. Annual range of temperature is high as summers are hot and winters are moderate.
2. Rainfall is scanty (less than 12 cm).
3. Relative humidity is only 10%
4. Days are hot and nights are cold. Therefore, the diurnal range of temperature is high.
5. Vegetation consists of xerophytic plants.

Most of the world's hot deserts lie within the latitude 15°N to 30°N and south. They occupy the western margins of the continent in the belt of permanent trade winds. The only exception is Sahara desert, which extends from west coast right across the continent into South-West Asia.

The most important regions having hot deserts are Sahara Desert, the Arabian, Iranian and Thar Desert, Australian Desert, the Kalahari and Namibia Deserts, the Atacama Desert and the California and Mexico Desert.

The warm dry summer and mild rainy winters with plenty of rainfall is the main feature of the Mediterranean climate.

In the northern hemisphere the maximum rainfall is received during winter between December to March while in southern hemisphere the rainy season last from May to August. This is because of the shifting of the pressure belts. These regions come under the influence of Westerlies. Onshore Westerly winds blow in the winter bringing cyclonic rain.

The main characteristics of Mediterranean vegetation are:

1. The plants in this region have adapted themselves to the summer drought, by storing water obtained from winter rains, e.g. bulbous roots.
2. They have thick wooden stem with thick needle type of spiny leaves to cut down rate of transpiration.
3. Other plants have tap roots which can reach down to the moist rock layer below the surface.
4. In the drier forests the vegetation is scrub like and consists of sweet smelling herbs and shrubs such as Oleander, Rosemary, Thyme and Lavender.
5. In the wetter parts, coniferous trees are found on mountain slopes.

Some trees that grow on land are teak, sheesham, oak, eucalyptus and fruit trees like mango, guava etc.

Few local winds of Mediterranean region are:

1. Sirocco — a hot dusty, dry wind which blows from Sahara desert during summer across Mediterranean.
2. Mistral — intensely strong cold wind which blows in winter down the Rhone valley from the North reaching Mediterranean coast.
3. Bora — winter wind blowing south across Yugoslavia to the Adriatic Sea.

Four climate types of the world are:

1. Mediterranean type
2. Temperate grasslands
3. Tropical desert
4. Tropical monsoon

The winters are very long in the Taiga region. Long and cold winters last from October to April and temperature can fall to -30°C or less. During winter precipitation is received in the form of snowfall because winter temperatures are generally below freezing point.

The Tundra lies beyond the Arctic circle (66°30'N) in the Northern Hemisphere. There is no tundra region in he Southern Hemisphere as there is no landmass present within this latitude. Northern coastal region of Alaska and Canada are in Tundra region.

Summers in Tundra region are cool and short. They last only for about 2-3 months and the temperature may vary between 2°C to 10°C. Although during summer the area is blessed with continuous sunlight, the sun hardly comes up the horizon.

Aurora Borealis or polar lights are a natural phenomenon in which there is a display of brilliant colors in sky. They occur when charged particles from the sun interact with gases in the earth's atmosphere. They occur in latitudes beyond 65° in northern hemisphere.

Equatorial Regions

Tropical Monsoon Regions

Mediterranean Regions

Mid-Latitude Deserts

Equatorial regions are economically backward as they are mostly inhabited by the primitive people who are primarily gatherers & hunters. Farming is also primitive type.

The extensive cloud cover and heavy rainfall prevents the rise and fall of temperature during day and night respectively. Therefore, the diurnal range of temperature is low.

The major hot deserts of the world are generally found on the western margins of the continent because the trade winds blow from north east to south west, shed their moisture in the east and the western margins are left dry. Trade winds are offshore in this region.

The region has rugged topography, climate, soil & vegetation is also varied & complex. In summer the region experiences acute scarcity of water. Therefore, it is very difficult to adapt a permanent settled life in this region.

Mediterranean climate is called resort climate because it is characterised by mild, comfortable temperatures year-round, making it an ideal climate for vacationing and leisure activities.

Due to extreme weather conditions characterised by very low beyond freezing point temperatures, strong winds, a polar desert environment and presence of a very small landmass, the Antarctic region beyond 66.5°S in Southern Hemisphere has no vegetation.

Tropical/Equatorial Rainforest

Brazil

Tropical deserts

Mediterranean climate

Mediterranean climate

(i) (d); (ii) (c); (iii) (b); (iv) (a)

Tundra

Taiga region

Citrus fruits

Equatorial region

Tropical Monsoon climate

Pygmies from the Congo Basin, Bushmen from the Kalahari Desert, and the Kirghiz from Central Asia all belong to different natural regions, yet share a similar nomadic lifestyle. This is mainly because the physical conditions in their regions are harsh and not suitable for permanent settlements. Limited availability of food, water, and grazing land forces them to keep moving from one place to another in search of basic resources for survival. Their way of life is an adaptation to the challenging environment in which they live.

The Prairies, located in the temperate grasslands of North America, are ideal for animal rearing due to their vast stretches of rich, natural grasses that serve as excellent fodder. Additionally, the temperate climate is well-suited for the health and growth of livestock. These favourable conditions have led to the development of large-scale animal rearing, making it a major source of income for farmers, who earn a substantial part of their livelihood from selling animals and animal products.

Both A and R are true and R is the correct explanation of A.

Explanation — The onshore winds blowing from sea to land pick up lots of moisture from the water bodies. These moist winds, called monsoon winds, then shed this moisture as rainfall, that supports intensive agriculture in the region. Hence, agriculture thrives and becomes the main livelihood for people.

A is true but R is false.

Explanation — During winter because of the shifting of the pressure belts Mediterranean regions come under the influence of Westerlies. Onshore Westerly winds blow in the winter bringing cyclonic rain.