CLIMATES OF INDIA

MAHESH DIGAMBER JOSHIM.Sc [First Semester]

Presentation

CLIMATE OF INDIA Likewise the specialty of

unity in diversity in India, we can observe similar features in the climates of India.

In the space of a couple of hours one can reach through a range of the cold crisp air of the mountains to the burning dry heat of the Rajasthan Desert where summer temperature regularly reach 45°C and beyond.

TROPICAL WEATHER India's geography and geology are

climatically important. The whole of India has a tropical

monsoonal climate, since the greater part of the country lies within the trophies, the climate is influenced by the monsoons.

The position of the mountain ranges and direction of the rain-bearing winds are the two main factors that determine the climate of India

FACTORS AFFECTING THE CLIMATE OF INDIA

Latitude: India lies between 8 0 N and 37 0 N latitudes. The Tropic of Cancer passes through the middle of India, thus making the southern half of India in the Torrid Zone and the northern half in the Temperature Zone.

Altitude: Temperature decreases with height. Places in the mountains are cooler than places on the plains.

Himalaya Mountains: The Himalayas play an important role in lending a sub-tropical touch to the climate of India. The Himalaya Mountains form a barrier which effects the climate of India. It prevents the cold winds of north Asia from blowing into India, thus protecting it from severely cold winters. It also traps the Monsoon winds, forcing them to shed their moisture within the sub-continent.

Distance from the sea: With a long coastline, large coastal areas have an equable climate. Areas in the interior of India are far away from the moderating influence of the sea. Such areas have extremes of climate.

Geographical Limits: Western Disturbances: The low pressure systems that originate over the eastern

Mediterranean region in winter and move eastwards towards India passing over Iran, Afghanistan and Pakistan are responsible for the winter rain in northern India.

Conditions in the Regions Surrounding India: Temperature and pressure conditions in East Africa, Iran, Central Asia and Tibet determine the strength of the monsoons and the occasional dry spells.

Conditions over the Ocean: The weather conditions over the Indian ocean and the China Sea may be responsible for typhoons which often affect the east coast of India.

Jet Streams: Air currents in the upper layers of the atmosphere known as jet steams could determine the arrival of the monsoons and departure of the monsoons. The Scientists are studying the jet streams and how it may affect the climate of India but much remains to be learned about this phenomena.

FACTORS AFFECTING THE CLIMATE OF INDIA

CLIMATIC REGIONS OF INDIAThe subcontinent has eight climatic zones all of which only have the monsoon rains in common.

Tropical Rain Forest: This type of climate is found on the west coastal plain and Sahyadris and in

parts of Assam The temperatures are high, not falling below 18.2 degree c even during winter

and rising to 29 degree C in April and May, the hottest months. Dense, forests and plantation agriculture with crops like tea, coffee and spices

are the characteristics in the area. Tropical savanna:

Most of the peninsula , except the semiarid zone in the leeside of the Sahyadris experiences this type of climate.

A long dry weather lasting through winter and early summer and high temperature remaining above 18.2 degree C even during the winter seasons and rising as high as 32 degree C in summer are the chief characteristics of this climate.

Nagpur has a mean temperature of 35.4 degree C for May which is the hottest month and 20.7 degree C for December the coldest month in the year.

The natural vegetation all over the area is savanna.

Tropical Semi-Arid Steppe Climate: The rain-shadow belt, running southward from

central Maharashtra to Tamil Nadu, in the leeside of the Sahyadris and Cardamom Hills come under this type of climate of low and uncertain rainfall.

Temperature varying from 20 degree C to 23.8 degree C for December and 32.8 degree C for May. Agriculturally, the climate is suitable only for dry farming and livestock rearing.

Tropical and Sub-Tropical Steppe: This type of climate occurs over a broad crescent

from Punjab to Kachchh between the Thar Desert to its west and the more humid climates of the Ganga Plain and the Peninsula to its east and south respectively.

The climate, therefore, is transitional between these two areas. The annual rainfall is not only low but it is also highly erratic.

CLIMATIC REGIONS OF INDIA

Tropical Desert : The western part of Barmer, Jaisalmer and

Bikaner districts of Rajasthan and most of the part of Kachchh form the sandy wastes of the Thar which experiences a typical desert climate.

Ganganagar has recorded a maximum temperature of 50 degree C, the highest record.

Humid Sub-Tropical With Winter: A large area to the south of the Himalayas, east

of the tropical and sub-tropical steppe and north of the tropical savanna running in a long belt from Punjab to Assam with a south-westward extension into Rajasthan east of the Aravalli Range, has this type of climate.

Winers are dry except for a little rain received from the westerly depressions.

CLIMATIC REGIONS OF INDIA

Mountain Climate: The Himalayan and Karakoram ranges experience this type of climate

with sharp contrasts between the temperatures of the sunny and shady slopes, high diurnal range of temperatures and high variability of rainfall.

The trans-Himalayan region, Ladakh, where the south-west monsoon fails to reach, has a dry and cold climate and a spare and stunned vegetation.

CLIMATIC REGIONS OF INDIA

Drought in India: The dry areas of Rajasthan and the adjoining part of Haryana and Gujarat are liable to frequent drought conditions. Another area liable to frequent drought lies on the leeward side of the western Ghats.

MONSOON India has 'Tropical Monsoon' type of climate. The word monsoon

has been derived from the Arabic word 'Mausim' which means seasonal reversal of the winds during the course of the year.

PHENOMENA OF MONSOON Monsoon is a four-month period when massive

convective thunderstorms dominate India's weather, is Earth's most productive wet season. 

A product of southeast  winds originating from a high-pressure mass centered over the southern Indian Ocean, supply over 80% of India's annual rainfall. 

Attracted by a low-pressure region centered over South Asia, the mass spawns surface winds that ferry humid air into India from the southwest. 

These inflows ultimately result from a northward shift of the local jet stream, which itself results from rising summer temperatures over Tibet and the Indian subcontinent.

PHASES OF MONSOON The southwest monsoon arrives in two branches: The  Bay of Bengal branch ,

The  Arabian sea branch. The latter extends towards a low-pressure area over the Thar Desert and is roughly three times stronger than the Bay of Bengal branch.The monsoon typically breaks over Indian territory by around 25 May, when it lashes the  Andaman and nicobar islands in the Bay of Bengal.

It strikes the Indian mainland around 1 June near the malabar coast of Kerala. By 9 June, it reaches Mumbai; it appears over Delhi by 29 June.

The Bay of Bengal branch, which initially tracks the Coromandal Coast northeast from cape comorin to Orissa, swerves to the northwest towards the indo-gangetic plain. The Arabian Sea branch moves northeast towards the Himalayas. By the first week of July, the entire country experiences monsoon rain; on average, South India receives more rainfall than North India. However, northeast India receives the most precipitation. Monsoon clouds begin retreating from North India by the end of August; it withdraws from Mumbai by 5 October. As India further cools during September, the southwest monsoon weakens. By the end of November, it has left the country

POST MONSOON During the post-monsoon months of October to December, a

different monsoon cycle, the northeast monsoon, brings dry, cool, and dense Central Asian air masses to large parts of India.

Winds spill across the Himalayas and flow to the southwest across the country, resulting in clear, sunny skies. 

Though the  india meteorological department (IMD) and other sources refers to this period as a fourth ("post-monsoon") season, other sources designate only three seasons. Depending on location, this period lasts from October to November, after the southwest monsoon has peaked. Less and less precipitation falls, and vegetation begins to dry out. Average daily maximum temperatures range between 28 and 34 °C (82 and 93 °F).

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