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Introduction to the Atmosphere

The Four Earthly Spheres

One of the unique characteristics of earth as a planet: its atmosphere

• why?

Air: same as atmosphere

• a mix of different gasses

• solid and liquid particles

• invisible, no smell or taste

The atmosphere completely surrounds the earth

• role of gravity

• dynamic and flexible

Dimensions of the atmosphere

• distance outward

• mass (weight): where concentrated

• McKnight fig 3.2: atmospheric mass

Atmosphere extends slightly below the surface of the Earth

1. Composition of the Atmosphere

What air is made of:

1a. The Gasses

McKnight fig 3.3: nitrogen, oxygen, and others (table 3.1 for more detail)

Nitrogen:

• generated and added to atmosphere: examples

• removed from the atmosphere: examples

• nitrogen cycle

Oxygen

• generated and added to atmosphere: examples

• removed from atmosphere: examples

• oxygen cycle: also a balance

Water vapor in the atmosphere

• significant influence on weather and climate: why?

Carbon dioxide in the atmosphere also influences climate: why?

• normally in balance: but global warming...

McKnight fig 3.4 (not in current text): ozone

Ozone: comprised of 3 joined oxygen molecules

• ozone layer (9 to 15 miles up): where it is and what it does

• human impact: in the news

Sum: various gasses in various amounts in the atmosphere

• normally a dynamic but stable system

1b. The Particles

Non gasses: mostly water and ice

McKnight fig 3.4: also dust

Particulates: sources

Particulates affect weather in two ways

• hygroscopic effect: what is it?

• absorb or reflect sunlight: effects

2. Vertical Structure of the Atmosphere

• what happens as we move from earth up into the atmosphere?

2a. Atmospheric Temperature

McKnight fig 3.5

Named thermal layers (-spheres) of the atmosphere

• troposphere, stratosphere, mesosphere, thermosphere, exosphere

Names for the boundaries (-pause)

• tropopause, stratopause, mesopause

Troposphere and Tropopause

• greek word for 'turn'

• characteristics

  
  

• McKnight fig 3.6: variation in troposphere around the earth

• McKnight fig 3.5: Zig zag

Stratosphere and Stratopause

• greek word for "cover"

• characteristics

Mesophere and Mesopause

• greek word for "middle"

• characteristics

Thermosphere and Exosphere

• above 50 miles: characteristics

Temperature variations and altitude

• our experience: troposphere (colder higher) only

• warmth in troposphere: from...

  
  
  

• warmth in stratopause: from...

2b. Atmospheric Pressure

• Atmospheric pressure: weight of the overlying air

• McKnight fig 3.7: variations in atmospheric pressure

• atmospheric pressure plays a large role in weather and climate

2c. Atmospheric Composition

McKnight fig 3.9: the Homosphere

• Composition of air in the first 50 miles (homosphere) is uniform: characteristics

  
  
  

• Above 50 miles, more variability in atmospheric composition: heterosphere: characteristics

McKnight fig 3.11

• Ozonosphere: ozone in greatest concentration

• Ionosphere: electrically charged particles

McKnight fig 3.12: Sum of Atmospheric Layers

3. Weather and Climate

• atmosphere is a dynamic system: why?

  
  

• distinguishing weather and climate is a matter of scale and time

Weather: short term atmospheric conditions in a given, limited area

Climate: aggregate of day-to-day weather conditions over a long period of time

• climate shapes human activity: examples

• climate shapes physical landforms: examples

• climate can also be shaped by human activity: examples

  

• climate can be shaped by physical landforms: examples

4. Elements of Weather and Climate

Four elements as the basis of weather and climate:

• DESCRIBE weather and climate

• temperature, pressure, wind, and moisture content

Changes in the four elements of weather and climate are driven by several controls

• latitude, atmospheric circulation, ocean circulation, distribution of land and water, elevation of landforms, topographic barriers

• they are interrelated

• they drive changes in the elements and lead to weather and climate

• EXPLAIN weather and climate

4a. Latitude

McKnight fig 3.14: differential heating

Same amount of energy spread out over larger area north and south of equator.

Solar radiation distribution varies over earth's surface.

4b. General Atmospheric Circulation

McKnight fig 3.13: General Circulation

why these patterns?

Expand explanation in Ch. 3 (reviewed in McKnight Chapter 5: pp. 111-123)

complicated: sketch in notes!

Hadley Circulation

PDF) Hadley Circulation

• equator: hot air rises

• mid latitudes: cool air sinks and reheats: rises again

• poles: cool air sinks

Basic Surface Windfield

PDF) Basic Surface Windfield

Coriolis Effect

Coriolis effect: rotation of earth deflects wind; results in deviation from north/south flows

General Ocean Surface Circulation

PDF) General Ocean Surface Circulation

Actual Ocean Circulation: January

McKnight fig 3.15: ocean currents: effects

McKnight fig 4.27: more detail

• warm currents off eastern coasts: shapes climate, weather

• cool currents off western coasts: shapes climate, weather

4d. Distribution of land and water

• Oceans heat and cool more slowly than land: seasonal effects

  
  
  

• Oceans also provide moisture for atmosphere

4e. Elevation of Landforms

• decrease upward of temperature, pressure, and moisture content: lower higher

4f. Topographic Barriers

McKnight fig 3.17: Orographic Effect

• orographic precipitation (ch. 6 p. 154)

  
  

• McKnight fig 6.26b (not in current ed.): orographic precipitation
  

  
  

  McKnight 6.31: (January rainfall)

  

These six factors drive day to day weather and longer term climate patterns

Sum: The Earth's Atmosphere

Very brief overview of the atmosphere, climate, and weather

1. Composition of the Atmosphere

2. Vertical Structure of the Atmosphere: variations (up/down) in temperature, pressure, composition of atmosphere

3. Weather and Climate

• Four elements describe weather and climate: temperature, pressure, wind, and moisture content

• Six controls drive changes in (explain) weather and climate
  • latitude
    
  • general atmospheric circulation
    
  • ocean circulation
    
  • distribution of land and water
    
  • elevation of landforms
    
  • topographic barriers

Basic environmental phenomenon which are necessary to understand landforms

• ex) erosion and weathering of landforms due to climate

McKnight fig 8.5: Major Climate Zones on Earth

related to landforms and processes which shape landforms
closely related to biomes (climate + life forms) regions

Also vital to understand: the role water plays in shaping landforms

• McKnight fig 9.5: the hydrosphere
  

E-mail: jbkrygier@owu.edu

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