Lesson161HowdoTropicalrevolvingStormsform.ppt

7/26/2019 Lesson161HowdoTropicalrevolvingStormsform.ppt

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Lesson 16Lesson 16

How do Tropical RevolvingHow do Tropical RevolvingStorms Form?Storms Form?


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We need to understandWe need to understand howhowtropicaltropicalrevolving storms are created, theirrevolving storms are created, their impactsimpactsand knowand know how peoplehow peoplerespond to themrespond to them

We should also take into account the e!!ectsWe should also take into account the e!!ectso! glo"al warming on such eventso! glo"al warming on such events


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What drives a TropicalWhat drives a Tropical

Storm?Storm?

Cold polar airmoves

towards thewarm

equator.

Hot tropicalair moves

towards thecold poles.

The planet is not evenl# heated

$t Athe heating is more direct %intense

Whereas at Bit is spread over a

larger sur!ace area % less intense


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What causes wind?What causes wind?This uneven heating causes air toThis uneven heating causes air to

move around the planet, trying tomove around the planet, trying to

even out the temperature.even out the temperature.

$ir moving$ir moving

around thearound the

planet causesplanet causes

our wind, whichour wind, which

generall#generall#!ollows a known!ollows a known

patternpattern


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Tropical storms

!orm "etween

&'and ()' *orth+ South o! the

euator

The# need warmwater - a"ove

(.'c/ hence their

location

$s the 0arth rotates, this provides the spin2

needed to start the tropical storm on its

3ourne# across the $tlantic towards $merica


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Tropical revolving storms occur all around

the world, "ut are called di!!erent names

11%1%

!%

11%"#%

$$%


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Warm ceansWarm ceansThe !ood2 o! a tropical

storm is the warm moistwater !ound near the

euator The air here is

under LOWpressure, which

means it can li!t easil#

This li!ting encourages the

air to cool and condense, as

it does latent heatisreleased This is the name

given to energ# produced

when a su"stance changes

state ie vapour to a liuid


8/16

Here is a check list

o! what is needed

!or a tropicalrevolving storm

to grow

$ storm can travel an#where !rom 1& to 4)mph

5nce the stormhas developed

it can grow 4))

miles wide


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Here is a 7

image o! a

Tropicalrevolving

storm *otice

the lowerlevel winds

"eing drawn in

and spiralling

counterclockwise

The lines iso"ars2 get closer together,

indicating !aster !lowing air


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Launch the h#per linkLaunch the h#per link

How Hurricanes &ormHow Hurricanes &orm


11/16

Tropical Storm / Hurricane KeyFacts

Hurricanes are located in the low8pressure "elt near the euator as the

sun heats the oceans to a critical temperature o! 27

CThe oceans heat up all through the summer making their warmesttemperatures in the $utumn 9speci!ic heat capacit#:; this is Hurricaneseason in the $tlantic

The hurricane starts as a tropical depression, gaining more and moreenerg# !rom the warm ocean as it crosses the $tlantic The circulation o!the depression gets tighter 9iso"ars are closer together: and the windspeed increases into a tropical storm

The wind speeds continue to increase, "ecoming a categor# 1 up tocategor# & !or the most violent storm $s the hurricane makes land!all

damage is done "# the winds and rain and an advancing storm surge,which raise sea level "# &m< in some cases

The hurricane uickl# looses its energ# as it crosses the cooler land, asthe energ# suppl# has "een cut o!! The hurricane dies

Sometimes remnants o! hurricanes are "rought across "ack across the$tlantic at the mid latitudes giving us ver# strong depressions in the =>


12/16

How are they measured?How are they measured?'lthough developed in the (S', the'lthough developed in the (S', the Sa)r*SimpsonSa)r*Simpsonscalescaleis used to grade tropical storm wind strength inis used to grade tropical storm wind strength inmany parts o& the world.many parts o& the world.

CategoryCategory WindWind

SpeedSpeed

+mhr+mhr

WindWind

SpeedSpeed

-ph-ph

StormStorm

Surge mSurge m

Tropical stormTropical storm #*"#*" ##

TropicalTropical

depressiondepression$*11$*11 #*#./#*#./

11 11/*10$11/*10$ */0*/0 1."*1.01."*1.0

"" 10*110*1 /*11#/*11# 1.!*".1.!*".

$$ 1!*"#/1!*"#/ 111*1$#111*1$# ".*$.".*$.

"1#*"/"1#*"/ 1$1*1001$1*100 .#*0.0.#*0.0


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Problems with the Saffri Simpson?Problems with the Saffri Simpson?

45 (sing wind speed and storm surge45 (sing wind speed and storm surgelevels 6 what pro7lems could youlevels 6 what pro7lems could you

encounter?encounter?

http8www.nhc.noaa.gova7outsshs.shtmlhttp8www.nhc.noaa.gova7outsshs.shtml


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' tropical storm has many' tropical storm has many

&riends9&riends95ther phenomena which can "e 3ust as damaging than the wind !reuentl#5ther phenomena which can "e 3ust as damaging than the wind !reuentl#

accompan# tropical stormsaccompan# tropical storms

high seashigh seas8 large waves o! up to 1& metres high are caused "# the strong8 large waves o! up to 1& metres high are caused "# the strongwinds and are ha@ardous to shipping;winds and are ha@ardous to shipping;

storm surgestorm surge8 a surge o! water o! up to several metres can cause eAtensive8 a surge o! water o! up to several metres can cause eAtensive

!looding and damage in coastal regions;!looding and damage in coastal regions;heav rainheav rain8 the tropical c#clone can pick up two "illion tons o! moisture8 the tropical c#clone can pick up two "illion tons o! moistureper da# and release it as rain This also leads to eAtensive !looding 8 o!tenper da# and release it as rain This also leads to eAtensive !looding 8 o!tenwell inland !rom where the tropical revolving storm hit the coast;well inland !rom where the tropical revolving storm hit the coast;

torna!oestorna!oes8 tropical c#clones sometimes spawn man# tornadoes as the# hit8 tropical c#clones sometimes spawn man# tornadoes as the# hit

land which can cause small areas o! eAtreme wind damage Theseland which can cause small areas o! eAtreme wind damage Thesephenomena can cause ma3or destruction, especiall# when the tropicalphenomena can cause ma3or destruction, especiall# when the tropicalc#cloneBs path takes it over land However, a path over land also causes thec#cloneBs path takes it over land However, a path over land also causes thedestruction o! the tropical c#clone itsel! $s it moves over land, its energ#destruction o! the tropical c#clone itsel! $s it moves over land, its energ#source is depleted and !riction across the land sur!ace distorts the air !lowsource is depleted and !riction across the land sur!ace distorts the air !lowThis leads to the e#e !illing with cloud and the tropical c#clone diesThis leads to the e#e !illing with cloud and the tropical c#clone dies


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$: model o& a Tropical$: model o& a Tropical

StormStorm

Create #our own 7

model / remem"er to

add a ke#D


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HomeworkHomeworkA"A A2 boo#A"A A2 boo#Eg 6)86 Read and make notesEg 6)86 Read and make notes

isit these we" sites and read around the topic / whatisit these we" sites and read around the topic / whatelse can #ou add to #our notes a"out tropicalelse can #ou add to #our notes a"out tropicalrevolving storm !ormation?revolving storm !ormation?

Waugh Eg (& + *agle Eg 4(1< has eAtra reading, 9pa#Waugh Eg (& + *agle Eg 4(1< has eAtra reading, 9pa#

particular attention to Elaces ) !or Stretch +particular attention to Elaces ) !or Stretch +ChallengeD:ChallengeD:

httpGGwww""ccoukGweatherG!eaturesGunderstandhttpGGwww""ccoukGweatherG!eaturesGunderstand

ingGhurricanec#cleshtmlingGhurricanec#cleshtmlhttpGGwwwmeto!!icegovukGweatherGtropicalc#clonhttpGGwwwmeto!!icegovukGweatherGtropicalc#cloneG!actshtmleG!actshtml

httpGGwwwnhcnoaagovGa"outsshsshtmlhttpGGwwwnhcnoaagovGa"outsshsshtml

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Lesson161HowdoTropicalrevolvingStormsform.ppt