Atmosphere Revision booklet, 2014 cg malia

5/19/2018 Atmosphere Revision booklet, 2014 cg malia

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REVISION ATMOSPHERE

AS GEOGRAPHY 9696 (PAPER 1)


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TERMS:

Condensation

Sublimation

Incoming solar radiation/short wave radiation

Terrestrial/Earths radiation

Reflected solar radiation

Latent heat transfer

Sensible heat transfer

Relative Humidity

Temperature inversion


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Condensation: Change of water from a vapour to liquid form inducedby cooling (e.g. saturated air reaching dew point temperature)

Sublimation: the direct change of water vapour to a solid (ice) state.Either by condensation onto a frozen surface or at altitude theproduction of ice crystals (e.g. cirrus clouds).

Incoming solar radiation/short wave solar radiation: radiation derived

from the sun that enters the earths atmosphere in the form of shortwave radiation.

Terrestrial (Earth) Radiation/long wave solar radiation: the long waveradiation that is transmitted from the earths surface after the heatingby solar radiation.

Reflected solar radiation is that radiation that is reflected back tospace from clouds or from features (e.g. snow) of the earths surface(albedo)


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One way it is being reflected when entering the atmosphere is reflected by waterdroplets and ice in clouds or it can be reflected at the earth's surface through thealbedo effect, e.g. ice sheets, etc.

Latent heat transfer is the heat emitted or absorbed in the change of state. Hence

water to vapour etc. Can also be expressed in terms of the transfer of energy from theground to the atmosphere.

Convection: the process whereby (usually) air is heated at the ground surface and thenrises because it is warmer and lighter

Evaporation is the changing of a liquid (water) to a gas (water vapour) by heating.Conditions include insolation (i.e. heating), proximity of water supply, low humidity of

air (vapour pressure), wind speed, ground surface.Water vapour is moisture in the atmosphere as an independent gas (i.e. evaporatedwater).

Relative Humidity: the ratio of the actual amount of water vapour in air to themaximum amount it can hold at that temperature. It is expressed as a percentage.

Relative humidity is important because it gives and indication of the humidity of an airmass and its capacity to hold moisture. This it allows some estimate of the chances ofprecipitation.

Sensible Heat Transfer: The transfer of heat by the process of convection (rising hotair) and conduction (the transfer of heat by being in contact with a warm surface).


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What?

An increase rather than a decrease oftemperature with height. They can form at the

surface (radiative cooling, anticyclonic, frontal,advection cooling) or in the upper atmosphere(stratosphere and thermosphere).

When?Radiative cooling, advective and frontalinversion.


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6 factor day model

Incoming solar radiation:

Affected by latitude, season & cloud cover. When sun is high in the

sky, more energy received by earth. The less cloud cover & higher

the cloud, more radiation received by earths surface

Reflected solar radiation:

Proportion of energy reflected

back to atmosphere

-albedo. Light material reflected

more dark materials.

Long-wave Radiation:

Radiation of energy from

The earth (cold body) into atmosphere.

(net radiation loss from surface)Outgoing > incoming solar radiation.

Sensible heat transfer-

Movements parcels of air into and out

Form area being studied.

Air is warmed by surface begin to rise

(convection)

& replaced by cooler air. (convective

transfer)

Surface absorption:

Energy reaches the earths surface potential

To heat it. Depend nature of surface; If energy concentrated at surface

Surface warm up but if surface can conduct heat to lower layers, surface remaincool

Latent heat transfer

(Evaporation):

When liquid water turned

into vapour, heat

Energy is used up. In

contrasts, when waterVapour turns into liquid,

heat is released.

When water present at

surface, energy will be

Used to evaporate it, and

less energy available

To raise local energy

levels and temperature.


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4 factor night model

Long-wave radiation:

During cloudless night,

Large energy is loss LWR

From earth. Little

Return to atmosphere

Due to lack of clouds.

Cloudy night, clouds

Returns LWR to surface,

Overall loss is reduced.

Hot desert, lack cloud cover

Loss of energy at night

Is maximised.

Latent heat

Transfer

(condensation)During night, water

vapour close to

surface can condense

to form water, since air

is cooled by cold

surface. When water

condenses, latent heat

is released

Sub-surface supply:

Heat transferred to soil & bedrockuring daytime may

be released back to surface at night.

This off-set night time cooling at the surface.

Sensible heat Transfer:

Cool air move into an area

May reduce temperatures

Whereas warm air may

Supply energy & raise

Temperature.


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BREEZE

Sea Breeze:

It occurs when the land is warmer than the sea. Warm air expands and rises on land creating

low pressure area. It is likely to occur during day time. The air parcel, which is now higher up

in the atmosphere, travels and cools over sea then creating high pressure area over the sea.The wind blows form the sea (HP) towards the land (LP).

Land Breeze:

It occurs when sea is warmer than the land. Warm air expand and rises on sea creating low

pressure area. It is likely to occur during night time.The air parcel, which is now higher up in

the atmosphere, travels and cools over the land then sinks, creating high pressure over the

land. The wind blows from the land towards the sea.


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HEAT TRANSFER -HORIZONTAL


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Ocean current

Warm currents carry water polewards and raise theair temperature of maritime (sea/marine)environments where they flow. For example Gulfstream is responsible for moving excess heat gained

in tropics to the poles. It moves toward the centralAtlantic, release heat to the atmosphere and raisingtemperature of coastal area in coastal region in theNorth such as Great Britain and bringing cold ocean

current such as Labrador back to the equator.Labrador current flowing down from the Arcticmakes the winters of New England and EasternCanada much colder than they otherwise would be.


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TRI-CIRCULAR CELLS


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Three cells circulation

This theory of circulation best describes the Earths generalcirculation because it considers effects of coriolis force dueto the Earths rotation. In this circulation model, theNorthern and Southern Hemisphere are each divided intothree cells of circulation, each spanning 30 degrees of

latitude. The latitudes that mark the boundaries of thesecells are the Equator, 30 North and South, and 60 Northand South. For our purposes, we consider only theNorthern Hemispheric cells shown in figure 212:

Hadley.

Polar.

Ferrel.


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Hadley cell

George Hadley, an English meteorologist, theorized this first circulationcell in 1735. The Hadley cell is the strongest of the three cells ofcirculation and is formed as warm air rises above the Equator andstarts to flow northward. The northward flow deflects to the right, dueto coriolis, becoming an upper-level westerly flow. As this air moves

northeastward toward the pole, it cools and a portion of it sinks atabout 30N. This sinking air spreads northward and southward as itnears the surface. The southward moving air again deflects to theright, becoming the northeasterly trade winds.

Because of the circulation in the Hadley cell, two pressure belts are

created. The first is a belt of semipermanent high pressure that resultsfrom the sinking air at 30. This belt of high pressure is called thesubtropical ridge. The second pressure belt is a trough of low pressurenear the Equator. It is called the near equatorial trough.


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Polar cell

This is the northernmost cell of circulation and its meanposition is between 60N and the North Pole. At the pole,cold, dense air descends, causing an area of subsidenceand high pressure. As the air sinks, it begins spreading

southward. Since the coriolis force is strongest at thepoles, the southward moving air deflects sharply to theright. This wind regime is called the surface polareasterlies, although the upper winds are stillpredominantly from the southwest. Near 60N, the

southeasterly moving air moving along the surfacecollides with the weak, northwesterly surface flow thatresulted from spreading air at 30N. This colliding airrises, creating a belt of low pressure near 60N.


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Ferrel cell

The mid-latitude circulation cell between the Polar cell and the Hadley cell iscalled the Ferrel cell. This cell is named after William Ferrel, a Nashville schoolteacher who first proposed its existence. Oddly enough, Mr. Ferrel publishedhis observations in a medical journal in 1856.

The Ferrel cell circulation is not as easily explained as the Hadley and Polarcells. Unlike the other two cells, where the upper and low-level flows arereversed, a generally westerly flow dominates the Ferrel cell at the surfaceand aloft. It is believed the cell is a forced phenomena, induced by interactionbetween the other two cells. The stronger downward vertical motion andsurface convergence at 30N coupled with surface convergence and netupward vertical motion at 60N induces the circulation of the Ferrel cell. This

net circulation pattern is greatly upset by the exchange of polar air movingsouthward and tropical air moving northward. This best explains why the mid-latitudes experience the widest range of weather types.


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WORLD WIND BELT


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The unequal heating makes the tropical regions warmer than the polarregions. As a result, there is generally higher pressure at the poles andlower at the equator. Air flows from areas of high to low pressure atthe earths surface. This horizontal flow of air is called as wind. Windflows from high to low pressure.

So the atmosphere tries to send the cold air toward the equator at thesurface and send warm air northward toward the pole at higher levels.

Unfortunately, the spin of the earth prevents this from being a directroute, and the flow in the atmosphere breaks into three zonesbetween the equator and each pole.


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These form the six global wind belts:

3 in the Northern Hemisphere (NH) and 3 in the Southern (SH). They are generallyknown as:

1) The Tradewinds, which blow from the northeast (NH) and southeast SH), are foundin the subtropic regions from about 30 degrees latitude to the equator.

2) The Prevailing Westerlies (SW in NH and NW in SH) which blow in the middlelatitudes. (30 to 60) in both Hemispher. Most of North America fits into this belt andthat is why our weather usually comes from west.

3) The Polar Easterlies which blow from the east in the polar regions. (From poles i.e.

90 to 60 latitudes in both hemisphere)

* Northern Hemisphere deflected to right and southern hemisphere it is deflected tothe left.


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World map showing distribu on

t e mp e ra t ur e an d p r es s ur e

ITCZI T CZ m o ve

N or th i n J ul y

summer

winter

JULYSUMMER (NH)

WINTER (SH)


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July (NH)

In July, the Northern Hemisphere is experiencing itssummer season because the North Pole is now tiltedtowards the Sun(ITCZ is shifting to the NorthernHemisphere). Some conspicuous hot-spots include the

south-central United States, Arizona and northwestMexico, northern Africa, the Middle East, India, Pakistan,and Afghanistan. Temperatures over oceans tend to berelatively cooler because of the land's ability to heatquickly. Two terrestrial areas of cooler temperatures

include Greenland and the Plateau of Tibet. In theseregions, most of the incoming solar radiation is sent backto space because of the presence of reflective ice andsnow.


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In July (S.H)

In the Southern Hemisphere, temperatures over

the major landmasses are generally cooler than

ocean surfaces at the same latitude. Antarctica

is bitterly cold because it is experiencing totaldarkness. Note that Antarctica is much colder

than the Arctic was during its winter season. The

Arctic consists mainly of ocean.


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FACTORS INFLUENCING TOTAL

VARIATION WITHIN GLOBAL PATTERNS

LATITUDE

LAND AND SEA DISTRIBUTION

INFLUENCE OF OCEAN CURRENTS


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Latitudes

Latitude-areas close to equator receive more heatthan areas that are close to the poles, because:

Incoming solar radiation (insolation) is concentrated

near the equator, but dispersed near the poles.Insolation near the poles has to pass through agreater amount of atmosphere and there is morechance of it being reflected back out to space.

At the equator insolation is concentrated, but nearthe poles it is dispersed over a wider area.


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Land and sea distribution

As the surface of the earth is not uniform, this

influences its response to solar radiation. Land

masses absorb short-wave energy and radiate

long-wave energy more rapidly than water (e.g.river, lakes, oceans) causing more extreme

temperatures than are found at the same

latitude over the oceans.


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Ocean currents

Water form an effective mechanism for the transfer of energy acrosslatitudes.

Major, long term flows of water which can extend over thousands of kms aretermed ocean currents, generated by prevailing winds that blows across thesurface.

The effects of ocean currents on temperatures depend upon whether thecurrent is cold or warm.

Warm currents from the equatorial regions raise the temperatures of polar

areas (with the aid of prevailing westerly winds) noticeable only in winter.

By contrast, other areas are cooled by ocean currents such as the Labradorcurrent off the north east coast of North America which reduce summertemperatures.


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TERMS

ALR

DALR

SALR ELR


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TERMS

ALR-Adiabatic lapse rate

The changes in temperature of a parcel of air as it expanded (cooled) orcompressed (heated). Often expressed as rising or falling.

For a parcel of air, the decrease in temperature with increasing in height are

expressed as:

DALR- Dry Adiabatic Lapse Rate

The rate at which unsaturated air cools as it rises or warms as it descends.

SALR-Saturated Adiabatic Lapse Rate

The rate at which saturated air cools.

ELR-the decrease in temperature expected with an increase in height ofsurrounding air. (o.5C per 100 m ascent)


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Stability


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STABILITY AIR

The state of stability is when a rising parcel of unsaturated air(DALR) cool more rapidly than the surrounding air (ELR). Ifthere is nothing to force the parcel of air to rise it will sinkback to its starting point. Hence the air is described as stablebecause the dew point may not have been reached and the

only clouds which might have developed would be shallow,flat-topped cumulus which do not produce precipitation.Stability give rise to dry, sunny conditions where anyconvection currents are suppressed/block by sinking air.

DALR cooler (denser) than ELR

sink-stable.


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Instability/unstable air


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INSTABLE AIR

Localised heating of the ground warms nearby air by conduction,creating higher lapse rate.

The resultant parcel of rising unsaturated air (DALR) cools less rapidlythan the surround air. The rising air remains warmer and lighter thanthe surrounding air. Should it be sufficiently moist and if dew point is

reached then the upward movement of air may be accelerated toproduce towering cumulus or cumulonimbus cloud. Thunderstorm arelikely to develop and the saturated air, following the release of latentheat, will cool at the SALR.

DALR is warmer and lighter than ELR-continued to rise-Instable air


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Conditionally instability air


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Conditionally instability:

At lower layers the rising air is stable and beingcooler than the surround air would normally sinkback again. However if the mechanism whichinitially triggered the uplift remains the air will becooled to its dew point. Beyond this point, coolingtakes place at the slower SALR and the parcel maybecome warmer than the surrounding air. It will

now continue to rise freely even if the upliftingmechanism is removed, as it is now in an unstablestate.


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Instability is conditional upon the air being force

to rise in the first place and later becoming

saturated so that condensation occurs. The

associated weather is usually fine in areas ofaltitudes below condensation level but cloudy

and showery in those areas at altitude above

condensation level as towering cumulus cloudstend to develop.


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WEATHER PHENOMENA:

S n o w

F r o s t

De w

Fo g

P r e c i p i t a t i o n i n t h e

f o r m o f s n o w f l a k e s o f

c o m p l e x h e x a g o n a l i c e

c r y s t a l s . I t i s f o r m e d i n

c o l d c l o u d s t h r o u g h t h e

p r o c e s s o f d e p o s i t i o n ,

w h e r e v a p o u r f o r m s

s t r a i g h t a w a y i n t o i c ec r y s t a l s ( s o l i d ) . T h e

l a r g e s t f a l l s o f s n o w

o c c u r w h e n a i r

t e m p e r a t u r e s a r e j u s t

b e l o w f r e e z i n g p o i n t .

T h e d e p o s i t o f f i n e i c e

c r y s t a l s o n t o a s u r f a c e

o f g r a s s , p l a n t l e a v e s

a n d w a l l s .

I t f o r m s u n d e r c l e a r ,

c a l m , a n t i c y c l o n i c

c o n d i t i o n s i n w i n t e r

w h e n t h e r e h a s b e e n ar a p i d l o s s a t n i g h t w i t h

t e m p e r a t u r e s b e l o w

f r e e z i n g p o i n t . W a t e r

v a p o u r c o n d e n s e s

d i r e c t l y t o i c e c r y s t a l s

b y d e p o s i t i o n o n t ot h e s e s u r f a c e s .

* G l a z e d f r o s t ( n e x ts l i d e )

D e p o s i t i o n o f w a t e r

d r o p l e t s o n t h e s u r f a c e

o f g r a s s & t h e l e a v e s o f

p l a n t s . A s w i t h f r o s t ,

d e w a l s o f o r m s u n d e r

c l e a r , c a l m , a n t i c y c l o n i c

c o n d i t i o n s ( c l e a r n i g h t s

w i t h n o c l o u d c o v e r )w h e n t h e r e i s a r a p i d

h e a t l o s s a t n i g h t . A s

n e a r b y a i r c o o l e d t o

d e w p o i n t , t h e m o i s t u r e

i n t h e a i r c o n d e n s e s a n d

d e p o s i t e d a s t i n yd r o p l e t s o n t o t h e s e c o l d

s u r f a c e s .

F o g i s a m a s s t i n y w a t e r

d r o p l e t s s u s p e n d e d i n

t h e a i r ( o f l o w e r

a t m o s p h e r e ) . T h e i d e a l

c o n d i t i o n s f o r f o g a r e

c a l m a i r , c l e a r s k i e s a n d

l o n g n i g h t s , w h e n

p r o l o n g e d c o o l i n g w i l ll e a d t o c o n d e n s a t i o n o f

m o i s t u r e i n t h e a i r a t

g r o u n d l e v e l . W h e n

c o n d e n s a t i o n o c c u r s a t

g r o u n d l e v e l , w a t e r

d r o p l e t s l i m i t v i s i b i l i t y .F o r m a t i o n o f f o g

r e d u c e s v i s i b i l i t y t o l e s st h a n o n e k i l o m e t e r .

( c o o l i n g r e s u l t 3 t y p e s

o f f o g ; R a d i a t i o n , f r o n t a l

a n d a d v e c t i o n .


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FOG

Fog is a mass tiny water droplets suspended in the air(of lower atmosphere). The ideal conditions for fog, arecalm air, clear skies and long nights, when prolongedcooling will lead to condensation of moisture in the airat ground level. When condensation occurs at groundlevel, water droplets limit visibility. Formation of fogreduced visibility to less than one kilometer.

Fog is formed by the cooling of air at ground level bycooling from below (either radiation, frontal or

advection). Condensation then takes place at groundlevel.


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TYPES

a) Radiative coolingsurface inversion, this is cause by radiational cooling of lower airwhen terrestrial radiation occur, land surface radiates more heat than the air, thusground is cooled more rapidly than the air. (snow-covered surface, long clear winternight, clear skies without clouds)

b) Advective cooling-a thick layer of warm air over a cold surface produces aninversion of temperature in the lower layers of the atmosphere - the warm air iscooled by conduction.

-warm air passes over a cold water surface.

-also occur over cold land surface or snow-covered ground

-same way, during summer the oceans are cooler than the adjacent land masses.

c) Frontal inversion- when differing air masses are brought together by convergingmovements; the warmer air being relatively higher tends to overlie the colder anddenser air in a horizontal layer.

-a mass of cold air moves into a region that was previously occupied by a warm airmass. The cold air, being more dense slides in underneath the warmer air lifting thewarm air up. This results in the warm air mass overlaying the cold air


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UPLIFT OF AIR


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FORMATION OF CLOUD

Clouds are visible masses of water droplets and/or icecrystals in the atmosphere. It consists of water dropletsthat are sufficiently small (below 0.04 mm) to remainsuspended in the air through external friction.

Clouds are formed when air cools to dew point and

vapour condenses into water droplets, a processknown as condensation.

It is formed due to the uplift if air through convectionalheating, orographic or frontal uplift causing air to cooladiabatically.


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FORMATION OF RAINFALL

Collision-Coalescence Process Temperatures in the cloud are above freezing

Cloud droplets exist in a variety of sizes (however, all are too small to fall as rain)

Heavier droplets begin to fall and collide with other droplets on their way down

After collision, the droplets merge or coalesce to form larger drops that continue the process untillarge enough to fall as rain

Bergeron Ice Crystal Process Both ice crystals and liquid water droplets must co-exist in clouds at temperatures below freezing

Water droplets existing as a liquid at temperatures below freezing are called supercooled waterdroplets

There are more water vapor molecules surrounding the water droplets than around the ice crystals- this is a difference in vapor pressure. Remember, there will be a flow from where there is toomuch of something to where there isn't enough.

There is a net flow of water vapor molecules from the supercooled water droplets to the ice

crystals, causing the ice crystals to grow (see diagram below). Therefore, the ice crystals grow by "using up" the water droplets.

Process is called accretionor riming.


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Urban Heat island

Large cities and conurbations experiences

climatic conditions that differ from the

surrounding countryside i.e. urban area is

warmer than surrounding area/countrysideduring daytime temperature is 0.6C and night

time 3C to 4C warmer than surrounding or

countryside.


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Why occur?

Dust and cloud acts as a blanket reducing

radiation and buildings giving out heat like

storage radiators.


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Urban environment (causes)

1. Lower wind speeds if compare to rural areas allow warmth toaccumulate. Wind velocities is reduced by buildings which createfriction and act as windbreaks.

2.Dark-coloured roofs, concrete or brick walls and tarmac roads have

high thermal capacity which means that they are capable of storingheat during the day and releasing it slowly during the night.

Compared to soil and vegetation, buildings have a higher capacity toretain and conduct heat: windows let is sunlight that is absorbed bydry surfaces.

3. The burning of fossil fuels in homes, offices, factories, powerstations, central heating and transportation are some of major sourcesof heat.


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4. Smog and pollution traps outgoing radiant energy and thiscan help maintain higher urban temperatures.

5. A kilometer of an urban area generally contain greater

surface area than a kilometer of countryside. Thus largeamount of surfaces in urban areas allows a greater area to beheated, contributing to higher urban temperatures.

6. Fewer bodies of open water (less evaporation) and fewer

plants (less transpiration) found in urban areas. As littleenergy is used for evapotranspiration thus more is available toheat the atmosphere contributing to high urbantemperatures.


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Climatic differences in urban areas

1. Localised differences in temperatures within the urbanenvironment:

-in forest shades, temperatures are lower during the day but at nightleaves trap radiant heat, keeping temperature higher

-other places might receive extra light reflected from glass buildings

-concentration of tall buildings may block out sunlight.

2. Humidity

lack of moisture due to:

-warmer air can hold more moisture

-lack of vegetation-water surface limits evapotranspiration

-high drainage density (sewers and drains) which remove water


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3. Precipitation

-Higher temperature encourage lower pressure over citieswhich draws air from the surroundings are. This thenleads to upward air movement and cooling of rising air

leading to condensation. Cumulus clouds builds uprapidly which in turn encourage convectional rainfall,further enhanced by orographic rainfall due to relief oftall buildings.

In cities huge quantities of dust and particles (3-7 greaterover cities than surrounding rural areas) which once inthe atmosphere form a dome over urban area.


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Hydroscopic nuclei encourage condensation to

take place. Studies conducted in St Louis in the

late 1970s showed that there was a higher

incidence of cumulus cloud development overthe city, particularly late in the day, and summer

rainfall totals were 20% higher than surrounding

area. This was because of a high concentrationof condensation nuclei and instability associated

with higher urban temperature.


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4. Pollution

Large quantities of gaseous and solid impurities areemitted into urban skies by the burning of fossil fuels, byindustrial processes and from car exhausts.

(urban areas may have 200X more sulphur dioxide & 10Xmore nitrogen oxide than rurals, as well as 10X morehydrocarbons and 2x carbon dioxide). These pollutantstend to increase cloud cover (thicker and up to 10% more

frequent cloud cover than rural areas) and precipitation,giver higher temperatures and reduce sunlight.


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5. Winds:Urban heat island effect seem capable of producing its ownwinds. Higher temperature in urban area lead to lowerpressure over cities, drawing air in from surroundings. Thiswinds can also be responsible for preventing a heat island

effect in smaller towns only when wind speeds are greaterthan 20km/hr.

The position of buildings, streets or path layouts can influencewind speeds to some extent.

Clustered buildings has the effect of concentrating windsbetween buildings.


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High rise buildings such as sky-scrappers of New York andHongkong form canyons through which wind may bechannelled.

These wind may be strong enough to cause tall buildingsto sway and pedestrians to be blown over and troubledby swirling litter and rubbish.

Streets built parallel to wind direction lead to powerfulgusts , streets built at right angles to the wind directionare sheltered by buildings and generated very little wind.

GREEN HOUSE EFFECT & GLOBAL


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GREEN HOUSE EFFECT & GLOBAL

WARMING


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GREENHOUSE EFECT

Warming of the atmosphere caused by entrapment of LongWave Radiation.

What is greenhouse gases?

Green house gases:Greenhouse gases i.e. Carbon Dioxide and other gases such asmethane, nitrous oxide and ozone are able to trap heat (LWR)from escaping into space. These gases also absorb and emitenergy back toward the earths surface and energy is stored

long enough before it can increase the temperature of theatmosphere.

(Like a greenhouse where it let sun through but allowingradiant energy from objects inside to escape)


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The increase in greenhouse gases concentration

are due to population increase and human

activities; agriculture and industries.

With the increase in amount of Green house

gases concentrations more heat will be trapped

thus leading to global warming.


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Global warming

Rise in the earths average temperature, possibly

due to increased emissions of greenhouse gases.


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Predicted possible effects

1. Increase in world temperature, in the future there will be a further increase oftemperature by 1.5 C to 4.5C by the year 2100.

2. Frequent storms:

increase heat in the atmosphere will also increase wind velocity hence increasing thefrequency of major storm events. If the Mediterranean heats to over 26C, hurricanes

could develop and devaste the coastal areas.

3. Change in global precipitation

With increase in temperature there is an increase in evaporation over the oceansleading to greater global precipitation. The distribution of precipitation across theworld is likely to change where some parts of the world will become wetter(agriculture more productive), esp those around 40N, will become drier with less

reliable rainfall. As these latitudes contain many cereal growing regions, there couldbe additional consequence of food shortage. Whereas in Greenland and Antarctica willget thicker as these areas experience increased snowfall.


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4. Rise in sea levelAs the atmosphere gets warmer so too will water in theoceans. As seawater warm, it will expand, causing eustatic risein its level by predicted 0.25 to 1.0 m by the year 2100. Thepredicted rise in sea level could partly submerged low-lying

coral islands such as Maldives, and increases the flood risk incountries with river deltas such as Egypt and Bangladesh.

5. Changes in ocean currents

These is evidence that the North Atlantic Drift will beweakened. If this occurred, one result of global warming forthe UK would be colder and more severe winters.

Atmosphere Revision booklet, 2014 cg malia

Documents

earths atmosphere

cg malia

transfer of heat

solar radiation latent

heatingby solar radiation

radiation derivedfrom

gas water vapour

sensible heat transfer