1. Distributing the Sun’s Heat - WIND
RULE #2 OF NATURE – Nature seeks balance (equilibrium)
Create Wind is the movement
of air from High pressure to Low pressure
HOT
air
RISES
COLD
air
SINKS

2. Precipitation – Nature’s Thermostat
There are 3 basic causes for rain. They are:
Convection – due to evaporation and cooling
Sun’s energy causes surface water to evaporate and become humidity
As the day cools off, the air cools and condenses, causing storms and rain
Usually in tropical environments

3. Precipitation Frontal – due to changes in temperature
Starts with warm, moist air at the surface and above
As a cold front approaches, it stays low, forcing the moist air aloft
This cools and condenses the air, creating rain on the “leading edge” of the front
Usually in mid-latitudes where warm and cold air systems collide

4. Precipitation cont. Orographic – due to changes in elevation
Moist air travels over land and approaches a steep rise in elevation
As the air is forced up the side of the rise, the air cools, causing precip. on the “windward” side of the mountain
As the (now dry) air continues over and down the “leeward” side of the mountain, it warms up and absorbs any available moisture, creating a “rain shadow desert”
Found in areas of mountains or other rapid elevation change

5. Latitude
Due to the Earth’s tilt, the amount of sun energy changes over the earth’s surface…
Polar (High Latitude) zone – either mild temps. or extreme cold
Temperate (Mid-Latitude) zone – seasonal, most varied climates
Tropical (Low Latitude) zone – year-round direct sunlight, always hot
RULE: The HIGHER the latitude, the COLDER the temps.

6. Altitude (Elevation)
Higher elevation = thinner less air, therefore less air to hold heat makes it colder.
RULE – The HIGHER the elevation, the COLDER the temperatures.

8. 30 degree change in Houston 45 degree change in Denver
Nearness to Water
Land heats up and cools down QUICKLY.
Water heats up and cools down SLOWLY.
Therefore, water acts like a blanket… holding heat and releasing it slowly.
This results in smaller daily and seasonal temperature changes near large bodies of water.
“Coastal” areas are humid, “continental” areas are dry
30 degree change in Houston
45 degree change in Denver

9. Direction of Currents
Global wind and ocean currents transfer heat and moisture around the world, and help carry moisture from the oceans to the land
Warm water moving toward the land brings moisture (H2O)
Warm water moving parallel to the coast brings heat, no H2O
Cool water brings cool, dry air -> mild or desert climates

10. Reading check
How do humans impact the atmosphere and how does this affect our lives?

11. Climate Zones
Climate zones are divided into regions: The three climate zones of the world are the tropical zone, the temperate zone, and the polar zone.
There are two key characteristics differences:
Amount of moisture (rain), and
Typical temperature range through the year
These two characteristics are affected by balancing the effects of four factors:
Latitude
Altitude
Nearness to water
Direction of atmosphere and ocean currents

12. How it Works... Tropical Wet Climate
Latitude – in the tropics HOT
Altitude – low land doesn’t stop air flow until mtns. in the west
Nearness – flat land “acts coastal”, allows moisture inland
Direction – air flow
brings in warm, moist air
from the ocean which then hits the mountain and rains

13. The Tropical Zone
Figure 1 Biomes of the Tropical Zone
                                          

14. Temperate and Polar Zones

15. Temperate and Polar Zones

16. Why are there different climates on the earth? Explain with details.
Reading check
Why are there different climates on the earth? Explain with details.

17. Student led closing
The arrows in the cross section below show winds moving across northern New York State into Vermont during the summer.
Compared to the climate of location A, the climate of location B is… Why?
a. warmer and wetter c. cooler and drier
b. cooler and wetter d. warmer and drier
The map shows an imaginary continent on Earth. Arrows represent wind direction. Letters A through D represent locations on the continent. Locations A and B are at the same latitude and at the same elevation at the base of the mountains.
The climate at location C is much drier than at location D. This difference is best explained by the fact that location C is located….
a. at a latitude that experiences longer average annual daylight
b. at a latitude where air is sinking and surface winds diverge
c. farther from any mountain range
d. closer to a large body of water
ANSWER:  B