GEOGRAPHY (IX)-LESSON-4
CLIMATE
(LESSON NOTES)
____________________________________________________________
v INTRODUCTION
Ø
There are three basic elements to know about the natural environment of
any area as landforms, drainage and climate.
Ø
In this lesson we will know about the climate of India.
v CLIMATE AND WEATHER
WEATHER |
CLIMATE |
The atmospheric condition
of any area in a point of time is referred as weather. |
Climate refers to the sum total of weather
conditions and variations over a large area. |
It is measured as point
of time. |
It is measured over a
long period of time (30 years average) |
Example- Sunny day,
cloudy day, calm day |
Example-moderate climate,
extreme climate, |
v ELEMENTS OF CLIMATE AND
WEATHER
Ø The elements of climate and
weather are same as: -
§ Temperature
§ Humidity
§ Air pressure
§ Cloudiness or sunshine
§ Precipitation (Rainfall or
snowfall)
§ Wind
Ø As we know that the weather
conditions fluctuate very often within a day. Based on the generalized
atmospheric conditions, the year is divided into seasons such as winter, summer
and rainy seasons.
Ø The world is divided into a
number of climatic regions. In Asia, India and other South and South-Eastern
countries have monsoon type of climate.
v MONSOON
Ø
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.
v
REGIONAL CLIMATIC VARIATION IN INDIA
Ø
Although there is an overall unity in the general climatic pattern in
India, there are some perceptible regional variations. We will see the
variation by taking two elements: -
Ø
TEMPERATURE
§
The temperature in the winter in North-Western mountainous regions can
go down to – 45° C (at Drass in Jammu and Kashmir), while it is 22°C in
Thiruvananthapuram in Kerala.
§
Similarly, it can go up to 50°C in summer in some parts of Western
Rajasthan and 20°C in Shillong.
§
In many areas, there is a wide variation between day and night
temperatures. In the Thar Desert, the day temperature may rise up to 50°C and
drop down to near 15°C the same night. On the other hand, there is hardly any
difference in day and night temperatures in the Andaman and Nicobar Islands or
in Kerala.
Ø
PRECIPITATION
§
There is a wide variation observed in its amount and seasonal
distribution. The annual precipitation varies from over 400 cm in Meghalaya to
less than 10 cm in Ladakh and Western Rajasthan.
§
Precipitation in the form of snowfall occurs only in upper parts of
Himalayas, the rest of the country receives rainfall.
§
Most parts of the country receive rainfall from June to September, but
the Tamil Nadu coast gets most of its rain during October and November.
Ø CONCLUSION
§
By these variations we can see that Coastal regions experience mild
temperature compare to the interior regions.
§
The rainfall also decreases from East to West.
§
Such differences help to create a variety in lives of people— the food
they eat, the clothes they wear, the kind of houses they used for living and so
on.
v
CLIMATIC CONTROLS
Ø
Permanent factors which govern the general nature of the climate of any
location on the earth are called factors of Climatic Controls. There are six
major controls of the climate of any place.
§
Latitude: - Due to the curvature of the earth, latitude changes the amount of
solar energy received. As a result, temperature decreases from the equator
towards the poles.
§ Altitude: -It refers to the height above mean sea level. With increase of height from the earth surface, the temperature decreases and air becomes less dense. Therefore, hilly regions are cooler in summer.