this lesson talks about tropical environment specially tropical climate which helps to A level Cambridge exam students to prepare themselves

1. CHAPTER SEVEN
Tropical
Environment
A Level

2. TROPICAL
CLIMATES
Mr. Yonas Gemeda
Addis Ababa
2019

3. LEARNING OUTCOMES
 At the end of this lesson students will be
able to:
 Describe about features of tropical
environment
 Define tropical humid climates
 Classify tropical climates

4. INTRODUCTION
 The tropical environment is the area between
23.5 degree N and 23.5 degree S.
 There are three types of tropical climate
 1. these include rainforest climate
 2. monsoon climate and
 3.savanna climate

8. TROPICAL CLIMATE
CHARACTERISTICS OF AIR MASS
 An air mass is a large body of air in which
horizontal gradients of the main physical
properties, such as temperature and humidity,
are fairly gentle.
 It applied only to the lower layer of the
atmosphere.
 An air mass can cover an area up to ten
thousands of km square.

9. CONT’D
 Air mass can be modified when they leave
their sources.
 A maritime tropical (mT) air mass refers to
one that is warm and moist
 A continental tropical (cT) air mass refers to
one that is warm and dry.
 Air mass moves from their source regions
they can be changed by the area over which
they move.

10. INTER TROPICAL CONVERGENCE ZONE
The inter tropical convergence zone is an
area in the tropics in which the northeast
trade winds and the southeast trade
winds converge.
If there is a difference in temperatures
between the winds the warmer air rises
over the denser, colder air can produce
rain.

11. CONT’D
The ITCZ or equatorial trough is a few
hundred kilometers wide and lies at 5
degree N.
Winds at the ITCZ are commonly light or
non existent, creating calm conditions
called the doldrums, but there are
occasional bursts of strong westerlies.

12. SUBTROPICAL HIGH PRESSURE
The subtropical high or warm anticyclone
is caused by cold air at the tropopouse
descending .
The main causes of subtropical high
pressure belt is cold air at tropopause
descending. This is descending air of
Hadley cell.

13. OCEANIC INFLUENCE/ OCEANIC CURRENTS
 The oceanic gyre (swirl of currents) explains
why east coasts in the southern hemisphere
and west coasts in the northern
hemisphereare usually warm and wet,
because warm currents carry water polewards
and raise the air temperature of maritime
areas.

14. CONT’D
In contrast cold currents carry water
towards the equator and so lower the
temperature of coastal areas.
 West coast tewnd to be cool and dry due to:
 The advection of cold water from the poles
and
 Cold upwelling currents

15. WIND
 The temperature of the wind is determined by
the area where the wind originates and by the
characterstics of the surface over which it is
subsequently blows.
 A wind blowing from the sea tends to be
warmer in winter but coolerin summer than
the corresponding wind blowing from the
land.

16. WORLD CLIMATES : CLASSIFICATION
 The most widely used classification of climate is
that of W. koppen.
 His classifacation first appeared in 1900
 Koppen classified climate with respect to two
main criteria
 1. temperature
 2. seasonality of rainfall

17. TYPES
 Indeed, five of the six main climatic types are
based on mean monthly temperature:
 A. Tropical rainy climate
 B. Dry
 C. Warm temperature rainy climate
 D. Cold boreal forest climate
 E. Tundra
 F. Perpetual frost climate

18. TOPIC REVISION QUESTION
 1. define the term:
 A. tropical humid climate
 Seasonality humid climate
 2. explain about the tropical environment