Climate
(l-4) class 9th
Q1. Distinguish between weather and climate.
Ans. Climate refers to the sum total of weather conditions
and variations over a large area for a long period of time.
Weather refers to the state of the atmosphere over an area
at any point of time.
Q2. What are the elements for measuring weather and climate of a place?
Ans. Temperature, atmosphere, atmospheric pressure, wind,
humidity and precipitation.
Q3. Define the monsoon.
Ans. The word monsoon is derived from the Arabic word ‘mausim’
which literally means season. Monsoon refers to the seasonal reversal in the
wind direction during a year.
Q4. Mention the factors that affect the climate of a place?
Ans. There are six major controls of the climate of any
place. They are lattitude, altitude, pressure and wind system, distance from
the sea, ocean currents and relief features.
Latitude- Due to the curvature of the earth, the amount of
solar energy received varies according to latitude.
Altitude - As one goes from the surface of the earth to
higher altitudes, the atmosphere becomes less dense and temperature decreases.
Pressure and wind - The pressure and wind system of any area
depend on the latitude and altitude of the place.
Distance from the
sea- As the distance from the sea increases, its moderating influence decreases
and the people experience extreme weather conditions. (i.e. very hot during summers and very cold
during winters).
Ocean currents- Ocean
currents along with onshore winds affect the climate of the coastal areas.
Relief- relief too plays a major role in determining the
climate of a place. High mountains act as barriers for cold or hot winds; they
may also cause precipitation if they are high enough and lie in the path of
rain-bearing winds. The leeward side of mountains remains dry.
Q5. Explain how latitude and altitude affect the climate of
India?
Lattitude- The Tropic of Cancer passes through the middle of
the country from the Rann of Kuchchh in the west to Mizoram in the east. Almost
half of the country, lying south of the Tropic of Cancer, belongs to the
tropical area. All the remaining area, north of the Tropic, lies in the
sub-tropics. Therefore, India’s climate has characteristics of tropical as well
as subtropical climates.
Altitude- India has mountains to the north. The Himalayas
prevent the cold winds from Central Asia from entering the subcontinent. It is
because of these mountains that this subcontinent experiences comparatively
milder winters as compared to central Asia.
Q6. Mention 3 atmospheric conditions which govern the
climate and associated weather condition in India?
Ans. The climate and associated weather conditions in India
are governed by the following atmospheric conditions:
• Pressure and
surface winds;
• Upper air
circulation; and
• Western cyclonic disturbances and tropical cyclones.
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Q7. Discuss the mechanism of monsoon in India.
Ans. The monsoons are experienced in the tropical area roughly
between 20° N and 20° S. To understand the mechanism of the monsoons, the
following facts are important.
(a) The differential
heating and cooling of land and water creates low pressure on the landmass of
India while the seas around experience comparatively high pressure.
(b) The shift of the position of Inter Tropical Convergence
Zone (ITCZ) in summer, over the Ganga plain .
(c) The presence of the high-pressure area, east of
Madagascar, approximately at 20°S over the Indian Ocean.
(d) The Tibetan plateau gets intensely heated during summer,
which results in strong vertical air currents and the formation of high
pressure over the plateau at about 9 km above sea level.
(e) The movement of the westerly jet stream to the north of
the Himalayas and the presence of the tropical easterly jet stream over the
Indian peninsula during summer.
Q8. State the main features of cold weather season in India.
Ans. The cold weather season begins from mid November in
northern India and stays till February. 2. December and January are the coldest
months in the northern part of India.
3. The temperature decreases from south to the north.
4. Days are warm and nights are cold.
5. Frost is common in the north and the higher slopes of the
Himalayas experience snowfall.
Q9. State the main features of hot weather season in india.
Ans. The hot weather season begins from March and stays till
May.
2. The summer months experience rising temperature and
falling air pressure in the northern part of the country.
3. A striking feature of the hot weather season is the
‘loo’.
4. Dust storms are very common during the month of May in
northern India.
5. Days are long and nights are short.
Q10. State any 3 characteristic features of advancing
monsoon?
Ans. By early June, the low-pressure condition over the
northern plains intensifies.
2. It attracts, the trade winds of the southern hemisphere.
3. As these winds blow over warm oceans, they bring abundant
moisture to the subcontinent. These winds are strong and blow at an average
velocity of 30 km per hour.
Q11. State any 3 characteristic features of retreating
monsoon monsoon?
Ans. During October-November, with the apparent movement of
the sun towards the south, the monsoon trough or the low-pressure trough over
the northern plains becomes weaker.
2. The south-west monsoon winds weaken and start withdrawing
gradually.
3. By the beginning of October, the monsoon withdraws from
the Northern Plains.
Q12. “The monsoon of india is known for its uncertanities.”
Explain
Ans. The monsoon is known for its uncertainties. The
alternation of dry and wet spells vary in intensity, frequency and duration.
While it causes heavy floods one part, it may be responsible for droughts in
the other. It is often irregular in its arrival and its retreat. Hence, it
sometimes disturbs the farming schedule of millions of farmers all over the
country.
Q13. Explain the distribution of rainfall as a result of
monsoon winds in India
Ans. The western coast and northeastern India receive over
about 400 cm of rainfall annualy.
2.it is less than 60
cm in western Rajasthan and adjoining parts of Gujarat, Haryana and Punjab.
3. Rainfall is
equally low in the interior of the Deccan plateau, and east of the Sahyadris.
4. A third area of
low precipitation is around Leh in Jammu and Kashmir.
5. The rest of the
country receives moderate rainfall. Snowfall is restricted to the Himalayan
region.
Q14. Explain how monsoon acts as a unifying bond in India.
Ans. The seasonal alteration of the wind systems and the
associated weather conditions provide a rhythmic cycle of seasons.
2. Even the uncertainties of rain and uneven distribution are
very much typical of the monsoons.
3. The Indian landscape, its animal and plant life, its
entire agricultural calendar and the life of the people, including their
festivities, revolve around this phenomenon.
4.Year after year, people of India from north to south and
from east to west eagerly await the arrival of the monsoon.
5. These monsoon winds bind the whole country by providing
water to set the agricultural activities in motion.
