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Chapter 1: The Earth’s Atmosphere Overview of the Earth’s atmosphere Overview of the Earth’s atmosphere Vertical structure of the atmosphere Vertical structure of the atmosphere Weather and climate Weather and climate Q: You can live for a few minutes only: a) without air b) without water c) without food 2

Overview of the Earth’s Atmosphere 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 (through vegetation roots) 3

Composition of the Atmosphere permanent gases permanent gases Nitrogen Nitrogen source: decaying of plant and animal matter source: decaying of plant and animal matter sink: soil bacteria; sink: soil bacteria; ocean plankton ocean plankton Oxygen Oxygen source: plant photosynthesis (sun + CO 2 + H 2 O source: plant photosynthesis (sun + CO 2 + H 2 O lead to sugar and O 2 ) lead to sugar and O 2 ) sink: organic matter decay sink: organic matter decay breathing (take in O 2, release CO 2 ) breathing (take in O 2, release CO 2 ) Q: which one is larger between the production and destruction rates: a) production; b) destruction; c) equal rates: a) production; b) destruction; c) equal 4

380 ppm = 380/10 6 = 380 * /10 2 = 0.038% Q: which is the most important greenhouse gas in the atmosphere? a) carbon dioxide; b) water vapor; c) methane, d) ozone 5

Composition of the Atmosphere Carbon dioxide and the greenhouse gases Carbon dioxide and the greenhouse gases ozone ozone aerosols aerosols pollutants pollutants Ozone at high altitudesOzone at high altitudes (stratosphere) is “good”; ozone at low altitudes (stratosphere) is “good”; ozone at low altitudes (troposphere) is “bad.” (troposphere) is “bad.” 6

Q: List three sources and two sinks of CO 2 in the atmosphere Q: why is the global CO 2 concentration is lower in summer than in winter? 7

The Early Atmosphere the first atmosphere: hydrogen, helium (most abundant gases found in the universe) the first atmosphere: hydrogen, helium (most abundant gases found in the universe) the second atmosphere through outgassing from the hot interior (via volcanoes and steam vents): water vapor, carbon dioxide, nitrogen the second atmosphere through outgassing from the hot interior (via volcanoes and steam vents): water vapor, carbon dioxide, nitrogen evolution of the atmosphere: evolution of the atmosphere: water vapor leads to oceans (via precipitation); water vapor leads to oceans (via precipitation); carbon dioxide is dissolved in oceans; carbon dioxide is dissolved in oceans; nitrogen is not active chemically; nitrogen is not active chemically; water vapor is splitted (by energetic rays from the sun) water vapor is splitted (by energetic rays from the sun) into oxygen and hydrogen (and hydrogen escapes) into oxygen and hydrogen (and hydrogen escapes) The evolution of life and the atmosphere are closely linked.The evolution of life and the atmosphere are closely linked. 8

Vertical Structure of the Earth’s Atmosphere Rawinsonde is launched twice a day to measure temperature, humidity, wind, and pressure of the lowest 30 km above Surface. It is called radiosonde if wind is not measured. Q: where is the balloon launched in Tucson? a) airport; b) Mt. Lemmon, c) UA campus Q: balloon is released at 00:00 UT (or GMT). What is the Tucson time? a) 5am, b) 3pm, c) 5pm 9

A Brief Look at Air Pressure and Air Density air density: mass per unit volume air density: mass per unit volume air pressure: air weight (mass times gravity) above a level air pressure: air weight (mass times gravity) above a level sea-level pressure sea-level pressure Surface pressure: 1013 mb = 1013 hPa = in.HgSurface pressure: 1013 mb = 1013 hPa = in.Hg Q: Baseballs travel farther in higher-altitude air (e.g., in Denver) than they do in lower-altitude air. This Denver) than they do in lower-altitude air. This statement is: a) true; b) false, c) undecided. statement is: a) true; b) false, c) undecided. 10

Ps =14.7 psi =1013 hPa Q: what is the typical tire pressure of your car? a) 1Ps; c) 2Ps; c) 3Ps 11

Q: what is the percentage of O 2 at the top of Mt. Everest relative to the sea level value? a) 13% b) 23% c) 33% d) 43% 12

Layers of the Atmosphere vertical temperature profile vertical temperature profile Troposphere Troposphere lapse rate: 6.5 o C/1km; lapse rate: 6.5 o C/1km; temperature inversion temperature inversion Stratosphere Stratosphere O 3 absorption O 3 absorption mesosphere mesosphere Thermosphere Thermosphere O 2 absorption O 2 absorption 13

The Ionosphere electrified regions of the atmosphere: with large concentrations of ions and free electrons. Ions are atoms and molecules that have lost or gained electrons. electrified regions of the atmosphere: with large concentrations of ions and free electrons. Ions are atoms and molecules that have lost or gained electrons. D, E and F regions D, E and F regions radio waves radio waves When the radio was invented by G. Marconi in the early 20th century, it was not known how radio waves traveled long distances through the atmosphere.When the radio was invented by G. Marconi in the early 20th century, it was not known how radio waves traveled long distances through the atmosphere. 14

AM radio travels farther at night than during the day 15

Weather and Climate Satellites Radar Radiosonde Aircraft Weather station See ATMO web site 16

Elements of Weather air temperature air temperature air pressure air pressure humidity humidity clouds clouds precipitation precipitation visibility visibility wind wind Certain weather elements, like clouds, visibility and wind, are of particular interest to pilots.Certain weather elements, like clouds, visibility and wind, are of particular interest to pilots. 17

Climate Statistics of weather, such as Statistics of weather, such as mean values; mean values; mean variations (e.g., seasonal cycle); mean variations (e.g., seasonal cycle); extremes extremes Q: A city’s maximum temperature is 105 o F. This information is related to: a) weather; b) climate; c) neither; d) either. Q: Today’s maximum temperature is 75 o F. This information is related to: a) weather; b) climate; c) neither; d) either. 18

A Satellite’s View of the Weather geostationary satellites geostationary satellites Atmospheric observation from satellites is an important technological development in meteorology. Other important developments include computers, internet, and Doppler radar.Atmospheric observation from satellites is an important technological development in meteorology. Other important developments include computers, internet, and Doppler radar. visible band visible band 19

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Storms of all Sizes midlatitude cyclonic storms midlatitude cyclonic storms hurricanes and tropical storms hurricanes and tropical storms thunderstorms thunderstorms tornadoes tornadoes Storms are very exciting, but they also play an important role in moving heat and moisture around throughout the atmosphere.Storms are very exciting, but they also play an important role in moving heat and moisture around throughout the atmosphere. Q: based on prior slide, which system is larger? a) midlatitude cyclonic storm; b) hurricane a) midlatitude cyclonic storm; b) hurricane 21

Doppler radar 22

A Look at a Weather Map wind speed and direction wind speed and direction cyclones and anticyclones cyclones and anticyclones fronts fronts Wind direction is defined in the opposite way as ocean currents: a southerly current means water is moving towards the south.Wind direction is defined in the opposite way as ocean currents: a southerly current means water is moving towards the south. 23

Q: What is the wind direction in Chicago? a) southerly, b) northerly, c) easterly, d) westerly 24

Weather and Climate in our Lives wind chill, frostbite and hypothermia wind chill, frostbite and hypothermia heat exhaustion and heat stroke heat exhaustion and heat stroke cold spells, dry spells and heat waves cold spells, dry spells and heat waves severe thunderstorms and flash floods severe thunderstorms and flash floods The mathematical formula for determining the wind chill temperature has recently been revised due to new experiments.The mathematical formula for determining the wind chill temperature has recently been revised due to new experiments. 25

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Ice storm caused utility poles and power lines to be weighed down, forcing road closure. 27

Tucson, AZ 28