Atmosphere Students know the origin/effects of temperature inversions.

Earth’s Atmosphere A thin envelope of gases, aerosols, and falling precipitation

Atmospheric Gases Permanent gases: ~78% N 2 ~21% O 2 ~0.9% Ar ~0.1% Others Variable gases:H 2 0 (g), CO 2, O 3, CH 4

Proportional Volumes of Gases

Formation and Evolution of the Atmosphere 1.Earth formed ~4.6 billion years ago 2.First atmosphere likely predominantly H and He 3.Second atmosphere formed by volcanic outgassing and small comets, mostly water vapor and CO 2

4. Water cycle begins, oceans form 5. Anaerobic bacteria, primitive plants, develop and photosynthesis starts 6. O 2 replaces CO 2 7. N 2 not going anywhere in a hurry

Greenhouse Gases 1. CO 2 – Carbon Dioxide CO 2 is currently less than 0.04%, but rising. Increased CO2 due to increases in combustion combined with deforestation.

2. O 3 - Ozone Good up there, bad down here O 3 shield the earth by absorbing UV radiation. At ground level, it is a pollutant. –Chlorofluorocarbons (CFCs) break down, chlorine attack O3, get ClO 2 and an O.

3. CH 4 - Methane

Sources of methane include decomposing organic matter, coal mines, and…

cow burps and farts

Thermal Structure of the Atmosphere

Layers of the Atmosphere 1.Troposphere – bottom layer of atmosphere (where weather happens) 2.Stratosphere – where ozone layer is found – temperature inversion occurs here. 3.Mesosphere 4.Thermosphere – temperature inversion occurs here.

Temperature Inversion The laying of warm air on top of cool air. Temperature increases (warmer) as you go up in altitude. Can make air pollution worse.

Density Structure of the Atmosphere As you increase in altitude: –Density decreases –Air pressure decreases

Energy The ability to do work Work is done when something is moved Two broad categories: –Potential energy –Kinetic energy

Ch 22 Energy Transfer

Ways Energy is Transferred 1.Conduction between things that are in physical contact 2.Convection occurs within a fluid (like air) “heat rises” 3.Radiation does not require a medium

Section 2 Solar Energy and the Atmosphere Chapter 22 Conduction The transfer of energy as heat through a material –The molecules in a substance move faster when heated. –Collisions between the particles result in the transfer of energy, which warms the substance.

Section 2 Solar Energy and the Atmosphere Chapter 22 Convection The movement of matter due to differences in density that are caused by temperature variations; –The continuous cycle in which cold air sinks and warm air rises.

Radiation Radiation - all forms of energy that travel through space as waves. Radiation travels in waves at approximately 300,000 km/s.

Electromagnetic Radiation Emitted by all matter Travels at 186,000 miles per second Several categories, based on wavelength

Radiation, continued electromagnetic spectrum all of the frequencies or wavelengths of electromagnetic radiation

Section 2 Solar Energy and the Atmosphere Chapter 22 Radiation, continued The diagram below shows the the varying waves of the electromagnetic spectrum.

The Electromagnetic Spectrum

Section 2 Solar Energy and the Atmosphere Chapter 22 Absorption and Infrared Energy, continued The Greenhouse Effect greenhouse effect the warming of the surface and lower atmosphere of Earth that occurs when carbon dioxide, water vapor, and other gases in the air absorb and reradiate radiation

The Seasons NOT related to earth’s proximity to the sun Earth is closest to the sun on January 3, furthest away on July 3! Occur because the earth is tilted on its axis.

Earth orbits the sun once every 365 ¼ days. Perihelion=closest point Aphelion=furthest point

Solar Angle Beam spreading reduces intensity of solar energy

Atmospheric Beam Depletion

Effects of Latitude on Solar Angle

Section 3 Atmospheric Circulation Chapter 22 The Coriolis Effect Coriolis effect the curving of the path of a moving object from an otherwise straight path due to Earth’s rotation

Section 3 Atmospheric Circulation Chapter 22 The Coriolis Effect, continued The diagram below shows the movement of air due to the Coriolis effect.

Trade Winds prevailing winds that blow from east to west from 30º latitude to the equator in both hemispheres In Northern Hemisphere, the northeast trade winds flow from the northeast. In the Southern Hemisphere, they are the southeast trade winds. Global Wind Belts

Global Winds, continued Westerlies prevailing winds that blow from west to east between 30º and 60º latitude in both hemispheres –In this region, some of the descending air moving toward the poles is deflected by the Coriolis effect.

Section 3 Atmospheric Circulation Chapter 22 Global Winds, continued Polar Easterlies prevailing winds that blow from east to west between 60 and 90 latitude in both hemispheres Surface winds deflected by the Coriolis effect become the polar easterlies.

The Doldrums and Horse Latitudes The trade wind in Northern and Southern Hemisphere meet at the equator in a zone called the doldrums. horse latitudes - As the air approaches 30º latitude, it descends and a high-pressure zone forms. –surface winds are weak and variable in both of these zones.

Section 3 Atmospheric Circulation Chapter 22 Global Winds, continued The diagram below shows the different wind belts on Earth.