1 Unit 2: atmosphere

2 Earth’s atmosphere and oceans shapes our climate and weather Introduction Earth’s atmosphere and oceans shapes our climate and weather The atmosphere is complex, and in a state of dynamic balance Today, humans are altering this balance

3 The structure of the atmosphereNitrogen, oxygen, argon, & water vapor make up most of the atmosphere Trace amounts of other gases Composition and ratio of gases remain relatively constant

4 The structure of the AtmosphereEarth’s atmosphere extends 560 km above the surface 4 layers, each with different properties

5 The structure of the atmosphereTroposphere- lowest layer (8-16 km up) Most weather occurs here Warmed up from below when solar radiation heats the surface of Earth Temp decreases 6.5 degrees C per kilometer of altitude

6 The structure of the atmosphereTropopause- layer of cold air (-60 C), causes water vapor to condense Stratosphere- from tropopause to 50 km up

7 The structure of the atmosphereStratosphere- temps increase with altitude 90% of the ozone is here Not much water vapor due to tropopause Stratopause- temps peack at (-3 C)

8 The structure of the AtmosphereMesosphere- temps fall as you go up Lowest temp is -93 C at 85 km up Thermosphere- temps increase higher than 1700 C

9 The structure of the atmosphereAtmospheric pressure is greatest at sea level (14.7 lbs/in^2) Pressure decrease as you increase your altitude (less air pressing down on you)

10 Earth’s temp has remained fairly constant over time Greenhouse effect Earth’s temp has remained fairly constant over time Earth radiates energy back to space balancing energy that we receive from the sun

11 The albedo of Earth reflects some of the solar radiation back to spaceGreenhouse effect Solar radiation may be absorbed by clouds, the atmosphere, or the surface of Earth. The albedo of Earth reflects some of the solar radiation back to space

12 Some reflected energy from Earth is trapped in the atmosphereGreenhouse effect Some reflected energy from Earth is trapped in the atmosphere Greenhouse Effect Clouds, water vapor, and greenhouse gases can absorb this solar radiation

13 Greenhouse effect The greenhouse gases (carbon dioxide, methane, and nitrous oxide) radiate the energy back to Earth and warms the planet even more

14 You have a container holding 150 parts of atmospheric gas. MATH You have a container holding 150 parts of atmospheric gas. Calculate the following amounts of gases in the container

15 Nitrogen Helium Oxygen Methane Argon Nitrous Oxide Carbon Dioxidemath Nitrogen Helium Oxygen Methane Argon Nitrous Oxide Carbon Dioxide Ozone

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18 Major Greenhouse gasesGreenhouse Gas= GHG Most occur naturally in the atmosphere Some are synthetic

19 Natural sources= volcanoes, breathing, firesMajor GHGs Carbon Dioxide= CO2 GHG affected directly by humans Combustion of fuels or decay of biomass Natural sources= volcanoes, breathing, fires

20 Main sources of CO2 increaseMajor GHGs Main sources of CO2 increase Burning fossil fuels Deforestation less plant life or different plant life means the ecosystem cannot store as much carbon

21 Methane= CH4 Anaerobic decay (without oxygen)Major GHGs Methane= CH4 Anaerobic decay (without oxygen) Fermentation (farts) in ruminant animals like cattle Manure/wastewater treatment Fossil fuel combustion

22 Nitrous Oxide= N2O Fertilizer use Animal waste managementMajor GHGs Nitrous Oxide= N2O Fertilizer use Animal waste management Fossil fuel combustion Industrial activities

23 Hydrofluorocarbons (HFCs) & Perfluorocarbons (PFCs)Major GHGs Hydrofluorocarbons (HFCs) & Perfluorocarbons (PFCs) Synthetic chemicals By-product of aluminum smelting Refrigeration, air conditioners Foam-blowing insulation

24 It takes many years to notice the temp. changeMajor GHGs The increase in GHGs increases the ability of Earth’s atmosphere to trap radiant energy It takes many years to notice the temp. change Oceans can store lots of heat

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26 Vertical motion in the atmosphereMany weather patterns start with rising air Increasing the temp of air with constant pressure causes it to expand. Warmer air is less dense Less dense air is more buoyant than denser air

27 Vertical motion in the atmosphereWater is a key factor in weather/climate 1-2% of atmosphere is water vapor

28 Vertical motion in the atmosphereRelative humidity= compares amount of water vapor present to the max amount air can hold 100% relative humidity=air cannot hold any more water vapor (muggy air)

29 Vertical motion in the atmosphereAs air warms, the amount of water vapor air can hold increases. Water vapor concentrations are highest in warm regions, and lowest near the poles

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31 Vertical motion in the atmosphereAdding moisture to air makes it less dense (wet air will rise) Latent energy= moist air has the potential to warm the surrounding air when the water condenses

32 Vertical motion in the atmosphereDew point= temperature at which air would have to cool to be fully saturated (can’t hold any more water) When air cools to its dew point, clouds form and precipitation can start

33 Vertical motion in the atmosphereUnstable atmosphere is more likely to produce clouds and storms Air masses rise and form clouds if they have enough water vapor to warm them as they expand

34 Vertical motion in the atmosphereAir masses rise by: Winds pushing them up mountain ranges, cooling the air and forming clouds Convergence= air masses collide, pushing one up (thunderstorms)

35 Vertical motion in the atmosphereConvergence continued: Cold & warm front collide Cold=denser, so it sinks Warm air rises, cools, and clouds form If it is lifted fast/strong enough, you get intense storms

36 Atmospheric circulation patternsAtmospheric circulation= movement of air masses Vertical=Warm air rising=vertical horizontal-=Wind created by air moving from high to low pressure

37 Atmospheric circulation patternsIsobars= parallel lines on a weather map indicating areas of air with the same pressure

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39 Atmospheric Circulation patternsSea breezes (Day) The land heats up faster on land, air rises Warm air moves over water and cools Air of water is cooler, moves in to land

40 Atmospheric Circulation patternsSea Breeze (Night) Land cools quicker than water, cool air moves out to water Air over water warms, rises Warm air moves back over land and cools

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42 Atmospheric Circulation patternsWind over very long distances appear to curve Coriolis Fore=caused by Earth’s rotation Equator spins faster than near the poles

43 Atmospheric Circulation patternsEarth spinning causes objects on Earth to have angular momentum Objects spin faster the closer they are to the reference point Figure skater pulling in their arms

44 Atmospheric Circulation patternsSame effect on air mass going from equator to pole The closer to Earth’s reference point (the poles) the faster the air mass spins Northern hemisphere (turn right) Southern hemisphere (turn left)

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46 Atmospheric Circulation patternsCoriolis force causes hurricanes in the Northern Hemisphere to spin counterclockwise and clockwise in the Southern Hemisphere

47 Atmospheric Circulation patternsAir circulates clockwise in a high pressure system Air circulates counterclockwise in a low pressure system

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49 Atmospheric Circulation patternsAir move towards and up in low pressure systems Air move down and out of high pressure systems

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51 Atmospheric circulation patternsHadley Circulation (starting at the equator) Warm, moist air rises The warm air moves to cooler regions north or south of the equator

52 Atmospheric circulation patternsAs the air mass moves, it looses its moisture through precipitation Cool, dry air descends The air then warms and collects moisture up and along the surface Repeat

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54 Climate, Weather, and StormsWeather=atmospheric conditions at a certain place and time Climate= long-term weather trends in a specific region Climate is what you expect, weather is what you get

55 Climate, Weather, and StormsCirculation patterns create predictable climate zones 50-60 degrees north & south latitudes have lots of precipitation 30 degrees north and south latitudes are dry from descending air

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57 Climate, Weather, and StormsAir pressures increase sharply between middle latitudes (40 degrees) and the poles This causes the jet stream

58 Climate, Weather, and StormsJet stream flows west to east Transport heat as they shift north and south Jet stream bring much of the weather to our area In the winter, a dip in the jet stream from Canada brings arctic air to us

59 Climate, Weather, and StormsHurricanes Form over tropical waters (8-20 degrees latitude) Most active area is western Pacific

60 Climate, Weather, and StormsSigns of a potential hurricane Appearance of a tropical disturbance Feedback loop: falling pressure pulls more air in, making more warm air rise, releasing more pressure. Counterclockwise circulation

61 Climate, Weather, and StormsPressure near the top of the storm rises Air flows outward at the top, cools, and then drops down forming powerful winds This circulation keeps the storm strong

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63 Climate, Weather, and StormsIf hurricanes move over cooler water or land, they will diminish in size and strength

64 Global carbon cycle GHG emissions are affecting the natural carbon cycling between land, atmosphere, and oceans The rate land and ocean takes in carbon determines how much is left over in the atmosphere

65 Humans are interfering with the natural balance of the carbon cycle Global carbon cycle Humans are interfering with the natural balance of the carbon cycle Atmospheric CO2 is rising rapidly and higher than it has been in 650,000 years.

66 The oceans and land stored the restGlobal carbon cycle In recent decades, only half the CO2 added by humans stayed in the atmosphere The oceans and land stored the rest

67 On average, carbon spends this much time in :Global carbon cycle On average, carbon spends this much time in : Atmosphere=5 years Land plants=10 years Oceans=380 years Ocean sediments/fossil fuels=millions of years

68 Global carbon cycle Oceans can take in CO2, almost all in the atmosphere, but it would take 500 years Only a small portion of the ocean contacts the atmosphere

69 Photosynthesis from marine and land plants can take up CO2 Global carbon cycle Photosynthesis from marine and land plants can take up CO2 Most returns to the atmosphere later, but some is stored for a long time