air weather and climate chapter 17 apes march 2009
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TRANSCRIPT
Air Weather and Climate
Chapter 17
APES March 2009
What do you know about weather?
Weather vs. Climate
What is weather?
The current weather conditions
(temperature, precipitation, winds, pressure)
What is climate?
Long term weather patterns for an area
Composition and Structure of the Atmosphere
• What is it made of?
• What does it look like?
• How do we organize it?
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?
H and HE
C, N, O, S, and others added by volcanoes
Free O2 and water vapor due to PLANTS
Composition of air
Air Pressure
• What causes air pressure?
Pressure is measured in mb
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
Layers of the Atmosphere
The layers
• Take notes on the characteristics of the layers on pages 371-372
WEATHER
Driven by the sun
Global cycling of air
Creates our climate
Distributes energy and material around the world!
Electromagnetic spectrum
Solar Radiation
Why is it not the same all over?
Greenhouse effect is natural.
WE are making it stronger….
Cyclonic Storms
• Hurricanes
CLIMATE
Patterns of weather over time.
Why do Climates Change?
The Milankovitch Theory
Periodic shifts in the Earth’s orbit and tilt result in global climate change.
Evidence
El Nino
El Nino/La NinaThe 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…..
La Nina
La Nina
La Nina
La Nina effects us!
Why study this?
There is evidence these natural cycles are being disrupted/exacerbated by global climate change.
Know how these changes affect us.
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.
Human-Caused Global Change?
WHY?
Green house gas emissions
Energy Consumption
BBC SITE
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
Greenhouse GasesOther 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)
Effects of Climate Change
Effects
IS it happening?
Photographer site
Regional change
Hot spots
UCSCool fingerprints