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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

Q: You can live for a few minutes only: a) without air b) without water c) without food

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

AtmosphereAtmosphere• when the earth is scaled to the size of an apple, 99% of atmosphere is no thicker than the skin on an apple

• Water vapor molecules are invisible: clouds;

sink: condensation/deposition source: evaporation/sublimation transpiration

Fig.1.2

Composition of the Composition of the AtmosphereAtmosphere

permanent gasespermanent gases

• NitrogenNitrogen source: decaying of plant and animal matter source: decaying of plant and animal matter sink: soil bacteria; sink: soil bacteria; ocean planktonocean plankton

• OxygenOxygen source: plant photosynthesis (sun + COsource: plant photosynthesis (sun + CO22 + H + H22OO lead to sugar and Olead to sugar and O22)) sink: organic matter decaysink: organic matter decay breathing (take in Obreathing (take in O22, release CO, release CO22))

Table 1-1, p. 3

380 ppm = 380/106 = 380 * 10-4/102 = 0.038%

Q: which is the most important greenhouse gas in the atmosphere? a) water vapor; b) carbon dioxide; c) methane, d) ozone

Composition of the Composition of the AtmosphereAtmosphere

Carbon dioxide and the greenhouse Carbon dioxide and the greenhouse gasesgases

ozoneozone aerosolsaerosols pollutants pollutants

• Ozone at high altitudes Ozone at high altitudes (stratosphere) is “good”;(stratosphere) is “good”;

ozone at low altitudes ozone at low altitudes (troposphere) is “bad.”(troposphere) is “bad.”

Fig. 1.4Fig. 1.4

Q: List threeQ: List three

sources and sources and twotwo

sinks of COsinks of CO22 in in

the the atmosphereatmosphere

Stepped Art

Fig. 1-3, p. 4

The Early AtmosphereThe Early Atmosphere

the first atmosphere: hydrogen, the first atmosphere: hydrogen, heliumhelium

outgassing and the second outgassing and the second atmosphereatmosphere

water vapor, carbon dioxide, nitrogenwater vapor, carbon dioxide, nitrogen

evolution of the atmosphere: evolution of the atmosphere: carbon dioxide and oxygencarbon dioxide and oxygen

• The evolution of life and the atmosphere are closely The evolution of life and the atmosphere are closely linked.linked.

Vertical Structure Vertical Structure of the Earth’s of the Earth’s AtmosphereAtmosphere

Radiosonde launched twice aday to measure temperature,humidity, wind, and pressureof the lowest 30 km abovesurface

Q: where is the balloon launched in Tucson? a) airport; b) Mt. Lemmon, c) UA campus

A Brief Look at Air A Brief Look at Air Pressure and Air DensityPressure and Air Density

air density: air density: mass per unit volumemass per unit volume

air pressure: air pressure: air weight above a levelair weight above a level

sea-level pressuresea-level pressure

• Surface pressure: 1013 mb = 1013 hPa = 29.92 in.HgSurface pressure: 1013 mb = 1013 hPa = 29.92 in.Hg

Q: Baseballs travel farther in higher-altitude air (Denver)Q: Baseballs travel farther in higher-altitude air (Denver) than they do in lower-altitude air: true or false? than they do in lower-altitude air: true or false?

Fig. 1-7, p. 8

Fig. 1-8, p. 9

Q: what is the percentage of O2 at the top of Mt. Everest compared with sea level? a) 13%

b) 23% c) 33% d) 43%

Layers of the AtmosphereLayers of the Atmosphere

vertical temperature profilevertical temperature profile TroposphereTroposphere lapse rate: 6.5degC/1km;lapse rate: 6.5degC/1km;

temperature inversiontemperature inversion

StratosphereStratosphere OO33 absorption absorption

mesospheremesosphere ThermosphereThermosphere OO22 absorption absorption

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 When the radio was invented by G. Marconi in the early 20th century, it was not known how radio early 20th century, it was not known how radio waves traveled long distances through the waves traveled long distances through the atmosphere.atmosphere.

Fig. 1-11, p. 13

Weather and Weather and ClimateClimate

• Satellites• Radar• Radiosonde• Aircraft• Weather station

See ATMO web site

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 pilots.of particular interest to pilots.

ClimateClimate

average weatheraverage weather extremesextremes

Q: What is the difference between weather and climate?

A Satellite’s View of the A Satellite’s View of the WeatherWeather

geostationary satellitesgeostationary satellites• Atmospheric observation Atmospheric observation

from satellites was an from satellites was an important technological important technological development in development in meteorology. Othermeteorology. Otherimportant developments important developments include computers, internet, include computers, internet, and Doppler radar.and 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 Storms are very exciting, but they also play an important role in moving heat and moisture around important role in moving heat and moisture around throughout the atmosphere.throughout the atmosphere.

Fig. 1.17

Fig. 1.15

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.

Fig. 1-13, p. 17

Q: What is the wind direction in Chicago? a) southerly, b) northerly, c) easterly, d) westerly

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 wind

chill temperature has recently been revised due to newchill temperature has recently been revised due to newexperiments.experiments.

Fig. 1-16, p. 19

Fig. 1-18, p. 20

Fig. 1.19