1. Changes in the Atmosphere
Earth Science
Chapter 11.2

2. SIX Factors to Consider
1. Temperature 2. Humidity 3. Pressure 4. Wind 5. Precipitation 6. Clouds

3. What Happens to the Sun’s Rays?
TOP OF ATMOSPHERE
What’s the Point?
IR Radiation reflected back by Earth?
CO2 gases from combustion?
TROPOSPHERE
4% Reflected by Earth’s Surface

4. What Happens to the Sun’s Rays?
6% Reflected by Atmosphere
TOP OF ATMOSPHERE
15% absorbed by Atmosphere
25% reflected back by clouds
TROPOSPHERE
4% Reflected by Earth’s Surface
50% of all rays ABSORBED by Earth
Earth

5. Warm air can hold more water vapor compared to cold air!!!!
Relative Humidity
Humidity is the amount of water vapor in the air
Relative humidity is the % of water vapor
compared to what the air can hold
Warm air can hold more water vapor compared to cold air!!!!

6. Air Pressure Pressure changes as the temperature changes:
HOT AIR rises, putting less pressure on the ground
COLD AIR sinks, adding more pressure to the ground
Pressure also changes with altitude:
pressure is low at high elevations, and vice versa

7. Effects of Pressure
High Pressure pushes air away. Wind, clouds and rain go away as air leaves the high.
Low Pressure is where the air ends up. The wind, clouds, and rain move toward the low. L H

8. WIND
Wind is the horizontal movement of air from areas of high density and high pressure to areas of low density and low pressure. Unequal heating causes these differences.
High density
High pressure
Low density
Low pressure
High density
High pressure
Low density
Low pressure

9. Types of Precipitation
Rain
Snow
Sleet
Hail

10. Largest Hailstone in US History: 8” across, 18” around, 1.94 pounds

11. Three Requirements for Clouds to Form:
1. Moisture in the air
2. Temperature drops below the dew point
3. Condensation Nuclei

12. Temperature versus Heat
Temperature is a measurement of how fast or slow molecules move
Temperature is measured in either Fahrenheit, Celsius or Kelvin
Heat is the transfer of energy from a warmer substance to a cooler substance.

13. Air Temperature and Cloud Formation
Condensation Nuclei – dust, pollen, salt or other small particles around which cloud droplets form
Dew Point – temperature at which condensation occurs
Condensation= water vapor turns into a liquid

14. Four Ways Clouds Form

15. Orographic Lifting – Warm moist air is forced up when the wind hits a mountain, then clouds form.

16. We also see how the terrain in Tahoe and Nevada is very different , due to orographic lifting

17. Clouds form when air fronts of different temperatures collide
Clouds form when air fronts of different temperatures collide. The warm air is forced up and cools, causing water vapor to condense… clouds form.

18. Types of Clouds
Clouds are classified according to the height at which they form and their shape
Height (prefix)
Shape (prefix) and Latin meaning
Cirro – high clouds
Cirrus “hair” – wispy, stringy clouds
Alto – middle clouds
Cumulus “pile or heap” – puffy clouds
Strato – low clouds
Stratus “layer” – flat, blanket like clouds
Nimbus “cloud” – low grey rain clouds

19. The Water Cycle