characteristics, distribution and trends of precipitation in india · 2017-09-08 · precipitation...

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International Journal of Informative & Futuristic Research ISSN: 2347-1697

Volume 4 Issue 12 August 2017 www.ijifr.com

Abstract

In India dominantly tropical monsoon climate prevails. Among the climatic elements temperature and rainfall are the most significant one. Rainfall is main source of water in India. From precipitation, India receives 4000 BCM (Billion Cubic Metres) water. Out of the total precipitation, about 75 per cent is received in months from June to September in the form of rainfall. Rainfall is required not only for water security but also for food security of the country. Monsoon rainfall is highly uncertain and irregular. The spatio-temporal variability of rainfall plays havoc with agriculture which shatters the very foundation of economy in a predominantly agricultural country like India. Indian rainfall is basically torrential in nature. It is generalized that it pours in India and rarely rains. Another important aspect of Indian rainfall is that it is largely controlled by relief.The objectives of the present paper are – (i) to describe the characteristics of Indian rainfall; (ii) to provide causative explanation of the spatial distribution of precipitation; (iii) to highlight the seasonal distribution of precipitation; (iv) to explain the variability of rainfall and (v) to describe the trend of rainfall in India from 1901 to 2013.

I. INTRODUCTION

In India dominantly tropical monsoon climate prevails. Among the climatic elements

temperature and precipitation are the most significant one. Precipitation provides water

security along with food security. Except for the Himalayan region, in all parts rain is the

dominant form of precipitation. Monsoon rainfall is highly uncertain and irregular. The

spatio-temporal variability of rainfall plays havoc with agriculture which shatters the very

foundation of economy in a predominantly agricultural country like India. Indian rainfall

Characteristics, Distribution and Trends

of Precipitation in India

Paper ID IJIFR/V4/ E12/ 034 Page No. 8599- 8614 Subject Area Geography

Key Words Precipitation, Spatial, Seasonal, Irregular and Orographic

Dr. Jitender Saroha

Associate Professor,

Dr. Bhim Rao Ambedkar College,

University of Delhi, Delhi

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International Journal of Informative & Futuristic Research (IJIFR)

Volume - 4, Issue -12, August 2017

Continuous 48th Edition, Page No. : 8599- 8614

Dr. Jitender Saroha :: Characteristics, Distribution and Trends of Precipitation in India

is basically torrential in nature. It is generalized that it pours in India and rarely rains.

Another important aspect of Indian rainfall is that it is largely controlled by relief. In the

absence of Himalayas the whole of India would have been a vast desert.

In India precipitation is dominantly of orographic form. However, the winter

precipitation in north India is associated with western disturbances or temperate cyclones.

Tropical depressions contribute to summer monsoon rain also. The frequency and

intensity of the tropical depressions developing over the Bay of Bengal and entering into

the Ganga Plain determine the amount of rainfall in summer season also. Convectional

rainfall is confined to the interior regions like parts of the peninsular plateau and

Rajasthan. The pre-monsoon rains along the eastern coast and in Ganga Valley are also

partly convectional.

Majority rainfall in India is received during the period of southwest monsoon winds. The

rainy season of India dominates from June to September. Of the country’s total rainfall,

about 75 per cent is received in this rainy season, 13 per cent in post monsoon season, 10

per cent in the pre-monsoon season and the remaining 2 per cent in the winter season

(Table 1). Only a small part of the country in the north and Tamil Nadu receive some

precipitation in winter. Rainfall by southwest monsoon dominates in India. In some areas

this dominance is more pronounced. For instance, the average annual rainfall over the

Northern Great Plains of India in this rainy season is about 92 cm which is about 87 per

cent of the total annual rainfall and rest of the months receive only 13 per cent of the total

i.e. about 14 cm rainfall.

Table 1: Seasonal Distribution of Rainfall in India

Season Annual Rainfall (per cent)

Pre-monsoon 10

Monsoon 75

Post-monsoon 13

Winter 2

Indian rainfall is largely torrential in nature. Most of the rainfall is received over a limited

number of rainy days. Cherrapunji has a record of receiving 103.6 cm rainfall in 24

hours. Here the number of rainy days is also the largest(180 days). In most places the

number of rainy days ranges between 45 and 50. Sri Ganganagar in the western part

receives 12 cm of rainfall over 10 - 12 rainy days. That is the reason people say, 'it pours,

it never rains in India'. The sudden heavy downpour results in flash floods in many areas.

The rainfall received in different parts of India varies a great deal in amount and intensity

over years. There are wide variations in the actual precipitation from the normal. Also

the monsoon is occasionally delayed leading to drought conditions in several parts of the

country. Occasionally the rains exceed the normal amount by a large margin leading to

floods in many parts. A large amount of rainfall in the northeast causes frequent floods in

that part. Parts of Odisha, Rajasthan and Gujarat are highly prone to droughts and most

areas in the Ganga Plains are prone to frequent floods.

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Another important aspect of Indian rainfall is that it is largely controlled by

topography or relief. The impact of the Himalayas, the Western Ghats and the Meghalaya

plateau on the amount and distribution of rainfall is well known. Similarly, the position of

the Aravalis parallel to prevailing winds is responsible for arid conditions in this part of

India. The whole of India would have been a vast desert but for the size and position of

Himalayas and Western Ghats. The summer season would have been hot and dry and

winter season in northern part of India would have been mainly dry and too cold.

Therefore, it can be concluded that the rainfall over India is primarily orographic.

II. DISTRIBUTION OF RAINFALL

India receives 4000 BCM (Billion Cubic Metres) of water from precipitation. Out of the

total precipitation, the rainy months from June to September receive 3000 BCM. India as

a whole on an average receives 118 cm annual precipitation. However, the distribution of

rainfall in India is highly variable. About 11 per cent area receives over 200 cm of annual

rainfall, 21 per cent area receives 125 to 200 cm, 37 per cent area receives 75 to 125 cm,

24 per cent area gets 35 to 75 cm and 7 per cent area gets less than 35 cm average annual

rainfall (Table 2).

Table 2: Distribution of Rainfall in India

Annual Rainfall (cm) Area (per cent)

> 200 11

125 – 200 21

75 – 125 37

35 – 75 24

< 35 7

The rainfall is heavy along the western coast and in Assam, south Meghalaya, Tripura,

Nagaland and Arunachal Pradesh. All these regions receive rainfall above 200 cm. The

whole of Rajasthan, Punjab Haryana, western and southwestern parts of Uttar Pradesh,

western Madhya Pradesh and practically the entire Deccan Trap or plateau region east of

Western Ghats except for a narrow strip along Tamil Nadu coast receive a low rainfall of

less than 100 centimeters. The rest of the areas receive a rainfall ranging between 100 and

200 centimeters. The distribution of rainfall is represented in Fig.1. The distribution of rainfall is highly variable. Large parts of Meghalaya receive about

1,000 cm annual rainfall while on the other hand; districts of south-west Rajasthan hardly

receive annual rainfall of 15 cm. The average annual rainfall received at Cherrapunji is

1,102 cm.

Earlier it was considered as the place receiving highest rainfall in the world. But the

recorded data of recent years has established Mawsynram as the place receiving the

highest rainfall in the world. It is located about 16 km west of Cherrapunji in Meghalaya.

It receives the highest annual precipitation i.e. 1,221 cm in India as well as world. The

average annual rainfall at Jaisalmer rarely exceeds 12 cm. At place Tura (Garo Hills,

Meghalaya) the single day rainfall equals to the rainfall received for about 10 years at

Jaisalmer in Rajasthan.

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Figure 1: Annual Rainfall The three major regions of high rainfall in India are – the western side i.e. the windward

side of Western Ghats – this includes the west coast from Thiruvananthapuram in the

south to Mumbai in the north. The average annual rainfall in this area is 200 – 400 cm;

(ii) seven sisters and Sikkim Himalaya region – it includes almost whole of Assam,

Arunachal Pradesh, parts of Manipur, Tripura, Nagaland, Mizoram, Sikkim and north

eastern part of West Bengal and Meghalaya. This region receives more than 200 cm

average annual precipitation. Meghalaya (abode of clouds) is the wettest part of the

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country. Cherrapunji and Mawsynram are located on the southern slopes of the Khasi

Hills at the northern end of a funnel shaped valley running south to north; and (iii) the

islands (Andaman and Nicobar and Lakshadweep). The wind ward position of slopes and

proximity to seas are common factors for high precipitation in these three regions of high

rainfall.

The three regions of low and least rainfall in the country are - (i) Leeward side or the

rain shadow zone of the Western Ghats - it extends over the majority parts of Karnataka

and Maharashtra states. Here the average annual rainfall received is in the range of 35 to

75 cm. These areas are frequently prone to droughts; (ii) arid and semi-arid areas – it

includes the large parts of Rajashtan and Kachchh region. In this part south west

monsoon winds blow parallel to the Aravali mountain range. As this mountain range fails

to work as a barrier for moist winds arid conditions prevail. The average annual rainfall is

less than 50 cm; and (iii) the cold desert i.e. Ladakh region – it receives rainfall less than

25 cm because of its leeward position on the northern side of the Greater Himalaya. The

low rainfall areas are leeward sides or rain shadow regions of mountain ranges. For

instance, Mumbai on the west coast in wind ward slope position receives about 190 cm

rainfall but Pune located about 160 km away from Mumbai receives only 50 cm rainfall

due to its location on the leeward side or rain shadow zone position.

III. VARIABILITY OF RAINFALL

As described above rainfall is not only uneven, it is highly variable also. Variability of

rainfall is taken as a measure of reliability of rainfall. The rainfall variability and

reliability have inverse relationship. Stated simply, more variable the rainfall, less

reliable it is.

Variability of rainfall is studied in terms of co-efficient of variability (CV) which can be

calculated using the following formula:

Co-efficient of Variability (C.V.) = 𝑺𝒕𝒂 𝒂𝒓 𝑫 𝒗𝒊𝒂𝒕𝒊 ×𝑴 𝒂

A high value of the C.V. indicates a higher degree of fluctuation in the amount of rainfall

at a station or in an area. It is thus an indicator of deviation of rainfall in a particular year

from its long term average. C.V generally ranges between 15 and 30 per cent for the

country as a whole. It is high in Rajasthan, Gujarat and parts of Haryana and Punjab

where the figure is above 40 per cent. In the extreme western part of Rajasthan and

Gujarat the co-efficient value is above 60 per cent. The variability is lower in the western

coastal region, sub Himalayan belt including Sikkim, Arunachal Pradesh, Assam and

West Bengal. The northeastern region also has a low variability of rainfall (15 to 20 per

cent). Thus by looking at the spatial distribution of absolute amount of rainfall and

variability, it becomes clear that the areas receiving a lower amount of rainfall suffer

from a high degree of variability. These areas not only receive very limited amount of

rainfall on an average, the reliability of rainfall is very low here. On the other hand areas

receiving ample precipitation have a lower variability, thus making rainfall more reliable

in these areas. The drier parts thus suffer from not only limited availability of rainfall but

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also from a very low reliability of it. The distribution of rainfall variability and rainfall

reliability is represented in Fig. 2

Figure 2: Variability of Rainfall

Rainfall is variable over time also. It has already been pointed out that most parts of the

country receive bulk of the precipitation during a very short period and the rest of the

year remains dry. The spatio-temporal variability of rainfall intensifies the risk of failure

of crops and other indirect consequences. Thus the very foundation of national economy

suffers from the consequences of this high variability and low reliability of rainfall.

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IV. SEASONAL DISTRIBUTION OF PRECIPITATION

Climatic year of India is divided into four seasons. These four seasons are: hot dry

season; hot wet season; cool dry season; and the cool wet season. The rainfall varies

according to seasons in India.

The season which extends from March to June is known as hot weather season or hot dry

summerseason or pre-monsoon season. The beginning of this season is marked by the

rising temperature during the latter half of March. The vertical rays of the sun start

moving towards the Tropic of Cancer at this time and the temperatures start rising. The

southern parts of the country experience the highest temperatures during the month of

April and as the vertical rays of the sun approach the Tropic of Cancer in mid-June, the

northern parts of the country experience high temperatures. During this season hot and

dry weather conditions prevail.

This phase continues up to the end of May and sometimes up to the mid of June. This is

the time when the ITCZ (Inter Tropical Convergence Zone) shifts over the northern part

of India around the Tropic of Cancer. As the temperature rises in the northwestern part of

the country, a thermally induced low pressure begins to develop over Rajasthan. This

area of low pressure becomes more intense by end of May when a trough of low pressure

extends over the entire Ganga Plain. The fall in pressure continues up to first week of

July. This extensive area of low pressure is often called the 'monsoon trough' and it

coincides with the tropical position of the ITC.

Due to intense heating in the western part of India at this time hot winds called "loo"

blow from Rajasthan towards the northern plains. They are harbingers of heat wave in the

northern plains as far east as Bihar. In the month of May that is the hottest month of

India, dust storms especially in evening are common in Punjab, Haryana, eastern

Rajasthan and Utter Pradesh.

Occasionally moist air is pulled to the periphery of the low pressure area and the

interaction between dry and moist air masses gives rise to strong local storms

characterised by violent winds, torrential rains and even hailstorms. Due to their

northwesterly direction these storms are called "norwesters" in West Bengal, Jharkhand,

Odisha and Assam. They also have local names such as "kalbaisakhi", meaning a

calamity of the month of Baisakh, in West Bengal and "Bardoli Chheerha" in Assam.

Showers in this season are beneficial to tea, jute and rice but the hailstorms

accompanying them sometimes lead to heavy damage to standing crops, trees and

structures.

Kerala and coastal parts of Karnataka receive pre-monsoon showers towards the end of

dry summer period. As these showers assist in ripening of mangoes, these are locally

called “mango showers.” They are also known as "cherry blossom"due to their

association with blossoming of coffee flowers in Kerala and neighbouring areas.

The Hot Wet Season starts with the onset of the southwest monsoon in June and extends

up to mid-September. This is also called the monsoon season or the rainy season or the

southwest monsoon season. High heat, high humidity, cloudy atmosphere and frequent

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spells of moderate to heavy rain are the chief characteristics of this season. The trough of

low pressure over the Indo-Gangetic plain attracts winds of maritime origin from

equatorial region towards India. This represents the onset of southwest monsoon season.

The southwest monsoon advances quite suddenly and it is accompanied by cloud

formation over the region leading to thunder, lightning and heavy rains. It is also called

the burst of monsoon. Bursting first over the southern part of India, monsoon progresses

northwards. The normal dates of burst of monsoon are May 20 in Andaman and Nicobar

Islands, June 3 in Konkan, June 15 in Kolkata and July 1 in Delhi.

The onset of southwest monsoon is affected by the northward shift of the sub-Tropical Jet

Stream from its winter position over India. Unless this westerly jet shifts to the north of

India, the pressure over northern part of the country does fall sufficiently to herald a

sufficiently strong southwest monsoon. During the summer months a tropical easterly jet

also develops over India. This jet is favourable to the development of the low pressure

over India and thus strengthens the southwest monsoon. The normal dates of onset or

arrival of southwest monsoon are represented in Fig.3

Figure 3: Normal Dates of Onset of Southwest Monsoon

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The peninsular landmass of India divides the southwest monsoon winds into two

branches, one each blowing from the Arabian Sea and the Bay of Bengal. The Arabian

Sea branch of southwest monsoon first of all strikes on the western side of the Western

Ghats and these ascending moist monsoon winds produce atmospheric instability and

cause heavy rainfall on the windward side all along the western coast.

On the eastern side of the Ghats, the rainfall is much lower due to the rain-shadow effect

and interior Tamil Nadu remains almost dry during this season. This branch of monsoon

also moves over Rajasthan and Gujarat but here there are no barriers obstructing the

winds. The Aravalli Ranges are aligned parallel to the wind direction and hence form no

effective barrier. Therefore, this area also remains arid or dry during the season of

southwest monsoon and similar conditions prevail during other seasons.

The winds crossing over the Western Ghats provide rainfall over a large part of the

northern section of the peninsular plateau. The amount of rainfall over the plateau region

depends upon landform characteristics and also the distance from the sea. Mumbai on the

west coast receives about 190 cm, Khandala, about 50 km east and a bit below the crest

of the Western Ghats, receives 460 cm and Pune, about 160 km away from Mumbai on

the lee side of the Ghats, gets only 50 cm rainfall during this period. This pattern of

rainfall is common all along the Western Ghats. The ridge-line part or crest of the

Western Ghats receives about 400 -500 cm rainfall and it decreases to about only 30-50

cm within a distance of 80-100 km leeward of the ridge-line and represents the rain

shadow area.

This shows the extent of the effect of orographic factors on the monsoon rainfall. After

crossing a narrow arid belt on the leeside of the Ghats the air starts rising again leading to

an increasing amount of rainfall further east.

Wind direction during this season over the Bay of Bengal is modified by the existence of

low pressure trough over the Ganga Valley and the physical barrier of the Arakan

Mountains. Winds in this region attain a southeasterly direction. This branch of monsoon

is obstructed by the Himalayas and gets bifurcated into two parts, one going into the

Brahmaputra Valley and the other moving westward over the Ganga Plains. The current

entering the Brahmaputra Valley encounters mountain barriers on three sides and this

causes the maximum rainfall in the country around Cherrapunji. Mawsynram is located at

an absolute height of 1329 metres on the windward side of Khasi Hills near Cherrapunji

receives the highest amount of rainfall (1221cm) in the world. Most of northeastern part

of India receives a rainfall of more than 200 cm but the amount decreases sharply on the

leeside of the Khasi Hills. Guwahati receives only 161 cm average annual rainfall though

it is located only 90 km away from Cherrapunji. The broad generalization about rainfall

associated with the Bay of Bengal is this that rainfall decreases with increasing distance

from the sea.Amount of rainfall over the Ganga Plain decreases westwards with

increasing distance from the sea and also southwards with increasing distance from the

Himalayan barrier. Kolkata gets 119 cm, Patna receives 105 cm, Allahabad records 76

cm, Delhi 56 cm and Bikaner only 24 cm.

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The Arabian Sea Branch and the Bay of Bengal Branch meet over the northern and

central parts of the peninsular plateau and the western part of the Ganga plains and the

combined current proceeds towards northwest over Punjab and Jammu and Kashmir.

However, by the time these winds reach the extreme northwest of India in Ladakh region

of Jammu and Kashmir, they have shed their moisture practically completely and the

rain-shadow effect is also observed over this region. Hence this part also received little

precipitation in this season. The southwest monsoon remains active over India up to

middle of September.

There are short periods of monsoon inactivity during the rainy season, particularly in July

and August, when cloud cover decreases and there is no rainfall over areas outside the

Himalayan belt and southeast peninsula. Such periods are called breaks in monsoon.

Rains during the rainy season take place in short wet spells of a few days each. The wet

spells are thus interspersed with rainless intervals. The intensity of monsoon in northern

India is related to the frequency and intensity of cyclonic depressions developing over the

head of the Bay of Bengal. These depressions move inland and bring heavy rainfall in

their wake. Monsoon breaks coincide with periods of no cyclonic activity. The trajectory

of these temperate or wave cyclones or depressions determines the distribution of

precipitation over north India.Distribution of rainfall in this season is depicted in Fig. 4.

Figure 4: Summer Rainfall

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The cool dry season lasts from mid-September to mid-December. This is the season of

retreating southwest monsoon. The weather for most part remains unsettled at this time

which is a result mainly of frequent and quick changes in temperature due to the

southward shift of the ITC. As the vertical rays of the sun start shifting towards south, the

ITC also starts moving southwards and higher pressure starts developing over the north

Indian plain. The southwest monsoon starts retreating gradually, first from the north (Fig.

5). By early November the temperatures start falling in the entire country and the

southwest monsoon completely withdraws from India. This is the beginning of cool dry

season or winter season of India. This period is characterized by low temperature, low

northerly winds, clear skies and low humidity. Although the season is dominated by

easterly or northeasterly winds over the peninsula, winds generally blow from a westerly

direction in the northern part of the country.

Figure 5: Normal Dates of Withdrawal of Southwest Monsoon

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A number of severe tropical cyclones originate over the Indian seas, especially the Bay of

Bengal, in this season. They are most frequent in October and first half of November. The

tropical cyclones develop over the Bay of Bengal in October mainly between 8º and 14

º

N. Initially they move in a westerly or northwesterly direction, but many of them later

turn to move towards the northeast. Coastal belts of Tamil Nadu, Andhra Pradesh, Odisha

and West Bengal are most vulnerable to these cyclones.

Most parts of India remain dry during the period of retreating monsoon. However,

October and November are the main rainy months in Tamil Nadu and adjoining parts of

Andhra Pradesh to the south of the Krishna delta. These months also represent a

secondary rainy season in Kerala. Kerala has bi-model pattern of rainfall with main

season associated with the southwest monsoon season and subsidiary season in these

months. The Coromandel coastal region receives about 50 per cent of its annual rainfall

during this season.

By October the southwest monsoon withdraws from most parts of India and the northeast

monsoon establishes itself over the entire area from which the southwest monsoon has

withdrawn. The weather remains dry during up to the end of November in most parts.

Gradually the temperate weather systems start invading northern parts of the country and

although the Himalayas act as a major climatic barrier preventing most of the temperate

phenomena from penetrating deep into northern India, some of the western disturbances

do invade the northern parts of the country. These western disturbances are cyclonic

systems that develop in the belt of the westerly winds and they bring unsettled weather in

their wake. These disturbances cause rain or snowfall in Jammu and Kashmir and north

Indian Plains and break the dry spell. This period of the year is called the cold-wet

season.Winter rain and snowfall in northwestern India is caused by the western

disturbances. The sub-tropical westerly jet stream plays an important role in causing

these disturbances. Himalayan region receives about 60 cm precipitation during

December to February while Punjab gets about 12 cm. Delhi and other areas of northern

plain receive a lesser amount of precipitation in this season. However, even this small

amount of rainfall in northern plains is very beneficial to rabi crops, especially wheat.

The north eastern part of India also gets rainfall during the winter months. Arunachal

Pradesh and Assam generally get up to 5 cm rainfall during this period. Distribution of

winter rain is shown in Fig. 6. Unlike the northern part, the peninsular region of India

does not have a well-defined winter season. Due to maritime influence temperature

remains quite equable in the coastal areas. The temperature remains relatively lower in

the upper parts of the Western Ghats.

Rainfall occurs during this season in Tamil Nadu also. The northeast monsoon, that has

established itself over much of the country by this time, causes the winds to blow from

the Indian landmass towards the sea. The winds blowing towards Tamil Nadu from the

northeast pick moisture as they blow over the Bay of Bengal and they cause rainfall in

Tamil Nadu and parts of Andhra Pradesh. Thus part of the area remaining dry during the

season of southwest monsoon due to the rain shadow effect of the Western Ghats,

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receives some rainfall during winter. Out of the three regions that fail to get much

precipitation during the summer, two receive some precipitation in winter but the third

region, namely the Rajasthan and Gujarat region, remains dry during this season also.

Figure 6: Winter Rainfall

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V. LONG TERM RAINFALL TRENDS IN INDIA:

An Indian Meteorology Department (IMD) analysis of long-term rainfall data points to a

worrisome trend. The Indian Meteorological Department (IMD) study assessed trends of

seasonal and annual rainfall in 34 meteorological sub-divisions distributed over 632

districts of India, except the islands and Ladakh region. The study is based on the

analysis of rainfall data of period extending from 1901 to 2013. The study indicates that,

in last half century period, many areas of north India have been receiving declining

average annual rainfall. There are 85 districts across the country which constitute about 8

per cent of the geographical area of India where a ‘significant decreasing’ trend of

rainfall has been recorded since 1960s.

The trend of declining rainfall is most well established in north India as more than half of

these districts are located in this part. These districts constitute the most important

agricultural belt of India. In Uttar Pradesh about 43 per cent (32 out of 75) of its districts

have recorded a significant decline in amount of average annual rainfall. In Haryana 5

(Gurgaon, Jhajjar, Karnal, Panipat and Sonipat) out of 22 districts, in Delhi eight out of

nine districts and in Punjab 9 (Barnala, Bathinda, Mansa, Gurdaspur, Firozpur, Faridkot,

Muktsar, Moga and Amritsar) out of 22 districts showed the decreasing rainfall trend. In

this study the researchers found no trend in country wide rainfall but subdivision and

district wise trends were apparent.

Many other studies conducted by research scholars and institutions also confirm the

weakening of monsoon in many areas of north India. From 1999 the decreasing rainfall

trend is more pronounced. Out of 18 southwest monsoon rainy seasons, in 13 years

during this period, Haryana recorded 10 per cent less than the normal monsoon rainfall.

For Punjab the corresponding figure was 12 per cent. The decreasing rainfall has obvious

impacts on levels of ground water which is increasingly being used in agriculture as well

as cities in this region. Over-exploitation of ground water in northern parts of India is

well known to locals and well recorded and quantified by the scientific research studies.

However, this study also revealed an increasing rainfall trend in several districts,

including many in Jammu and Kashmir (Baramula, Mirpur, Punch, Riasi and Udhampur),

Bihar (Bhagalpur, Kathihar, Munger and Purnia) and a few in Jharkhand ( Purbi

Singhbhum, Sahebganj, Saraikela), Punjab and Chhatishgarh. However, the scientist

associated with this research work could not identify the causes or determinants of

increasing or decreasing average annual or seasonal rainfall trends. An IIT-Bombay

analysis shows change in rainfall pattern in about 40 per cent districts across India

because of deforestation. Between 1880 and 2013 about 40 per cent forest cover loss has

taken place in India. According to Prof, Subimal Ghosh due to the deforestation there is a

significant reduction in the recycled precipitation and hence in total precipitation. The

states with most dip in rainfall also are the ones that have seen highest deforestation. This

study reported change in precipitation in 238 districts out of total 632 districts. Out of 238

districts, 82 districts showed increasing trend whereas 156 saw decline in rainfall (The

Hindustan Times).

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Figure 7: State - wise Changes in Rainfall in India (1901 – 2013),

Source: The Hindustan Times, 27 July 2017, P-Plus One

VI. CONCLUSION

India has tropical monsoon climate. The southwest monsoon season rainfall from June to

September alone accounts for about three-fourth of the total precipitation of India.

Rainfall is required not only for water security but also for food security of the country.

Monsoon rainfall is highly uncertain and irregular. The spatio-temporal variability of

rainfall plays havoc with agriculture which shatters the very foundation of economy in a

predominantly agricultural country like India. Indian rainfall is basically torrential in

nature. It is generalized that it pours in India and rarely rains.

Another important aspect of Indian rainfall is that it is largely controlled by relief. In the

absence of Himalayas the whole of India would have been a vast desert. In India the areas

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receiving ample precipitation have a lower variability, thus making rainfall more reliable

in these areas. On the other hand, the drier parts suffer from not only limited availability

of rainfall but also from a very low reliability of it. In recent studies about long term

trends of rainfall in India the researchers have found no trend in country wide rainfall but

subdivision and district wise trends were apparent. The regional analysis indicates trends

of increase in rainfall in some areas and decrease in some other areas. But the scholars

have still to identify the factors responsible for these changes in trends of rainfall.

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[3] Menon, P.A. (1993): Our Weather, National Book Trust, New Delhi.

[4] Pedelaborde, P. (1963): The Monsoon, Methuen and Company Ltd., London.

[5] Rama Sastry, A.A. (1983): Weather and Weather Forecasting, Publication Division,

Ministry of Information and Broadcasting, Govt. of India, Delhi.

[6] Ramage, C.S. (1971): Monsoon Meteorology, Academic Press, New York and London.

[7] Singh, S. and Saroha, J. (2014): Geography of India, Access Publishing, New Delhi.

[8] Tiwari, R.C. (2013): Geography of India, Pravalika Publication, Allahabad.

[9] The Times of India, 30 July 2017, P-10. IMD analysis reveals falling rainfall trend in

north India.

[10] The Hindustan Times, 27 July 2017, P-1.

[11] Guhathakurta, P. and Rajeevan, M. (2006): Trends in the Rainfall Pattern Over India,

National Climate Centre, Indian Meteorological Department, Pune.

[12] Rathore, L.S., Attri, S.D. and Jaswal, A.K. (2013): State Level Climate Change Trends in

India, Meteorological Monograph No. ESSO/IMD/EMRC/02/2013, IMD, Ministry of

Earth Sciences, Government of India.

AUTHOR DETAIL

Dr. Jitender Saroha is senior Associate Professor at Dr. B. R. Ambedkar

College (University of Delhi). He did B.A. (Hons.) in Geography from D.U. in

1991 and M.A. Geography (1993) from Delhi School of Economics, University

of Delhi. From this institute he completed M.Phil (1997) and Ph.D (2006)

research work on ‘Integrated Watershed Management in the Sikkim

Himalayas’. He has 19 years teaching experience. He has specialization in

Resource Geography, Climatology, Remote Sensing and GIS, and Disaster

Management. He has done M.Sc in Disaster Mitigation. He has participated

and presented papers in many national and international seminars and

conferences. He has completed two certificate courses in Remote Sensing and

GIS from Indian Institute of Remote Sensing (IIRS), Dehradun. He has also

worked as Joint Secretary (On Deputation) in University Grants Commission

(UGC), MHRD, GOI, New Delhi.

TO CITE THIS PAPER

Saroha, J. (2017) :: “Characteristics, Distribution and Trends of Precipitation in India” International Journal of Informative & Futuristic Research (ISSN: 2347-1697), Vol. (4)

No. (12), August 2017, pp. 8599- 8614, Paper ID: IJIFR/V4/E12/034.

Available online through- http://www.ijifr.com/searchjournal.aspx

http://www.ijifr.com/searchjournal.aspx

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