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SAI INTERNATIONAL SCHOOL, BHUBANESWAR.
Class IX: SOCIAL STUDIES – GEOGRAPHY

CHAPTER - 4- CLIMATE
(VIRTU AL CLASSES)

MODULE No:04

NOTES FOR CHAPTER-4- CLIMATE

1. Sub Topic-THE INDIAN MONSOON (pg 28-30)

India has a monsoon type of climate as its climate is strongly influenced by the monsoon
winds. It is
important to keep certain facts in mind before studying the monsoon season in India. These
are
a. The differences in heating and cooling of land and water results in the creation of low
pressure on the
Indian mainland. The seas at the same time experience high pressure conditions.
b. Inter Tropical Convergent Zone (ITCZ) is a broad trough of low pressure in the equatorial
latitudes.
c. The presence of high pressure area east of Madagascar over the Indian Ocean affects the
Indian
monsoon.
d. The movement of the westerly jet stream to the north of the Himalayas and the tropical
easterly jet
stream over the Indian Peninsula also affect the rainfall in India.
It has been seen that apart from other factors, the changes in the pressure conditions over
the southern
oceans also affect the monsoons. Generally, when the tropical eastern South Pacific Ocean
experiences
high pressure, the tropical eastern Indian Ocean experiences low pressure. However, it has
been noticed
that there has been a reversal in the pressure conditions. While the eastern South Pacific
Ocean has low
pressure conditions, the eastern Indian Ocean has relatively high pressure conditions. This
periodic
change in pressure conditions is known as the Southern Oscillation or SO.

The Intertropical Convergence Zone refers to a belt that is characterized by a belt of low
pressure.