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Answer for Test Questions

Test No: 3

Subject: Geography

Division: Climatology (Physical Geography)

Topics: Monsoon

1.

Indian monsoon’s increasing unpredictability calls for greater efficiency in rainwater storage and use? Is it so, Evaluate with Suitable example. (250 words)

The unpredictable nature of Indian monsoon has become a major challenge for the citizens, especially the farmers. A Campaign called “JAL SHAKTI ABHYAN” launched by central govt on collaboration with various Indian State Govts for conservation of water, itself says how important the water issues have become in India.

RECENT EVENTS/NEWS RELATED TO WATER CRISIS:

  • Chennai Water Crisis: The Chennai city ran out of all the crucial sources of water supply and there was a major water scarcity.

  • Recently a Report by NITI AAYOG said that if water will not be conserved , by 2030 , 40% of Indians will not have drinking water.

  • IMPACT OF UNPREDICTABLE NATURE OF MONSOON ON INDIAN ECONOMY, AGRICULTURE,LIFE :

  • Damages to farmers crop , since the farmer’s livelihood mainly depends on selling of crops , loss of crops due to uncertain monsoon also weakens his financial conditions and increases his/her Problems.

  • Loss of property & Damage to infrastructure

  • For example: Recent floods in Kolhapur and Sangli in Maharashtra heavily damaged the houses and personal vehicles of people.

  • Loss of lives

Example: Two people drowned in Mumbai , As their car got stuck in water logged subway due to heavy rains and eventually the died inside the car.This all happened due to the extreme rains which happened that day and immediately stopped for couple of other days.

WAY AHEAD:

  • Create Awareness among people for water conservation and use of groundwater resources in limited capacity.

  • Harvesting of Rainwater in reservoir or farm ponds will benefit the farmers thereby providing them a greater flexibility in Cropping operations.

  • Creating awareness amongst Farmers to adopt the method of Drip Irrigation and Zero Budget Farming.

  • Despite the measures taken by the govt, the people still haven’t taken the issue of water crisis that seriously and still many people don’t feel the need to conserve water due to lack of understanding it’s consequences. Behavioural change, General Awareness and a strict policy related to water conservation is the need of the hour.

2.

Explain about the Dam Mismanagement played vital Role in recent flood, Critically Analyse about the recent flood which is due to main factor of dam mismanagement in India? (250 words)

Recent floods in the western coast of India where Kerala has most effected in due to excessive rain fall in various district of the states.

 

Factors responsible for flood in Kerala.

1. Development of construction activity and illegal mining whereas development causes to landslides.

2. Diversion flow of river into another is also caused of floods in many time in Kerala.

3. Unfollow the dam safety rule and regulation. In case of Idukki Dam entire catchment area has encroached along with dam construction.

4. Dam has emptied before pre monsoon which also can be preventive action.

5. Rejection of various committee report such as Madhav Gadgil, Kasturirangan.

 

Recent flood is not only natural disaster but it also man-made disaster since to avoid such extreme disaster in future we need to have string strategy to tackle such disaster.

1. Implementation of Madhav Gadgil committee report such as restriction on mining activity, Quarrying and construction activity in Western Ghats.

2. Strict implementation of dam Safety rules. Dam can control flood and disaster since need to manage properly.

3. Unjustified human intervention into nature need to stopped.

4. Focus also need to give Sendai framework on disaster management where it can take lesson from other country.

3.

Why break in monsoon occurs?, Elucidate what happens during break monsoon period  (250 words)

During the south-west monsoon period after having rain for few day, if rain fails to occur for one or more weeks, it is known as break in the monsoon.

 

These breaks in different regions are due to different reasons :

 

1. In the northern India rains are likely to fail if the rain-bearing storms are not very frequent along the monsoon trough or the ITCZ over this.

 

2. Over the west coast, the dry spells are associated with days when wind blows parallel to the coast.

 

The spatial distribution of rainfall is determined by the northward or southward movement of monsoon trough and its axis. When the trough moves closer to the Himalayas there are longer dry spells in the plains, and widespread rain occurs in the mountainous catchment areas of the Himalayan rivers.

4.

Explain about the ‘western disturbances’?  How it’s being originate? Discuss the impact of western disturbance in Indian Economy. Critically analyse western disturbances have been blamed for most of the freak weather events in India in the past decade? (250 words)

Western Disturbance is the term used to describe an extra-tropical storm that brings sudden winter rain and snow to the north-western parts of the Indian subcontinent. This is a non-monsoonal precipitation pattern driven by the Westerlies.

 

  • The moisture in these storms usually originates over the Mediterranean Sea and the Atlantic Ocean.

  • They carry moisture usually in the upper atmosphere (unlike tropical storms where it is carried in the lower atmosphere).

  • In India, moisture is sometimes shed as rain when the storm system encounters with the Himalayas.

  • In the Himalayan region of India, monsoon current progresses from east to west. But the WDs move across north India from west to east, with consequent rise in pressure and cold pool of air in the rear.

 

Effects on Economy:

  • Western Disturbances are important to the development of the Rabi crop in the northern subcontinent, which includes the locally important staple wheat.

  • Their effect sometime extends up to Gangetic plains and Northeast India, also.

 

But in the past few years western disturbances have been linked to disasters.

In this year hailstorm and rains in Gujarat, MP, UP and Rajasthan has caused severe damage to Cotton, Mango, Wheat and gram crops. It has weakened economic conditions of farmers in these states.

 

So, though beneficial, western disturbances are causing problems in agriculture output of India, due to climate change all over world.

5.

Why the arrival of frequency of the western disturbances has increased over the Indian subcontinent in recent years? (250 words)

Western Disturbance (WD) is extratropical storm, where moisture is carried in upper atmosphere so it travels larger distances comparatively. It originates in the Mediterranean and brings sudden winter rain to NW India, Pakistan, and Afghanistan. The main driving force is westerlies and moisture originates from Mediterranean Sea, Atlantic Ocean.

 

Main period of its activity is October to May and usually 4 to 5 disturbances used to come and bring water Rabi crops. But recently there is change in its pattern and intensity. Starting from the Uttarakhand Disaster to recent unusual rains of March which destroyed Rabi crops. Scientists are not able to ascertain the reasons behind it. Reasons speculated are:

 

1. Warming of higher latitudes like Tibetan, West Central Asia intensifying these winds and increasing their frequency.

2. Changes in Jet stream i.e. Upper tropical circulating air which separates cold temperate region from South Asia. Jet stream is most complex of phenomenon and it decides the depression and wind movement of the region.

 

India is an Agriculture based economy and it agriculture is majorly Rain fed agriculture. So the impact of WD can be estimated to affecting life of more than half of population and large section of economy. Normal WD increases harvest and farm income. Man-made reason are still speculated to leading climate change and its consequences. But so much coincidence in rising pollution and changes in wind pattern must have some correlation.

6.

Describe how the jet streams impacts the south west monsoon in India? (250 words)

Jet streams are strong winds blowing in the upper part of atmosphere from west to east.

The jet streams move in a meandering path It's width may be between 150 to 500 km and speed between 100 to 200 km/hr and they can be classified as subtropical jet streams ,subpolar jet stream and arctic jet streams out of these subtropical jet streams are most strong

 

Subtropical jet streams are bifurcated due to mechanical obstruction of the Himalayas and Tibetan plateau during winter .The northern branch moves from west to east to the north of Himalayas while southern branch moves from west to east to the south of Himalayas.

 

Main branch of upper jet stream follows anticyclone path and upper high pressure is developed therefore winds descends conversely main branch to the south of Himalayas follows cyclonic arc therefore upper air low pressure and cyclonic air circulation are developed over Tibetan plateau.

Tropical westerly jet streams which are oriented over Kolkata -Bangalore spread the southwest monsoon.

Somalia jet streams when it is weak results in monsoon break which is called 'lull' in monsoon.

Hence jet streams are helpful in onset of monsoon.

7.

Explain about Polar Vertex What do you understand by tropospheric and stratospheric polar vortex? What impacts happened in USA due to Polar Vertex? (250 words)

US Mid region states like North Dokota, Wisconsin, Michigan and Illinois has been in a state of emergency because of extreme cold weather caused by Polar vortex over mid region.

 

Polar vortex are tropospheric and stratospheric low pressures winds whirling around 150 km/hr in polar region. There are two polar vortex in the atmosphere, with Counter clockwise rotation in North pole and Clockwise rotation in South pole.

 

Tropospheric vortex is largely responsible for our weather. Our weather largely remains insulated from Stratospheric vortex. Sometimes Stratospheric polar vortex is disrupted, loses its shape and clash with Jet stream which in turn affects Tropospheric vortex. This results in Tropospheric vortex moving Southwards as in the case of recent event in USA.

 

1. Sharp drop in temperature in the areas of Polar vortex.

2. Polar winds further decreases the Real feel temperature which is much lower than actual temperature.

3. Exposure to such low temperatures can cause frost bites, hypothermia.

4. This leads to Large scale disruptions in economy.

 

Scientists believe Stratospheric polar vortex is disrupted because of warm temperatures in polar region directly blaming Global warming for such extreme weather events.

 

Adaptation and mitigation strategies need to be relooked at global platforms for such extreme weather events arising out of Global warming. Need of the hour is consensus among nations to tackle global warming.

8.

Critically Examine the Causes of El-Nino event And Its Impact on India’s Weather System. (250 words).

The El Nino which occurs every 3 to 5 years, is caused by warmer water in the eastern pacific ocean. The warmer water because of lessen or reverse of trade winds direction. In other words, winds from west push warm surface water towards to the east in the direction of the continent of south America. Therefore, there is less cold water pulled up from below as a result of this increase in warm water.

In essence El Nino is caused by the interaction between the surface layers of the tropical pacific ocean and the atmosphere over the tropical pacific ocean.

The equatorial Pacific ocean current usually flows from East to West under normal conditions which are called La Nina. The flow forms warm surface waters near the Philippines coast which in turn warms the air layer above it. This layer of air rises and convectional rainfall occurs in the entire region. But when the ocean current flow reverses in the equatorial pacific ocean, warm waters get accumulated near the Peru coast subsequently reversing the climatic conditions. This causes ample rainfall in the South American coast with scanty rainfall or drought like conditions on the Philippines coast. This reversal is called El Nino.

 

Impact on India’s Climate:

El Nino conditions affect the Indian climate in an adverse way. Indian monsoon which depends on the level of pressure difference that is created between the Indian mainland and the Arabian Sea is affected due to low pressure in South East Asia. This reduces the monsoonal rainfall in India by as much as 30% creating drought in several states.

Such drought has multidimensional affect on Indian climate as well as economy:

1. Untimely rainfall occurs in many parts damaging the agricultural yields.

2. Dry winds increase the frequency of adverse climatic events like Heat waves.

3. Average annual temperatures rise across the country further intensifying the heat island effects.

4. Increased temperatures may result in unprecedented disasters. For example floods in Kashmir(2016) and then in Kerala(2018).

9.

Analyse the Impact of La Nina and El Nino in various parts of the world? How its affects the world agriculture? (250 words)

EL NINO: Unusual warm water appears in Eastern Pacific Ocean off Peruvian Coast.

Drought situation in Australia, Southeast Asia and Africa. Floods in Brazil and USA Midwest.

 

LA NINA: Unusual cold water appears in Eastern Pacific Ocean off Peruvian Coast.

 

Effects On World Geography:

 

El-Nino:

1) America Continent

  • Lower corn yields, harvest of summer crops delayed due to increased rainfall, fertilizer price in south America tends to go up.

  • Frequent rains reduce tilling and yield of winter wheat

  • Yield of winter vegetables such as tomato, bell pepper, sweet corn are lower

  • Fungal and bacterial diseases pose higher risks

  • As up-welling is reduced the availability of fish is reduced

  • The migrant birds are reduced.

  • Food price escalate

 2) Drought conditions in South Asia

  • Reduce coconut and palm yields, higher and more volatile prices for these products

  • production of bananas and plantains for local consumption could be adversely affected by prolonged drought

  • Commodities prices rise especially sugar, pulses and edible oil.

  • Livestock and the fisheries are affected severely by the drought.

  • In India, drought like, shortage of commodities and black marketing/hoarding, forced revision of MSP and MEP, RBI has to change interest rates and monetary policy

 

La-Nina:

1) American Continent

a) Cold water from Peruvian coast brings nutrients (up-welling) leads to improved fishing

b) Wheat Yields and corn yields are higher

c) Less Fungal and Bacterial diseases

d) Pasture crops yield is lowered

 

2) Intensified Monsoon in South Asian region, increases overall crop production

10.

Explain about the onset of Indian monsoon? (250 words)

The phenomenon of monsoons in India, is a phenomenon that is believed to take place due to a seasonal reversal in the direction of winds. There have been a number of theories to explain their origin, but the theory based on the shift of the Inter-Tropical Convergence Zone, is the most accepted one.

 

The climate of India is strongly influenced by Monsoon winds. They are experienced roughly between 20S and 20N in tropical areas .Various atmospheric conditions influence the monsoon winds. The basic cause of monsoon climate is the difference in the rate of heating and cooling of land and sea. Climatic conditions by which Indian monsoons Originate are :

 

1. South-West Monsoon: Tibetan plateau gets intensely heated during summer which results in strong vertical air currents and formation of intense low pressure areas. At the same time southern hemisphere experiences winter and a region of high pressure develops over Australian continent. Winds blow Outwards as South-East Monsoon, and after crossing equator are drawn towards the Indian sub-continent as South-West monsoon resulting in torrential downpours which sweep across the entire country.

 

2. North-East monsoon: In winter the conditions are reversed with high pressure over sub-continent resulting in North-East monsoon winds. When they blow over the Bay of Bengal it acquires moisture and brings rainfall to south Eastern tip of peninsula. After crossing equator winds gets attracted towards low pressure Australian continent.

 

The origin of the monsoon can be explained through the following points.

1. During the summer season, there is a northward shift in the ITCZ, due to the movement of the sun.

2. As a result, the moisture laden south-east trade winds are able to reach up to India.

3. On crossing the equator, these trade winds are deflected towards the right, and in this manner, the south-west direction of flow of the moisture-laden winds takes place.

4. The south-west monsoon takes place due to two separate branches of winds. One is the Bay of Bengal branch, and the other is the Arabian Sea Branch.

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