PHYSICAL GEOGRAPHY - Classmate SSC

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PHYSICAL GEOGRAPHY


Solar System

Size: 8 6 5 7 1 2 3 4

Satellites/: 0 0 1 2 61 31 21 11 Moons


Solar System

Sun:

1. Sun is a large hot gaseous body with H2 and He as its main constituents in 3:1

2. Nuclear Fusion occurs b/w H atoms giving rise to He and large amount of energy

3. 60000c- surface temp. of the sun. 2 crore0c- core temp. of the sun 4. Sun spots: Sun spots are areas of relatively less temperature. 5. Plages: Plages are areas of relatively higher temperature. 6. Solar flares: Solar flares are sudden intense brightening of a small portion of sun

releasing X-rays and high energy charged particles. 7. Sun constitutes of 98.85% of all matter of solar system. 8. Sun rotates on its axis and sun also revolves around galactic centre at a speed of

250 km/sec taking 250 million years to complete one revolution. 9. Auroras: Bright display of colours in upper atmosphere at an altitude of 100 km

caused due to the ionization of gases by the charged particles from solar Flares. Aurora Boralis at the North pole. Aurora Australis at the South pole.




Planets:

1. All planets revolve around the sun in anticlockwise direction. 2. The period of revolution increases with increasing distance from the sun. Mercury least Neptune highest 3. All planets rotate on their axis in anticlockwise direction from west to east

except UV (Uranus Venus) planets

Planets Inner/Terrestrial Outer/Jovian

MVEM JSUN

All outer planets have rings


Astrological Planets: Meaning (European) Meaning (Vedic) Sun Golden god of prophecy The sun God. Son of Aditi and Kashyap

Moon Goddess of Hunt The Moon God Associated with impatience of human nature

Mercury Messenger God A planet God known for his Intelligence. Venus Goddess of Romance The mentor of ‘Asuras’. Associated with Fertility and enthusiasm Earth Goddess of the earth Goddess of Earth

Mars God of war Son of earth. Associated with (unluckiness of brides) and (strength) Jupiter Leader of the Gods Mentor/Guru/teacher of gods Saturn God of Agriculture God of Duty

Uranus God of the sky A mythological snake king in Indian Puranas. Neptune God of the sea God of rain in Indian mythology

Pluto God of the underworld God of wealth

Ceres Goddess of the seasons The Great divine mother in Hinduism


Mercury : 1. Shortest period of revolution

2. Mercury has no atmosphere and water 3. It has the maximum diurnal range of temperature (daily range)

Venus: 1. Venus is called earth’s twin because of mass, size and density similar to

earth but less comparatively. 2. Venus has longest period of rotation. A day on Venus is longer than its year 3. 243 days to complete one rotation

4. 223 days to complete one revolution

5. Venus has no magnetic field. 6. Venus is called veiled planet. Atmosphere of Venus is 92 times more denser

than earth’s 7. Albedo: Albedo is the amount of solar energy reflected without being

absorbed. Venus directly reflects 75% of solar energy. Albedo for Venus is highest. So, it appears as white and brightest planet of solar system.

8. It is the hottest planet. 9. The atmospheric pressure on Venus is 92 bar.


Earth: Moon:

1. Diameter of moon is ¼ of earth’s 2. Gravity on moon is 1/6 of earth’s 3. Distance b/w earth and moon is 3,85,000 km

4. Moon has no atmosphere and has extreme temperatures. 5. Moon takes the same time for rotation as well as revolution.

Hence same face of the moon is always seen from the earth. 4. Moon completes one revolution around the earth in 27 d 7 h 43 min: Sidereal month.

Time b/w one new moon/ Full moon and the next subsequent is 29d 12 h 44 min: Lunar month/ synodic month.




Mars: 1. Mars is called the red planet because it has the iron rich rocky surface. 2. Its atmosphere has co2, water vapour etc

3. Two moons: - Phobos Deimos.

Jupiter: 1. Largest Planet 2. Fastest rotating planet discovered by Galileo Galilie. Hence it is also

called Galileo planet. 3. Ganymede, IO, Europa are some of its satellites. Ganymede is the largest

moon of the Jupiter Saturn: 1. Saturn is the ringed planet, called jewel of the solar system. 2. Rings are made up of ice and dust particles

3. Titan is the largest moon. Uranus: 1. It is greenish blue because of Ammonia

2. Titania is the largest satellite. Neptune: 1. It is greenish blue in colour 2. Triton is its largest moon.


•Dwarf Planets: Pluto, Charon

Ceres Eris Charon was earlier called moon of Pluto but both of them are included in the dwarf planets. •Asteroid belt/Asteroids: Asteroids are small planetary bodies that orbit around the sun b/w mars and Jupiter. •Meteors/Meterorites: Meteors are chunks/pieces of iron and stone flying in space. When they enter the earth’s atmosphere many of them burn but some of them (meteorites) reach the surface giving an impact. Lonar lake (Maharashtra) formed due to the meteoritic impact (crater lake in Maharashtra) •Comets: Comets are bodies of dust and frozen gases. Tail of comets always points away from the sun due to solar winds or solar flares.


Big Bang Theory: According to this theory around 15 bn yr ago all the matter of the universe is in a compressed state. A sudden explosion created Nebula-an expanding disc of hot gases and dust. Nebula condensed to form Galaxies and stars. ‘ Red shift’ is the evidence that supports the Big Bang Theory. Light - EMR V I B G Y O R


Facts about EARTH: 1. Diameter of sun is 109 times that of earth. 2. Diameter of earth: Equatorial diameter – 12753 km

Polar diameter – 12710 km

3. Shape of earth: Geoid shape/ obligue spheroid circumference: 40, 000 km 4. Earth’s density is 5.51 gm/c.c- Highest density in the solar system.

Land water

29.2% 70.8% 5. 150 million km (148-152) is the distance b/w earth and sun

Distance b/w earth and sun is taken as astronomical unit (AU)

1AU= 150 million km. 1 Light year = 60,000 AU

Time taken for the light to reach the earth is 8 min 16 sec


6. Mean surface temperature: 140C 7. Orbital speed: 30 km/sec 8. Escape velocity : 11.2 km/sec 9. Length of the day (period of rotation): 23 hr 56 min 4 sec Length of the year 365 d 5 hr 48 min. 10. Distance b/w earth and moon: 3,85,000 km Time taken by light to travel : 1.3 seconds. 11. Composition Whole- earth Surface Iron - 35% Oxygen Oxygen - 30% Si Si Al Mg Iron Ni


Effects of Rotation: Axis of rotation of earth is inclined at an angle of 23 0 to the vertical and inclined at an angle of 66 0 to the elliptical plane.

a) Day and night effect

b) Magetic field i.e. N-S poles c) Coriolis force: It is a deflective force which deflects moving objects (wind, water

etc) to their right in Northern hemisphere and left in southern hemisphere d) Apparent movement of stars, sun, moon etc. from east to west.

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Coriolis force


All rockets are launched from west to east. To take advantage of earth’s rotation satellites are launched from west to east. And hence all satellite launching stations are on the eastern margin of the continent and towards equator. Rocket launching stations are not exactly placed at equator due to heavy rains and thunder storms (bad weather) conditions) at the equator. Eg. Sriharikota Eg . Cape Canaveral of NASA in USA Kourou (French): EU launch pad Baikonur (Kazakhstan): Russian launch pad.


ISRO Centres: 1. ISRO Satellite centre at Banglore- HQ 2. VSSC- Vikram Sarabhai Space Centre Thiruvananthapuram and Thumba Formerly called TERLS TERLS: Thumba equatorial rocket launching station. 3. SDSC- Satish Davan space centre (Sriharikota) SHAR- Sriharikota high altitudinal range. 4. Liquid propulsion system centre: Mahendra giri Banglore Thruvananthapuram 5. SAC- Space Application Cente Ahmedabad. Commercial arm of ISRO- Sells satellite images. 6. INSAT Master Control facility Hassan Bhopal 7. National Remote sensing Agency – Hyderabad 8. Physical Research Laboratory- Ahmedabad PRL 9. National Mesosphere, Stratosphere, Troposphere Radar facility (or) National MST Radar Facility- Tirupati (Nagari Hills)


Effects of Revolution and Inclined axis: Season cycle/ year cycle is due to the earth revolution around the sun. Norway is called land of midnight sun. Dawn: It is the period between sunrise and full daylight. Twilight: It is the period between sunset and complete darkness. Duration of Dawn and twilight increases from equator towards the poles.




Latitudes: Latitude is an imaginary line joining places having same angular distance North and south of equator. Longitudes: Prime meridian- passes through Greenwich Longitude is the angular distance measured in degrees along the equator east or west of prime meridian (passes through Royal Astronomical Laboratory at Greenwich near London)

1800W 00 1800 E

1800W=1800E The significance of longitude is the time measurement In 24 hr earth completes 1 rotation (w.r.t sun) i.e. 3600 24 hrs 3600 1 hr 150 10 4 min




Local Time: It is fixed with reference to Sun’s path in the sky. It is 12’0 clock noon when the shadow is least. Standard Time: It is the uniform time adopted by countries based on a central meridian Indian standard meridian is 82 0 E.

+5:30 a head of Greenwich meridian

International Date Line: The 1800 E or 1800 W longitude which when crossed changes the date. Travelling east across IDL a day is gained.

DST (Daylight saving Time): It is the convention of advancing clocks so that afternoons have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in Autumn. Adding day light to afternoons benefits retailing sector, sports and other activities. DST is common in region of high latitudes. Pakistan adopted DST for 3 months. June 1st to Aug 31st. It will be 30 min ahead of India instead of 30 min behind for this three months.

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Geological Time Scale: Eras Periods Epochs Azoic 4600-600 my ago Pre Cambrian

Paleozoic Primary Cambrian

600-225 my ago Ordovician Silurian Devonian Carboniferous Permian

Mesozoic Secondary Triassic

225-70 my ago Jurassic Cretaceous

Cenozoic Tertiary Paleocene

70-1 my ago Eocene Oligocene Miocene Pliocene

Neozoic Quardarnary Pleistocene

1 my ago- present Holocene


Earth’s Interior Crust: 1. Density 2.7-3 2. Thickness varies from 6-48 km 3. Upper crust – sial (Silicon Aluminium) Also called granitic crust (lightest type of rock) 4. Inner crust- sima (Silicon Magnesium) Also called Basaltic crust 5. Sima is much more denser than sial. - Sial is much thicker underneath the continents than oceans. - Sima is thicker underneath the oceans than continents Oceanic crust is denser than the continental crust. 6. Isostacy: It is the dynamic gravitational equilibrium that exists between high elevated

regions and low elevated regions (Isostactic adjustment)



Mantle: Mantle consists of mixed silicates of Mg and Fe. Density of mantle is 3-5.5 Core: Density: 12-15 Consists mainly Fe and Ni Inner core: Fe mainly Outer core: Ni mainly 1. Through the study of earth quake waves (seismic waves) we came to know the

interior structure of the earth. 2. Temperature increases with depth at the rate of 10c/ 32 m depth (valid till top

layers). 3. As we go inner the rate of increase decreases with depth. 4. Lithosphere: Uniform depth of 0-100 km


Geomorphology: It is the study of earth’s relief features Relief features Exogenic Endogenic Mountains, Volcanism, Earth quakes (formed due to endogenic forces) Mountains: Orogeny (technical term for mountain building) Mountains Fold Block Volcanic/ Accumulated Fold Mountains: They are created by the process of folding where in sedimentary rocks are deformed, folded and upthrust by the action of horizontal compressive endogenic forces.


Examples of fold mountains: 1.North America: Rocky mountains Appalachian mountains Appalachian are old compared to Rocky (Since they are eroded more) Highest peak in N.A. mt. Mckinley (Alaska)

Highest peak of mainland U.S.A mt. whitney 2.Europe: Alps 3.South America: Andes. Highest peak: Aconcagua (chile) Second: Ojos del salado (Border of chile and Argentina) Ojos del salado is the highest volcanic peak. Cotopaxi and Chimborazo: volcanic peaks (Ecuador)

4.Aisa: Himalayas Ural mountains: Border of Asia and Europe. 5.Africa: Atlas mountains: only fold mountains of Africa, part of alpine system

6.New Zealand: Southern Alps


Block Mountains: These are formed due to horizontal tensional endogenic forces [up thrown and down thrown] Examples: Vindhya Range Satpura Range East African Rift valley Mitumba mts, Muchinga mts


Plate Tectonics: (By Tuzo Wilson, Strahler, Morgan in 1960s) According to this theory entire earth surface is divided into series of lithographic plates. These plates could be of continental crust, oceanic crust or both. •Oceanic crust is denser. •These plates are in a state of constant motion in relation to one another Based on the relative motion of these plates three types of plate margins are identified 1.Convergent plate margin: Two plates move towards each other and collide. 2.Divergent plate margin: Two plates move away from each other. 3.Conservative/ transverse plate margin: where two plates slide past each other.





Convergent: 1. Ocean – Continent: • Fold mountains • Trenches (deep tectonic depressions formed along the converging plate margin) • Volcanism • Earth quakes 2. Continent- continent: • Fold mountains • Earth quakes


3. Ocean- Ocean •Trenches •EQ •Volcanism •Island arcs Ex. Philippine Plate Vs pacific plate. Mariana Trench is the world’s deepest trench


Divergent: 1. Ocean floor: •Mid ocean ridges •Volcanoes •EQ Eg: Iceland 2. Continent floor: •Rift valley •Block Mountains •EQ •Volcanoes 3. Conservative •Faults •EQ


Volcanism: It is the process by which molten rock material or magma moves towards the surface. Magma on reaching the surface is called Lava. Along with Lava CO2, SO2 etc are also released

Volcanoes:

Active Frequently erupt

Dormant Possible eruption

Extinct Ceases to erupt

Active Volcanic Peaks: •St. Helena, USA •Mt. Stramboli, Italy- also called light house of Mediterranean •Mt. Etna, Italy •Mouna Loa, Howaii, USA •Mt. Hekla and Laki, Iceland •Ojos del salado •Barren Isl. India

Dormant volcanic Peaks: •Mt. Vesuvius, Italy

Extinct: •Aconcagua •Mt. Kenya •Mt. Kilimanjaro (Tanzania) •Mt. Elbruz (Europe) • Gorongoro National Park (Tanzania) •Crater of volcanic peak.


Types of Magma Basic Magma Acidic Magma 1. Lower melting point Higher melting point 2. Solidifies slower Solidifies faster 3. Less viscous More viscous 4. Less silica content and more of More silica and less of Ferro magnesium Ferro magnesium 5. Results in volcanic sheets or plateau Results in volcanic cones Lava Plateaus: Deccan trap/ Deccan Lava Plateau Deccan lavas and black soil formation (for cotton cultivation) Yunnan plateau Columbia plateau


Volcanic Land Forms: Extrustive Features Intrusive Features Extrusive Features: Crater Lake, Oregon state, USA L Toba of Indoneisa L. Rotorua of New Zealand Gorongoro National park (Tanzania)


Intrusive Features: •Batholiths: They are largest intrusive features formed when reservoirs of magma are cooled down. These are irregular in shape •Dykes: They are vertical intrusions of magma -Kimberlite pipe: Dykes formed by basic magma and are a source of diamonds. Ex. Wajrakarur kimberlite pipe of Anantapur, Raichur, Gulbarga. •Sills: They are horizontal intrusions of magma •Lacoliths: They are dome shaped intrusions. •Lappoliths: They are saucer shaped intrusions. •Phacoliths: They are anticlinal and synclinal intrusions of magma. (also called lens shaped intrusions)


Caldera crater lake– Mt. ASO , JAPAN


Geysers Hot springs Geysers are fountains of super Continuous eruption of hot water heated steam and hot water without any interruptions. that is emitted intermittently Ex: EX: The old faithful Geyser, - Manikaran (near Kullu) Yellow stone National park USA Himachal Pradesh (after every 63 mins it erupts) - Jwala mukhi, Himachal Pradesh. -Rotorua Geyser, NZ - Iceland Geyser.


Earth quakes: Earthquakes refers to series of tremors experienced on earth surface caused by sudden release of stress from the crustal rocks. Earth quakes Natural Anthropogenic Folding/ Faulting dams impounding huge amount of water Volcanism Ex:Koyna Dam Plate motion Nuclear explosions. • The point of origin of earth quake is called seismic focus or hypo centre. •The point on the earth surface that is vertically above seismic focus is called epicenter. •Intensity of the earthquake is max. at epicenter.

Epicentre

Hypocentre Or Focus


Seismic waves 1. Body waves

• P - waves • S - waves

2. Surface waves

1030

1430

1030

1030 103

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P-waves: ( Primary waves/ compressional waves) 1. Compressional waves influence the strata through which they pass through 2. P- waves passes through both solid and liquid medium. (Faster in solid medium). 3. 7km/ sec- velocity of p- waves (max. than other waves) 4. P-waves undergo refraction when they change the medium. 5. Shadow zone of p-wave lies from 1030-1430 on either side S-waves: (secondary waves/ distortional waves) 1. They influence the shape of the rock through which they pass. 2. S-waves only pass though solid medium, not through liquid medium. 3. Travels at 3.5 km/sec Surface waves: (long waves) -They have the max. geomorphic effects. -Velocity 2.5 km/sec

(a) Vertical sea swell motion- Rayleigh waves. (b) Love waves – Horizontal whipping motion.


Measurement of Earthquakes: Magnitude Intensity •Measure of the total energy released. To measure the effect of the earthquake •Richter scale used to measure magnitude. Rossi Ferral scale (open ended scale) MSK scale • 1 Unit increase -10 times increase in change in amplitude. -30 times increase in energy. Isoseismal: The lines having same intensity of earthquake. Intensity will be maximum at epicenter For a single earth quake magnitude remains same.


Deltas: •Triangular Delta - Nile •Bird Foot/ Digitate Delta - Mississippi •Cuspate Delta - Ebro



Rocks Composition of earth’s crust Predominant elements : O2-46% Si-28% Al Iron Rock is a composite mass of two or more minerals. Mainly rocks are formed by the following minerals:

•Feldspar (most abundant rock forming mineral) •Quartz •Ferro magnesium •calcite


3 Types of rocks:

Igneous(primary) Sedimentary Metamorphic

Formed due to solidification of magma or molten rock.

Formed from the material derived from pre-existing rocks and from organic sources. -Hence they contain fossils -They are also called stratified rocks.

Formed by the process of alteration of the pre-existing rocks by high temperature, pressure or both. Changes could be physical, chemical or both. Process is called metamorphism.

Acidic igneous Basic igneous

-More Silica -Lighter in wt. and colour Ex: Granite

-More Ferro magnesium -Heavier and dark in colour Ex: Basalt, Gabbro


Igneous:

Extrusive Intrusive

Occur on the surface. Solidify in less time (rapid cooling due to exposure to atmosphere) Smaller/fine grained rocks are formed Subjected to weathering/ erosion Ex: Basalt is a weaker rock and forms black soils

Beneath the surface Get longer time to solidify. Larger crystals are formed. Difficult to erosion. Mostly acidic. Ex: Granite

*Igneous rocks never contain the fossils. Due to high temperature the organic matter destroys.

Sedimentary: 1. Clastic sedimentary rocks: mechanically formed from the fragments of pre-existing rocks.

This fragments are generally cemented by calcite or silica etc. Ex: Sand stone Grit stone Clay stone/shale Silt stone Conglomorate Breccia


2. Chemically precipitated rocks: These are formed by chemical precipitation from sea water or salty inland lakes:

Ex: Lime stone CaCO3 Dolmite CaCO3. MgCO3 Chert (silica) ( Tools of IVC) 3. Organic sedimentary rocks: Ex: Coal Corals Chalk 75% of the earth’s surface is covered by sedimentary rocks but they constitute only

5% of earth’s crust. Sedimentary are known for areal extent but not for depth.

Metamorphic: Lime stone - Marble

Coal - Graphite Granite - Gneiss

Shale - Slate Basalt - Schist

Sand stone - Quartzite

Quartz is a rock forming mineral. Quartzite is a rock.


Oceanography: Total surface area of earth = 510 million sq.km Hydrosphere 361 million sq.km Land- 149 million sq.km

Oceans:

•Pacific ocean (Larger than all continents together) •Atlantic ocean •Indian ocean •Arctic ocean •Southern ocean (South of 600 S latitude)

Ocean Bottom Relief:

1. Continental shelf: It is an extension of the continental crust into the ocean. It has a shallow water body with avg. depth of 200m.

Phytoplankton Zoo plankton Humans. •Due to shallow depth sunlight penetrates to the floor supporting marine plant life which in turn supports fish on it. •Water bodies with wider continental shelf supports fishing grounds called banks. Ex: Dogger Bank of North Sea Grand Bank of Newfound land Isl. (Canada George Bank- Long IsI. of USA


•Higher (height) is the relief along the coast, narrower is the continental shelf and deeper is the water body. Vice versa. Ex: Coast along Rockies and Andies. *Indian ocean is an exception. Western coast has a wider continental shelf inspire of western Ghats due to the epirogenic subsidence

2. Continental slope: It is the transition between continental and oceanic crust.

3. Deep sea plain/abyssal plain: Avg. 3 to 5 km deep.


Trenches: Trenches are long narrow tectonic depressions formed along converging plate margins. Deep: Deep is the deepest point of a trench represents depth. Pacific ocean: Deepest: Mariana Trench off Guam island Deepest point in Mariana Trench is challengers deep Philippine Trench Japan Trench Kuril Trench Aleutian Trench Tonga Trench Kermadec Trench Peru chile Trench (longest linear Trench) Atlantic ocean: Cayman Trench Puerto Rico Trench Milwaukee Deep Naves Deep Indian Ocean: Java Ob Amirante Diamentina


Mid oceanic Ridges: They are the submarine mountain ranges of volcanic origin formed along diverging plate margins. Ex: Mid Atlantic Ridge – equator divides it into Dolphin ridge (Northern part) and Challengers ridge (Southern part) Sometimes the mid oceanic ridges raises above the mean sea level forming islands Ex: Azores, St. Helens Sea Mounts/submarine volcanic peaks: Sea mounts are submarine volcanic peaks Guyots are eroded sea mounts with flat top. Atolls are seamounts or guyots with coral deposits have built up around the rim.


CHARACTERISATICS OF OCEAN WATER

1. OCEAN SURFACE TEMPERATURE

i. LATITUDE – OST decreases with increase in latitude ii. Cloudiness and precipitation – reduces OST at equator belt. Hence

highest OST is NOT recorded at equator iii. Winds and Ocean currents- on shore winds result in piling up of the warm

water along the coast and higher OST recorded at coasts; off shore winds drive away the surface water resulting in upwelling of cold water. So, less OST is recorded at coasts

iv. Continentality - Water body that is more in contact with the land mass acquires the temperature characteristics of the land mass. If the surrounding land mass is hotter, then the water temperature will also be higher at that altitude. Annual range of temperature is higher in smaller and more enclosed water bodies


2. Salinity of Ocean

CHARACTERISATICS OF OCEAN WATER

i. Salinity is the total amount of solid material in grams contained in 1kg of sea water and is expressed as parts per thousand (ppt-%o ) - Avg. Salinity 35.2 %o

NaCl (77%), MgCl2 (11%), MgSO4, CaSO4, K2SO4 ii. Though salinity varies from place to place the proportion of these salts is always

the same and constant in all the oceans.

Factors influencing salinity

i. Latitude: As temperature decreases salinity decreases. ii. Cloudiness and precipitation (all kinds of rainfall) Decreases salinity. iii. Influx of fresh water River mouths Polar/glaciated iv. Ocean currents v. Continentally


• Salinity is lower at equator due to excess of addition of fresh water. It increases towards subtropics where dry condition prevails. It again decreases towards poles due to lower evaporation.

• Evaporation and addition of fresh water are the two factors controlling the distribution of salinity

• Places having greater evaporation will have higher salinity and places having an excess of addition of fresh water over evaporation will addition of fresh water over salinity

• The most saline water bodies are: a) Lake Van 420 %o

b) Salt Lake 340 %o

c) Dead Sea 170 %o

Dead sea shores are deepest on the land surface (-411) • More saline water freezes slowly in comparison to less saline water-

Depression in freezing point • B.P of saline water is higher than the fresh water- Elevation in Boiling Point


OCEAN TIDES Regular rise and fall in sea level due to gravitational force of attraction of moon and sun. The gravitational pull of moon is much larger than that of sun because of its proximity to the earth (ratio of lunar gravity to that of solar gravity is 11:5). At any point of time earth experiences two high tides and two low tides High tides at 1. A - caused by moon’s Gravitational pull 2. C - caused by centrifugal force Low tides at B and D Time b/w two high tides caused by force of attraction is 24h 52 min The time lag of 52 min is due to the revolution of the moon. The time interval b/w two high tides is 12h 26 min.


C A


‘syzygy position’

‘quadrature position’

• The tide travelling uninterrupted in the southern ocean from east to west is called primary or progressive wave.

• In other enclosed (or northern) water bodies there will be stationary waves • Amplitude of tide is Less in open ocean Becomes more along the coast More along shallow water bodies Much more along narrow gulfs having broader front and narrower back. • Ex:- Amplitude of highest tide is 18mt

Bay of Fundy Okhla in Gujarat -3 mts Southampton in Uk-4 high tides are experienced in a day because English

channel and North sea push water at different times Tidal Ports: Calcutta on Hugli river London on Thames river


• Amplitude of tide also depends on the relative positions of sun, moon and earth.

• If they are in same lime then the combined gravitational pull of moon and sun will give a high tide called ‘spring tide’ and the positioning of sun, moon and earth is called ‘syzygy position’

• In quadrature position i.e. in moons first and third quarter a neap tide is experienced.

• In spring tide high tide is very high and low tide is very low • In neap tide high tide is lower and low tide is higher than the normal times. • Tidal Ports: Calcutta on Hugli river; London on Thames river


Ocean currents: Ocean currents refer to continuous movement of huge mass of water in one particular direction. Causes of ocean currents: • Density differences • Rotation of earth • Due to wind

Warm currents

• EQ to polar

• Western pars of oceans and eastern parts of continents.

• Clock wise direction and northern hemisphere (mostly)

Cold currents

• Polar to EQ

• Eastern parts of ocean/ western margins of the continents

• Anti clock wise direction, Southern hemisphere (mostly)



Effects of ocean currents: 1. Climatic condition Cold current: Flowing along western margins of continents result in arid (dry) conditions giving rise to formation of deserts. [moisture condensed] Ex: canaries current sahara Desert Benguela current Namib Desert W. Australian current Great sandy desert & Great Victoria desert Peru current Atacama desert California current Mojavia desert Warm Current: EX:- North Atlantic drift influences the climatic conditions of western Europe making it habitable 2. Meeting point of warm and cold ocean currents result in the dense fog. Such point is favorable for fishing 3. Phytoplankton and zooplankton are supported. 4. Trade routes are influenced. 5.‘ELNino’ refers to the occasional development of warm ocean currents along the Peruvian coast as a temporary replacement of the cold Peruvian current Kills marine life along Peruvian coast. Effects global climatic conditions including monsoons ‘LA Nina’ refers to the re-establishment of cold current along Peruvian coast after EL Nino


6. Source of alternative energy-The energy could be possibly to be captured and converted it into a usable from through the use of water turbines.

7. Transport of debris; formation of trash isands



CORAL REEFS: Coral Reefs are submarine organic textures formed by the accumulation and composition of the calcareous secretions and skeletal remains of microscopic organisms called coral polyps. Conditions for the formation of coral reefs: • Ocean temperature 21-250C Tropical Oceans • Depth not more than 200 mts • Clear water: water free of sediments • Normal salinity 33 %o

The death of a coral reef is called coral bleaching. Global warming is also responsible for coral bleaching. TYPES OF CORALS: • Fringing reef: attached to the coast of continents or islands ---- boat channel • Atolls: Circular or Oval shaped reefs. Sometimes there will be a island at the centre of

the atolls. Ex:- Fiji, Lakshadweep, Maldives • Barrier reef: Runs parallel to coast with a lagoon separating it from the coast - lagoon

lake Ex:- Great Barrier Reef ( NE coast of Australia)




Atmosphere Atmosphere is the gaseous envelope surrounding the earth attached to the earth surface by gravitational force. • Height of atmosphere b/w 16-29000 km • 97% of effective atmosphere is found up till 29km

Gaseous Particulate matter

Nitrogen (78%) Aerosols

Oxygen (21%) dust /volcanic dust/pollen grains/

Argon (0.93%) sea salts etc.

Co2

Neon

Helium

ozone

• Variable constituent is water vapor



Scattering refers to the break up of solar radiation by dust and water vapour molecules in the atmosphere. Scattering is more effective in shorter wave length (blue) than in the longer wavelengths (red) The reduction of blue light due to scattering makes the sun appear as yellow or red object in the mornings or evenings



Troposphere: • Altitude varies from 8-18 km. 8km over the polar regions and 18km over equator. • All the weather phenomena like cloud formation, rainfall, cyclones are associated

with Troposphere alone. Hence it is called zone of mixing. • With increase in altitude, temperature decreases in troposphere at the rate of

6-6.5 0C/km or 165 mts/10C called Normal Lapse Rate (NLR) • Due to normal lapse rate lowest temperature in Troposphere is recorded over the

equator at the tropopause level. Stratosphere: • Between 20-35 km stratosphere has the concentration of ozone called

ozonosphere • As ozone absorbs harmful UV radiation it gets heated up increasing the

temperature of stratosphere • Jet liners prefer stratosphere for navigation • Temperature increases with increase in altitude.


Mesosphere: • Temperature decreases with increase in altitude. • The lowest temperature in the entire atmosphere is recorded in mesosphere. Thermosphere: Thermosphere lower part is called Ionosphere. Above thermosphere it is called Exosphere. •Ionosphere consists of multiple belts of charged particles reflecting radio waves back to earth. •Auroras occur in the Ionosphere. Temperature increases due to the absorption of x-rays . Insolation: Insolation refers to solar radiation received by the earth. It is 0.0005% of the total solar radiation emitted by the sun. Avg. energy received by an unit area of earth facing the sun=2gm cal/sq cm/min= 2 Langley


Factors influencing Insolation: • Latitude: Less Insolation

More Insolation

• Season cycle: In summers more insolation In winters less insolation • Atmospheric factors: Cloud cover Dust particles Albedo for earth is 34% Black soils 3% Fresh snow 80% Water surface: High sun – 5%, Slating/Low sun-70% Atmospheric Temperature: Sources of heat Terrestrial radiation Insolation Atmosphere is near transparent for the short wave incoming radiation. And

is near opaque for the longwave terrestrial radiation. Long wave terrestrial radiations are effectively absorbed by atmosphere. www.classmateacademy.com 87

SUN RAYS

Factors influencing Atmospheric Temperature: • Latitude • Altitude : Temperature @ NLR as altitude increases. • Land water distribution (on same latitude) At tropical regions temperature of land body is more than water body At temperate regions temperature of water body is more than land body. • Nature of ground surface • Prevailing wind • Ocean currents • Distance from the coast/sea • Aspect of slope.

Inversion of temperature: It is the temporary phenomena in which temperature increases with increase in altitude It occurs only in certain conditions • Long winter nights + • Cloudless clear skies + • Les or no humidity + • Weak winds or no winds


Climatic zones based on temperature: • In torrid region amount of energy received through insolation is more than the

radiation lost. Rest of the energy is distributed to higher latitudes through ocean currents and winds.

• At 400 latitude amount of insolation received is equal to amount of energy lost IR=TR Insolated radiation =Terrestrial radiation. • Temperate region: avg.IR<TR • Frigid region: IR<< TR Thermal equator: • It is the line joining the places receiving the highest insolation and recording

higher temperature conditions. • It shifts north and south of equator with apparent movement of sun.


400

400

Atmospheric Pressure: • It is the weight of column of air Avg. Pressure at mean sea level is 1013 millibar.

1.013 bar = 76 cm of Hg • Barometer is used to measure pressure. Factors influencing Atm. pressure: • Temperature : with increase in temperature there will be decrease in pressure • Altitude: Pressure decreases with increase in altitude • Rotation : with velocity being higher at equatorial region pressure is lower


Pressure belts : ( 7 belts) 3 belts Thermally induced:Equatorial LP belt Polar HP belts (2) 4 belts Mechanically induced caused by earth’s rotation. Sub- tropical HP belt (2) Sub-polar LP belt (2) • These pressure belts shifts with the apparent movement of the sun Especially EQLP belt shifts drastically up to 200 • EQLP – Belt of calm/Doldrums • STHP- Horse latitude No wind movement in these belts.



Winds: • Horizontal movement of air caused by pressure gradient. • Wind always blows from high pressure to low pressure • Wind velocity depends on pressure gradient • Wind is named after the direction from which it blows • Coriolis Force changes the direction of wind PRESSURE CELLS: Cyclones occur in LP cells; Anticyclones occur in HP cells. Cyclonic circulations: • Anti clock wise in Northern hemisphere • Clock wise in southern hemisphere Anti cyclonic circulations: • Clock wise in Northern hemisphere • Anti clock wise in southern hemisphere Planetary winds: North westerlies/southern hemisphere westerlies/ North westerly winds are also called Roaring Forties/Furious Fifties/Shreiking sixties/Gloomy sixties. This is due to no friction on the water body in southern hemi sphere where as in northern hemisphere more land body.


Local Winds: • Anabatic wind refers to the upslope movement of warmer wind along the valley slopes

during day time. • Katabatic wind refers to the downslope movement of cold air along the valley slopes

during night time. • (a) See Breeze in the mornings & (b)Land Breeze in the nights. • See Breeze much stronger than Land Breeze.


CYCLONES: Tropical cyclones: • Tropical cyclones are low pressure systems of tropical latitudes. • Tropical cyclones develop on warm ocean surfaces • Never originate on land surface. • The source of energy is the latent heat present in the moist air. Warm ocean OST> 270C • Tropical cyclones originate in the Western Parts of the tropical oceans and they

form only b/w 80-200 North and South of equator


Characteristics of Tropical cyclones: • Size: Diameter 80-300 km (Small compared to temperate cyclones) • Velocity of winds in tropical cyclones is 80-400 km/hr (high compared to temperate) • Isobars: For tropical cyclones pressure gradient is very high making the isobars

circular. • They move from east to west under the influence of trade winds and hence influence

the eastern margins of the continents. • Tropical cyclones are strong over ocean bodies and they become weak and die out

on reaching the land mass as the supply of moisture is cut-off • Tropical cyclones are more destructive and have devastating effects when compared

to temperate cyclone. • Life of Tropical cyclone is 2-3 days • Stronger in summer.


Name Region • Cyclone India • Typhoon South china sea • Hurricane Caribbean sea • Willy-willies Australia (Northern) • Tornadoes USA • Baguio Philippines • Taifu Japan

Temperate cyclones: • They are frontal in origin. Front is a plane differentiating two approaching air

masses of contrasting characteristics • Source of energy for temperate cyclones is the temperature difference across the

front Characteristics of temperate cyclones: • Temperate cyclones originate both on land and water in temperate latitudes b/w

350-600 latitudes. • Size: diameter 150-3000 km (large) • Velocity: 20-40 km/hr (small) • Pressure difference/gradient is less making the isobars elliptical in shape. • They move from west to east under the influence of westerlies. • They persist for longer durations with a life of 10-15 days • Stronger in winter than in summer.


Anti cyclones: •Anti cyclones are high pressure cells from which winds blow out. •Clear skies and fair weather conditions are associated with anti cyclones. •They occur in winters and generally are preceded and followed by temperate cyclones.


Evaporation: Factors effecting rate of evaporation • Temp/Latitude • Higher the air temp. higher is the evaporation • Vapour pressure /Humidity • Cloths take longer time to dry in equatorial region due to high vp, rate of evaporation is

lowest in equatorial region. • Wind velocity-Higher the wind velocity higher the rate of evaporation.


Humidity: • Humidity is the measure of water vapour present in the atmosphere. • Absolute Humidity (gm/m3) It is the total amount of water vapour present in a given volume of air • Specific Humidity (gm/kg) The amount of water vapour present in a given mass of air. • Relative Humidity The ratio b/w quantity of water vapour present in atmosphere at a given temperature to the max. quantity of water vapour that the atmosphere can hold at that temperature. Actual amt. of W.V @ T1 Max. amt. @ T1 If relative humidity is 100% air is said to be saturated and the temperature at which air is saturated is called ‘Dew point’ Hygrometer is used to measure R.H Wet and dry bulb thermometer-R.H No (Less) diff. in temperature: Air is saturated (humid) Large difference in temp: Low humid conditions (dry)

R.H=


Condensation: Condensation occurs when • Air is saturated • Hygroscopic nuclei is present in air. Condensation starts when air gets cooled to temperature below dew point or saturation level

On surface Near Surface Upper air

• Dew (tiny droplets) • Fog • Clouds

• Frost • Mist Clouds are visible aggregates of

water droplets and and ice crystals

formed by the ascent of air

Frost is frozen dew Visibility <1 km - It is called Fog

Dew occurs when water vapor

condenses in the form of tiny

droplets on surface features like

grass blades etc.

Smog=fog+dust+smoke

Dew point >00 C dew

<00C frost

When dew point <00c crystals of

ice gets deposited called frost


Clouds: Classification based on shape: cumulus, Stratus, Cirrus Classification based on altitude: • Low Clouds: <2km ( all low clouds has rain bearing capacity) Cumulo Nimbus Nimbo stratus Nimbus clouds Nimbus clouds are thunder storm and heavy rain bearing clouds Cumulus Stratus Cumulo stratus (Cumulus+ Stratus) Low lying fog like clouds • Middle clouds : (2-6 km) Alto cumulus Alto stratus Alto clouds Rainfall occurs in the wide spread showers • High clouds: (cirrus clouds) (6-12 km) Cirrus: made up of tiny ice crystals Cirro cumulus Cirro stratus Based on shape They are not rain bearing clouds. Never give rainfall.

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Snow fall Hail/Hail storms Rain fall

Occurs when tiny ice crystals

combine to form a powdery

mass called snow

10-12 cm of Snowfall=1 cm of

rainfall

Occurs at temperate and high

altitude regions

Hail storms occurs in tropical

regions having high surface

temperature conditions. Hail

stone forms from repeated

tossing of ice crystals by strong

convective currents. Occurs in

tropical and equatorial region

All rainfalls

Occurs only when there

is ascent of air

Precipitation: Condensed water reaches to the earth surface.

Sleet is a mixture of rain and snow. It is a frozen rain


Rainfall: Convectional rainfall: caused by the ascending currents of hot and humid air resulting in adiabatic process. Ex: Occurs in equatorial region through out the year (almost daily) In tropical and middle latitudes in summer. Orographic rainfall: caused when the air is forced to ascend the slope of mountain range or plateau Frontal Rainfall: Occurs when warm air mass is forced to ascend over a cold air mass along a frontal zone. Cyclonic (or convergent) Precipitation. Ex: Orographic rainfall Mumbai receives more rainfall than pune Mumbai: Wind ward & lope Manglore > Banglore (Sohra) Chirrapunji/ Mawsynram > Wind ward than Guwahati



Climate zones: 1. Equatorial climatic belt: 50N-50S of equator generally •Africa - Congo Basin - Guinea coast •South America - Amazon Basin - Coastal plains of Columbia •Asia - Indonesia and New Guinea Islands. Equatorial belt is not continuous due to the variation in relief. Ex: Quito (Ecuador) at high altitude Kampala (Uganda) Nairobi (Kenya)


Characteristics: • Not continuous due to variation in relief • Uniform temperature (high) • High humidity • Heavy rainfall through out the year. • Avg. annual range of temp. is least (30C) • Daily range of temp. in equatorial climate is the least (due to humidity)

( Energy is stored in the atmosphere itself) • Rain fall is above 200 cm. • Natural vegetation: Ever-green tropical rain forests (also called selvas) Selvas especially called in Amazon Forest is evergreen because trees have no distinct shedding period • Equatorial climate covers only 6% of the geographical area. But has

50% of the biodiversity • Undergrowth is not dense as sunlight doesn’t reach the floor. • Economically unviable • Hardwood (little use to man) • Variety of free species is high Not gregarious/not found in pure stand • Soils are less fertile. (lateritic soils) • Due to heavy rains – soil erosion


2. Tropical Desert climate: Occurs on the western margins of the continents between 150 to 300 latitudes. Africa - Sahara Desert Asia - Thar- India Gobi desert (Temperate cold deserts) Takla makan desert (Temperate cold deserts) Characteristics: • Rainfall <50 cm • Daily range of temp is highest • Vegetation: xerophyte vegetation • Tribals of Australian deserts: Australian Aborigines or Bindibue of Australia Kalahari desert - Bushmen (Tribes) Arabian desert – Bedouins (Tribes)


3. Tropical Grasslands : ( Savanna grasslands ) Tropical grasslands climate is found b/w 5-300 latitudes towards the continental interiors These are transitional b/w monsoon climate and desert climate &b/w desert and rain forest/equatorial climate. America - Llanos (Venezuela and Columbia) Campos (Brazil) Vegetation: Parkland vegetation. Tall grasses and short trees. Tribals: Negroes of Savanna (Hunting) Masai tribes (Kenya, Tanzania, Uganda) Masai tribes (cattle herding)


4. Temperate Grasslands/steppe: Found in continental interiors of temperate regions Prairies - USA-canada Pampas - Argentina-Uruguay Velds - S. Africa Downs - Australia Steppes - Ukraine, Russia and Kazakhstan Pustaz - Hungary Manchurian Plains - China Temperate grasslands are called graneries of the world (suitable for wheat cultivation) Wheat triangle is in steppes Wheat crescent is in Pampas.





steppes Pustaz

Pampas

Prairies

Downs

manchuria

campos

savannas australia

Llanos

velds



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PHYSICAL GEOGRAPHY - Classmate SSC