Rains in india essay
Essay on Monsoon
Essay on Monsoon!
Meaning of Monsoon:
The word Monsoon is derived from an Arabic word which means season. Monsoons are systems of seasonal wind which blow with consistency and regularity from oceans to continents in summer and in the reverse direction in winter. These wind changes are caused due to differential annual heating and cooling of continents and adjoining oceans. These winds are largely confined to tropical belt. They are especially more pronounced over Indian subcontinent between June and September each year. The monsoons associated with other continental masses are not so marked as the Indian monsoons.
The Indian monsoons are widely known owing to its excessive rainfall during summer and equally excessive dryness during winter. From October to December, however, a branch of north-east trade winds sweep across the Bay of Bengal and causes precipitation over Southern half of the Indian Peninsula. This is called North-East or Winter Monsoon of India. Due to its vagaries the monsoons create great impact on the Indian Agriculture. It calls for greater understanding of the processes involved in creation of monsoons.
Classification of Clouds and Monsoon Clouds:
The first classification of clouds is due to Luke Howard who, in 1803, introduced the Latin names Cirrus, Cumulus, Nimbus and Stratus for different forms of clouds. The International Cloud Atlas published by the World Meteorological Organisation recognizes ten main types of clouds.
Their main features are:
Cloud base at 6 km or higher:
I. Cirrus (meaning curl):
It is a detached fibrous cloud in the form of white feathers of narrow bands. All cirrus type clouds are composed of minute ice crystals and do not cause precipitation.
They are thin white layers of high clouds, without shading.
They are transparent white clouds through which halos are often seen.
Cloud base at or above 2 km.
It is a white or grey layer cloud sometimes seen in the form of rolls or round globules.
It is a greyish cloud sheet. Halos cannot be seen through Altostratus clouds.
Clouds extending from the surface to 2 km.
It is generally a grey cloud layer of uniform base. It resembles fog but does not rest on ground.
It is in the form of grey or white patches. They often appear as rolls or rounded masses of clouds.
Another three species which are frequently observed during the monsoon months are the following:
They are detached clouds with sharp outlines. Rising towers or domes are often seen within a Cumulus cloud.
They are heavy and dense shower clouds with tops spread out in the form of an anvil.
They are grey or dark cloud layers from which we observe continuous rain.
Monsoon Weather Systems:
Over 70 per cent of annual rainfall over India is recorded during southwest monsoon from June to September. The heaviest rainfall is recorded along west-coast, in which orographic features play important role. It may be mentioned that it is however, not the sole factor of importance for monsoon rain.
Rainfall also comes in association with thunder storms, for example, in April and May. This type of rainfall is generally of transient nature. Often the intensity of precipitation is very high. On the contrary monsoon rain is continuous rain spread over days and its intensity is not as high as that of convective rain. During monsoon there are occasions of “cloud bursts”. The cloud bursts are the result of violent convective activity over small areas of limited extent of course such occasions are comparatively rare.
A significant portion of monsoon rainfall over the greater portion of India is closely associated with movement of cyclonic depressions from the Bay of Bengal. When a cyclone or a depression representing a region of low pressure forms in the Bay of Bengal the pressure begins to fall over a wide region of several hundred kilometers.
The wind, in response to the pressure gradient adopts anticlockwise cyclonic circulation. As the depression moves from the head of the Bay of Bengal towards the coast, a belt of heavy rainfall extends to the southern and south-eastern parts of West Bengal and lower Assam. With further movement of the storm westward the rain belt extends to Orissa and Bihar.
As the storm proceeds and enters Madhya Pradesh the presence of this depression strengthens the Arabian Sea branch of the monsoon. This causes another spell of moderate to heavy rain over Madhya Pradesh and southern parts of Uttar Pradesh. The depression then may carry rainfall further to Rajasthan and Gujarat. Sometimes the depression may re-curve towards the north and breakup in the sub-himalayan region of Punjab. In such situation the Arabian Sea branch of the Monsoon feeds extra moisture in the storm area and heavy rainfall is recorded in Punjab.
Generally after the passage of a depression the monsoon weakens and the rains slacken. After a gap of few days, however, the monsoon tends to revive and another depression is formed at the head of the Bay of Bengal.
Thus, with a certain degree of periodicity monsoon rainfall occurs over northern and central parts of India. On an average about 8 cyclonic depressions pass from the Bay of Bengal over the Indian land mass between June and September. The monsoons are also frequently accompanied by violent storms of hurricane type. Sometimes the atmospheric pressure falls much below than what is observed in depression. The region of low pressure is more localized and air acquires much greater cyclonic spin. The depression is then said to concentrate into a tropical storm or a cyclone.
The Distribution of Rainfall in India – Essay
Rainfall is the important element of the Indian economy. Although the monsoons affect most part of India, the amount of rainfall varies from very heavy to scanty on different parts.
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There is great regional and temporal variation in the distribution of rainfall. Over 80% of the annual rainfall is received in the four rainy months of June to September. The average annual rainfall is about 125 cm. but it has great spatial variations.
(a) Areas of Heavy Rainfall (Over 200 cm): Assam, West Bengal, West Coast and Southern slopes of eastern Himalayas.
(b) Areas of Moderately Heavy Rainfall (100-200 cm): Western Ghats, eastern Maharashtra, Madhya Pradesh, Orissa, the middle Ganga valley.
(c) Areas of Moderate Rainfall (50-100 cm): Upper Ganga valley, eastern Rajasthan, Punjab, Southern Plateau of Karnataka, Andhra Pradesh and Tamil Nadu.
(d) Areas of Scanty Rainfall (Less than 50 cm): Northern part of Kashmir, Western Rajasthan and Punjab and Deccan Plateau. The two significant features of India’s rainfall is that (a) in the north India, rainfall decreases westwards and (b) in Peninsular India, except Tamil Nadu, it decreases eastward.
Variability of Rainfall:
The large variation in actual amount of rainfall from year to year is expressed in terms of co-efficient of variation as per the following formula:
Coefficient of Variation
(C)= Standard Deviation/Mean × 100
The values of coefficient of variation show the change from the mean values of rainfall. The coefficient of annual rainfall in India generally ranges from 20 to 50%. A variability of less than 25 per cent exists on the western coasts, Western Ghats, north eastern peninsula, eastern plains of Ganga, north eastern India, Uttarakhand and H. P and south western parts of J and K. These areas have an annual rainfall of over 100 cm.
A variability of over 50% exists in the western parts of Rajasthan, northern parts of J & K and interior parts of Deccan plateau. These areas have an annual rainfall of less than 50 cm. The Rest of India has a variability of 25 to 50%. Higher the rainfall, lower is the variability of rainfall.
Land of Rain:
It is Cherrapunji is the land of rain, the village, which receives rain throughout the year is the rainiest place on earth for many centuries, is situated about 56kms from Shillong, the capital of Meghalaya in a height of about 4500ft above MSL in between Khasi, Gharo and Jaintia hills.
The Britishers pronounced the word Sohra as Chira. ‘Sohra’ means not suitable for cultivation, ‘punji’ means soil. ‘Cherrapunji’ means the soil not suitable for cultivation. This region has very poor topsoil has large reserves of coal and limestone beneath.
Therefore water is not available in the wells in this region although the topsoil is wet due to rainfall year round. The coveted place of Cherrapunji with an average rainfall greater than 1080 cms was taken over by another place in India some years back.
Mousinram, 6 km away from Cherrapunji was the place that captured the position. The Hawaiian Islands have also claimed the honour of being the rainiest spot on earth. But recently Cherrapunji has come back to regain the first place. Our neighbouring country Bangladesh prays not to have heavy rains in Cherrapunji for the reason that when heavy rainfall occurs in Cherrapunji many places in Bangladesh will get inundated.
Spatio Temporal Variation in the Rainfall:
1. Though the jet streams go a long way in explaining the origin of monsoon some questions remain unanswered. The great variation in the amount of rainfall both spatially and temporally, the high degree of uncertainty related to the date of arrival etc. are unexplained. Meteorologists have been trying to explain these phenomena from different angles relating to wide variety of generalisation.
They have been monitoring huge high pressure or anticyclone zones that form a few kilometers below the jet streams. This ridge hovers over south Goa. It has been noticed that if the ridge moves towards karwar in Karnataka it does not augur well for the monsoon. This high-pressure zone, it is reasoned, blocks the low flowing south westerly monsoon from intensifying over the west coast. When it is not positioned well, several meteorologists remain skeptical about the monsoon’s performance.
2. The unusual cooling of surface temperatures over the Arabian Sea by as much as 3 to 4 degrees before the onset of monsoon is another curious phenomenon. This is due to the cool Somali current. It pushes the cool waters of the Indian Ocean towards the Arabian Sea and the drop in temperatures seen to have an impact on the progress of the rains.
3. Just before the monsoon sets over south-east Asia the atmospheric pressure over the Indian Ocean drops. Simultaneously about 10,000 kilometers away in the South Pacific there is rise in pressure, when the rain is over, this reverses. This phenomenon called southern oscillations is key indicator of the south-west monsoon. When the pressure over Indian Ocean is low than normal it augurs well for the good monsoon.
351 Words Essay on Life in India During the Rains
The most important event in the Indian year is the monsoon. India is an agricultural country, and the year’s crops depend on the character of the rainy season. A good monsoon means prosperity, but an excess of rain means destructive floods, and the failure of the monsoon spells drought and famine.
The monsoon, or trade winds, reach India about the month of June. Coming as they do over thousands of miles of sea, they are laden with moisture; and when they meet the cool heights of the Western Ghats, and later the Himalayas, clouds form, which soon condense in heavy rain. In a good monsoon, the rainy season continues until about the end of September.
How eagerly the monsoon is looked for! Before it breaks, the heat is well-nigh intolerable. Day after day the sun blazes down from an unclouded sky.
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The ground is baked and parched, the air is like the blast of a furnace, in many places water is scarce, and men and animals gasp and pant in the heat. At last a thunderstorm rolls up from the south-west, and, with lightning, thunder and wind, the welcome rain pours down.
The change is almost magical. The air becomes delightfully cool and moist; the sun’s heat is day by day moderated by clouds; the dry, parched land is quickly covered with green vegetation; and life becomes bearable. Except, however, when it is actually raining, it is still hot in the rainy season; but the heat is not fierce and dry, but steamy and sticky.
The farmers now begin to be busy, ploughing and sowing the rain-soaked land for the Kharif, or autumn crops.
The rainy season, though a pleasant relief from the fierce heat, has its disadvantages. Swarms of insects appear, flying ants, flies, mosquitoes, etc., which often make life a burden. And the mosquitoes, bred by the million in the standing pools, bring malarial fever with them.
And other more terrible diseases, like cholera, work havoc among the poor. But the peasants much prefer to put up with these inconveniences than a failure of the rains, with means famine.