0part 7 chapter 13.6 wind and 13.9oceancurrents1

7/25/2019 0part 7 Chapter 13.6 Wind and 13.9oceancurrents1

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13.6 Wind and

OceanCurrents

Science 10


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A Little Background

Atmospheric Pressure is theforce of the air pressing downon the earths surfaceAtmospheric pressure is

measured using a barometer.

Since air molecules are so spreadout lots of empt! space"# wedont feel the pressure that the!e$ert

%ifferences in air pressure helpcause winds and affect airmasses. &he! are also factorsin the formation of storms suchas thunderstorms# tornadoes

and hurricanes.


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'hat is 'ind(

'ind is a mo)ement of air in theatmosphere

*ow 'ind %e)elops

+aused b! a difference in air pressure

due to une,ual heating of theatmosphere.

-uestion 'here on the planet does thesurface get heated more than otherareas(...

At the /arths surface# wind alwa!sblows from areas of high pressure toareas of low pressure


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*ow are 'inds +reated(

'inds are created b!.

0. *eating the air# decreases pressure warm airrises creating a low pressure"

1

2. +ool air rushes into replace the warm air

cooler dense air# produces high pressure"1

3. As air goes from high to low pressure windsform

&his is a +456/+&745 st!le +on)ection+urrent %emo &ime88

http99www.!outube.com9watch():;$''ow


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+lassif!ing 'inds

I. Localized

= affect onl! small areas

Tpes of Local Winds

Sea Bree>es= from sea to land Land Bree>es= from land to sea

II. !re"ailing winds

= affect large areas#= t!pes to follow after we look at

what causes pre)ailing winds


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+auses of Pre)ailing

'inds %ue to a combination of

con)ection currents and

coriolis effect

air at the e,uator is warmed

and rises# forming a

con)ection current called the

e,uatorial con)ection current


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&he +oriolis /ffect

/arths rotation causes an!thingthat mo)es L45? %7S&A5+/S#

such as pre)ailing winds# to

APP/A@ to change directions.

&he apparent change in direction

of a mo)ing obect in a rotating

s!stem is called the +4@74L7S

//+&.%emo 6ideo

http99www.!outube.com9watch():mcPsC4d-4DE


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+oriolis cont

/)ident on the earth because as

/arth rotates eastward# an obect

tra)elling from north to south will

appear to mo)e to the right 7n the southern hemisphere

obects mo)ing from the pole

appear to mo)e to the left

&he +oriolis effect is more

predominant closer to the poles


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10/22

Pre)ailing 'ind

&erms !olar easterlies occur between

FG degrees latitude and the polesand mo)es east to west

#id$latitude westerlies occurs

between 3G degrees and FG degreeslatitude and mo)e from west to east %ortheast trade winds occur ust

north of the e,uator and mo)e eastto west

Southeast trade winds occur ustsouth of the e,uator and mo)e eastto west


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/ffects of Pre)ailing

'inds *elp distribute large amounts

of solar energ! from the

e,uator to the colder parts of

the world.

Also carr! moisture# causing

a )ariet! of precipitation

snow# rain# etc"


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'ind terms cont

?usts occur because of a

rapid air pressure change

and mo)e in no fi$ed

direction

S,ualls gusts accompanied

b! rain

'ind speed indicator

ane&o&eterane&o&eter9weather )ane


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Sooooooo %o !outhink the Coriolis 'ffect

and Windeffect how

water mo)es in the

ocean(


14/22

4cean +urrents


15/22

4cean +urrents

Hass mo)ement orflow of ocean water

@i)er within theocean

&wo t!pesSurfaceSurfaceand (eep(eep


16/22

Surface +urrent

*ori>ontal# stream=likemo)ements of water thatoccur at or near the

surface of the ocean +an reach depths of

se)eral hundred meters

Surface +urrent Animation


17/22

@ed current : warm current

Blue current : cold current

Surface currents flow in a circular pattern 5orthern *emisphere flows clockwise

Southern *emisphere flows counter=clockwise

Poles flow in opposite direction

5otice that the warm currents flow from the e,uator

S f


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Surface

+urrents +ontrolled b! three factors

!re"ailing winds: +ause

surface currents to flow inthe direction the wind isblowing top IGG m"

Coriolis 'ffect

Continental (eflections:shape of the land it flowsup against


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%eep +urrents

Stream like mo)ement ofocean water far below thesurface. &*7S 7S 'AD %4'5&*/@/8

+aused b! changes in densit! &his change in densit! is the

result of changingtemperature and salinit!


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+auses# broken down Change in te&perature

%ecreasing the temperature its colder" ofwater increases densit! water sinks"

Change in salinit 7ncreasing the salinit! of water increases

densit! again# making water sink" Salinit! increases because when water at the

poles free>es# the salt doesnt free>e so itsleft behind and sinks to the ocean floor and isreplaced b! new water hence the current"

Both &/HP/@A&E@/ A5% SAL757&D causes

warmer less dense water from the e,uatormo)es to replace it water will alwa!s want tobe le)el and that is wh! the water that lea)esgets replaced"

&he Pic on the ne$t page does a good ob

e$plaining this phenomena


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0part 7 chapter 13.6 wind and 13.9oceancurrents1

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