geographi l5 2
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• Latitudinal variation
• It decreases fromequator to poles
• But highest
temperature is notat the equator butat the tropics
• Reason: high
rainfall, cloud cover(high albedo/reection ofsunrays
!emperature "attern of the #cean
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•
$emisphericvariation
•%orthernhemisphere
&armer thansouthern
•Reason: largeland mass in
northernhemisphere 'high energy
!emperature pattern of the #ceans
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• nclosed seas
• )arginal seas oftropics &armerthan open #cean
* marginal seas oftemperate regioncooler than openseas
• Reason: lessmi+ing of &ater
!emperature pattern of the #ceans
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• #cean
currents
• armocean
current '&arminge-ect
• .old ocean
currentcoolinge-ect
!emperature pattern of the #ceans
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• p0&elling and
do&0&elling
• p&elling bringcool &ater from
depth 'lo&erdo&n the surfacetemp
!emperature pattern of the #ceans
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•Bigger thesi3e of ocean0better mi+ingof &ater and
heat• Lo&er annual
range
•
"aci4c ocean 'lo&er annualrange than5tlantic #cean
5nnual range of temperature
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"relims6778
9 .onsider the follo&ingstatements:
; 5nnual range oftemperature is greater in"aci4c ocean than in
5tlantic ocean6 5nnual range of
temperature is greater in
northern hemisphere thatin southern hemisphere
"
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"relims6778
hich of the statement iscorrect=
a ; only
b 6 only
c Both ; and 6
d %either ; or 6
5ns B"aci4c #cean ' bettermi+ing
"
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!emperature of the ocean
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• 5mount of salt found in ;777 gm of&ater
• %acl (8A, )g.l6 (;;, )g, .a
• %a and .l has high residual time inocean &ater ' very gradual removal '
thatDs &hy, they remain in thehighest proportion
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• Irrespective of absolute salinity of the&ater, the proportion of the saltremain same in all parts of the
oceans
• 5mount of addition or e+traction offresh &ater compared to salt content
in the #cean &ater decides absolutesalinity of the #ceans
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• "hysical removal ' &aves brea2 atthe beaches, salt0spray
• Biological removal ' marine life formse+tract calcium from sea &ater fortheir bones
Removal of
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• 5ddition of fresh &ater EF Rainfall,ino& of large river, melting ofglacier EF less salinity
• Reduction of fresh &ater EF increasein temperature, high evaporation,&indy (&ind accelerate the
evaporation
@ariation in salinity
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• > ppt ' salinity of 5tlantic #cean
• 1ead 7 salinity, La2e van(C77, La2e rmia
• )an seldom dro&ned in sea &ithhigh salinity
• Because, high salinity E high density
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•
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• %orthern
hemisphere '&armer ' highevaporation 'saline
• But in southern"aci4c0 roaringC7, furious >7and shrin2ing G7screaming 87 'very fast &inds
• $igh evaporation
EF high salinity
"attern in variation of salinity
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• ;st 0 #cean
currents
• &arm oceancurrent li2e,
highevaporation
• .old currentled to p0
&elling: cooler&ater fromdepth come atthe surface EF
lo& salinity
Local @ariations in
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• ?th ' ino& of
large rivers• Hanga '
Brahmaputra o&
into Bay of Bengal• Bay of Bengal less
saline than5rabian sea
Local @ariations in
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Mississippi in G.ofMexico
Amu darya, Syr
darya to Aral sea
Rivers ino& to the seas
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Black seaPersian gulf
Rivers ino& to the seas
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• Cth ' glaciers
• Baltic sea receivefresh &ater from
melting of glaciers' lo& salinity
Local @ariations in
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•
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• quator ' salinity increases &ithdepth upto some layer 'thandecreases &ith depth
• Beyond equator ' salinity decreases&ith depth
• @ertical salinity variation of oceans is
complicated
• %o uniform layering
@ertical pattern of salinity
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!emperature of ocean&ater
variations
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• arly atmospherehas $ and $e in
abundance0lighter gasesescaped
• 1uring early life ofthe earth 'e+tensivevolcanism0
degassing %,
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• ater vapour
condensed 'clouds ' rainfall'&ashed outbul2 of the .#6
into #ceans .o6E 77?
• #+ygen ' fromanaerobicrespiration ofbacteria li2e,.ynobacteria
#rigin of the 5tmosphere on arth
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• %, #, $ and 5rgon are permanentgases
• ater vapour, .o6, o3one 0F variablegases, H$H
• %, 5rgon ' inert gases
• 5tmospheric gases0 no chemicalinteraction among them
• !hey donDt lose their properties
• !hey act as a single uni4ed gas
"roportion of gases
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• 7 of
atmosphere&ithin ?6 2m
• !ropopause E
$eight A 2m atpoles, ;A 2m atequator
• 5t equator
cumulonimbusclouds
!roposphere
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• !emperature
decrease as heightincreases
• !ransparent toinsolation
(short&ave
• $eated byterrestrial radiation
(long&ave• H$Hs absorbs long
&ave terrestrialradiation
Hreenhouse e-ect in troposphere
9uestio
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"relims
67;6
9 normally, the temperaturedecreases &ith increase in
height from the earthDssurface, because,
; 5tmosphere can be
heated up&ard only fromearthDs surface
6 !here is more moisture in
upper atmosphere? !he air is less dense in
upper atmosphere
"
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"relims
67;6
a ; only
b 6 and ?
c ; and ?
d ;,6 and ?
5ns .
Less dense E lessamount of H$Hs E lo&temp
"
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• !emperatureincreases &ithheight
•Because ofthe presenceof o3one layer
• #3one
absorbs @rays fromisolation
stratosphere
9uestio
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"relims
67;;
9 !he Jet aircrafts y veryeasily and smoothly in lo&er
stratosphere hy=; !here are no clouds or
&ater vapour in lo&er
stratosphere6 !here are no vertical
&inds in lo&er
stratosphere
5ns ; in &rong, 6 is correct
"
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•5bsence of H$Hs
• !emperaturedecreases &ithheight
)esosphere
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)esospheric
clouds• .louds visible
at highlatitudes
• 1uring summerseason
• .ondensation
of mi+ture ofmeteoric dustand somemoisture
%octilucent clouds
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• !emperatureincrease &ithheight
•
Hases in ionic state' trap insolation 'e+tremely hot
• But ions are highly
dispersed• p to A77 2m from
earth
!hermosphere
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• Krom A72m toGC7 2m
•
%umber ofionic layers
• seful inradio0
communication
Ionosphere
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• $igh energy
sunrays andcosmic raysbrea2 the atomsof air molecules '
become ionised(*ve charged
• Behave as free
particles• 5t night time,
only cosmic raysioni3ation 0&ea2
Ionosphere
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lay
ers
#eig#
t
$re%u
ency
Prese
nce
format
ion1 G70
72mLK 1ay0
time70?A72m
)K,$K
1aynight
H FC772 )K, 1ay
Layers of Ionosphere
9uestio
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"relims
67;;
9 5 layer in arthDsatmosphere called
ionosphere facilitates radiocommunication hy=
; "resence of o3one cause
reection of radio &avesto earth
6 Radio &aves has long
&avelength
Both statements are &rong
"
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• Beyond GC7 2m
• $ighly rari4edatmosphere
• @ery high
temperature0but di-erentfrom airtemperature0
because noe+istence of air0temp canDt befelt
+osphere
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• Hlo&ing lightsat mid0nightsat high
latitudes• 5t height of
e+osphere andmagnetospher
e
5urora
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• sun emit solar&ind/storm fromits corona
•
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• .ollision of charged
particles(isoni3ation inmagnetosphere
• Ionised particles
emit light 'releaseenergy
• charged particlesinteract &ith
geomagnetic 4eldlines
• !hus, visible onhigh latitudes
5uroras
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• !he averagetemperature of theearth ;> degree
• arth maintains inu+and out0u+ of theenergy, but out0u+ isnot immediate, it haslong time gap !hat is
&hy, the temperatureis maintained
$eat budget
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• Kirst ?>
absorbed by#3one layer
• !hen ;>by cloud
cover• #nly >7
energyreached tothe earthsurface
$eat budget 0 Incoming
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• 67 is lost in
latent heat ofevaporation;7 lost insensible heat
(temperature ofthe body
• ;> absorbed
by H$Hs• Remaining >
&as released inthe space
$eat budget 0 outgoing
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• Ratio bet&een thetotal solar radiationfalling upon asurface and theamount reected
• Represents as
• arthDs avg 5lbedo
E ?>• Lo&est0 dar2 soil
• highest 0 sno&fall
5lbedo
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surface AledoKresh
sno&
A707
1esert ?>0C>
Hrasses 6G.rops ;>
Bri 2 0 ; 06
5lbedo 0 table
9 hi h f th f ll i 9uestio
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"relims
67;7
9 hich one of the follo&ingreect bac2 more sunlight as
compared to other three=a sandy desert
b "addy crops
c Land covered &ith freshsno&
d "rairie land
5ns .
"
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!ori"ontal
•
&hen there is pressuregradient
• from high pressure tolo& pressure EFadvection
•
&hen air get &arm,gets e+pands,becomes lighter EFmove up&ards EFconvection
&ertical
)ovement of air
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• hen air gets
hotter thansurrounding air, itrises up&ard
• If it has moisture 0latent heat ofcondensation 'more heated ' &ill
go up 0 formclouds 0can bringrainfall Einstability
@ertical movement of air 0 instability
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• hen air is coolerthan surrounding 'it cannot move
up&ard• sin2ing air
• atmosphericstability or anti0
cyclonic condition• $igh pressure on
ground
@ertical movement of air 0 stability
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Lo& pressure ' $igh pressure
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• !he rate at &hich airpac2et cools &hilerising
• 5vg adiabatic lapserate is GC degree/2m
• !hat is air pac2etgets cool by GCdegree aftercovering one 2mup&ard
5diabatic lapse rate
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• if air pac2et has highmoisture content0 notget cool so fast
• Its adiabatic lapserate MGC degree/2mN C degree/2m EF5LR
• et air can reachhigher distances &ithlo& lapse rate EFcreate instability
et adiabatic lapse rate
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• If air pac2et is dry,
it does not havemuch moisture, it&ill get cool veryfast )ore thanGC degree/2m 'li2e, ;7degree/2m
•1ry air createstable condition
1ry 5diabatic Lapse rate
.onditions of stability and
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situation condition
.onditionalstability
&hen &et5LRM normal
5LR M dry 5LR5bsolute
stability
&hen normal
5LRM &et 5LRM 1ry 5LR
.onditions of stability andInstability
increasing
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increasingheight
temperature of airdecreasing,but reverseis
happenedthan it iscalled
tem eratur
!emperature Inversion
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• ;st
• 5t !ropopause' temperaturestartsincreasingfrom here
•
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• 6nd
• 5 cool &internight, the airabove the coldsurface gets cool
• But the air layerabove that coollayer is till
&armer !hen, bygoing up&ard, airdoes not getcooler but &armer
+ #f temperature Inversion
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• ?th
• @alley inversion• &inter ' cool air
descends tovalley
• plift the &armair of valley
• 1escending
cool air0damage crops0frost
+ #f temperature Inversion
Implications of temperature
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$ormation
of fog
'arm air cooled
y cold airelo( )condensation )
tiny (aterdroplets* lo(&isiility
Kormation offrost
ater moisturefro3en &ithcontact cold
surface0 dama e
Implications of temperatureinversion
9 hat do you9uestio
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mains67;?
9 hat do youunderstand by
phenomenon ofOtemperature inversionP
in meteorology= $o&does it a-ect &eatherand habitants of the
place= (>
"
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Condensation of(ater droplet +esult
5t heights .louds
5t lo&er level Kog
on the cold
surface
1e&
drop !urn into ice
crystal in e+treme
Krost
.ondensation of &ater droplets
f f i f f
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Ad&ection
Mo&ing of (armair o&er cold
Radiat
ion
inter nights '
loss of heat dueto terrestial
radiation ' coldsurface )oving of
&arm air over
Reason for formation of fog
1 i l l f i ibili
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1ecreasing level of visibility
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fog
•
ater dropletcondensed around adust particle
• It reduces thevisibility, damage thecrops
• ater droplet
condensed around aparticle of pollutant,li2e
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9 "hotochemical smog is 9uestio
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"relims
67;?
9 "hotochemical smog isresultant of reaction among
a %#6, #? and pero+yacetylnitrate in the presence ofsunlight
b .#6, #6 and pero+yacetyl
nitrate in the presence ofsunlight
c .#,.#6 and %#6 at lo&
temperatured $igh concentration of %#6,
#? and .# in the evening
"
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"relims
67;?
"hotochemical smog:
%#6, #3one * sunlight
5ns 5
"
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evaporationprecipitation
ti
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; $igh temperature
6 L" conditions
? Kast moving &ind• ater vapour
evaporate from the&ater body
• vaporation addsmoisture in the air
vaporation
$ idit
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Asolute !umidity
• eight of &atervapour in unit volumeof moist air
• eight of &atervapour per unit &eightof dry air
Specic !umidity
$umidity
" i it ti
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• "recipitation ' &henair is saturated &ith&ater vapour and anye+tra addition result
in precipitationRelative $umidity:
• 5mount of &atervapour present in air
' to amount of &atervapour required forsaturation
• "recipitationdepends upontemperature andmoisture content ofthe air
• $ot air ' saturationreach &ith more
moisture contentthan cold air
"recipitation
! f l d
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!ypes of clouds
! f i f ll
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Con&ectional rainfall
Orograp#ic rainfall
!ypes of rainfall
! f i f ll
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Cyclonic rainfall
$rontal rainfall
!ypes of rainfall
" t f th ld
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• ntire earth is divided into C large pressurebelts
• In reality, belts are not continuous butpoc2ets of lo& and high pressure
• But pressure can be created throughthermal or dynamic reasons
• !hermal: high temperatureEF L", lo&
temperature EF $"• 1ynamic: air rises EF L", air descends EF
$"
"ressure system of the &orld
" t f th ld
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• C belts:
• equatorial lo&pressure belt
• sub0tropical
high pressurebelt
• sub0polar lo&pressure belt
• "olar $ighpressure area
"ressure system of the &orld
quatorial L" belt
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quatorial L" belt
• .onstant insolation• 5ir gets &arm 0L"
• 5ir move up&ard
0F cloud formation0F instability 0Frain in the eveningdaily
• .umulonimbusclouds
• .onvectional
rainfall
quatorial L" belt
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quatorial L" belt
• 5bsence ofadvection of air
• Belt of calm /
1oldrum• Because light,
feeble &inds 0calm region
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• !he air above
equator moveto&ards pole, butcoriolis force 0 theirpath get deected
• !he length of pathincreases !heirenergy reduced inmid0path 0cooled
air subside near ?70C7 deg latitude
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• Krom the pole, cold
&inds moveto&ards equator
• !he both &armand cold &inds
collide, the &armer&inds from
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• 5ir risen at
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ind system of the &orld
"lanetary &inds
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• &inds blo&ing at
the same directionthroughout the year
• cover largedistances
• $ori3ontalmovement,"ressure beltsystem provide
them the pressuregradient
• .orilis force modifytheir direction
"lanetary &inds
!h i d!rade &inds
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• !he &inds moveto&ards equatorial
lo& pressure EI!.
• I!. ' intertropicalconvergence3one, &here &indconverges
•
!heir direction iseast to &est dueto coriolis force
!rade &inds
!ropical deserts and trade &inds
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• !ropical
easterlies o&s'east to &est
• ind becomesdry &hen they
reaches the&estern coast ofthe continents
• #- 'shore trade
&inds• !rade &ind
deserts
!ropical deserts and trade &inds
!ropical desert and cold currents
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•
6nd• .old currents
providedesiccating
e-ect to trade&ind deserts
• .old current
o& on&esternmargins ofcontinents
!ropical desert and cold currents
9 )aJor hot deserts in9uestio
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)ains67;?
9 Jnorthern hemisphere
are located bet&een670?7 degree %orthlatitudes and on the&estern side of thecontinents hy= (;7
"
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• Krom &est to east
• Krom
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• Krom &est to east
•
Krom
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"relims
67;;
hemisphere are stronger andpersistent than northern
hemisphere hy=
;
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• Krom east to&est
• Krom poles to
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Summer
'inter
5pparent movement of the sun
movement of the pressure system
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Summer
'inter
movement of the pressure system
ind system of the &orld
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ind system of the &orld
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• )onsoon &inds:
seasonal reversalof &inds
• Keature oftropical latitude
• In &inter ' trade&ind blo&s northto south, insummer ' trade
&ind blo&s southto north Sbut inlimited areaT
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• 1ue to apparentnorth&ardmovement of thesun in summer
!hus, the I!. (L"also moves up&ard
• !hus, the area &hich&as under northerntrade &inds in&inter, &ill come
under southern trade&inds in the summer
)onson &inds
ind system of the &orld
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ind system of the &orld
Local &inds : mountains &inds
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Cold (ind
country
(ind
Hreece
Hragale
Italy !remonta
Mountains
'ind
5lps Kohn
Roc2ies
.hinoo2
5ndes on
'arm (inds
Local &inds : mountains &inds
Local &inds : land
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Cold (ind- land
• $" condition in &inter
• 1ivergence of cold air
•
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summer
• $ot0dusty &ind E QlooD
states 'ind
Bihar,
B,5ssam
Ualbais
ha2hi
U% Blosso
msho&er
UR )ango
Pre*monsoont#understorm
Local &inds: India
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)ountain bree3e
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• 1uring night
time: top getscooler thanvalley E $",valley EL"
• ind move hill0top to valley EFmountain bree3e
• 5griculture '
frost bite, chill inhabitation in thevalley
)ountain bree3e
• 1uring day@alley bree3e
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• 1uring daytime: top
gets &armerthan valleyE L", valleyE $"
•
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Land bree3es
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Land bree3es
•
1i-erentialcooling of landand &ater
• 1uring night:
• land cooler E$",
• &ater EL"
• ind move land
to &ater EF landbree3e
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&orld
"lanetary &ind system@ariable &inds
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• 5roundtropopause, there
is only onegradient
• ind accumulatedabove equatorand rari4edatmosphere abovepoles
•
$" at the equatorand L" at thepoles
pper tropospheric &inds
Heo0strophic &inds
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• strong coriolis
force attropopause
• Because friction isless 0 high speed 0
stronger thecoriolis force
•
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esterlies &inds• !he upper
tropospheric &inds /geo0strophic
&inds blo&from &estto east at
the veryhigh speed
Rossby &aves
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• esterlies at
poles ' tomaintain theangularmomentum0 they
meander EFRossby &aves
• Rossby &aves donot meander
consistently, butfollo& a cycle EInde+ cycle
ossby a es
Vet streams
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•
In &esterlies,there are strong,narro& bands ofhigh speed &ind
EF Vet stream•
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• !here are
situated at themargins ofmeridional cells
•
C permanent Vet streams: 6"olar Vet and 6V
/ t Vet streams
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Permanent et stream
/emporary etstream
V
• Vet stream Vet streams
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• Vet streamembedded in
&esterlies(Rossby &avesat highlatitude, causepressurevariability
• !hatDs &hy
they are calledtravellingdepression
V
Vet
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V g p
eather of )id and high latitude
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• eather of higher latitude is more comple+than &eather of equatorial or tropical regions
• Because tropical and equatorial region areheat surplus region' thermal reasons play
the dominant role• But higher latitude are heat de4cit region '
dynamic reasons play dominant role
•
!hese include ' localised * upper0tropospheric circulations (Rossby &aves, Vetstreams, temperate cyclones
g
5ir mass
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• Large e+tensive bodyof air0mass
(;777sq2m
• $eight upto !ropopause
• 5t particular height,
one air mass &ill haveuniform temperatureand moisture across its&idth
•
5irmasses can bedi-erentiate accordingto their temperatureand moisture content
5i i d5ir mass
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• 5ir mass acquiredproperties fromthe source regions' land, marine,polar, arctic,
5ntarctic E givethem identity +m", c!
• +tensive
homogeneoussurface * longerstay ($"
5ir masses
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• 5ir masses do notstay at theirsource regionsforever, they
move out hilemoving they cameacross other airmasses
Kront
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• !he relativedi-erence bet&eentemperature andmoisture decide
their interaction&ith one another
• !he border/
meeting region ofthe t&o air0massEF Kront
If cold air mass.old front
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• If cold air massmove faster thanthe other than it &illlift the &armer oneup&ard EF coldfront
• the slope &ill besteep E there &illbe sudden up0liftment of the &armair E cumulonimbusclouds Efrontalrainfall
If iarm front
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• If &armer airmass is moreactive than coldfront EF &armfront
•
slope &ill begentler E there&onDt be suddenup0liftment of
&arm air Euniformprolonged rain 'dri33le
Kronts
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Krontal cyclone
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• 5lso called ase+tra0tropicalcyclone,travelling
depressions,cold0corecyclone,&ave
cyclones
)eaning of cyclone
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; Intense L" system
6 5ir converges to&ards thecentre
? .losed isobarsC In %orthern hemisphere
convergence ' anti0cloc2&ise
Isobar
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Normal isoar
Closed isoar
.onditions for L"
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/#ermally induced
•
Because of hightemperature
• + L" at equator
• .onvectional rainfall
at equator
•
pliftment of &arm air• + L" at sub0polar L"
belt
• Krontal rainfall
0ynamically induced
) t f1evelopment of Krontal cyclone
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• )ovement of
airmasses fromtheir source region
• !he &arm andcold air mass face
each other• 5 front is created
bet&een them
•
.alled
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1ocation of air
masses
Circular mo&ement
• .old air mass1evelopment of Krontal cyclone
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• .old air mass
pushed the &armair mass
• Korced upliftmentof &arm air mass
at the cold frontEL"
• !&o cold air massconvergence 'circular due tocoriolis force
)ature stage
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2nteraction of air
masses
1P ) closed isoars
• #ne cold air mass#ccluded front
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• #ne cold air massclimb over othercold air mass'&armfront is destroyed
• .alled occluded
front• Rapid change in
temperature andpressure
• nstable &eatherconditions
• Krontolysis '1issipation of frontal cyclone
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no great
temperaturedi-erencebet&een t&ocold air
masses 'frontdissipated 'L" reduced 'cyclonedissipated
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#ccludedfront
$rontolysis
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"ath of the temperate cyclone
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• 5l&ays &est toeast direction
• Because inuence
of the &etserlies• Hradual
movement0"redictable
&eather
1istribution of temperate cyclones
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$urricane '% !ropical cyclone
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$urricane '%5merica
!yphoon 0 .hina
• Late summer
• Increased sea
surfacetemperature E L"
• .onvergence of airaround L" 3one
• Rising moist (&etair EF absoluteinstability
!ropical cyclone
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•.loud formationEmore and moremoisture ' latentheat of evaporation
EF cumulo nimbuscloud EF cyclone
• .oriolis force
induce spiralmovement of air
• Intensi4cation of
)ature !ropical cyclone
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• Intensi4cation of
L"• .onverging air
near &atersurface
• .irculating airrises above(coriolis force
•
1iverging air atthe top ofcyclone
h f h
ye of the tropical cyclone
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• 5t the centre of the
cyclone ' QeyeD of thetropical cyclone
• It is a pressuredefect Because, atQeyeD a narro&
stream of &inddescend E is $" atQeyeD
• 5t the eye, there is
clear s2y• Beyond eye &all '
e+treme lo& pressure
"roperties of tropical cyclones
-
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•
)ove s&iftly• It is fuelled by
moisture ' so&hen cyclone is
cut0o- from seaand moveto&ards land ' itstarts
&ea2ening
1istribution of tropical cyclone
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comparison
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/emperate cyclone
• ?70C7 degree latitude
• 1ynamically induced
•
1ue to frontalinteraction
• Kormed over largearea
•
)ove &est to east• Hradual movement '
predictable
• A067 degree latitude
• !hermally induced
• 1ue to increasing •
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/emperate cyclone
• ind speed C70>72mph
• "ressure gradient A7mb
• "o&erful on land
• 5-ect mainland
• )ore time to dissipate
• ind speed F;672mph
•
"ressure gradientMAA7 mb
• ea2ens on land
• 5-ect only coastalareas
• 9uic2ly dissipate aftercoming on land
/ropical cyclone
9 !ropical cyclones arelargely con4ned to
9uestion
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)ains
67;C
largely con4ned to
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&ater
6 arm oceancurrents
? Increase C !ropicalcyclonemove east to&est
> Landmass on&esterncoast
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