NOTES
Links to summaries of key issues for each topic
VISUALS
Links to images employed in lectures on a topic-by-topic basis
TEXT
Link to chapter outlines at online learning center at McGraw Hill.
NOTES
Links to summaries of key issues for each topic
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Notes on Topic:
The notes represent summaries
of key issues for each topic
They emphasize the terminology used to
describe the various phenomena.
| 1. The Atmosphere: |
| Learning Objectives: |
- Understanding features of the layering of the atmosphere
- Recognition of the characteristics of the atmosphere and controls
on pressure
|
| Structure of the Atmosphere: |
- A series of layers defined by temperature shifts:
- troposphere (with clouds)
- temperature decreases with elevation in troposphere
- stratosphere (ozone layer)
- temperature increases in stratosphere
- little circulation in stratosphere (volcanic eruptions and dusts)
- mesosphere, thermosphere
- boundaries, tropopause, stratopause, mesopause
- Density stratified, more compressed at the Earth's surface
- pressure decreases with altitude
- warmed at surface, cooled at top
|
| Composition of Air and Pressure: |
- Composed of transparent, odorless gases:
- N2 (78.1%), O2 (20.9%)
- others: Ar (0.9%), CO2, inert gases, water
vapor (variable, ~1.4%)
- dust particles (trace ó wind-borne from continents)
- Atmospheric pressure
- measure of air density
- increases when cooled or water vapor content decreases
- density decreases when air is warmed
- standard pressure: 760mm Hg
- where >760mm high pressure zone
- where <760mm low pressure zone
- lines of equal pressure are isobars
|
| 2. Atmospheric Gases: |
| Learning Objectives: |
- Recognition of the climatic effects of atmospheric gases
- Comprehension of separate roles of CO2, ozone
and sulfur compounds
|
| Changes in Carbon Dioxide Concentration: |
- Three reservoirs for CO2
- atmosphere (smallest), ocean (largest), terrestrial system.
- Properites of CO2
- transparent to incoming solar radiation
- absorbs outgoing long-wave radiation
- causing warming: greenhouse effect.
- Changes in CO2 concentrations
- annual cycle of CO2 uptake and release by plants
- increase in CO2 from combustion of fossil fuels
and deforestation
- measured on Mauna Loa (Hawaii) since late 1950's
- has risen from 280 to 350 ppm since 1850
- effects a global temperature rise of perhaps 2 - 4°C in 100a
- leads to sea level rise
|
| The Ozone Problem: |
- UV radiation shield:
- "hole" over Antarctica in Spring
- chlorofluorocarbons in stratosphere are broken down by UV radiation
- CFC's form Cl, which destroys ozone
- N compounds destroy Cl, but are removed by cold clouds in polar regions
- methyl bromide also suspect.
- Enhanced UV reduces plant production 2 - 4%
|
| The Role of Sulfur Compounds: |
- Dimethyl sulfide (DMS)
- gas produced by plants in ocean
- aids cloud nucleation, increases build up
- self-regulating climate feedback?
- Sulfur dioxide (SO2)
- aids cloud nucleation
- emissions from volcanoes (Mt. Pinatubo in 1991) affect global climate
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Department of Geological Sciences,
1001 E. Tenth Street, Bloomington, IN 47405-1403
Phone: (812) 855-5582 Last updated: 7 October 2000
Comments: simon@indiana.edu
Copyright
2000, The Trustees of Indiana University
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