INDIA:CLIMATE, VEGETATION AND WILDLIFE

THE CLIMATIC VARIATIONS

Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric pressure, wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time.

Climate is different from weather, in that weather only describes the short-term conditions of these variables in a given region. India has 'Tropical Monsoon' type of climate. The word monsoon has been derived from the Arabic word 'Mausim' means season. Monsoon refers to the seasonal reversal in the wind direction during a year .The whole of India has a tropical monsoonal climate, since the greater part of the country lies within the trophies, and the climate is influenced by the monsoons.

In summer the temperature of some parts of Rajasthan desert is 50 degree C. Whereas it may be 20 degree C in Pahalgam in Jammu & Kashmir. On a winter night, temperature at Drass in Jammu & Kashmir may be as low as -45 degree. Tiruvanantapuram, on the other hand, may have a temperature of 22 degree C. The position of the mountain ranges and direction of the rain-bearing winds are the two main factors that determine the climate of India . Alternating seasons is the chief characteristic of India's Climate. There are variations not only in the form and types of precipitation but also in its amount and the seasonal distribution Precipitation is mostly in the form of snowfall in the upper parts of Himalayas, it rains over the rest of the country. The annual precipitation varies from over 400 cm in Mawsynram in Meghalaya to less than 10 cm in Ladakh and western Rajasthan.

CLIMATIC ZONE OF INDIA

FACTORS THAT EFFECT CLIMATE

Latitudinal Extent:The latitudinal extent (from about 8 °N to 37 °N) is an important factor which influences the climatic conditions of this region. The southern half of India lies in the tropical belt close to the Equator, and is surrounded by water bodies.The northern half which is above the Tropic of Cancer lies in the temperate belt. This part is not only away from the Equator, but also away from the moderating influence of the water bodies. These two parts of India enjoy different climatic conditions due to their location and latitudinal extent.

Location of the Himalayas and Western and Eastern Ghats: Relief forms an important factor that affects the climate of India. The high Himalayan Mountain in the north act as a barrier to the south-west monsoon winds forcing the winds to shed most of its rainfall in India before crossing the Himalayas. The cold winds in winter from Central Asia are mainly obstructed from coming into India by these high Himalayas. So the severity of winter in India is not that intense. The Western and Eastern Ghats on either side of the Peninsular in South India force the monsoon winds to give plenty of rainfall in the coastal regions. Again, the eastern slopes of the Western Ghats fall in the rain-shadow area as the Western Ghat obstructs the monsoon winds and get heavy rainfall on the western slopes. .

Impact of Prevailing Winds:The monsoons are the prevailing winds over the whole of India. These winds are a unique feature of the climate of India. During the summer season, the monsoon wind covers the entire India and brings rainfall to practically every part of the country.

Altitude: Temperature decreases with increase in height at the rate of 6.5°C per 1000 meters difference in height. The high peaks of the Himalayas are thus always covered by snow. Shimla is therefore cooler than Delhi as it lies at a higher elevation. Ooty in the Nilgiris in the Western Ghats is cool even in summer because of its height though it lies near the equator.

Influence of the Water Bodies:The water bodies surrounding India, i.e. The Indian Ocean, the Bay of Bengal and the Arabian Sea, exert moderating influence on the climatic conditions. These water bodies provide much needed moisture to the summer monsoons, which provide heavy rainfall. Moreover, the climate of the coastal areas is also modified by the influence of these water bodies.The places which are in the interior experience continental climate, as they are far away from the moderating influence of the water bodies. Thus, such places experience very hot summer and cold dry winters. In contrast the coastal areas enjoy almost the same type of climatic conditions throughout the years.

LATITUDE

THE HIMALAYAS

IMPACT OF PREVALING WINDS

ALTITUDE

INFLUENCE OF SEA

SEASONS

The climate of India may be described as tropical monsoon. Even northern India, lying beyond the tropical zone, acquires a tropical touch marked by the relatively high temperatures. The large size of the country and its varied relief play a crucial role in determining the climatic variations in different part of India. But the seasonal rhythm of the monsoon is apparent throughout India. It may conveniently from the basis for dividing the year into different seasons. The most characteristic feature of the monsoon is the complete reversal of winds. It eventually leads to the alternation of seasons. India is known as the "land of the endless growing season". The year is divided into fours seasons :Winter, Summer ,Advancing Monsoon and Retreating Monsoon

WINTER

The winter season begins from mid-November and stays till February in northern India. December and January are the coldest months in the northern part of India. The temperature ranges between 10°-15°C in the northern plains, while it ranges between 24°-25°C in Chennai. The northeast trade winds prevail over the country in this season. As these winds blow from land to sea, most parts of the country experience a dry season. The inflow of the cyclonic disturbances from the west and the northwest is a characteristic feature of the cold weather over the northern plains. These low-pressure systems originate over the Mediterranean Sea and Western Asia and move into India. They cause winter rains over the plains and snowfall in the mountains. The winter rainfall is in small amount but is very important for the rabi crop in the north western India . This rainfall is locally known as mahawat The peninsular region does not get a well-defined winter because of the moderating influence of the sea.

WINTER-TEMPERATURE

WINTER-PRESSURE

WINTER RAINFALL

SUMMER

The summer season is from March to May. During this period, the global heat belt shifts towards north because of the apparent northward movement of the sun. During summer, the temperatures rise and air pressure falls in the northern part of the country. In March, the highest day temperatures of about 38 degree C occur in the Deccan Plateau. Therefore, Peninsular India places south of Satpuras experience temperature between 26-32 degree C. Central India, comprising of Delhi and Madhya Pradesh experience temperature between 40-45 degree C . North-West India, comprising mainly of Rajasthan has very high temperature more than 45 degree C, due also to features like sandy soil, direct insulation and lack of cloud cover. Towards the end of May, an elongated low-pressure area develops in the region which extends from the Thar Desert in the northwest to Patna and Chota Nagpur Plateau in the east and southeast . 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 .These cyclones contribute to the bulk of the rainfall of the Coromandel Coast.

SUMMER-LOCAL STORMS

Mango Showers (since the rain showers are good for the mango trees) occurs along the coast of Kerala .Kalbaisakhi in the month of Baisakh occurs in Assam and West Bengal. These are thunderstorms, accompanied with strong winds are heavy rainfall. This is good for the tea crop in Assam and the jute and rice in West Bengal. In Assam these storms are called Bardoli chherha .Loo is the name given to the hot, dry winds that blow in the Northern Plains. It is very common in Punjab, Haryana, Western Uttar Pradesh (called “Aandhi") and Bihar. Blossom Shower with this shower, coffee flowers blossom in Karnataka and its nearby areas.

SUMMER-TEMPERATURE

SUMMER-PRESSURE

LOCAL STROMS

ADVANCING MONSOON

The rainy season begins from early June. The low-pressure condition over the northern plains intensifies at this time. It attracts the trade winds from the southern hemisphere. These south-east trade winds cross the equator and blow in a south-westerly direction to enter the Indian peninsula as the south-west monsoon winds. These winds bring abundant moisture to the subcontinent. These winds blow at an average velocity of 30 km/h. The monsoon winds cover the country in about a month; barring the extreme north-west .The windward side of the Western Ghats receives very heavy rainfall, early in the rainy season. The Deccan Plateau and parts of Madhya Pradesh also receive some rain, in spite of lying in the rain shadow area. The north-eastern part of the country receives the maximum rainfall of this season. Mawsynram (Meghalaya) receives the highest average rainfall in the world. Rainfall in the Ganga valley decreases from east to west. Rajasthan and parts of Gujarat get scanty rainfall. The monsoon is famous for its uncertainties. It may cause heavy floods in one part of the country, and may be responsible for droughts in other part. Because of its uncertain behaviour, it sometimes disturbs the farming schedule in India. This affects millions of farmers all over the country.

RETREATING MONSOON

During October to November, the sun apparently moves towards the south. During this period, the monsoon over the northern plains becomes weaker. The south-west monsoon winds weaken and start withdrawing gradually. The monsoon withdraws from the northern plains by the beginning of October. The retreat of the monsoon is marked by clear skies and rise in temperature. While day temperatures are high, nights are cool and pleasant. Humidity is still present. High temperature and humidity, makes the weather quite uncomfortable during the day. This is commonly known as “October Heat”. The temperature begins to fall rapidly in northern India by the second half of October. The low-pressure conditions over north western India move to the Bay of Bengal by early November. This shift leads to cyclonic depressions over the Andaman Sea. These cyclones usually cross the eastern coasts of India and cause heavy and widespread rain. These cyclones may also arrive at the Coasts of Orissa, West Bengal and Bangladesh.

Difference between the Retreating S.W. Monsoon and North East Monsoon

They blow during the months of October to November

They blow during the months of January to mid March.

This is a season of transition between the hot, rainy season and the cold, dry season

This is the cold weather season

Characterised by oppressive head and humidity known as "October Heat"

This is a very pleasant season with low temperatures, low humidity, clear skies

They blow in the S.W. direction but are not strong enough to blow right into the Northern Plain.

These winds blow in N.E direction from the land to the sea.

The withdraw in stages which results in decreasing rain

They do not give rain.

IMPORTANCE OF MONSOONS

Rains are also important as they give respite to people after summers. Rains are also important for India as they help in maintaining the ecology and bio diversity of nature. Himalayan forests are completely dependent on rainfall as there is shortage of ground water in hilly areas. Though there are lakes in the hills, they too need to be recharged, for which they depend on monsoon showers. As 60% of India's economy depends on agriculture sector that provides employment to lacks of farmers, who in turn produce food grains for millions of people of our country. Steps should be taken to address the problems of global warming and deforestation. If proper efforts are made for water, soil and forest conservation, surely it would result in increased rains during monsoons which is a must for agriculture economy in India these days.

THE RAINFALL DISTRIBUTION

The distribution of rainfall surface of the Earth and the direction in any region is mostly influenced by the relief features on the of the rain-bearing winds in that region. Another important factor which influences the distribution of annual rainfall in India is the path followed by the cyclonic depressions. The region located on the windward side of mountains, hills or plateaus receives comparatively more rainfall than the leeward side.The average annual rainfall in India is about 120 cm. Most of this rainfall is received during four months (June, July, August and September) of the Southwest Monsoon season. The amount of annual rainfall varies not only from place to place, but also from season to season. In general, the monsoon rainfall is highly erratic.Many areas of the north-eastern part of India receive more than 500 cm of annual rainfall, while many parts in the Thar Desert receive less than 10 cm of annual rainfall. There are yearly variations in the distribution of annual rainfall and they are the root cause of floods, droughts and famines in India.Broadly, India can be divided into the following four regions, depending upon the average annual rainfall received by those regions.

Areas of Very Heavy Rainfall: The areas receiving an average rainfall of more than 200

cm are included in this region. The highest rainfall occurs along the Western Coastal plain, extending from Mumbai to Thiruvananthapuram, the western slopes of the Western Ghats, the southern slopes of the Eastern Himalayas, the sub-Himalayan areas in the northeast, the hills of Meghalaya. In certain parts of the Khasi and Jaintia Hills, in north-eastern India, the average annual rainfall generally exceeds 1000 cm, but drops to about 200 cm or even less in the Brahmaputra valley and the adjoining hills, which are located in the rain-shadow area. Meghalaya is the wettest part of India with Mawsynram and Cherrapunji getting about 1220 cm and 1100 cm of average annual rainfall respectively. This region does not experience drought conditions, but is subjected to frequent floods.

Areas of Heavy Rainfall: The areas receiving an average annual rainfall between

100 cm and 200 cm are included in this region. The eastern slopes of the Western Ghats, northern and middle Ganga valley, north-eastern peninsula, Manipur, coastal areas of Andhra Pradesh and Tamil Nadu are included in this region. Here irrigation is needed as a protective measure against drought.

Areas of Low Rainfall: The areas receiving an average annual rainfall between 50 cm

and 100 cm are included in this region. The Upper Ganga Valley, eastern Rajasthan, Punjab, Haryajia, Kashmir and large parts of Gujarat, Maharashtra, Western Madhya Pradesh, Andhra Pradesh, Karnataka, and Tamil Nadu, are included in this region. Large irrigation projects have been developed to overcome the danger of droughts and famines.

Areas of Very Low Rainfall: The areas receiving an average annual rainfall of less than 50

cm are included in this region. Here the desert and semi- desert conditions prevail. The areas included are the rain-shadow areas in the Deccan Plateau, north Kashmir, southern Punjab, western Rajasthan and Kachchh. There is an acute shortage of water in these areas.

NATURAL VEGETATION

NATURAL VEGETATION

We see a variety of plant life in our surroundings. How nice it is to play in field with green grasses. There are also small plants called bushes and shrubs like cactus and flowering plants etc. Besides there are many tall trees some with many branches and leaves like neem, mango or some which stand with few leaves such as palm. The grasses, shrubs and trees, which grow on their own without interference or help from human beings are called natural vegetation. Do you wonder how these differ from each other. Different types of natural vegetation are dependent on different climatic conditions, among which the amount of rainfall is very important. Due to varied climatic conditions, India has a wide range of natural vegetation. Vegetation of India can be divided into five types – Tropical evergreen forest, Tropical deciduous forest, Thorny bushes, Mountain vegetation and Mangrove forests.

TYPES OF VEGETATION

(i) Tropical Evergreen Forests

(ii) Tropical Deciduous Forests

(iii) Tropical Thorn Forests and Scrubs

(iv) Mountain Forests

(v) Mangrove Forests

Natural Vegetation

TROPICAL EVERGREEN FORESTS

These forests are restricted to heavy rainfall areas of the Western Ghats and the island groups of Lakshadweep, Andaman and Nicobar, upper parts of Assam and Tamil Nadu coast. They are at their best in areas having more than 200 cm of rainfall with a short dry season. The trees reach great heights up to 60 meters or even above. Since the region is warm and wet throughout the year, it has a luxuriant vegetation of all kinds – trees, shrubs, and creepers giving it a multilayered structure. There is no definite time for trees to shed their leaves. As such, these forests appear green all the year-round. Some of the commercially important trees ofth is forest are ebony, mahogany, rosewood, rubber and cinchona. The common animals found in these forests are elephants, monkey, lemur and deer. The one horned rhinoceros are found in the jungles of Assam and West Bengal. Besides these animals plenty of birds, bats, sloth, scorpions and snails are also found in these jungles.

TROPICAL DECIDUOUS FORESTS

TROPICAL DECIDUOUS FORESTS

These are the most widespread forests of India. They are also called the monsoon forests and spread over the region receiving rainfall between 200 cm and 70 cm. Trees of this forest-type shed their leaves for about six to eight weeks in dry summer. On the basis of the availability of water, these forests are further divided into moist and dry deciduous. The former is found in areas receiving rainfall between 200 and 100 cm. These forests exist, therefore, mostly in the eastern part of the country – northeastern states, along the foothills of the Himalayas, Jharkhand, West Orissa and Chhattisgarh, and on the eastern slopes of the Western Ghats. The dry deciduous forests are found in areas having rainfall between 100 cm and 70 cm. These forests are found in the rainier parts of the peninsular plateau and the plains of Bihar and Uttar Pradesh. Some of the commercially important trees of the forest are Teak, Sal, Peepal, Neem grow. A large part of this region has been cleared for cultivation and some parts are used for grazing. In these forests, the common animals found are lion, tiger, pig, deer and elephant.

THE THORN FORESTS AND SCRUBS

THE THORN FORESTS AND SCRUBS In regions with less than 70 cm of rainfall, the natural

vegetation consists of thorny trees and bushes. This type of vegetation is found in the north-western part of the country including semi-arid areas of Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Uttar Pradesh and Haryana. Trees are scattered and have long roots penetrating deep into the soil in order to get moisture. The stems are succulent to conserve water. Leaves are mostly thick and small to minimize evaporation. These forests give way to thorn forests and scrubs in arid areas. Some of the commercially important trees of the forest are Acacias, palms, euphorbia's and cacti. In these forests, the common animals are rats, mice, rabbits, fox, wolf, tiger, lion, wild ass, horses and camels.

MOUNTAIN FORESTS

MOUNTAIN FORESTS

In mountainous areas, the decrease in temperature with increasing altitude leads to the corresponding change in natural vegetation.The wet temperate type of forests are found between a height of 1000 and 2000 meters. Evergreen broad-leaf trees such as oaks and chestnuts predominate. Between 1500 and 3000 meters, temperate forests containing coniferous trees. These forests cover mostly the southern slopes of the Himalayas, places having high altitude in southern and north-east India. At higher elevations, temperate grasslands are common.These are used extensively for grazing by nomadic tribes like the Gujjars and the Bakarwals. At higher altitudes, mosses and lichens form part of tundra vegetation. The common animals found in these forests are Kashmir stag, spotted dear, wild sheep, jack rabbit, Tibetan antelope, yak, snow leopard, squirrels, Shaggy horn wild ibex, bear and rare red panda, sheep and goats. Some of the commercially important trees of the forest are pine, deodar, silver fir, spruce and cedar.

MANGROVE FORESTS

MANGROVE FORESTS

The mangrove or tidal forests are found in the areas of coasts influenced by tides. Mud and silt get accumulated on such coasts. Dense mangroves are the common varieties with roots of the plants submerged under water. The deltas of the Ganga, the Mahanadi, the Krishna, the Godavari and the Kaveri are covered by such vegetation. In the Ganga-Brahamaputra delta, sundari trees are found, which provide durable hard timber. Royal Bengal Tiger is the famous animal in these forests. Turtles, crocodiles, gharials and snakes are also found in these forests. Some of the commercially important trees of the forest are Palm, coconut, keora, agar & sundari trees. The common animals found in these forests are tigers ,turtles, crocodiles, gharials and snakes.

WHY ARE FORESTS NECESSARY?

Forests are very useful for us. They perform various functions. Plants release oxygen that we breathe and absorb carbon dioxide. The roots of the plants bind the soil; thus, they control soil erosion. Forests provide us with timber for furniture, fuel wood, fodder, medicinal plants and herbs, lac, honey, gum, etc. Forests are the natural habitat of wild life. Natural vegetation has been destroyed to a large extent because of the reckless cutting of trees. We should plant more trees and protect the existing ones and make people aware of the importance of trees. We can have special programmes like Van Mahotsav to involve more people in making our earth green.

WILDLIFE

WILDLIFE

Forests are home to a variety of wild life. There are thousands of species of animals and a large variety of reptiles, amphibians, mammals, birds, insects and worms which dwell in the forest.

The tiger is our national animal. It is found in various parts of the country. Gir forest in Gujarat is the home of Asiatic lions. Elephants and one-horned rhinoceroses roam in the forests of Assam. Elephants are also found in Kerala and Karnataka. Camels and wild asses are found in the Great Indian desert and the Rann of Kuchchh respectively. Wild goats, snow leopards, bears, etc. are found in the Himalayan region. Besides these, many other animals are found in our country such as monkey, wolf, jackal, nilgai, cheetal, etc.

India is equally rich in bird life. The peacock is our national bird. Other common birds are parrots, pigeons, mynah, geese, bulbul and ducks. There are several bird sanctuaries which have been created to give birds their natural habitat. These provide the birds protection from hunters.

Some birds such as the Pelican, Siberian Crane , Stork, Flamingo, Pintail Duck and Curlew migrate to our country in the winter season every year. Siberian Cranes migrate from Siberia. They arrive in December and stay till early March.

There are several hundreds of species of snakes found in India. Cobras and kraits are important among them.

CONSERVING WILDLIFE

Due to cutting of forests and hunting, several species of

wildlife of India are declining rapidly. Many species have already become extinct. In order to protect them many national parks, sanctuaries and biosphere reserves have been set up. The Government has also started Project Tiger and Project Elephant to protect these animals.

We can also contribute in conserving wildlife. You can refuse to buy things made from parts of the bodies of animals such as their bones, horns, fur, skins and feathers. Every year we observe wildlife week in the first week of October, to create awareness of conserving the habitats of the animal kingdom.

PRESENTED BY:AARUSHI GOYAL