Chapter 4

Class 9
2. Answer the following questions briefly. (i) What are the controls affecting the climate of India?


Answer the following questions briefly.

(i) What are the controls affecting the climate of India?

(ii) Why does India have a monsoon type of climate?

(iii) Which part of India does experience the highest diurnal range of temperature and why?

(iv) Which winds account for rainfall along the Malabar Coast?

(v) What are Jet streams and how do they affect the climate of India?

(vi) Define monsoons. What do you understand by “break” in monsoon?

(vii) Why is the monsoon considered a unifying bond?


(i) Six major controls are affecting the climate of India. These are latitude, altitude, pressure and wind system, and distance from the sea, ocean currents and relief features.

(ii) The occurrence of seasonal reversal of wind system makes the climate of India monsoon type. In other words, during summer, the winds blow from sea to land and during winter the reverse occurs.

(iii) The highest diurnal range of temperature is found in desert areas because sand gains and losses heat very quickly.

(iv) The South-West winds cause rainfall along the Malabar coast.

(v) Jet Streams are a narrow belt of high altitude (above 12,000 m.) westerly winds in the troposphere. Their speed varies from about 110km/h in summer to 184km/h in winter.

Jet streams blow over the south of the Himalayas all through the year, except for summer. In winter, the western cyclonic disturbances enter India by these jet streams.

Jet streams blow over peninsular India and it is considered to be responsible for the sudden outbreak of the South-West monsoon in India.

(vi) The word monsoon is derived from the Arabic word 'Mausim' which means the seasonal reversal in wind direction throughout the year. The monsoons are experienced in the tropical area roughly between 20° N and 20° S. Monsoons have wet and dry spells. Monsoon rains occur for a few days continuously and take a break for a few days. So, this duration of no rainfall or dry spell is called a monsoon break.

(vii) The unifying influence of the monsoon on the Indian subcontinent is quite visible. The seasonal changes of the wind systems and the related weather conditions give a rhythmic cycle of seasons. The uncertainties and unequal distribution of rain are typical traits of monsoons. The Indian landscape, animal, and plant life, entire agricultural schedule and the life of the people, including their festivities, revolve around this phenomenon.

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