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The Atmosphere. The Atmosphere. Weather and Climate Atmospheric Composition Atmospheric Structure Energy, Heat, & Temperature Review of Earth-Sun Relationships Incoming Solar Radiation Atmospheric Heating What Controls Air Temperature? World Temperature Distribution. Terms. Weather - PowerPoint PPT Presentation
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The Atmosphere
The Atmosphere
• Weather and Climate• Atmospheric Composition• Atmospheric Structure• Energy, Heat, & Temperature• Review of Earth-Sun Relationships• Incoming Solar Radiation• Atmospheric Heating• What Controls Air Temperature?• World Temperature Distribution
Terms• Weather
– Short-term conditions; change often
• Climate– Long-term composite of weather conditions; changes
more slowly
• Albedo– How reflective a surface is; higher albedo=more
reflective
Terms• Ozone
– O3 molecules; shield Earth from UV rays
• Climate proxy– Way of measuring climate conditions before
records were kept– Ice cores, deep ocean sediments, others
Weather and Climate
PSCI 131: The Atmosphere
Weather and Climate
• Weather: short-term condition; local
• Climate: long-term conditions; regional or global
PSCI 131: The Atmosphere
Weather and Climate
PSCI 131: The Atmosphere
Weather data Climate data
Atmospheric Composition
PSCI 131: The Atmosphere
Major ComponentsPSCI 131: The Atmosphere: Composition
• Don’t vary significantly
Variable ComponentsPSCI 131: The Atmosphere: Composition
• Vary by location and over time
• Three important ones:– Water vapor– Aerosols– Ozone
Variable Components: Water vaporPSCI 131: The Atmosphere: Composition
• Clouds, precipitation
• Greenhouse gas (traps heat)
• State changes absorb or release energy
Variable Components: AerosolsPSCI 131: The Atmosphere: Composition
• Suspended solid or liquid particles
• Dust, pollen, liquid water, bacteria, etc.
• Refract light, give sky its color
Variable Components: OzonePSCI 131: The Atmosphere: Composition
• O3 molecules
• Absorbs UV radiation
• Concentrated in “ozone layer”
Atmospheric Structure
PSCI 131: The Atmosphere
PressurePSCI 131: The Atmosphere: Structure
• Weight of air over a given location
• Decreases with increasing altitude
• 50% of atmosphere’s mass concentrated in lowest 4 miles (out of 90+ miles)
Pressure
PSCI 131: The Atmosphere: Structure
World-record parachutists• Kittinger
– 1960– 19 miles– 614 mph max speed
• Baumgartner– 2012– 24 miles– 843 mph max speed
PSCI 131: The Atmosphere: Structure
Temperature-based StructurePSCI 131: The Atmosphere: Structure
• Four temperature-based layers– Troposphere (lowest)– Stratosphere– Mesosphere– Thermosphere (highest)
Temperature-based Structure
PSCI 131: The Atmosphere: Structure
Energy, Heat, & Temperature
PSCI 131: The Atmosphere
Heat Energy
PSCI 131: The Atmosphere: Energy, Heat, Temperature
• Drives atmospheric activity
• Creates “weather”
• Moves from hotter to cooler
Heat TransferPSCI 131: The Atmosphere: Energy, Heat, Temperature
Earth-Sun Relations (review)
PSCI 131: The Atmosphere
PSCI 131: The Atmosphere: Earth-Sun Relations
PSCI 131: The Atmosphere: Earth-Sun Relations
Incoming Solar Radiation
PSCI 131: The Atmosphere
Incoming Solar Radiation
• Atmosphere can do three things to solar energy:– Reflection
• Albedo: % of incoming energy that is reflected
– Scattering– Absorption
• All three keep energy from reaching surface
PSCI 131: The Atmosphere
PSCI 131: The Atmosphere: Incoming Solar Radiation
100 % Incoming
Absorbed: 50% land/sea, 20% atmosphere
Reflected: 5% land/sea, 20% clouds
Scattered: 5% atmosphere
Atmospheric Heating
PSCI 131: The Atmosphere
The Greenhouse Effect
PSCI 131: The Atmosphere: Atmospheric Heating
1) Short-wavelength (light) energy absorbed by surface. 2) Energy re-radiated at longer wavelengths (heat) by surface. 3) Greenhouse gases absorb heat, re-radiate it again.
What Controls Air Temperature?
PSCI 131: The Atmosphere
Sun Angle
• Sun angle controlled by– Latitude– Season
PSCI 131: The Atmosphere: Controls on Air Temperature
Other Controls on Air Temp
• Geographic location
– Proximity to large bodies of water
– Leeward vs windward side of continent
PSCI 131: The Atmosphere: Controls on Air Temperature
Other Controls on Air Temp
• Geographic location– Proximity to
large bodies of water
PSCI 131: The Atmosphere: Controls on Air Temperature
Other Controls on Air Temp
• Geographic location– Leeward vs
windward
PSCI 131: The Atmosphere: Controls on Air Temperature
Other Controls on Air Temp
• Altitude– Higher = cooler average temps
• Cloudiness
• Ocean currents– Move heat from tropics to colder areas
PSCI 131: The Atmosphere: Controls on Air Temperature
End of Chapter