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!

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.

Energy In = Energy Out 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?