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Air Weather and Climate Chapter 17 APES March 2009
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What do you know about weather?
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Weather vs. Climate What is weather? The current weather conditions (temperature, precipitation, winds, pressure) What is climate? Long term weather patterns for an area
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Composition and Structure of the Atmosphere What is it made of? What does it look like? How do we organize it?
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History of the air We are unique as a planet: we have an atmosphere! What does that do for us? Have we always had an atmosphere? How did we get one?
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H and HE
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C, N, O, S, and others added by volcanoes
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Free O2 and water vapor due to PLANTS
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Delicate balance: carbon levels
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Composition of air
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Air Pressure What causes air pressure?
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Pressure is measured in mb
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Pressure Sea level: 1000mb (14.5 lbs/square inch) 8,850 feet Above sea level: 500 mb 12,500 feet Above sea level: 0 mb
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Layers of the Atmosphere
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The layers Take notes on the characteristics of the layers on pages 371-372
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WEATHER Driven by the sun Global cycling of air Creates our climate Distributes energy and material around the world!
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Electromagnetic spectrum
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Solar Radiation
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Why is it not the same all over?
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Greenhouse effect is natural.
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WE are making it stronger….
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Cyclonic Storms Hurricanes
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Cyclonic Storms Tornadoes
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CLIMATE Patterns of weather over time.
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Why do Climates Change? The Milankovitch Theory Periodic shifts in the Earth’s orbit and tilt result in global climate change.
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Evidence
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El Nino
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El Nino/La Nina The El Nino Southern Oscillation Every three to 5 years, El Nino occurs. In between years are called El Nina. El Nino: Indonesian Low collapses and warm surface water surges across the Pacific. Several theories why: trade winds shifting, ocean currents changing…..
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La Nina
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La Nina effects us!
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Why study this? There is evidence these natural cycles are being disrupted/exacerbated by global climate change. Know how these changes affect us.
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Pacific Decadal Oscillation (PDO) The change in location of the cold and warm water masses alters the path of the jet stream. Put simply, the jet stream in the northern hemisphere delivers storms across the United States. The PDO phase that we appear to have entered will act to steer the jet stream further north over the Western United States.
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Human-Caused Global Change? WHY? Green house gas emissions Energy Consumption BBC SITE
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Greenhouse Gases Carbon dioxide (absorbs IR radiation and warms surface air) Human Activities that release this gas: Burning fossil fuels, making cement, burning biomass How is it taken up by nature? Terrestrial ecosystems, absorbed by oceans
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Greenhouse Gases Other gases include: Methane (released by rice patties, coal mines, ruminant animals, landfills, pipeline leaks) Chlorofluorocarbons (regulated in our country, but still a problem) Nitrous oxide (Burning organic material and dentrification) Sulfur hexafluoride (electrical insulation, magnesium production, and medical inhalers)
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Effects of Climate Change
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Effects
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IS it happening? Photographer site Regional change Hot spots UCS Cool fingerprints
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