Unit 7 Flashcards
What Problems Plague the Atmosphere?
Pollutants released into the atmosphere accumulate and affect atmospheric dynamics: energy budget (incoming vs. outgoing), reactions that generate harmful chemicals that harm humans and biota
- Climate Change (Carbon Dioxide and other greenhouse gases influence Earth’s energy budget)
- Smog (particulates combine with sulfur, nitrogen, other chemicals and water)-smoke and fog combined
- Acid Rain (water reacts with sulfur and nitrogen compounds to form strong acids)
- Ozone Depletion (CFCs react with stratospheric ozone causing a thinning of beneficial ozone)-Canada has banned CFCs, ozone is recovering and will be fully recovered
Component Parts of Earth’s Climate System:
-The sun (gives off radiation energy), oceans (70% of surface, absorb incoming energy, generates heat), water (3 phases of water-liquid absorbs, ice reflects heat and no generation of heat, vapour influecnes the heat escaping to space, the outgoing energy and trapping heat as a green house gas), atmosphere (screens out radiation from the sun, moves heat around), land (what is it covered with, soil organic matter lost to carbon dioxide, producer will release heat when consumed and will release back out into the atmosphere)
Incoming - Solar Radiation
- External influence on Earth’s climate
- 11 year cycle in activity – sun spots and solar flares
- Changes in the amount of total solar radiation and its spectral distribution
- Scientists believe intensity of solar radiation reaching the Earth relatively constant throughout the last 2000 years, with variations of around 0.1-0.2%
Incoming Radiation – The Electromagnetic Spectrum
Long wave radiation-not harmful, moves back to space
Visible light-used for photosynthesis, doesn’t use green it’s reflected back
-Infrared radiation-is heat, generation, goes to the atmosphere, outgoing
-Incoming energy, radiation coming into the earth
Short wave-atmosphere, comes from space
-UV radiation
Features of the Atmosphere - Composition of Gases
Nitrogen and oxygen occupy largest volume of gases in atmosphere
Trace Gases
-Fixed Concentration– carbon dioxide, helium, hydrogen
-Variable Concentration– water vapour (related to temperature), methane, ground level ozone, nitrogen oxides, particulate matter, chlorofluorocarbon
-Could relate to industrial activities occurring in vicinity
The atmosphere has distinct layers and provides numerous services essential to life
- Troposphere-closest to earth, our pollutants go here, lots of wind currents
- Stratosphere-ozone layer affecting UV radiation, remove incoming radiation, energy absorbed generates heat so warm layer
- Mesosphere
- Thermosphere (80 to 5000 km)-extreme short ray radiation is absorb, very hot
The relationship between temperature and altitude
- Basis for determining which atmospheric level we are in
- Based on temperature (high temperature, absorption)
- The _pause-the temperature does not change
Incoming Solar Radiation – Includes Absorption and Reflection
- Energy hits the surface, the layers absorb the radiation and only visible light comes through to the surface
- 30% of the radiation will be reflected off the surface and from the atmospheric particles
- 50% absorption at the surface, generating heat
- Reflective surfaced disappear and the more heat will be absorbed into the earth, generating more heat
Incoming Solar Radiation – Influenced by the axis of inclination
Earth’s tilt leads to variability in the exposure to incoming solar radiation
-Higher the latitude the greater the Albedo effect
More intense sunlight (smaller illumination) when light hits perpendicular to surface than at an angle (greater area for same energy)
-The equator gets direct beams of light, warmest and gets more energy
Leads to a temperature gradient and seasonal differences with latitude
Not All Surfaces Are Equal in Energy Absorption/Reflection - Albedo
Albedo is a measure of the reflectivity of the Earth’s surfaces
- Light coloured surfaces have highest albedo because they reflect more energy than they absorb; dark coloured surfaces, vegetation and oceans have low albedo because they absorb more than they reflect
- Cities absorb more incoming light, generating more heat
Redistribution of Heat by the Thermohaline Gradient (Ocean Conveyor Belt)
- Conveyor belt is continuous cycle, defines climatic differences in the Northern Hemisphere
- Driven by temperature and salinity differences
- Water changes to ice at polar regions and expels salts, water lets off heat
- The colder denser water sinks to the sea floor pushing water
- In other areas of the ocean, upwelling brings nutrients back to the surface
Surface Energy Budget - Evaporation, Convection and Thermal Radiation
-The heat absorbed dissipates in three ways, evaporation, convection (less dense air rises), and thermal radiation
Outgoing Radiation – Infrared Radiation in the Electromagnetic Spectrum (Convection and Latent Heat Evaporation, redistribution of heat)
- sun’s energy heats ground surface
- warmed ground heats air above it
- warm, less dense air rises carrying heat upward
- rising air cools, radiates heat to the atmosphere, and becomes dense, moisture condenses, forming clouds and precipitation
- air is pushed aside toward low pressure area
- cool dense air sinks to low pressure area on surface
- Descends-dry, no precipitations
- Rises-precipitation
- Describes types of vegetation locations on the earth’s surface
The Atmosphere Radiates IR or Heat
The atmosphere radiates the equivalent of incoming sunlight back to space as thermal infrared energy, or heat. This includes:
-Energy that was absorbed by the atmosphere (particles, clouds, ozone)
-Energy that was transferred to the atmosphere from the Earth’s surface by evaporation, convection, and thermal infrared radiation.
-Greenhouse Gases absorb a portion of this IR in the troposphere
Some of the thermal infrared energy escapes to space through a “window” effect.
6 Giant Convection Cells Distribute Heat Toward Poles and Contribute to Long Range Transport
- Temperature and Precipitation Gradients - warm air at the equator rises and cooler air at the poles descends.
- Earth’s rotation pushes air in an east-west direction and creates Hadley and Ferrell cells.
- Prevailing winds and latitudinal belts of low and high air pressure are created. Precipitation patterns leads to arid bands at defined latitudes. Also contributes to the long range transport of air pollutants (grasshopper effect)
