Transcript Atmospheric Heating Chapter 15 section 2

Atmospheric Heating
Chapter 15 section 2
Objectives:
 Describe what happens to solar energy that
reaches the Earth.
 Summarize the processes of radiation,
thermal conduction, and convection.
 Explain the relationship between the
greenhouse effect and global warming.
The Earth and its atmosphere are
warmed by the energy radiating
from the sun.
 It takes a little over 8 minutes for the energy
to reach your face from 149,000,000km
away!
Heat!
Energy from the sun is called
Radiation
Radiation- transfer of energy as
electromagnetic waves.
The Earth receives only about two- billionths
of the total sun’s energy.
This radiant energy drives the weather cycle
and makes the earth inhabitable.
Energy from the sun is absorbed by
the atmosphere, land, and water
and is changed into thermal energy.
 25% - scattered and reflected by the clouds
and air.
 5% - reflected by the Earth’s surface.
 50% - absorbed by Earth’s surface.
 5% - reflected by Earth’s surface.
Conduction: Energy Transfer by
Contact
Thermal Conduction- transfer of thermal
energy through a material.
 Always moves from warm to cold areas.
 When air come in direct contact with the
warm surface, thermal energy is transferred
to the atmosphere
Conduction
Convection: Energy Transfer by
Circulation
Convection- the transfer of thermal energy
by the circulation or movement liquid or
gas. Due to differences in Density!
 convection currents are created as warm
air rises and cool air sinks.
Convection
The Greenhouse Effect
and Life on Earth
The Greenhouse Effect and Life on
Earth
Greenhouse Effect: gases in the
atmosphere (H2O and CO2) absorb
thermal energy and radiate it back to
Earth.
This process functions like the glass of a
greenhouse, allowing solar energy to enter
but preventing it from escaping.
The Radiation Balance
For Earth to remain livable, the amount of
energy received from the sun and the
amount of energy returned to space must
approximately equal.
Energy In = Energy Out
Is it balancing out?!?!?
Global Warming
 The gradual increase in average global
temperatures
 Data shows that the average global temperatures
have increased in the past 100 years.
 Scientists hypothesize that greenhouse gases
may be the cause.
What would the effects be of the Greenhouse
Effect on the Earth as we know it?