1. Chapter
21:
The Atmosphere

2. •The atmosphere is a collection of gases that gravity holds
in a thin envelope around earth.
•

3. •The troposphere are responsible for moderating the flow
of energy to the earth. It extends up to 10 miles in the
tropics and 5 miles in higher latitudes, and contains most
of the watervapor and clouds.
•Capping the troposphere is the tropopause, and above
the tropopause is the stratosphere, a layer that increases
with altitude. It increases because of ozone.
•Beyond this stratosphere are two more layers the
mesosphere and the thermosphere.

4. Weather is the day to day variations in
temperature, air pressure, wind, humidity, and
precipitation.
Climate is the average temperature and
precipitation in a given region.
Oceans play an importante role in determining our
climate, with the ability to absorb energy.
The scientific study of the atmosphere, both
weather and climate, is meteorology.
Oceanic currents bring us the day to day changes
in our weather as they move in a general pattern of
west to east.
Conveyor system: water masses move according
to density from surface to deep oceans and back

5. •Warming process
•The greenhouse effect is the rise in temperature that the Earth experiences
because certain gases in the atmosphere (water vapor, carbon dioxide,
nitrous oxide, and methane, for example) trap energy from the sun.
•Global Cooling is the Planetary Albedo , the reflection of sunlight by clouds.
Greenhouse Gases
•Water Vapor
•Methane
•Nitrous Oxide
•CFC

6. Anthropogenic atmospheric warming vs.
Cooling

7. It is certain that levels of CO2 and the other greenhouse
gases are increasing in te troposphere as a result of human
activities.
Impacts of global warming
Rising global temperatures are linked to two major impacts:
regional climatic changes and a rise in the sea levels.
This will affect rainfall and agriculture, it will become very
evident in a few decades.
Weather change: winters in Europe, El Niño events are
becoming more frequent and intense

9. • Our Knowledge of the workings of the atmosphere has
been appallingly poor, and one consequence of that lack
of understanding is the strong possibility that UV radiation
will increase in intensity all over Earth.

10. • On penetrating the atmosphere and being
absorbed by biological tissues, UV
radiation damages protein and DNA
molecules at the surfaces of all living
things.

11. Halogens in the
Atmosphere
Chlorofluorocarbons
• Replace hydroatoms
• Gases at room temp.
• Heat transfer fluid, plastic
foams, cleaning computers
parts, pressure
• Damage ozone → Cl + CFCl
• CFCl + UV
3 2
• Cl + O3 → ClO + O2
• ClO + ClO → 2 Cl + O2

12. The Ozone “Hole.”
• Chlorine Reservoirs
• Nasa Discovery
• no “hole” yet
• consequences: arctic air spreads over muchof the
densely populated Northern Hemisphere
Controversy over
Ozone Depletion
More Ozone Depletion
Coming to Grips with
ozone Depletion