A abampere (aA) The unit of electric current in the CGSeniu system, defined as that current that, if flowing through two parallel conductors of negligible cross section and infinite length, placed 1 cm apart in vacuo, would produce on each conductor a force of 1 dyne per centimeter of length. 1 abampere = 1 abcoulomb/s = r statampere (where c = speed of light in cm/s) = 10 ampere. aberration Imperfect image formation due to geometric imperfections in the optical elements of a system ablation 1 . The wasting of glacier ice by any process (calving, melting, evaporation, etc.). 2. The shedding of molten material from the outer sur- face of a meteorite or tektite during its flight through the atmosphere. absolute age The age of a natural substance, of a fossil or living organism, or of an artifact, obtained by means of an absolute dating method. See absolute dating method. absolute density Density in kg/m' or, more commonly, in g/cm\ both at STP. Cf. density, relative density abso
Climate class 11 geography MCQ & SAQ
Climate class 11 geography NCERT SOLUTION:
(i) What causes rainfall on the coastal areas of Tamil Nadu in the beginning of winters?
(a) South-West monsoon
(b) Temperate cyclones
(c) North-Eastern monsoon
(d) Local air circulation
Answer: (c) North-Eastern monsoon
(ii) What is the proportion of the area of India which receives annual rainfall less than 75 cm?
(a) Half
(b) One-third
(c) Two-third
(d) Three-fourth
Answer: (b) One-third
(iii) Which one of the following is not a fact regarding South India?
(a) Diurnal range of temperature is less here.
(b) Annual range of temperature is less here.
(c) Temperatures here are high throughout the year.
(d) Extreme climatic conditions are found here.
Answer: (d) Extreme climatic conditions are found here.
(iv) Which one of the following phenomena happens when the sun shines vertically over the Tropic of Capricorn in the southern hemisphere?
(a) High pressure develops over North-western India due to low temperatures.
(b) Low pressure develops over North-western India due to high temperatures.
(c) No changes in temperature and pressure occur in north-western India.
(d) ‘Loo’ blows in the North-western India.
Answer: (a) High pressure develops over North-western India due to low temperatures.
(v) In which of the following states in India do we find ‘As’ type of climate as per Koeppen’s classification?
(a) In Kerala and coastal Karnataka
(b) In Andaman and Nicobar Islands
(c) On Coromandel Coast
(d) In Assam and Arunachal Pradesh
Answer: (c) On Coromandel Coast
2. Answer the following questions in about 30 words
(i) What are the three important factors which influence the mechanism of Indian weather?
Answer:
a. Distribution of air pressure and winds on the surface of the earth.
b. Upper air circulation caused by factors controlling global weather and the inflow of different air masses and jet streams.
c. Inflow of western disturbances during the winter season and tropical depressions during the south- west monsoon period into India, creating weather conditions favorable to rainf
(ii) What is the Inter-Tropical Convergence Zone?
Answer: Inter-Tropical convergence Zone is a low pressure zone located at equator where trade winds converge and the air tends to ascend.
(iii) What is meant by ‘bursting of monsoon’? Name the place of India which gets the highest rainfall.
Answer: Bursting of monsoon refers to the sudden change in weather conditions during the southwest monsoon, characterized by an abrupt rise in the mean daily rainfall in India during the monsoon season. Mawsynram, located in the crest of Khasi hills in Meghalaya, receives the highest rainfall in the world.
(iv) Define ‘climatic region’? What are the bases of Koeppen’s classification?
Answer: A climatic region generally possesses a broad uniformity in climatic conditions caused by the combined effect of climatic factors. Koeppen's regions are based on the monthly values of temperature and precipitation.
(v) Which type(s) of cyclones cause rainfall in north-western India during winter? Where do they originate?
Answer: Cyclones known as western disturbances cause rainfall in north-western India during winter. These cyclones originate in the Mediterranean Sea.
3. Answer the following questions in not more than 125 words.
(i) Notwithstanding the broad climatic unity, the climate of India has many regional variations. Elaborate this statement giving suitable examples.
Answer: The climate of India has many regional variations, expressed in the pattern of temperature, winds and rainfall, rhythm of seasons, etc. The main examples of diversities in the monsoonal unity of Indian climate are following:
- Jaisalmer in Rajasthan may record a temperature of 50°C or more on a June day while the mercury hardly touches 19°C in Tawang (Arunachal Pradesh) on the same day.
- On a December night, the temperature may dip to – minus 45°C at Drass in Jammu and Kashmir, while it may be as high as 20°C-22°C at thiruvananthapuram.
- Mawsynram receives 1080 cm of annual rainfall, while Jaisalmer in Rajasthan rarely gets more than 9 cm of rainfall during the same period.
- Cities like Hyderabad, Bhubaneswar and Patna get rains by the first quarter of June, while cities like Agra, Delhi and Chandigarh are expecting rain till the end of June or early July.
- In Kerala, the difference between day and night temperatures may be hardly 10 degree Celsius, but in the Thar Desert it may be 35°C.
- Most parts of India get rainfall during June- September, but coastal areas of Tamil Nadu get rainfall in the beginning-of the winter season.
(ii) How many distinct seasons are found in India as per the Indian Meteorological Department? Discuss the weather conditions associated with any one season in detail.
Answer: The Indian Meteorological Department has recognised the following four seasons:
a. The cold weather season
b. The hot weather season
c. The South-West monsoon season
d. The retreating monsoon season.
The summer Season: It starts in the month of April and continues till the end of June. During these months, the days are long and nights are short. In the Northern plains, very hot winds called loo blow and cause dust storms. The southern part of India, specially the coastal areas of India, is less hot. The sea breeze keeps the temperatures low. The Thar Desert in Rajasthan and the western part of Gujarat is extremely hot. Dust storms occur almost every day in the desert areas. The mountainous states like Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and north eastern states of India have a cool climate during this time of the year. The weather in this season is characterized by feeble high pressure conditions over the northern plain. As a result, winds start blowing from the northwestern high pressure zone to the low air pressure zone over the Indian Ocean in the south. Western disturbances from the Mediterranean Sea cause rainfall in Punjab, Haryana, Delhi and western Uttar Pradesh. Northeast monsoon, while crossing over the Bay of Bengal, picks up moisture and causes torrential rainfall over the Tamil Nadu coast, southern Andhra Pradesh, southeast Karnataka and southeast Kerala.
Climate class 11 geography MCQ :
1. October is hot due to
(a) the absence of rain.
(b) combination of high temperature and high humidity.
(c) dry hot weather.
(d) low pressure.
► (b) combination of high temperature and high humidity.
2. Which one of the following states suffers from loo?
(a) Tamil Nadu
(b) Assam
(c) Gujarat
(d) None of the above
► (c) Gujarat
3. What is the cause of the climatic difference between Agra and Darjeeling?
(a) Latitude
(b) Altitude
(c) Distance from the sea
(d) The Himalayan Mountains
► (b) Altitude
4. Deccan plateau comes under area of
(a) Inadequate rainfall.
(b) High rainfall.
(c) Medium rainfall.
(d) Low rainfall.
► (d) Low rainfall.
5. Which place in India receives the lowest rainfall?
(a) Leh
(b) Jaisalmer
(c) Bikaner
(d) Jodhpur
► (a) Leh
6. Dry winter is experienced in the
(a) Ganga plain.
(b) Eastern Ghats.
(c) Western Ghats.
(d) Deccan Plateau.
► (a) Ganga plain.
7. Which type of climate is found in the Coromandel coast?
(a) Amw
(b) Bwhw
(c) Cwg
(d) As
► (d) As
8. Where do you experience a dry winter?
(a) The Ganga plain
(b) North-eastern India
(c) Kashmir
(d) Coromandel coast
► (a) The Ganga plain
9. The dreaded evening thunderstorms in West Bengal are locally known as
(a) Loo.
(b) Kalbaisakhi.
(c) Chheerha.
(d) Mango Shower.
► (b) Kalbaisakhi.
10. According to Koppen's scheme of climatic regions the monsoon with short dry season is represented by
(a) As.
(b) Cwg.
(c) Amw.
(d) Aw.
► (c) Amw.
11. Name the coldest place in India.
(a) Dras
(b) Ladakh
(c) Mawsynram
(d) None of the above
► (a) Dras
12. Name the rainiest place in India.
(a) Dras
(b) Ladakh
(c) Mawsynram
(d) None of the above
► (c) Mawsynram
13. What type of winds are monsoons?
(a) Seasonal Winds
(b) Western Winds
(c) Northern Winds
(d) None of the above
► (a) Seasonal Winds
14. Name an upper air movement which brings monsoons to India.
(a) Western disturbances
(b) Jet Stream
(c) Mango showers
(d) None of the above
► (b) Jet Stream
Question : Which one of the following states suffers from loo?
(a) Tamil Nadu
(b) Assam
(c) Gujarat
(d) None of the above
Answer : C
Question : Mango showers occur in which one of the following groups of two states?
(a) Bihar and West Bengal
(b) Tamil Nadu and Andhra Pradesh
(c) Karnataka and Kerala
(d) Maharashtra and Andhra Pradesh
Answer : C
Question : Which place in India receives the lowest rainfall?
(a) Leh
(b) Jaisalmer
(c) Bikaner
(d) Jodhpur
Answer : A
Question : The local name of thunderstorm in West Bengal is
(a) Jetstream
(b) Mausim
(c) Kalbaishakhi
(d) Loo
Answer : C
Question : Which of the following places of India experiences an extreme type of climate?
(a) Shillong
(b) Bengaluru
(c) Chennai
(d) Delhi
Answer : D
Question : The Indian subcontinent experiences comparatively milder winters as compared to Central Asia due to which of the following factors?
(a) The Tropic of Cancer
(b) The surrounding seas
(c) The Himalayas
(d) Ocean currents
Answer : C
Question : In which of the following stations of India's mainland do the monsoons arrive first?
(a) Thiruvananthapuram
(b) Kolkata
(c) Chennai
(d) Delhi
Answer : A
Question : Which one of the following states suffers from loo?
(a) Tamil Nadu
(b) Uttar Pradesh
(c) Gujarat
(d) None of these
Answer : C
Question : Dry climates cover a large area extending over large latitudes from
(a) 35° to 60° north
(b) 15° to 60° north
(c) 15° to 35° north
(d) 35° to 60° north
Answer : B
Question : Name the gas which has more effect on greenhouse effect
(a) carbon dioxide
(b) oxygen
(c) nitrogen
(d) hydrogen
Answer : A
Question : The retreating monsoon season starts from
(a) October and November
(b) June to September
(c) March to May
(d) December to February
Answer : A
Question : The peninsular part of India experiences peak summers earlier than northern India because:
(a) There is less rainfall in the peninsula during that time.
(b) Cold waves from Central Asia sweep through the northern plains during this time.
(c) Due to northward movement of the sun, the global heat belt shifts northward
(d) Clouds do not form in those months
Answer : C
Question : According to Koppen’s scheme of climatic regions, the monsoon with a short dry season is represented by
(a) As
(b) CWG
(c) Amw
(d) Aw
Answer : C
Question : Name the coldest place in India.
(a) Dras
(b) Ladakh
(c) Mawsynram
(d) None of the above
Answer : A
Question : The dreaded evening thunderstorms in West Bengal are locally known as
(a) Loo.
(b) Kalbaisakhi.
(c) Chheerha.
(d) Mango Shower.
Answer : B
Question : The retreating monsoon withdraws itself from
(a) The west coast to the east coast
(b) North-East India to the west coast
(c) The north to the south
(d) North-West India to Bengal and then to Kerala
Answer : D
Question : Due to which of the following reasons is the southwest monsoon's rain bearing winds?
(a) They blow from low pressure area of north-eastern India towards the seas
(b) They are seasonal winds
(c) They blow over warm Indian Ocean and gather moisture
(d) They strike the Himalayas
Answer : C
Question : What is the proportion of the area of India which receives annual rainfall less than 75 cm?’
(a) Half
(b) One-third
(c) Two-third
(d) Three-fourth
Answer : D
Question : Where do you find the polar type of climate in India?
(a) Jammu & Kashmir
(b) Haryana
(c) Tamil Nadu
(d) Maharashtra
Answer : A
Question : Rainfall in India is not associated with ________
(a) Orography
(b) Convection
(c) Cyclones
(d) Anticyclones
Answer : D
Question . The classification of world climate which emphasizes the causes or origin of their formation based on weather condition:
(a) empirical classification
(b) genetic classification
(c) none of these
(d) both of these
Answer : B
Question : What type of winds are monsoons?
(a) Seasonal Winds
(b) Western Winds
(c) Northern Winds
(d) None of the above
Answer : A
Question : The concept of heating of the atmosphere indirectly from the earth’s surface is known as
(a) greenhouse effect
(b) global warming
(c) ice-coring programme
(d) none of these
Answer : A
Question . Name the rainiest place in India.
(a) Dras
(b) Ladakh
(c) Mawsynram
(d) None of the above
Answer : C
Question : The high velocity winds blowing in the upper troposphere are termed as
(a) Jet stream
(b) Monsoon
(c) Loo
(d) None of them
Answer : A
Question : The northeastern hills that block the South West Monsoon winds and cause heavy rains in Assam are
(a) Arakan Yoma and Pegu Yoma
(b) Garo Khasi and Jaintia hills
(c) Barail and Patkai hills
(d) Khasi and Pegu Yoma
Answer : B
Question : In which of the following states in India do we find ‘As’ type of climate as per Koeppen’s classification?
(a) In Kerala and coastal Karnataka
(b) In Andaman and Nicobar Islands
(c) On Coromandel Coast
(d) In Assam and Arunachal Pradesh
Answer: C
Question : The state with lowest range of temperature is
(a) Karnataka
(b) Arunachal Pradesh
(c) Himachal Pradesh
(d) Kerala
Answer : D
Question : Polar climatic group is represented by the letter:
(a) A
(b) C
(c) D
(d) E
Answer : A
Question : Warm temperate climates extend from:
(a) 300 – 500 latitude
(b) 40 – 50 latitude
(c) 35 – 40 latitude
(d) 450 – 50 latitude
Answer : A
Question : The wind blowing in the northern plains in summers in known as:
(a) Kaal Baisakhi
(b) Loo
(c) Trade winds
(d) None of the above
Answer : B
Question : Which one of the following characteristics is the cold weather season in India?
(a) Warm days and warm nights
(b) Warm days and cold nights
(c) Cool days and cold nights
(d) Cold days and warm nights.
Answer : B
Question : Kal Baisakhi is associated with:
(a) Punjab
(b) Odisha
(c) Karnataka
(d) West Bengal
Answer : D
Question : Which of the following terms refers to the sum total of weather conditions and variations over a large area for a long period of time (more than thirty years)?
(a) Atmosphere
(b) Annual range of temperature
(c) Climate
(d) Monsoons
Answer : C
Question : Which of the following is a component of upper air circulation?
(a) North-easterlies
(b) Jet stream
(c) South-west monsoon
(d) Kal Baisakhi
Answer : B
Question : In which of the following places of India precipitation is in the form of snowfall?
(a) Shillong
(b) Drass
(c) Chandigarh
(d) Haridwar
Answer : B
Question : Most parts of India receive rainfall during which of the following months?
(a) December to February
(b) March to May
(c) June to September
(d) October to November
Answer : C
Question : In which of the following places of India there is very little difference between day and night temperatures?
(a) Guwahati
(b) Nagpur
(c) Thiruvananthapuram
(d) Delhi
Answer : C
Question : Which one of the following is not one of the six major controls of the climate of any place?
(a) Latitude
(b) Temperature
(c) Pressure and wind system
(d) Distance from the sea
Answer : B
Climate class 11 geography SAQ:
Explain why the tropical humid climate is found in an irregular belt of 20° to 40° latitudes.
Answer:
The tropical belt extends across the two tropics, viz., Tropic of Cancer and Tropic of Capricorn in the Northern and Southern hemisphere respectively. It is one of the belts which, for part of the year, comes under the influence of trade winds but for the rest of the year is subjected to conventional rain. Moreover, the trade winds which blow from north-east and southeast also bring a considerable amount of rainfall.
What could be the possible consequences of the continued addition of carbon dioxide and methane gasses to the atmosphere?
The continued addition of carbon dioxide and methane gasses to the atmosphere will increase the atmospheric temperature to an extent that it will cause ice to melt in the Arctic Ocean and in Antarctica. As a result, sea levels will rise causing the drowning of central lowlands and islands, altering rainfall and evaporation patterns, creating new plant diseases and part problems, and enlarging the ozone hole. Enlargement of the ozone hole, in turn, will cause more and more ultraviolet radiation to reach the earth’s surface, leading to a further rise in temperature of the lower layers of the atmosphere.
Match the following :
Answer:
Discuss the bases of climatic classifications of Koeppen and Thornthwaite.
Koeppen’s classification is based upon annual and monthly means of temperature and precipitation. Native vegetation was considered as the best expression of the totality of climate. Similarly, Thornthwaite followed Koeppen’s principle that plants are nature’s meteorological instrument capable of integrating climatic elements like precipitation effectiveness and potential evapotranspiration.
Discuss the aims and objectives of Trewartha’s classification.
Trewartha believed that people who need to understand and use the climatic environment for their own purposes should have the parts of climate presented realistically. At the same time, he also recognized the merits of the genetic type of climatic classification. According to him, “genetics not only increases interest and adds to the scientific quality of climatic analysis, but also gives an extra dimension of insight to the student’s understanding of the description.” Genetic classification of climates emphasizes the causes or origin of their formation based on weather processes.
What type of weather conditions characterizes sub-tropical climate?
Sub-tropical climates are found between tropical and temperate climatic zones. In this type of climate, the temperature is above 18°C for nearly 8 months. Winters are mild and short. The coastal areas have rainfall throughout the year while continental areas receive less rainfall.
On the basis of seasonal distribution of precipitation, subtropical climates have two subtypes, viz., subtropical humid and subtropical dry summer climates.
How do the carbon dioxide contents of the atmosphere play a dominant role in causing world wide climatic changes?
The carbon dioxide contents of the atmosphere play a dominant role in causing world wide climatic change. Carbon dioxide is transparent to incoming solar radiation but absorbs outgoing longwave terrestrial radiation. The absorbed terrestrial radiation is radiated back to the earth’s surface. Thus, it is clear that any appreciable change in carbon dioxide content would bring about changes in the temperature of the atmosphere.
Explain the Greenhouse effect.
The concept of heating of the atmosphere indirectly from the earth’s surface is called the greenhouse effect. This effect of the atmosphere is analogous to that of a glasshouse, which lets through most of the incoming short wave solar energy but greatly retards the outgoing longwave earth radiation, thus maintaining surface temperatures considerably higher than they otherwise would be. One can build an instantaneous greenhouse. If the car is parked in the sun for about two hours with the windows closed, the interior temperature will rise. It will be more than the temperature outside.
Describe major reservoirs of carbon on earth.
The carbon in the system moves between several major reservoirs. The atmosphere contains more than 750 billion tons of carbon at any given time, while 2000 billion tons are stored on land, and approximately 4000 billion tons are contained in the ocean. Living terrestrial organic matter is estimated to contain between 450 and 600 billion tons. World fossil fuel reserves also constitute an important carbon reservoir of some 5000 billion tons. The burning of fossil fuels adds more than 5 billion tons of carbon dioxide to the atmosphere every year.
Explain why the tropical humid climate is found in an irregular belt of 20° to 40° latitude.
The tropical belt extends across the two tropics, viz., Tropic of Cancer and Tropic of Capricorn in Northern and Southern hemispheres respectively. It is one of the belts which, for part of the year, comes under the influence of trade winds but for the rest of the year is subjected to convectional rain. Moreover, the trade winds which blow from north-east and south-east also bring a considerable amount of rainfall.
What are ice-coring programs? How do they help us know about the climate of the earth in the past?
Answer:
Ice-coring programs analyze the trapped gasses in Greenland and Antarctica ice-caps during the last 1,00,000 years. Analysis of these trapped gasses, like oxygen, carbon dioxide, etc., reveals the cooling or heating trends of the earth, on the basis of which climatic changes have been studied in the past.
Distinguish between Genetic and Empirical classification of climate?
Answer:
Genetic classification of climates emphasizes the cause or origin of their formation based on weather processes. The Empirical classification, on the other hand, is based on observations related to factors for climatic differentiation.
Divide the world into temperature zones.
Answer:
The earth is divided into three main temperature zones :
1. Torrid Zone (Hot Zone): Occurs between 0° to 30° N and S latitudes with a mean annual temperature of more than 20°C.
2. Temperate Zones: Subdivided into
(a) warm temperate zone (between 10° to 20°C temperature, 30° to 40° N and S),
(b) cool temperate zone (0°C to 10°C temperature, 45° to 60° N and S).
3. Frigid Zones (Cool Zones): Occur between 60° to 90° N and S latitudes.
What is the significance of 10°C summer isotherm?
10°C isotherm in summer indicates the limit of tree growth. In the Tundra region, trees do not grow because the temperatures are below 1.0°C in summer.
In which latitudes does the tropical humid climate extend and what are its features?
The tropical humid climate (A) stretches along the equator in the irregular belt of 20° to 40° latitude in both hemispheres. The features of this climate are that the temperature and rainfall are high throughout the year. In the coastal region, the average temperature of the coldest month is 18°C.
Q. 1. What climatic data are used in Koeppen’s classification of climate ?
Ans. (i) Temperature
(ii)Rainfall
(iii) Evaporation
(iv)Evapo-transpiration
(v) Water balance.
Q. 2. Which are the two well-known classifications ?
Ans. Many different classifications of climates have been devised. Of these, two classifications are well known.
(i) The German meteorologist Wladimir Koeppen devised a system based on temperature and rainfall.
(ii) The American climatologist C. Warren Thornthwaite drew up a classification based on precipitation efficiency.
Q. 3. Divide the world into temperature zones.
Ans. Various attempts have been made by different climatologists to divide earth into different temperature zones. The early Greek philosophers distinguish three temperature zones :
(i) Torrid zone (Hot zone) Between 0°–30° N and S latitudes with a mean annual temperature of more than 20° C.
(ii) Temperate zone.
(a) Warm temperate (10° to 20°C temperature) 30° to 45°N and S.
(b) Cool temperate (0°C to 10°C temperature) 45° to 60°N and S.
(iii) Frigid zone (Cold zone) 60° to 90°N and South latitudes. (Less than 0°C Temp.).
Q. 4. Which type of climate is known for the minimum range of annual temperature ?
Ans. In an Equatorial type of climate the annual range of temperature is the minimum (Below 5°C).
Q. 5. Why is the amount of precipitation that defines the humid dry boundary variable ?
Ans. The seasonal distribution of precipitation is observed to define the humid dry boundary of climates. The temperature and potential evaporation also affect it. According to the effect of all these factors, the amount of precipitation varies.
Q. 6. What is the significance of 10°C summer isotherm ?
Ans. 10°C isotherm in summer marks the limit of tree growth. Trees do not grow in Tundra because the temperature is below 1.0°C in Summer.
Q. 7. What are the characteristics of the Savanna Climate ?
Ans. The annual average temperature is 23°C. The range of temperature is 5°C. The annual rainfall is 160 cm. mostly in summer.
Q. 8. Why is the marine West European climate formed only in a narrow belt along the coast in North and South America ?
Ans. The presence of mountain barriers of the Rockies and Andes limit the West European climate to a narrow belt in Chile and Canada.
Q. 9. Describe the atmospheric distribution of carbon and greenhouse effect.
Ans. The Carbon Cycle and Greenhouse Effect Three of the principal greenhouses gasses – carbon dioxide (CO2), methane (CH4) and the chlorofluorocarbon (CFC) – contains carbon, one of the most common elements in the environment, and one which plays a major role in the greenhouse effect.
It is present in all organic substances, and is a constituent of a great variety of compounds, ranging from relatively simple gasses to very complex derivatives of petroleum hydrocarbons. The carbon in the environment is mobile, readily changing its affiliation with other elements in response to biological, chemical and physical processes. This mobility is controlled through a natural biogeochemical cycle, which works to maintain a balance between the release of carbon compounds from their source and their absorption in sinks.
Q. 10. Describe the scheme of classification of climates according to Trewartha.
Ans. Trewartha modified Koeppen’s classification of climates and gave some new suggestions. He included empirical as well as genetic both types of classifications.
The main aim of Trewartha was to give a simple scheme of climates so that main types of climate can be identified.
So he tried to keep the number of climates as minimum.
Koeppen’s classification was difficult to remember.
Trewartha divided the earth into five major climatic groups.
1. A type of Climate—Tropical Humid Climate : These include low latitude areas which have high temperature and high rainfall throughout the year.
There is no winter season. It is subdivided into three subtypes.
Af = High rainfall throughout the year.
Aw = Low rainfall in winter.
Am = Monsoon type.
2. B Type of Climate (Dry Climate) This climate is found in tropical Humid and mid latitude climates. Its subtypes are :
(i) BWh — Tropical dry climate.
(ii) BSh — Subtropical steppe climate.
(iii) BWk —Mid-latitude dry climate.
(iv) BSk — Mid-latitude steppe climate.
The demarcation of tropical dry and steppe dry climate is by 32°F isotherm in the coldest month.
3. C Type of Climate — Mid-latitude Humid climate This type of climate has a short winter season. It has three sub-types.
(i) Cs—Sub-tropical semi-humid climate.
(ii) Ca — Subtropical humid climate.
(iii) Cb— Mid-latitude marine climate.
Cs climate is affected by anticyclones in Summer and Westerlies in winter. Ca climate gets Westerlies in winter. Cb gets Westerlies throughout the year.
4. D Type of Climate This climate is found in high mid-latitudes, where polar winds predominate in winter. It has sub-types :
(i) Da— Humid Continental climate (20°C temp. in hottest month).
(ii) Dh — Humid Continental climate (22°C temp. in hottest month).
(iii) Dc — Subpolar climate with a short summer. (iv) Dd — With the coldest month a temp. of – 38°C. 5. E. Type of Climate (Polar climate) There is no summer season. Polar winds blow throughout the year. It has two subtypes : (ET) — Tundra (ii) EF (ice caps), where temp. is below 0°C.
Climate class 11 geography long question:
Give an account of any four factors which control the climate of a region.
These are the following factors that control the climate of a region :
Altitude: Regions on the higher altitude have a cold climate and on the lower altitude have a warm climate.
Location: The climate of a region depends on the location of that region. If the location is close to the equator, the climate will be hot and wet.
Distance from the sea: Regions that are closer to the sea have a moderate climate and others have an extreme type of climate.
The direction of the mountains: The extension of the Himalayas does not allow the cold winds of Central Asia into India and the temperature of India does not come down.
Describe in brief Koeppen’s classification of climate.
Koeppen’s classification is strictly empirical as it is neither based on weather process (wind belt, air masses, fronts, and storms) nor does it emphasize causes of formation of climatic type. The classification is based upon annual and monthly means of temperature and precipitation. Natural vegetation is considered the best expression of the totality of climate. On the basis of the climate needs of certain types of vegetation, Koeppen identified five major groups: A to E, to which he added a sixth category of mountain zone (H).
‘A’ is the tropical zone, with a temperature exceeding 20°C all the 12 months.
‘B’ is the sub-tropical zone, where for 4 to 11 months temperature exceeds 20°C, and for 1 to 8 months the temperature ranges between 10° to 20°C.
‘C’ is the temperate zone, where the temperature ranges between 10° to 20°C for 4 to 12 months.
‘D’ is the cold zone, with temperature ranging between 10° to 20°C for 1 to 4 months and below 10°C for 8 to 11 months.
‘E’ is the polar zone, where the temperature remains below 10°C throughout the year.
These major climatic groups were subdivided on the basis of variation in rainfall and temperature characteristics.
Discuss the global climatic changes in detail.
The atmosphere is well structured and fairly dynamic in nature. The dynamism is more complex near the earth’s surface where the changes take place both spatially and temporally. These changes may be induced internally within the earth’s atmospheric system or externally by extra-terrestrial factors. Some of these changes are the results of human intervention and, hence, may be slowed down by human efforts. Global warming is one of the changes caused by man’s continual and growing introduction of carbon dioxide as well as some other so-called greenhouse gasses, like carbon and chlorofluorocarbon, into the atmosphere.
The atoms and molecules of atmospheric gasses cause absorption and back radiation of sunlight by the greenhouse gasses, especially water, carbon dioxide, and methane. The concentration of water in the atmosphere is controlled by evaporation from oceans. Carbon dioxide is introduced into the atmosphere by volcanism. Methane is produced by the metabolization of bacteria in wood/grass-eating animals.
Human activities also add methane and carbon dioxide to the atmosphere by burning fossil fuels and by various agricultural activities.
The carbon dioxide contents of the atmosphere play a dominant role in causing world wide climatic changes. The gas is transparent to incoming solar radiation but absorbs outgoing long-wave terrestrial radiation. This absorbed terrestrial radiation is radiated back to the earth’s surface. Thus, it is clear that any appreciable change in carbon dioxide content would bring about a change in temperature in the lower layers of the atmosphere. Methane, which rapidly gets oxidized into carbon dioxide, is 20 times more effective than CO2
Rapid industrialization and technological changes, a revolution in agriculture and transport sectors have resulted in large supplies of carbon dioxide, methane and chlorofluorocarbon gasses into the atmosphere.
Of the many climatic parameters, the temperature is the most affected due to urbanization and industrialization. The thermal characteristics of urban areas are in marked contrast to those of the surrounding countryside.
Man is considered as an engine of climatic change. In support of this, rice farmers, coal miners, dairy farmers, and shifting agriculturists contribute their rate to global warming.
Describe the advantages of Trewartha’s classification over Koeppan’s classification.
On the basis of grouping, climate types are either genetic or empirical. Genetic classification emphasizes the causes or origin of their formation based on weather processes. The empirical classification, on the other hand, is based on observation related to factors for climatic differentiation.
Koeppen’s classification is strictly empirical as it is neither based on weather process nor does it emphasize causes of formation of climatic type. The classification is based upon annual and monthly means of temperature and precipitation. Natural vegetation is considered the best expression of the totality of climate. Koeppen followed the principle that plants are nature’s meteorological instruments capable of integrating climatic elements like precipitation effectiveness and potential evapotranspiration.
The climate classification system devised by G.T. Trewartha represents a compromise between purely empirical and genetic methods. Besides being simple and explanatory, it combines the fundamentals of the empirical as well as genetic classification schemes. Trewartha, while proposing his climatic classification, was conscious of the fact that the classification systems of Koeppen, being based on certain statistical parameters. of a few weather elements, were cumbersome and complex. The empirical quantitative classification system, as devised by the author, produced such a large number of climatic types and sub-types that it was rather too difficult to remember them. Keeping this aspect in view, Trewartha recognized only a limited number of climatic types, i.e., 6 major types and 10 sub-types.
The major climatic groups included: Tropical humid climate
(A) Dry climate
(B) Subtropical
(C) Temperate climate
(D) Boreal climate
(E) Polar climate
(F) Each of these, except Boreal
(E) the climate has two subtypes.
Write a note on temperate climates.
The temperate climate is found in the vast landmasses of middle latitudes (40° and 65°). This climatic band of severe winters is found between the sub-tropical and boreal type of climates.
The two subtypes of temperate climate are temperate marine and temperate continental. They are primarily demarcated on the basis of summer temperatures.
The temperate marine climate has mild winters and fairly warm in- summers. Throughout the year, the average temperature is above 0°C. Rainfall is experienced throughout the year. This type of climate is found on the western sides of continents in the temperate zone.
The temperate continental climate is found in the interior of the continents in middle latitudes. The impact of land is visible as it is characterized by harsh winters and cool summers. The extreme cooling of the ground is associated with anticyclones. Annual precipitation is low, though it takes place throughout the year. This type of climate is found in north-eastern Asia, eastern Canada, and Eurasia.
Describe the broad climatic groups framed by Koeppen.
Ans. Koeppen’s Classification.
The aims and objectives of Koeppen climate classification were very clear. He opined that, people such as geographers, biologists, or agriculturists, who need to understand and use the climatic environment for their own purposes, should have the facts of climate presented realistically. At the same time he also recognised the merits of the genetic type of climatic classification.
Koeppen classified world climates in six great climatic groups, out of which, five (A, C, D, E, F) are based on temperature criteria, and the sixth (B) is the dry group based on precipitation.
Simplified Version of Koeppen’s Climatic Classification System
Climatic Groups Based on Temperature Criteria
(1) Tropical Humid (A) Climate. The tropical humid (A) climate stretches along the equator, in the irregular belt of 20o to 40o latitude in both the hemispheres. The temperature and rainfall are high throughout the year. In the coastal region the average temperature of the coldest month is above 18o C.
(i) Tropical Wet Climate (Ar). The core of the 'A' climatic region is constituted by a wet sub-type, the tropical wet climate (Ar). This climate extends approximately 5o to 10o on either side of the equator. Along eastern margins of continents, this type of climate is under the influence of an inter-tropical convergence zone and the subtropical jet-stream. It is also known as a tropical rainforest.
Closer inspection of tropical wet climate reveals that it extends (15o to 20oN and S) on the eastern margins of continents because trade winds blow on shore from northeast and southeast.
(ii) Tropical Wet and Dry Climate (Aw). The tropical wet and dry climate (Aw) exhibits the winter dry season. It is dominated by dry trade winds. In this region average precipitation is less than the one in tropical wet climates. This type of climate is called savanna climate because tall grasses that grow between trees and thorny bushes dominate the vegetation cover.
(2) Subtropical (C) Climates: Sub-tropical climates are found between tropical and temperate climatic zones. In this type of climate, the temperatures are generally above 18oC for nearly 8 months. Winters are mild and short. The coastal areas have rainfall throughout the year while continental areas receive less rainfall. On the basis of seasonal distribution of precipitation, subtropical climates have two subtypes: subtropical humid (Cfw) and subtropical dry summer (Cs).
(i) Subtropical humid climate (Cw): The subtropical humid climate is found on the eastern sides of continents. In this type, the rainfall is throughout the year. During summer, it is under the influence of subtropical anticyclone and in winter under temperate cyclones. The summer months receive more rainfall than winter.
(ii) Subtropical dry climate (Cs): Subtropical dry summer climate is characterized by moderate to scanty rainfall. Rainfall occurs in winter while summers are dry. This type of climate is found in the interior of 'C' climate region along the tropical margin of mid latitudes.
(3) Temperate (D) Climates. The micro thermal (D) climates receive a relatively small amount of heat. It is found in the vast landmasses of middle latitudes (40o and 65o). This climatic band of severe winters is found between sub-tropical and boreal types of climate. The two subtypes of temperate climates are temperate marine (Do) and temperate continental (Dc). They are primarily demarcated on the basis of summer temperatures.
(i) Temperate Marine Climate (Do). Temperate marine climate has mild winters and fairly warm summers. Throughout the year, the average temperature is above 0oC. The rainfall is experienced throughout the year. This type of climate is found on the western sides of continents in temperate zones.
(ii) Temperate Continental Climate (Dc): Temperate continental climate is found in the interiors of the continents in middle latitudes. The impact of land is visible as it is characterized by harsh winters and cool summers. The extreme cooling of the ground is associated with anticyclone. Annual precipitation is low, though it takes place throughout the year. This type of climate is found in north-eastern Asia, eastern Canada and Eurasia.
(4) Boreal (E) Climates. Boreal climate is found in the higher middle latitudes. In this climate, summers are short and cool, winters are long and cold with a very short frost-free season. Annual temperature ranges between 0o and 10o C. Annual precipitation is meager and most of it occurs during summers. This type of climate is noticed in the coniferous forest of the world.
(5) Polar (F) Climates. Polar climates are found in the high latitudes and higher reaches of the Himalayas and the Alps. These climates are confined to the northern hemisphere only. The average temperature does not exceed 10oC in any month. There is no summer season. On the basis of temperature the polar climates are classified into two types:
(i) tundra (Ft); and (ii) ice cap (Fi).
(i) Tundra Climates (Ft): The Tundra climate on land is found only in the northern hemisphere where it occupies the coastal fringes of the Arctic Ocean, the ice-free shores of the northern Iceland, southern Greenland and higher reaches of the Himalayas and the Alps. This climate is characterized by extreme cold in which the average temperature of the warmest month does not normally rise above 0oC, but never above 10oC. It is associated with permanent frost formation leading to frozen subsoil. During the summer, precipitation occurs in the form of snow and rain.
(ii) Icecap (Fi): Icecap climate has average temperature below freezing point. It is associated with the phenomena of permanent ice and snow. The winter and summer are windy and chilly and precipitation is very meager. This type of climate is confined to icecaps of Greenland and Antarctica.
(6) Climatic Group Based on Precipitation Criteria
Dry (B) Climates: The dry climates are found on the poleward margins of 'A' group climates on the western sides of the continents. The most important feature of a dry climate is the higher rate of moisture-loss through evaporation and evapo-transpiration in relation to the annual receipt of water gain from precipitation. This climate is characterized by dry weather with a high range of temperature – 25o to 30o C.
Dry B1 climates are associated with subsiding air of subtropical high pressure zone which results in intrusion of arid climate into continents of both north and south hemispheres. The extreme seasonal temperatures cause a large annual range of temperature. The average annual precipitation is meager (nearly 0 to 50 cm) and is highly variable.
On the basis of annual average range of precipitation, dry climates are subdivided into desert (BW) and semi-arid (BS) types of climate. The capital letters 'S' and 'W' indicate the degree of aridity in dry (B) climates, with 'S' and 'W' designating semi arid and fully arid conditions respectively. The boundaries of these two sub-climates are set at one half of the annual rainfall separating dry (arid) from the semiarid type.
(i) Desert type (Bw): Desert or arid type of climate has driest climatic variety in sub-tropical belt between 20o to 30o north and south latitudes. This type of climate is found in coastal deserts of Peru and Chile in South America, Kalahari deserts of coastal Angola, south-west Africa, Great Australian desert, Sahara and Arabian deserts. Thar desert of Pakistan and India and deserts of northern Mexico. In these regions stability of air mass leads to extreme dryness with no rainy days. The influence of cold ocean currents is also there. These areas receive the lowest annual rainfall in the world despite their location adjacent to the oceans.
This type of climate is associated with xerophytic (thorny / spiny) types of vegetation.
(ii) Semi-desert (Bs). The semi arid or steppe type of climate borders 'A' and 'C' type of climate and has an annual rainfall range of 30 to 60 cm. These areas lie in the heart of the grasslands of western North America and Eurasia. That is why they are called the steppe type of climate. The lands of this climatic type are away from the oceanic influence. It is found in both north and south tropical deserts from Morocco to Tunisia and from Dakar in Senegal to Ethiopia deserts of Afghanistan, large strip of land adjoining Thar Desert and rain shadow area of peninsular India.
. Describe Global Warming in detail.
Ans. Global Warming. Global warming means the increase in the average temperature of the earth.
Processes of Heating the Earth The atoms and molecules of atmospheric gasses cause absorption and back radiation of sunlight, by the greenhouse gasses (discussed in later part of this chapter) especially water, carbon dioxide, and methane. The concentration of water in the atmosphere is controlled by evaporation from oceans. Carbon dioxide is introduced in the atmosphere by volcanism. Equivalent amount of carbon dioxide is removed by precipitation as calcium carbonate in oceans. Methane, which is twenty times more effective than carbon dioxide, is produced by metabolization of bacteria in wood / grass eating animals.
The methane rapidly gets oxidized into carbon dioxide.
Effects of Human activities Human activities add methane and carbon dioxide to the atmosphere by burning fossil fuels and by various agricultural activities. The carbon dioxide contents of the atmosphere play a dominant role in causing world wide climatic change. The gas is transparent to incoming solar radiation, but absorbs outgoing long-wave terrestrial radiation. The absorbed terrestrial radiation is radiated back to the earth's surface. Thus, it is clear that any appreciable change in carbon dioxide content would bring about changes in the temperature in lower layers of the atmosphere.
Rapid industrialisation and technological changes, revolution in agriculture and transport sectors has resulted in large supplies of carbon dioxide gas, methane and chlorofluorocarbon gasses to the atmosphere. Some of these gasses are consumed by vegetation and part of it is dissolved in the ocean. However, about 50 per cent is left over in the atmosphere.
Examples : (i) During the past 100 years the concentration of methane has more than doubled (from 7.0 × 10–7 to 15.5 × 10–7).
(ii) Carbon dioxide has increased by 20 per cent (from 2.90 ×10–4 to 3.49 ×10–4).
(iii) In 1880-1890 the carbon dioxide content was about 290 parts per million (ppm). It rose to about 315 ppm in 1980, 340 ppm in 1990 and 400 ppm in 2000.
(iv) This means that the proportion of carbon dioxide had increased to 9 per cent by 1950 and nearly 17 per cent by 1990. The rate of increase has become greater during the last one decade.
Effects of industrialisation Of the many climatic parameters, temperature is the most affected one due to urbanization and industrialisation. The thermal characteristics of urban areas are in marked contrast to those of surrounding countryside. The analysis of temperature data for the last fifty years reveals that there is an increase of 0.7oC in winter and 1.4oC in summer in India.
Effects of Agriculture Man is considered an engine of climatic change. In support of this, rice farmers, coal miners, dairy farmers and shifting agriculturists contribute their mite to global warming. According to some estimates, rice cultivation in the world is responsible for 20 per cent methane being added to the atmosphere, and coal mining accounts for 6 percent of methane. Deforestation is responsible for 20 percent of the carbon dioxide gas being added to the atmosphere. Similarly, industrialisation is adding 25 percent of chlorofluorocarbon to the aerosol of the atmosphere. Consequently, global temperature increases by about 1.5oC.
Rise in Sea-level Today, there is much concern that continuing addition of carbon dioxide and methane gasses to the atmosphere will increase atmospheric temperature to an extent that it will cause ice to melt in the Arctic Ocean and in Antarctica. As a result, sea level will rise causing drowning of coastal lowlands and islands, altering rainfall and evaporation patterns, creating new plant diseases and pest problems and enlarging the ozone hole.
With a view to get a dependable picture of climatic changes in the past, ice-coring programmes have been undertaken in several countries particularly in Antarctica and Greenland Ice caps to analyze the trapped gasses during the last 1,00,000 years.The results have been fascinating and offer glimpses of the earth’s recent history going beyond the phenomena of global warming. During the last 10,000 years of the earth’s history, the climate regime has been exceptionally stable compared to earlier history. Study of oxygen isotope records in Greenland ice core suggests that cooling trend in the northern hemisphere started from 1725 to 1920.
These were associated with emissions of volcanic dust at a regular interval of two to three decades but after 1945 there has been an increase in temperature globally leading to warming without any major volcanic eruption and increase in level of carbon dioxide concentration in the atmosphere. Future scientists predict that by 2020, temperatures all over the world will be higher than ever during the last 1,000 years. As such, it is evident that increasing carbon dioxide content would lead to rise in global temperature.
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