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Write down the 4 layers of the atmosphere (in order) and 1 fact about each.

Today’s agenda

• Finish ozone reading• Review atmosphere• Radiation, reflection, and absorption notes• Lab

Atmosphere

• Layer of gases that surround Earth– 78% N– 21% 0– 1% other

• Has a weight = atmospheric pressure• 4 layers of the atmosphere

Radiation

Not that kind of Radiation

• All of the energy that Earth receives from the sun travels through space between Earth and the sun as radiation

• Radiation – transfer of thermal energy from the sun in the form of waves

• Radiation travels through space in the form of waves at a very high speed—approximately 300,000 km/s

Atmosphere and Radiation• Scattering - clouds, dust, water droplets, and molecules

in the atmosphere disrupt the paths of radiation from the sun– reflect and bend rays

• This causes the rays to travel in all directions w/o changing their wavelength

• Causes sky to be blue and sunrise and sunset to appear red/orange

Reflection and Absorption

• The sun gets reflected or absorbed

• The amount of sun absorbed or reflected depends on several factors– color, texture, composition, volume, mass, angle

• The intensity and time exposed affect how much energy is absorbed or reflected

Absorption and Infrared Energy• Radiation that is not reflected is absorbed

– rocks, soil, water, and other surface materials

• Gas molecules also absorb these infrared rays– water vapor and carbon dioxide

• The absorption heats the lower atmosphere and keeps Earth’s surface much warmer than if there were no atmosphere

Greenhouse Effect

• greenhouse effect - warming of the surface and lower atmosphere of Earth when gases in the air absorb and reradiate radiation

• Earth’s atmosphere slows the escape of energy that radiates from Earth’s surface

Greenhouse Effect Illustrated

• albedo -fraction of solar radiation reflected off the surface of an object

Surface Reflected Absorbed

Dark Soil 5-10 90-95

Desert 20-40 60-80

Grass 5-25 75-95

Forest 5-10 90-95

Water (high angle

5-10 90-95

Water (low angle)

50-80 20-50

Snow 50-90 10-50

Temperature Variation

• Radiation from the sun does not heat Earth equally

• The temperature of the atmosphere in any region on Earth’s surface depends on several factors– latitude, surface features, and the time of year and day

Latitude • Latitude is the primary factor that affects the amount of

solar energy that reaches any point on Earth’s surface

• Because Earth is a sphere, the sun’s rays do not strike all areas at the same angle

• The energy that reaches the equator is more intense than the energy that strikes the poles– average temperatures are higher near the equator than near the

poles

Temperature Variation Cont.

• Amount of water in the air affects the temperature of a region– Water vapor stores heat

• Land areas close to large bodies of water generally have more moderate temperatures

• Wind patterns in an area also affect temperature