Climate Flashcards
Name the type of climate India has
Tropical monsoon type of climate
Why does India have the climate it does?
India lies in the tropical belt and its climate is influenced by monsoon winds which are largely confined to the Tropics i.e., between 20° N to 20° S
What is the range of the Tropics?
20° N to 20° S
Give the main characteristics of tropical monsoon climate
Relatively high temperatures and dry winters
Name two features that prevent high temperatures and dry winters, characteristic of tropical monsoon climate
The Himalayas in the north, the Indian Ocean in the south
How do the Himalayas provide India with distinctive characteristic features?
They protect northern India from the cold winds of Central Asia and Siberia and give it a continental climate, the characteristics of which are the prevalence of land winds, dryness of air, and large diurnal range of temperature
What are the characteristics of continental climate?
Prevalence of land winds, dryness of air, and large diurnal range of temperature
How does the Indian Ocean provide India with distinctive climatic conditions?
Gives India a hot monsoon climate more typical of the tropical than of the temperate zone
Name the states which have a similar monsoon type despite having different climatic conditions
The climatic conditions of Bihar and UP in the north differ from that of Kerala and Tamil Nadu in the south, yet all of these States have a similar monsoon type of climate
What are regional diversities?
Variations in climate that occur in different regions of the country despite it having a broad unity of the monsoon type of climate
How are regional variations expressed?
Expressed in the pattern of winds, temperature, and rainfall, the rhythm of seasons, and the degree of wetness or dryness. These regional diversities are known as the sub-type of monsoon climate
In what forms do variations occur in precipitation?
In the type of precipitation, in its amount and seasonal distribution
How much rainfall do Cherrapunji and Mawsynram get in a year?
about 1100 cm
What is the rainfall in a single day in Tura in Meghalaya equal to?
10 years of rainfall at Jaisalmer in Rajasthan
What does climate refer to?
Climate refers to a generalized and composite picture of the average weather conditions spread over a long period, for a given large area
Name the factors which influence the climate of India
- The Himalayas
- Varied Relief
- The Monsoon Winds
- Latitude
- Altitude
- Influence of the Surrounding Seas
- Western Disturbances
- Jet Streams
- Distance from the Sea
- El-Nino Effect
State the function of the Himalayas for India
- The Himalayas prevent the cold Siberian winds from entering the Indian region and India from becoming a cold desert
- They force the moisture laden South West Monsoon winds to shed rainfall in India or else India would be a dry region
- They provide glaciers, perennial rivers, which are used to generate power. They provide employment as they have timber, wildlife, tourist attractions.
How does relief play an important role in the climatic conditions of Western Ghats?
The Western Ghats get heavy rainfall on the western side because they stand in the way of the South West Monsoon winds which come from the Arabian Sea
How does relief play an important role in the climatic conditions of Deccan Plateau?
The Deccan Plateau gets less rainfall as it lies in the rain shadow region of the Western Ghats
How does relief play an important role in the climatic conditions of Rajasthan?
In Rajasthan, the Aravalli Range is parallel to the direction of the SW Monsoon winds, so it is unable to stop the moisture laden winds. It is also lower in height. This makes Rajasthan a dry area.
Why do the southern hills of Assam get heavy rainfall and the northern hills do not?
The southern hills force the moisture laden winds to shed their moisture before they proceed northwards
Which factor has a universal effect in bringing summer rains over the whole of South Asia?
The monsoons winds
Where do the south westerly winds move during summer (in India)?
During summers, the winds move quickly into Peninsular India towards the low pressure system of north-west India from the Arabian Sea and Bay of Bengal
Why does Tibet remain dry?
The moisture carried by the south westerly winds from the Arabian Sea and Bay of Bengal brings rain to the entire Indian subcontinent, leaving Tibet dry in the rain shadow region of the Himalayas
When does the SW monsoon start retreating from Punjab and UP?
By the end of September
When does the SW monsoon start retreating from Central India?
By October
When does the SW monsoon start retreating from South India?
By the end of November
Where does the retreating SW monsoon bring rain?
In the eastern coastal region
Which winds blow in the winter? From where to where?
During winter, dry offshore NE monsoon winds blow from high pressure to low pressure region which is centred at the head of Bay of Bengal
Where do yeh NE monsoon winds originate?
Mongolia and North West China
What is the nature of the NE monsoon winds? Give reason
They are cold and dry as they blow over a vast landmass
Why does Tamil Nadu get rain in the winters?
The NE monsoon winds join the Trade Winds to pass over the Bay of Bengal. They pick moisture from the BOB to bring rain to Tamil Nadu in winters.
Which imaginary line divided India?
The Tropic of Cancer
Where does the northern portion of India lie?
In the temperate zone
Where does the southern portion of India lie?
In the tropical zone
What is the effect of a sub-tropical or warm temperate climate on the northern zone?
A cold winter season and a hot summer season
Why is the northern zone cooler than the southern?
The northern zone does not have the mid-day sun almost vertically overhead during any part of the year, but the southern zone has the midday sun almost vertically overhead at least twice every year
Why are the mountains cooler than the plains?
There is a decrease in 1 C for every 166 m rise in height, because temperature decreases as you move to higher altitudes
Why does Ooty have a much lower temperature than Kochi?
Because of its higher altitude
By which three water bodies is India flanked?
The Indian Ocean, the Bay of Bengal, the Arabian Sea
What is the impact of the water bodies surrounding India?
They act as the major source of moisture to the summer monsoons and bring heavy rainfall to the whole area. It is because of the nearness of the sea that these areas have a moderate climate.
What are the weather conditions during winter in the subcontinent generally influenced by?
The distribution pattern of pressure in Central and West Asia
In the winter, why is there rain in the Northern Plains and snow in J&K?
In the winter season, due to the shifting of the pressure belts, the westerlies blow from 20 N to 50 N latitude and North India comes under the influence of the winds and cyclones rising from the Mediterranean Sea. These cyclones bring rain to the Northern Plains and snow in J&K
What are jet streams?
They are cold fast blowing winds that develop in the upper layers of the atmosphere
How do the jet streams influence the climate of India?
The westerly jet stream prevails over the North Indian Plains during the winter months, while the easterly jet stream steers the tropical depression over India. These depressions play a significant role in the distribution pattern of monsoon rainfall in the subcontinent. The highest rainfall occurs along the track of these depressions
What type of climate do coastal areas have?
Equable or maritime climate
What type of climate do areas in the interior of India have?
Extreme or continental climate
What is responsible for moderate climate in coastal areas?
The effect of land breeze and sea breeze cause by differential rate of heating and cooling of land and sea
To what is the moderating effect of the sea limited?
The coastal areas
Which feature prevents the winds from carrying their moderating effects inwards in the Peninsula?
The Western Ghats
What is El-Nino?
It is a warm ocean current which sometimes appears off the coast of Peru in South America during the month of December
What is the effect of El-Nino on the Indian Ocean?
It increases the surface temperature of the sea and affects the movements of the monsoon winds in the Indian Ocean and causes weak drought like situation in the Indian subcontinent
Why do monsoon winds develop?
Because of differential heating as well as cooling of land and sea
Give another name for monsoon winds
Periodic or seasonal winds
Name the wind systems that the monsoon winds are divided into
The Summer Monsoon, and the Winter Monsoon
What is the Summer Monsoon?
In summer, the land gets heated more than the sea. Hence, a centre of low pressure develops on land. Over the adjoining sea, the air is comparatively cool, and a high pressure develops there. This causes the winds to blow from sea to lands. It is the Summer Monsoon.
When are the plains of the Indian subcontinent heated by the vertical rays of the Sun?
May, June, July
What is the SW summer monsoon?
Winds blow from the Indian Ocean northward and north-westward into Asia. As they blow from the sea to land, they bring heavy rainfall in some parts of India. The summer monsoon winds blow south-west, so they are known as SW summer monsoon
What is NE winter monsoon?
During winter season, a high pressure develops over a big landmass stretching from Central Asia up to north-west Indian plains. At the same time, a low pressure zone develops in the Indian Ocean. As the winds blow from land to sea, they bring cold dry weather and no rain.
What is the winter monsoon called? Why?
The winter monsoon winds blow north-east, so the monsoon is known as the NE winter monsoon
Which parts in India get rain from winter monsoons?
The Southern Coromandel Coast (Tamil Nadu and southern tip of Andhra Pradesh)
Why do the coastal areas not have very distinct seasons?
Due to the influence of the sea, they do not experience much variation in temperature though there occurs variation in the pattern of rainfall
Name the four principal seasons on the basis of monsoon variations
- The Hot and Dry Summer
- The Hot and Wet or Rainy Season or the South West Monsoon
- The Retreating South West Monsoon
- The Cold and Dry Winter Season or North-East Monsoon
What is the duration of the Hot and Dry Summer?
March to May
What is the duration of the Hot and Wet Season?
June to September
What is the duration of the Retreating South West Monsoon?
October to November
What is the duration of the Cold and Dry Winter Season?
December to February
Where do the vertical rays of the sun fall in the Hot Dry Summer? (21 March)
Directly over the Tropic of Cancer
Why does the length of the day increase in March-May?
Due to the apparent northward movement of the path of the sun’s vertical rays
What does the increasing length of the day in the hot dry summer result in?
In the increase in solar radiation which moves northward over the tropical areas of South Asia and the temperature starts rising
What is the temperature range in most parts of India in the Hot Dry Summer?
30 C and 32 C
What is the common temperature on the north-western part of India in the Hot Dry Summer?
Around 48 C
What keeps the temperature lower in South India in the Hot Dry Summer?
The moderating influence of the oceans together with the Peninsular situation of south India
What is the temperature range in South India in the Hot Dry Summer?
26 C and 32 C
Why are plateaus and hills relatively cool in the Hot Dry Summer?
Because of the elevation