INDIAN CLIMATE- notes

 

INDIAN CLIMATE

The main factors which influence on the climate of India are location, water bodies, relief features and monsoon winds. So, the climate of India varies from one region to another and from season to season. Climatic Seasons : The climate of India according to the meteorological department of India can be divided into 4 seasons. 1. The Winter Season (December to February) 2. The Summer Season (March to May) 3. The Rainy Season (June to Mid September) 4. The Retreating Monsoon Season (Mid September to November)

1. The Winter Season : During this season the rays of the Sun fall vertically over the Southern Hemisphere, India gets oblique rays of the Sun. Hence the temperature and humidity are low and the sky is clear. It is cool in the north and warm in the south. January is the coldest month. The hilly areas of Kashmir and Himachal Pradesh record the lowest temperature. The Dras near Kargil has recorded the lowest temperature (-40C). Dew and fogs are common. There is heavy snow fall in the mountain areas. India gets only 2% of its annual rainfall during winter.

2. The Summer Season : During this season the Sun’s rays fall vertically over the Northern Hemisphere. Hence the temperature is high in India. It is hot, dry and sultry. The highest recorded temperature is 49.40C at Ganganagar in Rajasthan. Convectional rain occurs locally in some parts of the country. It is known as ‘Andhis’ in Uttar Pradesh, ‘Kalabaisakhis’ in the West Bengal. ‘Mango showers’ in Kerala as it help the mango crop and coffee blossom in Karnataka as it is beneficial to the coffee crop. India receives only 10% of its annual rainfall during summer.

3. The Rainy Season : It is also known as “the South West Monsoon” season. Since the temperature rises by the end of summer season, a low pressure area is developed over central India. On the other hand there is high pressure over the Indian Ocean. Hence the moisture laden winds blow from the south-west towards India. They bring rainfall to different parts of the country. About 75% of the rainfall causes during this season. There are two branches of the South - West Monsoons: the Arabian Sea branch and the Bay of Bengal branch. The Arabian Sea branch strikes the western Ghats and causes heavy rainfall to the western side of the Western Ghats.

The rain fall decreases towards the eastern slopes of Western Ghats, as it lies in the ‘rain - shadow area’. The Bay of Bengal branch causes heavy rainfall, when it strikes against the hills of Meghalaya and Assam. The heaviest rainfall occures at ‘Mawsynram’ in Meghalaya. The rainfall decreases towards the north west. 4. The Retreating Monsoon Season :

 In early October due to decrease of temperature low pressure area is gradually replaced by high pressure over the land mass. A low pressure area is developed over the Bay of Bengal. As a result the south west monsoon starts to retreating and it blowing from North - East. Hence this season is also known as ‘North-East Monsoon Season’. It is a season of unsettled weather conditions. India receives only 13% of its annual rainfall during this season. The coast of TamilNadu, Andhra Pradesh and Odisha get rainfall during this season. Tropical cyclones frequently occur in the Bay of Bengal during this season and cause some damage along east coast. Distribution of Rainfall : On the basis of the amount of rainfall India can be divided into 3 broad zones.

i) Areas with low rainfall (less than 50cm) : It includes Western Kutch, the Thar desert o f Rajasthan and its adjoining areas like western Punjab, Haryana and Gujarat, north of Zaskar range and the rain shadow area o f the Western Ghats. Ruyly in Jaisalmar of Rajasthan is receives least amount of rainfall (8.3 cm) and is the driest place in India. ii) Areas with medium rainfall (50-100 cms) :

It is a long belt extending from Northern Punjab to cape of Kanyakumari. It is broader in the north and narrower in Peninsular India between the Western Ghats and the Eastern Ghats. iii) Areas with heavy rainfall (100-250 cm) : It is found in 4 separate belts - a) a narrow belt in Western Ghats, b) a belt from Jammu hills through Himachal Pradesh, Northern Uttar Pradesh, Bihar and West Bengal, c) North eastern India, Mawsynram located in this zone gets the heviest rainfall. d) West coast and the Western side of Western Ghats etc