Tropical Climates

Question 1

What is air mass?

Answer 1

A large body of air in which the horizontal gradients of the main physical properties are fairly slack

Question 2

What are the three main types of tropical climates?

Answer 2

1. rainforest climates
2. monsoon climates
3. savanna climates

Question 3

What are the main causes of the subtropical high-pressure belt?

Answer 3

It is caused by cold air at the tropopause descending. The position of the high pressure alter in response to the seasonal drift of the ITCZ.

Question 4

How and why does the subtropical high-pressure belt vary seasonally?

Answer 4

The subtropical high pressure belt tends to lie over the ocean, especially in summer, when there are low pressures over the continents caused by heating

Question 5

What is an oceanic gyre?

Answer 5

The oceanic gyre (swirl of currents) explains why east coasts are usually warm and wet, because warm currents carry water polewards and raise the air temperature of maritime areas. In contrast, cold currents carry water towards the Equator and so lower the temperature of coastal areas.

Question 6

What is a monsoon?

Answer 6

involves wind patterns that experience a pronounced seasonal reversal. The basic cause is the seasonal difference in heating of land and sea on a continental scale.

Question 7

What are tropical humid climates?

Answer 7

refer to areas in the tropics that are wet all year round

Question 8

What are seasonally humid climates?

Answer 8

refer to areas within the tropics where there is a distinct dry season as well as wet season

Question 9

What is succession?

Answer 9

refers to the spatial and temporal changes in plant communities as they move towards a seral climax

Question 10

What is sere?

Answer 10

an association or group of species that alters the micro-environment and allows another group of species to dominate

Question 11

What is community?

Answer 11

a group of populations living and interacting with each other in a common habitat

Question 12

What is plagioclimax?

Answer 12

refers to a plant community permanently influenced by human activity. It is prevented from reaching climatic climax by burning, grazing and so on. The maintenance of grasslands through burning is an example of plagioclimax.

Question 13

What is edaphic control?

Answer 13

In some areas, however, vegetation distribution may be determined by soils rather than by climate.

Question 14

What is a climax community?

Answer 14

the group of species that are at a dynamic equilibrium with the prevailing environmental conditions.

Question 15

Explain why tropical rainforests have very high rates of productivity?

Answer 15

Owing to the year-round growing season, constantly high temperatures (above 26°C), availability of moisture (over 2000 mm/year) and availability of light, productivity remains very high. In addition, due to the high biodiversity of the ecosystem there are species exploiting every ecological niche, which makes the ecosystem productive.

Question 16

Outline the ways in which savanna vegetation adapted to seasonal drought

Answer 16

Savanna vegetation is adapted to drought by having deep tap roots to reach the water table, partial or total loss of leaves and/or sunken stomata on the leaves to reduce moisture loss.

Question 17

Outline the ways in which savanna fauna are adapted to seasonal drought

Answer 17

Savanna fauna is adapted to drought by being migratory.

Question 18

What is xerophytic?

Answer 18

adapted to drought

Question 19

What is pyrophytic?

Answer 19

adapted to fire

Question 20

Describe the main types of weathering that occur in tropical environments

Answer 20

There may be deep weathering in many humid tropical areas because the availability of water and the consistently high temperatures maximise the efficiency of chemical reactions, and in the oldest part of the tropics these have been operating for a very long period – often millions of years.

Question 21

What are tors?

Answer 21

Tors are said to be joint-controlled as the original positioning and pattern of joints determines how weathered the granite will become. Where there are many joints the granite is more weathered; where there are few joints, the rock is less weathered and corestones may be preserved.

Question 22

What are inselbergs?

Answer 22

These residual hills are the result of stripping weathered regolith from differentially weathered surface.

Question 23

What are bornhardts?

Answer 23

Monolithic domed Inselbergs

Question 24

What are pediplains?

Answer 24

low-angled plains separated by rocky hills known as kopjes. They are formed as a result of parallel retreat of slopes. Pediplanation begins with tectonic uplift, resulting in accelerating river erosion forming knick points, falls, rapids and gorges.

Question 25

What is a cockpit karst?

Answer 25

a landscape pitted with smooth-sided, soil-covered depressions and conical hills

Question 26

What is a tower karst?

Answer 26

a landscape characterised by upstanding rounded blocks set in regions of low relief

Question 27

Explain why tors can be described as ‘joint controlled’

Answer 27

Tors are said to be joint-controlled as the original positioning and pattern of joints determines how weathered the granite will become. Where there are many joints the granite is more weathered; where there are few joints, the rock is less weathered and corestones may be preserved.

Question 28

Outline the two theories for the formation of bornhardts

Answer 28

The two theories of bornhardt formation are: the stripping or exhumation theory – increased removal of regolith occurs so that unweathered rocks beneath the surface are revealed; parallel retreat – the retreat of valley sides occurs until only remnant inselbergs are left.

Question 29

What is the difference between cockpit karst and tower karst

Answer 29

Cockpit karst is a landscape pitted with smooth-sided, soil-covered depressions and cone-like hills. Tower karst is a landscape characterised by upstanding rounded blocks set in a region of low relief.

Question 30

What are maritime tropical air mass?

Answer 30

refers to one that is warm and moist

Question 31

What are continental tropical air mass?

Answer 31

refers to one that is warm and dry