Chapter 1: The Chapter 1: The Earth’s Earth’s

AtmosphereAtmosphere Overview of the Earth’s atmosphereOverview of the Earth’s atmosphere Vertical structure of the Vertical structure of the

atmosphereatmosphere Weather and climateWeather and climate

Overview of the Overview of the Earth’s Earth’s

AtmosphereAtmosphereThe atmosphere, when scaled to the size of an apple, is no thicker than the skin on an apple

Composition of the Composition of the AtmosphereAtmosphere

permanent gasespermanent gases

variable gasesvariable gases• Roles of nitrogen and oxygenRoles of nitrogen and oxygen

• role of water vaporrole of water vapor

Composition of the Composition of the AtmosphereAtmosphere

Carbon dioxide and the greenhouse Carbon dioxide and the greenhouse gasesgases

ozoneozone aerosolsaerosols pollutantspollutants

• Ozone at high altitudes (stratosphere) is “good”;Ozone at high altitudes (stratosphere) is “good”; ozone at low altitudes (troposphere) is “bad” ozone at low altitudes (troposphere) is “bad”

The early atmosphereThe early atmosphere

the first atmospherethe first atmosphere outgassing and the second outgassing and the second

atmosphereatmosphere evolution of the atmosphere: carbon evolution of the atmosphere: carbon

dioxide and oxygendioxide and oxygen

• the evolution of life and the atmosphere are closely linkedthe evolution of life and the atmosphere are closely linked

Vertical structure Vertical structure of the Earth’s of the Earth’s AtmosphereAtmosphere

A brief look at air A brief look at air pressure and air densitypressure and air density

air densityair density air pressureair pressure sea-level pressuresea-level pressure

• baseballs travel farther in higher-altitude air (Denver)baseballs travel farther in higher-altitude air (Denver)than they do in lower-altitude air.than they do in lower-altitude air.

Layers of the atmosphereLayers of the atmosphere

vertical temperature profilevertical temperature profile tropospheretroposphere stratospherestratosphere mesospheremesosphere thermospherethermosphere

• temperatures, winds, humidity and pressures high abovetemperatures, winds, humidity and pressures high abovethe ground are measured twice-daily by the ground are measured twice-daily by radiosonderadiosonde

The ionosphereThe ionosphere

electrified regions of the atmosphereelectrified regions of the atmosphere D, E and F regionsD, E and F regions radio wavesradio waves

• when the radio was invented by G. Marconi in the earlywhen the radio was invented by G. Marconi in the early20th century, it was not known how radio waves traveled20th century, it was not known how radio waves traveledlong distances through the atmosphere.long distances through the atmosphere.

Weather and Weather and climateclimate

Elements of weatherElements of weather

air temperatureair temperature air pressureair pressure humidityhumidity cloudsclouds precipitationprecipitation visibilityvisibility windwind

• certain weather elements, likecertain weather elements, likeclouds, visibility and wind, areclouds, visibility and wind, areof particular interest to pilotsof particular interest to pilots

ClimateClimate

average weatheraverage weather extremesextremes

A satellite’s view of the A satellite’s view of the weatherweather

geostationary satellitesgeostationary satellites

• Atmospheric observation from satellites was an importantAtmospheric observation from satellites was an importanttechnological development in meteorology. Othertechnological development in meteorology. Otherimportant developments include computers, internet, andimportant developments include computers, internet, andDoppler radar.Doppler radar.

Storms of all sizesStorms of all sizes

midlatitude cyclonic stormsmidlatitude cyclonic storms hurricanes and tropical stormshurricanes and tropical storms thunderstormsthunderstorms tornadoestornadoes

• Storms are very exciting, but they also play an importantStorms are very exciting, but they also play an importantrole in moving heat and moisture around throughout therole in moving heat and moisture around throughout theatmosphereatmosphere

A look at a weather mapA look at a weather map

wind speed and directionwind speed and direction cyclones and anticyclonescyclones and anticyclones frontsfronts

• wind direction is defined in the opposite way aswind direction is defined in the opposite way asocean currents: a southerly current means water is ocean currents: a southerly current means water is moving moving towardstowards the south. the south.

Weather and climate in Weather and climate in our livesour lives

wind chill, frostbite and hypothermiawind chill, frostbite and hypothermia heat exhaustion and heat strokeheat exhaustion and heat stroke cold spells, dry spells and heat cold spells, dry spells and heat

waveswaves severe thunderstorms and flash severe thunderstorms and flash

floodsfloods• the mathematical formula for determining the windthe mathematical formula for determining the windchill temperature has recently been revised due to newchill temperature has recently been revised due to newexperiments.experiments.