Pg tp-class9, atmosphere

Physical GeographyPhysical Geography

Class 9 – Class 9 –

Earth’s AtmosphereEarth’s Atmosphere

Structure and CompositionStructure and Composition

Outline: AtmosphereOutline: Atmosphere

Definition, sizeDefinition, size

Changes in pressure, what is pressureChanges in pressure, what is pressure

Temperature layersTemperature layers

Components of clean, dry airComponents of clean, dry air

Variable ComponentsVariable Components

QuestionsQuestions

What is “air”?What is “air”?

Why does air stay where it is?Why does air stay where it is?

Is air always the same stuff no matter Is air always the same stuff no matter where you go on Earth? Up in where you go on Earth? Up in atmosphere?atmosphere?

What aspects/characteristics of air change What aspects/characteristics of air change on a daily basis? From place to place?on a daily basis? From place to place?

AtmosphereAtmosphere

Layer of gases that envelope the EarthLayer of gases that envelope the Earth

How big is the atmosphere?How big is the atmosphere?

Extends to 32,000 km (20,000 mi) from Extends to 32,000 km (20,000 mi) from surfacesurface

Thermopause is at 480 km (300 mi)—top Thermopause is at 480 km (300 mi)—top of the principal atmosphere of the principal atmosphere

100 km??100 km??

Atmospheric Atmospheric PressurePressure

Figure 3.3

Layers Layers of the of the AtmosAtmospherephere

Atmospheric TemperatureAtmospheric Temperature

TroposphereTroposphere– Surface to 18 km (11 mi)Surface to 18 km (11 mi)– 90% mass of atmosphere90% mass of atmosphere– Weather, most cloudsWeather, most clouds

Atmospheric TemperatureAtmospheric Temperature

TroposphereTroposphere– Normal environmental lapse rate – average Normal environmental lapse rate – average

cooling at rate of 6.4 C°/km (3.5 F°/1000 ft)cooling at rate of 6.4 C°/km (3.5 F°/1000 ft)– Environmental lapse rate – actual local lapse Environmental lapse rate – actual local lapse

raterate– Weather, most cloudsWeather, most clouds

Normal Environmental Lapse Rate in Normal Environmental Lapse Rate in TroposphereTroposphere

Atmospheric TemperatureAtmospheric Temperature

StratosphereStratosphere– 18 to 50 km (11 to 31 mi)18 to 50 km (11 to 31 mi)– Temperature risesTemperature rises– High, thin, ice crystal cloudsHigh, thin, ice crystal clouds– Ozone layerOzone layer

Atmospheric TemperatureAtmospheric Temperature

MesosphereMesosphere– 50 to 80 km (30 to 50 mi)50 to 80 km (30 to 50 mi)– Temperature fallsTemperature falls– Shooting “stars”Shooting “stars”

Atmospheric TemperatureAtmospheric Temperature

ThermosphereThermosphere– 80 km (50 mi) outward80 km (50 mi) outward– Temperature risesTemperature rises

Composition of AirComposition of Air

Variable Atmospheric Components  Variable Atmospheric Components  

Impurities and Pollutants in TroposphereImpurities and Pollutants in Troposphere

Harmful Gases and Other ChemicalsHarmful Gases and Other Chemicals

VirusesViruses

Water VaporWater Vapor

Carbon DioxideCarbon Dioxide

Aerosols/ParticulatesAerosols/Particulates

Aerosols and ParticulatesAerosols and Particulates

Where do small particles of Where do small particles of liquid and solids come from?liquid and solids come from?

Sources of AerosolsSources of Aerosols

Southern California WildfiresSouthern California Wildfires

Figure 3.8

USGSUSGS

Water VaporWater Vapor

Can you see this invisible gas?Can you see this invisible gas?

Variations in Atmospheric Variations in Atmospheric CompositionComposition

IonosphereIonosphere– Absorbs cosmic rays, gamma rays, X-rays, Absorbs cosmic rays, gamma rays, X-rays,

some UV rayssome UV rays

Ozonosphere (ozone layer)Ozonosphere (ozone layer)– Part of stratospherePart of stratosphere

– Ozone (OOzone (O33) absorbs UV energy and converts ) absorbs UV energy and converts

it to heat energyit to heat energy

Atmospheric Atmospheric PressurePressure

Figure 3.3

The endThe end