1. Characteristics of the Atmosphere Chapter 22.1

2. Atmosphere  Layer of gases that surrounds Earth  Most abundant gases are Nitrogen and Oxygen  Other Gases: Argon, Carbon Dioxide, Water Vapor  In addition gases, the atmosphere commonly carries various kinds of tiny solid particles, such as dust and pollen.

3. Air  what humans and animals breathe to survive  Goes up to 80 Km above the Earths surface  Made mostly of Nitrogen, Carbon Dioxide and Water Vapor

4. Nitrogen in the atmosphere  78% of the atmosphere is Nitrogen Gas (N 2 )  Maintained through the Nitrogen Cycle.

5. Oxygen and Carbon Dioxide in the Atmosphere  21% of Earth’s atmosphere is oxygen. (O 2 ) .035% of Earth’s atmosphere is CO 2  O 2 and CO 2 are maintained in the atmosphere by the Carbon Cycle.

6. Ozone  Ozone is another form of oxygen (O 3 )  Forms the ozone layer which absorbs harmful ultra violet light from the sun  Human activities are weakening and creating holes in the ozone layer.  file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec02/vc04/hq622_02_v04fs.htm file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec02/vc04/hq622_02_v04fs.htm file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec02/vc04/hq622_02_v04fs.htm

7. Atmospheric Pressure  Gravity holds the gases of the atmosphere near Earth’s surface.  The air molecules are compressed together and exert force on Earth’s surface.  Atmospheric pressure is exerted equally in all directions—up, down, and sideways.

8.  Because the pull of gravity is not as strong at higher altitudes, the air molecules are farther apart and exert less pressure on each other at higher altitudes.  Thus, atmospheric pressure decreases as altitude increases  Meteorologists measure atmospheric pressure by using an instrument called a barometer.  file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec01/vc04/hq622_01_v04fs.htm file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec01/vc04/hq622_01_v04fs.htm file:///B:/Earth%20Science/Earth%20Science%20Resourse/Visual%20Co ncepts%20CD/student/ch22/sec01/vc04/hq622_01_v04fs.htm

9. Layers of the Atmosphere

10. Patterns  There is a pattern of temperature changes with increasing altitude (height)  Comes from how solar energy is being absorbed  Scientists identify four main layers of the atmosphere based on these differences.

11. The Troposphere  Closest to Earth’s surface  Where weather occurs  Contains most of the atmospheric water vapor and carbon dioxide  Temp. decreases as altitude increases  Outer boundary is called tropopause where temperature stops decreasing.

12. The Stratosphere  Above tropopause up to about 50 Km  Almost all ozone is found here  Lower stratosphere is about -60°C  Temperature increases as altitude increases because air is heated from above by absorption of solar radiation by ozone.  Stratopause is upper boundary about 0°C

13. The Mesosphere  Above stratosphere  Goes from 50Km to 80 Km  Temperature decreases as altitude increases.  Upper boundary is called mesopause and has average temp of -90°C  Coldest temperature in the atmosphere

14. The Thermosphere  Above mesopause  Temp increases as altitude increases because nitrogen and oxygen atoms absorb the solar radiation.  Lower region, 80Km-400 Km= ionosphere. Auroras occur here.  Outer region is called the exosphere, extends thousands of kilometers above Earth.

15. The diagram below shows the different layers of the atmosphere

16. Temperature Inversions  Any substance in the atmosphere that is harmful to people, animals, plants, or property is called an air pollutant.  Today, the main source of air pollution is the burning of fossil fuels, such as coal and petroleum.  Certain weather conditions can make air pollution worse.  file://B:/Earth%20Science/Earth%20Science%20Resourse/Visual %20Concepts%20CD/student/ch22/sec01/vc07/hq622_01_v07fs. htm file://B:/Earth%20Science/Earth%20Science%20Resourse/Visual %20Concepts%20CD/student/ch22/sec01/vc07/hq622_01_v07fs. htm file://B:/Earth%20Science/Earth%20Science%20Resourse/Visual %20Concepts%20CD/student/ch22/sec01/vc07/hq622_01_v07fs. htm