1. The Atmosphere
Preview
Section 2 Atmospheric Heating
Concept Mapping

2. Energy in the Atmosphere
Section 2 Atmospheric Heating
Energy in the Atmosphere
Radiation: Energy Transfer by Waves
The Earth receives energy from the sun by radiation.
Radiation is the transfer of energy as electromagnetic waves.
Not all of the radiation from the sun reaches Earth’s surface. Much of it gets absorbed by the atmosphere.
As solar energy is absorbed by air, water, and land, it turns into heat energy. This energy causes winds, the water cycle, ocean currents, and changes in the weather.
Some of the radiation is scattered and reflected by clouds and gases.

3. Energy in the Atmosphere
Section 2 Atmospheric Heating
Energy in the Atmosphere
Conduction: Energy Transfer by Contact
Thermal conduction is the transfer of thermal energy through a material.
It is always transferred from warm to cold areas.
Convection: Energy Transfer by Circulation
Convection is the transfer of thermal energy by the circulation or movement of a liquid or gas.
As air warms it becomes less dense and rises. As air cools, it becomes more dense and sinks. This cycle of warm air rising and cool air sinking causes a circular movement of air called a convection current.

4. Section 2 Atmospheric Heating

5. Energy in the Atmosphere, continued
Section 2 Atmospheric Heating
Energy in the Atmosphere, continued
The Greenhouse Effect and Life on Earth
Earth’s atmosphere acts like the walls of a greenhouse which allow solar energy to enter but prevents thermal energy from escaping.
Sunlight travels through the atmosphere easily, but heat does not.
Gases in the atmosphere absorb heat energy coming from Earth then radiate it back to Earth’s surface warming the planet.
This process is known as the greenhouse effect.

7. Section 2 Atmospheric Heating

8. Energy in the Atmosphere, continued
Section 2 Atmospheric Heating
Energy in the Atmosphere, continued
The Radiation Balance: Energy In, Energy Out
The amount of energy Earth receives and the amount of energy returned to space must be approximately equal.
Greenhouse Gases and Global Warming
Some scientists think that an increase of greenhouse gases in the atmosphere may be the cause of global warming.

9. Section 2 Atmospheric Heating
Energy In = Energy Out