1. WEATHER & CLIMATE Atmosphere Composition: - 78% Nitrogen - 21% Oxygen
- Also contains:
water vapor
carbon dioxide
ozone

2. Atmosphere Structure * Air pressure and temperature decrease
with height.
Temperature Layers
1) Thermosphere- hottest layer (top)
2) Mesosphere- coldest layer
3) Stratosphere- contains ozone
4) Troposphere- weather occurs (bottom)

3. Atmospheric Layers

4. Weather Air Mass - area of atmosphere with a consistent temp.
and humidity
Front
- boundary between different air masses
example
Warm Front- warm air rises above cold air mass
- causes clouds & rain
Cold Front- cold air replaces a warm air mass
- causes larger thunderstorms

5. Cool
air mass
Warm air mass
Anvil top
Warm air mass
Cool air mass

6. Pressure Systems Highs - descending air that pushes outwards
- causes fair weather
- rotates clockwise in the north hemisphere
Lows
- rising air that moves outwards
- causes rain & storms
- rotates counterclockwise in the north hem.

9. Climate Coriolis Effect - determined by average temp. & precipitation
- caused by:
1) Uneven heating (equator vs. poles)
2) Earth’s tilt (seasonal changes)
3) Earth’s rotation (deflects winds circulating air)
Coriolis Effect

10. Uneven Heating

11. (sun aims directly at equator)
23.5º
Spring
(sun aims directly
at equator)
Winter
(northern hemisphere
tilts away from sun)
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Fall
(sun aims directly at equator)

12. Climate is also affected by:
4) Ocean Currents
- movements of the ocean bring warm/cold water
towards continents
- ocean temperature influences overall climate
Example
-Gulf Stream- brings up warm water
-Upwelling- warm water moves out, cold water
rises up taking its place
-El Nino- calming of winds that cause upwelling

13. Polar (ice)
Warm temperate
Highland
Warm ocean current
Cold ocean current
Subarctic (snow)
Dry
Major upwelling zones
Cool temperate
Tropical
River

14. 5) Greenhouse gases - gases that reflect Earth’s rising surface heat - natural process that keeps the Earth warm - key gases: water vapor, carbon dioxide, methane, nitrous oxide, CFC’s - creates the Greenhouse Effect - also aided by ozone in the stratosphere - blocks UV radiation - creates a thermal protection from hot gases high in the atmosphere

15. 6) Topography (Earth’s surface)
Land Breeze
- at night, land cools moving air away from land.
Sea Breeze
- during day, land heats moving air to the land.

16. - creation of rain on windward side of a mountain,
Rain shadow effect
- creation of rain on windward side of a mountain,
drying the air on the leeward side.

17. Rainshadow Effect in the Western U.S.

18. Microclimates
Local climatic conditions that may be different from the general climate of the region
Influenced by
Topography
Wind direction
Cities
Large bodies of water