The document discusses the intertropical convergence zone (ITCZ), a band near the equator where the northern and southern hemisphere trade winds converge. The intense sun and warm water at the equator heats the air in the ITCZ, raising its humidity and causing it to rise, creating a band of low pressure. The location of the ITCZ affects rainfall in tropical areas, resulting in wet and dry seasons rather than cold/warm seasons at higher latitudes. The ITCZ moves north during the northern hemisphere summer and south during the southern hemisphere summer, influencing rainfall patterns in places like western Africa.

1. Global Air Circulation
The ITCZ, is the region that circles the
Earth, near the equator, where the trade
winds of the Northern and Southern
Hemispheres come together.
The intense sun and warm water of the
equator heats the air in the ITCZ, raising
its humidity and causing it to rise.
Creating a band of low pressure.
Variation in the location of the ITCZ
drastically affects rainfall in many
equatorial nations, resulting in the wet and
dry seasons of the tropics rather than the
cold and warm seasons of higher latitudes.

2. The ITCZ
• The ITCZ will move
North during the
summer in the Northern
Hemisphere reaching its
furthest point North in
July.
• It then moves South
during summer in the
southern hemisphere
reaching its furthest
point South in January.

3. Rainfall at the ITCZ
• The trade winds will
converge at the ITCZ.

4. Rainfall at the ITCZ
• Where winds
converge, moist air is
forced upward. This
causes water vapour
to condense, or be
"squeezed" out, as the
air cools and rises,
resulting in a band of
heavy precipitation
around the globe

5. The influence of cT and mT

6. The impact of the ITCZ on the West
Coast of Africa
• In summer the ITCZ moves North bringing rain to the
Northern parts of Western Africa. In January the ITCZ
has moved South bringing hot dry weather to the
North of Western Africa.
• The ITCZ is a band of low pressure associated with
rainfall as two air masses meet and force air upwards
creating a band of heavy cloud.

7. THE ITCZ 2005 Q1
• Kano has a distinct _____ season from ______ to __________ with the highest rainfall of
________mm in July. This is caused by the movement of the ITCZ north during summer in the
____________ ______________.
• The ITCZ is a band of _________pressure or a zone of ___________ which is associated with
a band of _______________. In July the ITCZ id directly over Kano hence the peak rainfall. As
the ITCZ moves further North is allows _________ __________ air to reach further into
Northern Nigeria again this brings with it warm, moist air and rainfall. As a result for 6
months of the year Northern Nigeria experiences a ___________season. As the ITCZ moves
South for the remaining 6 months the North of Nigeria is affected by the_______
___________ air mass bringing _________and _________ weather to much of the area,
• Enugu has rainfall throughout the year with two distinct peaks in _________ and
_______________. Again these peak rainfall moths are when the ITCZ is directly overhead
bringing a band of low pressure and heavy rainfall. Enugu is influences by the __________
__________ air mass throughout the year with lowest rainfall in ____________ and
______________when the ITCZ will be slightly South of Enugu allowing ________________
_____________ air to influence the rainfall.

8. Sample answer
• Kano has a distinct wet season from May to September with the highest rainfall of 250mm in
July. This is caused by the movement of the ITCZ north during summer in the Northern
Hemisphere. The ITCZ is a band of low pressure or a zone of convergence which is associated
with a band of precipitation. In July the ITCZ id directly over Kano hence the peak rainfall. As
the ITCZ moves further North is allows mT air to reach further into western Africa again this
brings with it warm, moist air and rainfall. As a result for 6 months of the year Northern
Nigeria experiences a wet season. As the ITCZ moves South for the remaining 6 months the
North of Nigeria is affected by c T air mass bringing hot and dry weather to much of the area,
• Enugu has rainfall throughout the year with two distinct peaks in May and September. Again
these peak rainfall moths are when the ITCZ is directly overhead bringing a band of low
pressure and heavy rainfall. Enugu is influences by the mT air mass throughout the year with
lowest rainfall in January and December when the ITCZ will be slightly South of Enugu
allowing Ct air to influence the rainfall.