1. World Geography
Ch. 3 Weather & Climate

2. Earth’s Atmosphere & Climates
The Sun plays the major role in Earth’s weather and climate.
The four main attributes affecting climate are:
the Sun
Atmospheric pressure
Wind currents
The ocean

3. Global Energy Systems Temperature – the measurement of heat energy.
Greenhouse Effect – earth’s atmosphere allows sunlight to pass through it, but when the sunlight is changed into heat energy it is trapped by the atmosphere, and this keeps the planet warm.

5. Factors Affecting Climate
SECTION 1
Factors Affecting Climate
The Sun’s Effect on Earth
The Sun’s energy reaches Earth
Half of the energy is reflected back into space or absorbed by the atmosphere.
The other half is absorbed by Earth’s surface and converted into heat energy.
The atmosphere traps this heat in a process called the greenhouse effect.
The greenhouse effect helps keep the planet warm.

6. Air Pressure & Wind
Air Pressure is the force of air around you extending from the top of the atmosphere that is constantly pushing on you
Low Pressure Areas –bring unstable weather conditions.
High Pressure Areas – bring stable, clear, dry weather.
All low-pressure centers are called cyclones.
Wind – is the horizontal flow of air.
Wind always flows from high to low pressure areas.

7. Air Pressure & Wind
Air Pressure is the force of air around you extending from the top of the atmosphere that is constantly pushing on you
Low Pressure Areas –bring unstable weather conditions.
High Pressure Areas – bring stable, clear, dry weather.
All low-pressure centers are called cyclones.
Wind – is the horizontal flow of air.
Wind always flows from high to low pressure areas.

10. 4 major air pressure zones
Equatorial low pressure – at the equator
Subtropical high pressure – equator to 30° N and equator to 30° S
Subpolar low pressure – 30° N to 60° N & 30° S to 60° S
Polar high pressure – 60° N to North Pole & 60° S to South Pole

12. Wind Systems
Prevailing Winds – Winds that usually blow from the same direction
Trade Winds –blow from the subtropical high pressure zone toward the equatorial low pressure zone. There are NE and SE Trade Winds.
Doldrums – calm areas with no prevailing winds along the equator.
Westerlies – West-to-East winds at Middle Latitudes.
Polar Winds –mainly come from the east and occur at the poles.

14. Wind Systems
Front – two air masses with very different temperatures and amounts of moisture meet. Fronts usually cause stormy weather.
Jet Stream – High speed westerly moving winds in the upper atmosphere. Not felt directly, but they move major weather patterns.

15. Ocean Circulation
Ocean Currents – occur from the prevailing winds blowing across the surface of the ocean

16. El Nino
El Nino: The warming of the waters off the west coast of South America and is a natural change in the climate.
About every 2 – 7yrs the easterly winds will slow or reverse direction, changing the ocean temperature and thus affecting the weather world wide.

18. Water & the Atmosphere
Evaporation – process where water is changed to gas
Humidity – amount of water vapor in the air
Condensation – process by which water vapor changes from a gas into a liquid
Precipitation – Rain (condensed droplets become large and fall)

19. Weather Factors SECTION 2 Formation of Precipitation evaporation
humidity
Condensation clouds, dew, fog, frost
rain
snow
sleet
hail

20. Elevation & Temperature
Orographic Effect – Air comes off the ocean and hits the mountains. It is forced to rise and it cools and condensation begins. This results in rain or snow
Rain Shadow Effect – Deserts form on the side of the mountain away from the wind, because areas in the rain shadow do not receive much rain

21. Orographic & Rain Shadow Effect

22. The 12 types of climate regions
Tropical humid
Tropical wet and dry
Arid
Semiarid
Mediterranean
Humid Subtropical
Marine West Coast
Humid Continental
Sub artic
Tundra
Ice Cap
Highland

23. Climate and Vegetation Patterns
SECTION 3
Climate and Vegetation Patterns
Tropical humid climate
Tropical wet and dry climates
close to equator
warm temperatures, rainfall all year
receives Sun’s rays directly all year
rising warm, unstable air
monsoons
north and south of tropical humid
seasonal change in how Sun’s rays hit Earth
alternating wet and dry seasons
savannas

24. Global Warming
Global Warming and to the extent in which it is occurring is often a topic of controversy
However scientists have documented a rise of 1 degree and suggest that the increase will reach 3.5 degrees.

25. Two Different Points of View
Earth’s Natural Warming and Cooling Cycles
Greenhouse effect
Warming and cooling cycles
These scientist point to our past periods of cold and hot. When the glaciers advanced and retreated shaping our current landscapes.
Other scientist argue that the layer of gases released from the burning of coal and petro traps solar energy causing higher temperatures in the same way a greenhouse traps solar energy.