Specification: Major Climate Controls

8/14/2019 Specification: Major Climate Controls

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Lesson 1Lesson 1

Structure of theStructure of the

AtmosphereAtmosphere

Specification: Major climate controls


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DefinitionsDefinitions

Weather day to day changes inWeather day to day changes in

the state of the atmosphere.the state of the atmosphere. Climate average weatherClimate average weather

conditions over a longer period ofconditions over a longer period of

time 30 years.time 30 years.


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What is the Atmosphere?What is the Atmosphere?

An atmosphere is defined as the gaseousAn atmosphere is defined as the gaseous

envelope that surrounds a celestial body.envelope that surrounds a celestial body.

Therefore, the Earth, like other planets inTherefore, the Earth, like other planets in

the solar system, has an atmosphere, whichthe solar system, has an atmosphere, which

is retained by gravitational attraction andis retained by gravitational attraction andlargely rotates with it.largely rotates with it.


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Who studies the Atmosphere?Who studies the Atmosphere?

Learning about different states of theLearning about different states of the

atmosphere enables science to understandatmosphere enables science to understand

and predict changes on a range of scales.and predict changes on a range of scales.

Meteorology is the subject that studiesMeteorology is the subject that studies

the chemical and physical properties ofthe chemical and physical properties ofthe atmosphere together with its fields ofthe atmosphere together with its fields of

motion, mass and moisturemotion, mass and moisture..


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Vertical structure of the atmosphereVertical structure of the atmosphereThe atmosphere is dividedThe atmosphere is divided

intointo fourfour isothermal layers orisothermal layers or'spheres':'spheres': troposphere,troposphere,stratosphere, mesospherestratosphere, mesosphereand thermosphere.and thermosphere.

Each layer is characterised byEach layer is characterised bya uniform change ina uniform change intemperature with increasingtemperature with increasingaltitude.altitude.

In some layers there is anIn some layers there is anincrease in temperature withincrease in temperature withaltitude, whilst in others italtitude, whilst in others it

decreases with increasingdecreases with increasingaltitude.altitude.

The top or boundary of eachThe top or boundary of eachlayer is denoted by a 'pause'layer is denoted by a 'pause'where the temperature profilewhere the temperature profileabruptly changesabruptly changes ..


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TroposphereTroposphereThe troposphere contains aboutThe troposphere contains about 80%80% of the atmosphere and isof the atmosphere and isthe part of the atmosphere in which we live, and makethe part of the atmosphere in which we live, and makeweather observations.weather observations.

In this layer, average temperatures decrease with heightIn this layer, average temperatures decrease with height6.46.4ooc/1000m, as there is less air in contact with the ground toc/1000m, as there is less air in contact with the ground toheat up. This is known asheat up. This is known as Environmental Lapse rateEnvironmental Lapse rate (adiabatic(adiabaticcooling brought about by changes in temperature caused by acooling brought about by changes in temperature caused by a

decrease in pressure at height).decrease in pressure at height).

This sphere mixes vertically by convection, conduction andThis sphere mixes vertically by convection, conduction andturbulence more than any other sphere. These vertical motionsturbulence more than any other sphere. These vertical motionsand the abundance of water vapour make it the home of alland the abundance of water vapour make it the home of allimportant weather phenomena.important weather phenomena.

The troposphere is aroundThe troposphere is around 16 km high16 km high at the equator, with theat the equator, with thetemperature at the tropopause around 80 C. At the poles,temperature at the tropopause around 80 C. At the poles,the troposphere reaches a height of around 8 km, with thethe troposphere reaches a height of around 8 km, with thetemperature of the tropopause around 40 C in summer and temperature of the tropopause around 40 C in summer and 60 C in winter. Therefore, despite the higher surface60 C in winter. Therefore, despite the higher surfacetemperatures, the tropical tropopause is much cooler than attemperatures, the tropical tropopause is much cooler than at

the poles at the thickness is increased more cooling occurs.the poles at the thickness is increased more cooling occurs.
http://upload.wikimedia.org/wikipedia/commons/f/f9/Atmosphere_layers-en.svghttp://upload.wikimedia.org/wikipedia/commons/f/f9/Atmosphere_layers-en.svg


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MesosphereMesosphere

Temperatures in the mesosphere decreaseTemperatures in the mesosphere decrease

rapidly as there is no water vapour, cloud, dustrapidly as there is no water vapour, cloud, dustor ozone to absorb incoming radiation.or ozone to absorb incoming radiation.

Temperatures at the mesopause go as low as Temperatures at the mesopause go as low as 120 C with very strong winds 3000km/hr.120 C with very strong winds 3000km/hr.

As in the troposphere, the unstable profile meansAs in the troposphere, the unstable profile meansthat vertical motions are not inhibited. Duringthat vertical motions are not inhibited. Duringthe summer, there is enough lifting to producethe summer, there is enough lifting to produceclouds in the upper mesosphere at high latitudesclouds in the upper mesosphere at high latitudes


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ThermosphereThermosphereThe thermosphere extends upwards to altitudes ofThe thermosphere extends upwards to altitudes of

several hundred kilometres, where temperatures rangeseveral hundred kilometres, where temperatures rangefrom 250from 250ooc to as high as 1,700c to as high as 1,700ooc, getting warmer withc, getting warmer withincreasing height.increasing height.

Temperature ranges depend on the degree of solarTemperature ranges depend on the degree of solaractivity and as there is more atomic oxygen there (likeactivity and as there is more atomic oxygen there (like

ozone) to absorb the heat.ozone) to absorb the heat.

The temperature changes between day and nightThe temperature changes between day and night((DiurnalDiurnal) amount to hundreds of degrees.) amount to hundreds of degrees.

Above 500 km temperatures are very difficult to define.Above 500 km temperatures are very difficult to define.Molecules are so widely spaced that they moveMolecules are so widely spaced that they moveindependently, and there is no reason why theirindependently, and there is no reason why theirtemperatures should be the same.temperatures should be the same.


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Earths Annual Heat BudgetEarths Annual Heat Budget

Heating of the Atmosphere Heating of the Atmosphere

At A the suns energy is

more concentrated on a

small land area intenseheating.

At B the suns energy is

spread over a wider

surface area leading to

less direct heating.AB B


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Heat Budget in OUR WinterHeat Budget in OUR Winter

In the

North in

OUR Winter

there is a

deficit

In theSouth in

OUR Winter

there is a

surplus

At the

equator

there is a

surplus

Of course the Earths heat

budget is not that simple!

You have to remember the

effects of seasonality

the seasonal shift in thetrace of the sun on the

Earths surface during its

orbit.


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Heat Budget in OUR SummerHeat Budget in OUR Summer

In the South

in OUR

Summer

there is a

deficit

In the North

in OUR

Summer

there is a

surplusAt the

equator

there is a

surplus


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Earths Annual Heat BudgetEarths Annual Heat BudgetSo over the pattern of a year the Earths heat budget changes

with the seasons, however there is always a surplus at theequator.

The uneven distribution of heating

across the Earth is what drives the

air to move (WIND) in an effort to

redistribute the heat to areas of

deficit.


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HOMEWORKHOMEWORK

1.1. Waugh Pg 207-210 Make Notes onWaugh Pg 207-210 Make Notes onEnergy in the atmosphere incl.Energy in the atmosphere incl.incoming / outgoing radiation & albedo.incoming / outgoing radiation & albedo.

2.2. Sketch Fig 9.4 and label.Sketch Fig 9.4 and label.3.3. Notes on Heat Budget incl transfers.Notes on Heat Budget incl transfers.

Sketch Fig 9.6 and label.Sketch Fig 9.6 and label.

4.4. Print off handout of PPt for L2 readPrint off handout of PPt for L2 readthrough and bring to next lesson.through and bring to next lesson.


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Weather Climate &Weather Climate &

Associated HazardsAssociated HazardsWhat do you

know already?What do you want

to know?What have you

learnt?

Low pressure =rain Is global warmingactually happening?

Weather shortterm changes

Why are some citiesmore windy?

Specification: Major Climate Controls

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