1. The Atmosphere
APES

2. Composition of atmosphere
7 major components
Nitrogen 78%
Oxygen 21%
Water Vapor 0-4%
Carbon Dioxide <<1%
Methane <<<1%
Nitrous Oxide <<<1%
Ozone <<<1%
Nitrogen: Fundamental nutrient for living organisms. Nitrogen fixing into soils, denitrification back into air
Oxygen: Produced through photosynthesis; used in cellular respiration
Water Vapor: greater near equator, lower at poles
Carbon Dioxide: Major greenhouse gas; increased about 24% last 300 years; humans 5,500 million tons of CO2 per years; average CO2 molecule in the air for 100 years
Methane: Greenhouse gas; since 1750 methane has increased by 150%; 400 million tons/year by humans; life in atmos is 10 years
Nitrous oxide: greenhouse gas; increasing by 0.3%/year; source burning fossil fuels, fertilizers, deforestation; humans add 6 million tons/year;
Ozone: 97% found in stratosphere (ozone layer) about 9-35 miles above surface; absorbs UV radiation; “hole” occurs over Antarctica; broken down by CFCs (primary source)

3. Layers of the Atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere (ionosphere)
Troposphere: 0-7 miles: 75% of atmosphere’s mass; temperature decreases with height -76F at top; weather in this zone
Stratosphere: temperature increases with altitude because of heat absorption by ozone; contains ozone layer
Mesosphere: temp. decrease with altitude; coldest layer; ice clouds; meteors burn up here
Thermosphere or Ionosphere: Temp. increases with height due to gamma and x-rays, UV radiation; aurora borealis occur here;

4. Factors that Influence Climate
Air mass
Air pressure
Albedo
Altitude
Angle of Sunlight
Clouds
Distance to ocean
Fronts
Heat
Land (geography)
Land Changes
Latitude
Location
Humidity
Mountains
Pollution
Earth Rotation
Wind Patterns
Human Activity

5. Air Pressure Unequal heating of Earth Warm air rises – low pressure
clouds
Cool air sinks – high pressure
Clear
Wind – air movement from H – L
Coriolis pulls to right in NH

6. Global Circulation

7. Tornadoes Tornadoes Tornado Alley Windsor Tornado Fujita Scale
Average ¼ mile wide
Tornado Alley
Windsor Tornado
May 22, 2008 F3
1 Mile Wide

8. Hurricanes Most severe weather phenomenon Average size – 100 miles
Celia – 80 mile diameter
Carla – 500 mile diameter
Katrina – 240 mile diameter

9. ENSO = El Niño ENSO – El Niño Southern Oscillation
Next to the seasons, El Niño is the most powerful force driving global weather
Usually occurs in December
Dryer than normal across Pacific Northwest
Colder winters in southeast and southwest U.S.A
Effects of El Niño

11. La Niña
La Niña is characterized by unusually cold ocean temperatures in the Equatorial Pacific
Nearly opposite effects of El Nino
Wetter than normal N.W. USA
Increase in Atlantic hurricanes
Heavier than normal monsoons in India and S.E. Asia
Colder winters in Canada and N.E. USA
Warmer and drier winters in the S.W. and S.E. USA