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GC Leong Colour Coded Synopsis For UPSC Prelims

CERTIFICATE PHYSICAL AND HUMAN GEOGRAPHY

G.C. LEONG

INDEX

Sn.

No.

Name of the TopicPage No
  •  
Arid or Desert Landforms2
Coastal Landforms7
Island and Coral Reefs12
Lakes15
Landforms made by running water17
Landforms of Glaciation22
Limestone and Chalk Landform27
The Earth and The Universe28
The Earth’s Crust33
The Oceans39
Vulcanism  and Earth Quakes46
Weathering, Mass Movement and Ground Water48
The Cool Temperate Western Marine Climate or British Type Climate52
Climate55
The Warm Temperate Eastern Margin Climate or China Type Climate63
The Cool Temperate Eastern Margin or Laurentian Type Climate67
The Warm Temperate Western Margin Climate or Mediterranean Climate69
The Arctic or Polar Climate74
The Savanna or Sudan Climate76
The Cool Temperate Continental or the Siberian Type Climate78
The Temperate Continental or Steppe Climate81
The Hot Desert and Mid- Latitude Desert Climate83
The Hot ,Wet  Equatorial Climate86
The Tropical Monsoon and The Tropical Marine Climate90
Weather94

 

THE COOL TEMPERATE WESTERN MARGIN CLIMATE OR BRITISH TYPE CLIMATE

  • Cool temperate western margins are under the permanent influence of the westerlies all-round the year approx. at 50 degree North- South
  • They are also regions of much cyclonic activity, typical of Britain, & are thus said to experience the British type of climate.
  • From Britain, the climatic belt stretches far inland into lowlands of North-West Europe, including such regions as northern & western France, Belgium, Netherland, Denmark, Western Norway & North-West Iberia.
  • There is so much oceanic influence on both the temperature & precipitation that the climate is also referred as northwest European Maritime Climate.
  • In northern America, the high Rockies prevent the on shore westerlies from penetrating far inland & British type of climate is confined mainly to coastlands of British Columbia (West coast of Canada)
  • In the southern hemisphere, this type of climate is experienced in southern Chile, Tasmania (southern Australia) & Most parts of New Zealand, particularly in south island, surrounded by large expanses of water.
British Type Climate
  • The mean annual temperatures are usually between 5 degree Celsius in winters to 15 degree Celsius in summers thus have a short annual temperature range.
  • Summers are in fact never very warm and temperature above 20 degrees Celsius is rare; winters are abnormally mild & no station record a mean temperature of below freezing point.
  • Heatwaves are a welcome feature in such cool temperate climate.
  • Above climatic features especially the warming effect mentioned are the attributes to the moderating effects of the North Atlantic drifts & prevalence of southern westerlies.
  • Sometimes, unsual cold spells caused by the invasion of cold polar continental air from the interiors, may hit the western margins for the number of weeks.
  • Night frost does occur & snow falls in winters.
  • Hence the climate of this maritime region as a whole may be described as equable with moderately warm summers & fairly mild winters.
  • British type of climate is even more equable in the Southern – Hemisphere, due to lack of continental mass (Tasmania, New Zealand & Southern Chile) & more presence of oceanic water, which means extremes of temperature are not likely at all, hence annual temperature range is further reduced here.
  • Amount of rainfall decreases from western margin of the continents eastward,
  • Relief can also make great differences in annual rainfall, hence it is difficult to say how much annual rainfall is typical for British type of climate
  • Though if confined to lowlands, it receives 50 – 100 cm of mean annual rainfall.
  • British type of climate has adequate rainfall throughout the year with a tendency towards slight winter or autumn maximum from cyclonic sources.
Natural Vegetation
  • The natural vegetation of this climatic type is deciduous forests that shed their leaves in the cold season, to protect themselves against winter snow & frost.
  • Some of the common species which provide hardwoods from these deciduous forests are Oak, Elms, Birch, Neech, Poplar & Hornbeam; along with certain other species such as chestnut, maple & lime.
  • Unlike the equatorial forests, the deciduous trees occur in pure strands & have greater lumbering value from the commercial point of view; & are excellent for fuel, furniture & industrial purposes.
  • The open nature of the forests with sparse undergrowth is highly useful in logging operations as easy penetration means much cost can be saved in movement of the logs.
  • Higher up the mountains in Scavandian highlands, the Rockies and Southern Alps of New Zealand, deciduous trees are generally replaced by conifers which can survive a higher altitude, a lower temperature & poorer soils.
Economic Developments of British Type of Climates
  • North-West Europe is one of the crowded parts of the world.
  • Hence despite growing a large number of cereals, that too with the highest yield/acre, it remains the net importer of food crops.
  • Wheat from all over the wheat-lands across the globe.
  • Fishing is particularly important in Britain, Norway and British Columbia.
Agricultural Developments of British Type of Climates
  1. Market Gardening
  • Though practiced all over the world, where there is large urban population but is highly specialized in North-West Europe (France, Belgium, Britain, West Germany & Denmark).
  • Farms are usually small and located near large cities or industrial areas.
  • Soils are carefully maintained at a high degree of fertility & very selective fertilizers are applied to the crops.
  • Farming is carried out intensively, aiming at high yield & maximum cash returns.
  • Produces, such as potatoes, cauliflowers, lettuces, cabbages, tomatoes, onion, peas & fruits are conveyed by high-speed conveyances such as trucks or vans, hence also called as truck farming in US.
  • Bulbs & flowers (esp. tulips) from the Netherlands, and eggs, bacon & other dairy products from Denmark are sent to most of the industrialized areas of Europe.
  • In Australia, high-speed boats ply across Bass Strait daily from Tasmania to rush vegetables, tomatoes, apples & beans to most parts of the Australian mainland.
  1. Mixed Farming
  • Throughout Britain & N-W Europe, farmers practise both arable farming (cultivation of crops on ploughed lands) & pastoral farming (keeping animals on grass meadows).
  • Crops may be raised for cash sales or as fodder for cattle & sheep.
  • Among the cereals, wheat is most extensively grown, almost entirely for home consumption.
  • The next important cereal raised in mixed farm is Barley raised in drier areas, as a fodder crop, with better quality barley sold to breweries for making beers or distilling whiskey.
  • Denmark, Australia & New Zealand excels in dairy products; & are one of the world’s greatest exporters.
  • Amongst food crops, potatoes feature prominently as a staple food crop in supplementing wheat or bread.
  • Today almost, 2/3rd of world’s annual production of potatoes comes from Europe, of which Poland, Germany, France and Britain are major producers.
  • Besides its principle use as a substitute for bread, it also serves as animal fodder & a source of industrial alcohol.
Sheep Rearing
  • Well Developed in British type climate
  • Home of some best-known sheep breeds. E.g- Leicesters, Lincolns, South downs
  • Principal areas- Foothills, well-drained uplands, chalk, limestone, scarplands, and the light sandy coasts.
  • In the southern hemisphere sheep rearing is the chief occupation of New Zealand- Greatest Concentration-Canterbury Plain
Other Agricultural Activities
  • Amongst the food crops, potatoes feature prominently in the domestic economy of the cool, temperate regions.
  • It is the staple food in supplementing wheat or bread for millions of people.
  • Normally cooler and more northerly latitude is preferred because the crop will be less prone to the attack of blight (virus disease that is particularly infectious in warm and humid countries)
  • 2/3 rd of the world’s annual production of potatoes comes from Europe of which Poland, Germany, France, and UK are the major producers.
  • Beet Sugar-Found almost in north western Europe and parts of USA.

CLIMATE

    Atmosphere:

  • On the basis of chemical composition atmosphere can be divided into 2 parts.
  1. Homosphere
  • Upto 90 km (Uniformity in chemical composition)
  • Troposphere
  • Stratosphere
  • Mesosphere
  1. Heterosphere
  • Above 90 Km (non-uniformity in chemical composition)
  • Ionosphere
  • Exosphere
Troposphere
  • Average height is 16 Km-10 km at Poles & upto 18 km at Equator.
  • Greatest at Equator due to upward transportation of heat by strong conventional currents.
  • That is why height of troposphere at a given latitude is greater in summer.
  • Temperature decreases with height, roughly at 1 degree Celsius for every 165 meters i.e. Normal Lapse Rate.
  • Lowest, Densest & contains 75 % of earth’s atmosphere with 90% of water vapours & dust particles.
  • All major atmospheric processes take place in this layer.
Tropopause
  • Shallow transitional zone also known as unstable zone between Troposphere & Stratosphere i.e. Approx. 1.5 Km
  • Temperature stops falling in this layer
  • 80 degree Celsius over equator
  • 45 degree Celsius over poles
Stratosphere
  • This layer rises up-to 50 km
  • Thicker at Poles than at Equator
  • Temperature remains constant in its lower portion upto 20 Km & then gradually increases to 0 degree Celsius till its upper limit i.e. Tropopause.
  • Increases mainly due to the presence of ozone gas, which absorbs sun’s UV rays.
  • Practically no clouds, convection currents, Thundering or lighting, water vapours or dust particles hence airplanes fly in this region.
  • Few clouds called “Mother of Pearls / Narcreas” can be seen over Antarctica.
  • Its lower portion (15 – 35 Km) constitutes Ozone layer which prevents us from harmful UV rays.
  • amount of Ozone gas is found at Stratopause i.e. uppermost limit of Stratosphere
Depletion of Ozone Layer
  • Major cause CFCs i.e. mainly from Refrigerator, AC, Spray Cans, Plastic Packaging, Cleaning Fluids, Insulation materials
  • UV breaks CFCs & release Chlorine atom which reacts with Ozone & convert it into simple oxygen molecule, which is unstable to absorb UV rays.
  • Space probes are also responsible for depletion of Ozone layer, as every time a rocket is fired into space, 70 – 150 tons of Chlorine is injected into atmosphere
  • Another cause for ozone layer depletion is oxides of Nitrogen, esp. Nitric oxide, released from supersonic aircrafts, automotive exhaust, in form of nitrates in fertilizers etc.
  • Already a major Ozone hole is formed over Antarctica with risk countries New Zealand, Australia, South Africa, Chile, Argentina etc.
Mesosphere
  • Upto 80 ~ 90 Km, Temp. decreases gradually with height until – 100 *C at 80 km
  • Displays wispy clouds at high altitudes due to reflected sunlight from meteoric dust Particles.
  • Most weather balloons are placed in this region
  • Most meteors burn up in this layer ; Upper limit Mesopause
Ionosphere/ Thermosphere
  • Extends upto 400 km, contains electrically charged particles (ions) with max. conc. at 250 Km.
  • Starts rising with increase in height because of ionization by solar radiations.
  • Zone of Earths Satellites.
Auroras
  • Are formed when Earth’s magnetic field traps solar winds in atmosphere, resulting in collision between solar wind & atmospheric charged molecules (ions).
  1. Aurora Borealis
  • Northern light in northern hemisphere (Arctic circle)
  1. Aurora Australia
  • Southern light in southern hemisphere (Antarctic Circle)
  • All radio waves are reflected in this layer (Radio transmission)
  • D layer-Reflects signal of low frequency & absorbs of medium & high frequency
  • E layer (Kennedy Heaviside layer)-Reflects medium & high frequency radio waves to earth
  • F layer (Appleton layer)-Useful for long distance radio transmissions-reflects medium & high frequency radio waves to earth
  • G layer-Highest layer
Importance of Temperature
  • Temperature influences the actual amount of water vapour present in the air & thus decides the moisture carrying capacity of the air.
  • It decides the rate of evaporation & condensation, & therefore governs the degree of stability of the atmosphere.
  • As relative humidity is directly related to the temperature of the air, it affects the nature & types of cloud formation & precipitation
Factors influencing Temperature
  1. Latitude
  • Due to the earth’s inclination, temperature reduces from equator to poles.
  • Mainly due to direct & oblique sunrays falling differently on different latitudes
  1. Altitude
  • Since the atmosphere is mainly heated by conduction from the earth.
  • Hence places near to earth surface are warmer than those higher up.
  • Thus, temperature decreases with increasing height above the sea level
  1. Continentality
  • Land surfaces are heated more quickly than the water surfaces, due to higher specific heat of the water
  • Hence warmer summers & colder winters prevails in continental interiors as compared with maritime districts.
  1. Ocean currents & winds
  • Both ocean currents & winds affect temperature by transporting their heat or coldness into adjacent regions.
  • For e.g. the westerlies that come to Britain & Norway tend to be cool winds in summer & warm winds in winter.
  1. Slope, Shelter & Aspect
  • A steep slope experiences more rapid change in temperature than a gentle one.
  • Mountain ranges that have an eastward alignment like the alps show a higher temperature on the south facing sunny slope than the north facing sheltered slope.
  • The greater insolation of the southern slope is better suited for vine cultivation & has a more flourishing vegetative cover, consequently more settlements
  1. Natural vegetation
  • There is a definite difference in temperature between forested regions & open ground.
  • Thick amazon forest cuts off much of incoming insolation keeping the land surface of the jungle cool & few degrees lower than the open spaces in corresponding latitudes
  • Soil
  • Light soils reflect more heat than the darker ones which are better absorbers of heat, which may give rise to slight variations in temperature of the region.
  • Dry soils like sand are very sensitive to temperature compared to wet clayly soils which retains moisture & warms up & cools down more slowly.
Precipitation
  • Condensation of water vapour in air in form of water droplets or ice.
  • Their falling on earth surface is known as precipitation
  1. Snowfall
  • When condensation takes place below freezing point.
  • Means at 0*C, conversion of water vapour directly into solid state.
  • Precipitation occurs in forms of fine flakes of snow.
  1. Sleet
  • Sleet is frozen raindrops or refroze melted snow water.
  • When a layer of temp. above freezing point overlies a subfreezing layer near the ground, precipitation occurs in form of sleet.
  1. Hail
  • Sometimes, drops of rains after being released by the clouds become solidified into small rounded stone pieces of ice, known as hailstones
  • Formed by rainwater passing through colder layers hence have several concentric layers of ice, one over the another.
  1. Rainfall
  • Most common form of precipitation
  • Precipitation in form of water
  • Also known as cloud particles
Types of Rainfall
  1. Convectional Rainfall
  • Air on being heated becomes light & rises up as conventional currents
  • As it rises, it loses heat & consequently condensation takes place with the formation of cumulus clouds.
  • Under these conditions, heavy rainfall takes place along with thunder & lightening, but does not last for long.
  • Common in Equatorial & Tropical regions in summers daily.
  1. Orographic or Relief Rainfall
  • When a warm & moist air currents is obstructed by a mountain range, it is forced to ascent along its slopes.
  • It gets cooled while ascending & when its temp. falls below dew point, it causes rainfall on windward slope of mountain range.
  • However, when these winds cross mountain range & descend along its leeward side.
  • Here, they get warm & dry & causes only little rain (Rain shadow areas)
  • This type of rainfall may occur in any season.
  1. Cyclonic or Frontal Rainfall
  • Rainfall associated with cyclone is known as cyclonic or frontal rainfall.
  • Occurs along the fronts of the cyclone viz. cold front & warm front.
  • At the warm front, the warm lighter wind rises gently over the heavier cold air, which being heavy stays close to the ground
  • As the warm air rises, it cools, and the moisture present in it condenses to form clouds altostratus clouds.
  • This rain falls steadily for a few hours to a few days.
Planetary Winds
  • Planetary winds are also known as permanent or prevailing winds
  • Blow from high to low pressure, over the earth surface & oceans throughout the year & in a particular direction
  • These winds are divided into 3 categories viz.
  • Trade Winds (Tropical Easterlies)
    1. Westerlies
  • Polar winds (Polar Easterlies)
Trade Winds (Tropical Easterlies)
  • Winds blowing from the subtropical high-pressure area to the equatorial low-pressure area (Extremely steady winds).
  • Since they travel from high latitude to low latitude area, they become gradually hot & dry and hence have a great capacity to hold moisture.
  • They cause considerable rainfall on eastern margins of the continents as they get moisture after blowing over oceans.
  • These winds converge near equator & form ITCZ, Here these winds rises & causes heavy rainfall
  • Absent in N Indian Ocean which is dominated by Monsoon winds.
Westerlies
  • Winds blowing from subtropical high pressure belts towards subtropical low pressure belts.
  • Blow from S – W to N – E under Coriolis effect in Northern Hemisphere & from N – W to S – E in Southern Hemisphere
  • Blow from lower latitudes to higher latitudes
  • Cause considerable rainfall particularly on western margins of the continents
  • More consistent in direction & blow with stronger force in S – Hemisphere due to lesser obstructions from continents.
  • Also known as brave winds or roaring forties, furious fifties & shrieking sixties according to the varying degree of storminess in the latitudes in which they blow.
  • It must be noted that not all the western coast of the temperate zone (30 degree – 60 degree) receive.
  •  Westerlies throughout the year due to shifting of wind belts coz of earth’s inclination.
  • In June, when the overhead sun is over the tropic of cancer, all the belts move about 5 degree – 10 degree north of their average position. The Mediterranean parts of continents that comes under the effect of werterlies, receive rain in June & vice a versa in December, when sun is overhead tropic of Capricorn.
Polar Winds
  • Winds blowing from polar high to sub polar low pressure belt.
  • Are very cold in nature as originate in polar areas & do not cause much rainfall.
  • These winds give birth to cyclones when they come in contact with westerlies.
  • Brings frequent change in weather conditions & causes heavy rainfall
Shifting of Wind Belts
  • Wind belts described above keep on shifting northward & southward depending upon the movement of the sun.
  • March 21 & Sep 23 (Equinoxes).
  • Sun shines vertically over equator.
  • Equatorial low pressure belt lies between 5 degree North – 5 degree South.
  • After March 21, sun moves northward & with it whole system of pressure belts moves northward.

June 21

  • Sun shines vertically over Tropic of cancer & all the pressure belts move 5 – 10 degree northward from original position.

Dec 21

  • Sun shines vertically over Tropic of Capricorn & all the pressure belts move 5 – 10 degree southward from original position.
  • Thus, shifting of world’s pressure belts also causes shifting of world’s wind system.

Periodic / Seasonal winds

  • Winds which change their direction periodically.
  • Examples Monsoon Winds, Land & Sea Breeze, Mountain & Valley Breeze.
Monsoon Winds
  • Refers to system of winds which reverses their direction completely with change of seasons
  • Blow from sea to land during summers & land to sea during winters, due to differential in heating of continents & oceans-Halley’s law
  • In summers, sun shines vertically over Tropic of cancer resulting in high temp. & low pressure in central Asia, while pressure is sufficiently high at Bay of Bengal & Arabian Sea.
  • This induces air flow from Sea to land & induces heavy rainfall in India & neighbouring countries.
  • In winters, sun shines vertically over tropic of Capricorn, hence North – West part of India grows colder than Arabian Sea & Bay of Bengal which results in reversal of monsoon in India.
  • Above theory of differential heating was replaced by shifting of ITCZ for monsoon in India & neighboring countries
Land and Sea Breeze
  • Influence only a narrow strip of 20 – 30 km along the coast
  • During day sun shines hence sea breeze moves from sea to land (Sea Breeze)
  • In night it reverses its direction i.e. from land to sea (Land Breeze)
Mountain & Valley Breeze
  • During day, mountain slopes gets heated more than valley floor hence air from valley floor blows up the slope (Valley Breeze)
  • After sunset pattern is reversed i.e. Mountain Breeze
Fohn Winds & Chinook Winds
  • Both the Fohn & Chinook winds are local hot & dry winds experienced on the leeward side of the mountains when descending air become compresses with increased pressure.
  • Fohn wind is experienced in the valleys of northern Alps, particularly in Switzerland in spring.
  • Chinook winds are experienced on the eastern slopes of the Rockies in USA & Canada in winters.
  • While descending, most of the moisture of the wind is lost & hence it becomes dry & hot, which may lead to rise in temperature of leeward side.
  • In North America, it is called Chinook which means the snow eater, as it melts the snow & causes avalanches.
  • It has blessings too, it enhances the growth of crops & fruits & thaws the snow covered pastures by raising temperature of the region quite quickly.
Cyclones
  • A low pressure area surrounded by high pressure area from all from all the sides along with winds moving from all the sides towards central low.
  • Cyclones moves in Anti clockwise in North Hemisphere & in Clockwise direction in South – Hemisphere under the effect of westerlies due to coriolis effect.
  • No Cyclones at equator as coriolis force is 0 there.
Temperate Cyclone
  • Also known as wave cyclones or Extra Tropical
  • Originate mainly in zones between 35 degree – 65 degree North & South of latitudes

Polar Front Theory

  • Forms due to collision of 2 air masses of contrasting characteristics (in terms of temp. & humidity at about 60 degree latitude).
  • Here they do not meet each other readily but forms a front known as polar front
  • Cold air mass pushes the warm air mass upwards & a void is created due to decrease in pressure.
  • Air from surrounding area rushes to fill the void & a temperate cyclone if formed
  • Average speed of extra tropical cyclone is 32 km/hr in summer & 49 km/hr in winters.
Tropical Cyclone
  • Also known as Typhoons or Hurricanes
  • Originate mainly in zones between 5 degree – 30 degree North & South of latitudes
  • Are the violent storms that originate over oceans in tropical areas & move to coastal areas
  • Bring large scale destruction, caused by violent winds, heavy rainfall & storm surges
  • Favorable conditions for formation of tropical cyclones are
  • Large sea surface with temp. > 27 degree Celsius
  • Presence of coriolis force
  • Small variation in vertical wind speed
  • Upper divergence above sea level
  • Pre-existing weak low pressure area or low level cyclonic circulations
  • Energy that intensifies the storm comes from the condensation process in towering cumulonimbus clouds, surrounding center of the storm.
  • Hence, with constant supply of moisture from the sea, storm is further strengthened
  • On reaching land, moisture supply is cut off & the storm dissipates
  • Place where tropical cyclone crosses the land is called landfall of the cyclone.
  • Central low pressure is known as eye of the cyclone Calm with subsiding air having lowest pressure & highest temp.
  • Surrounding this area is zone of strong winds with clouds extending vertically.
  • Surrounding the eye is eye wall, a place of strong spirally ascending winds to a height reaching tropopause, having max. wind velocity
Tropical Cyclone Distribution & its various names world wide
  1. Cyclone
  • Indian ocean, Arabian sea & Bay of Bengal
  1. Hurricane
  • Atlantic sea (West indies) & USA
  1. Typhoons
  • China sea + Japan sea
  1. Willy Willies
  • Western Australia
Difference between Tropical & Extra Tropical Cyclones
Tropical CyclonesExtra Tropical Cyclones
Moves from east to westMoves from west to east
Wind velocity is very high &

more destructive

Low wind velocity & less destructive
Originate only on sea &

dissipates on reaching land.

Affect much larger area & can

originate on land as well as sea.

Anticyclones
  • An anticyclone is just opposite to a cyclone.
  • Basically it is a large-scale circulation of winds around a central region of high atmospheric pressure
  • Clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
  • Anticyclones are formed from air masses, cooling more than their surroundings, which causes the air to contract slightly making the air denser.
  • Since dense air weighs more, the weight of the atmosphere overlying a location increases, causing increased surface air pressure.
  • Anticyclones herald fair weather, clearing skies, calm air with high temperature in summers & cold in winters.
  • Fog can also form overnight within a region of higher pressure.

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