The Atmosphere

Chapter 17.1

Lesson ObjectivesIdentify the major components of Earth’s

atmosphere

Explain how air pressure changes with altitude

Explain how temperature changes with altitude

Describe the layers of the atmosphere

Explain how the processes of radiation, conduction and convection distribute energy in the atmosphere

What is Air?A mixture of gases and particles each with their own properties

Nitrogen and Oxygen make up 99% of the volume of air

Argon gas 0.93%

CO2 0.039%

Also contains: H2O vapor, ice,

dust particles, hydrogen, salt and ozone

Structure of the Atmosphere

The Atmosphere is made up of 5 different layers.

Each layer is different in composition and temperature

It is thickest near the surface of Earth and thins out with height until it eventually merges with space.

Layers of the Atmosphere-Troposphere

Closest to Earth surface

Contains most of the mass of the atmosphere

Weather takes place

Pollution collects

There is a decrease in temperature as you travel up the Troposphere Lapse Rate

The upper-limit of the Troposphere is called the Tropopause

Layers of the Atmosphere-Stratosphere

Located above the Tropopause

Made up primarily of concentrated ozone

Ozone absorbs ultraviolet radiation from the sun

So…what do you think happens here in terms of temperature?

The top of the Stratosphere is called the Stratopause

Layers of the Atmosphere-Mesosphere

Located above the Stratopause

No ozone …so what happens to the temperature?

Top of the Mesosphere is called the ……

Layers of the Atmosphere-Thermosphere

Contains only a minute portion of the atmosphere’s mass

Air that does exist in this layer increases in temperature to more than 1000°C

Ionosphere is with thermosphereNitrogen and oxygen atoms absorb harmful solar

energy…X-rays and gamma raysCauses the high temperaturesGas particles lose electrons and become ionsAuroras- Northern and Southern Lights occur

Layers of the Atmosphere-Exosphere

Outermost layer of the atmosphere

Lighter elements are found in this layer

Above the Exosphere is outer space

Solar FundamentalsThe sun is the source of all of the energy in the

atmosphere

This energy is transferred to the Earth and throughout the atmosphere by convection, conduction and radiation

Heat TransferConvection

The transfer of energy by the flow of a heated substance

Responsible for the vertical motions of air, which causes different types of weather

Works based on density

ConductionTransfer of energy that occurs when molecules

collideAffects only a very thin atmospheric layer near

Earth’s surface

Heat TransferRadiation

Transfer of energy through space by visible light, UV radiation and other forms of electromagnetic waves

Earth’s surface absorbs the solar radiation and then radiates energy with longer wavelengths, which warm the atmosphere through convection and conduction