ST 215 Handout, 9/10/09
Vertical Structure of the Atmosphere
LAYER
A (km)
P (atm)
T (oC)
COMMENTS
Exosphere
500+
0
103+
Edge of space, light gases escape
Thermosphere 90+
10-7
-90 to103
Stable, Solar absorption by O and O2
Mesosphere
60-90
10-5
0 to -90
Mixed layer, coldest region
Stratosphere
20-50
10-2
-40 to 0
Stable, Solar UV absorbed by O3
Troposphere
0-10
1 to 0.1
40 to-40
Layer of weather, water vapor rules
Beach Ball Earth
Sphere
Rotating
Tilted
Revolving
Sun (light and tides)
Oceans
Continents
Clouds
Ice Sheets
Deserts
Mountains
Life (O2)
Precipitation
Temp. differences
Winds
Lightning
Aurora
Moon (tides)
Natural Greenhouse Effect
Orbit “wobbles” long-term
Stratospheric Ozone
Artificial satellites
Air pollution
Political boundaries
It’s Your Atmosphere
Only planet with abundant O2 atmosphere.
Oceans cover 2/3 of planet.
Natural greenhouse effect keeps urface
temperatures 40 to -40 C allows three
phases of water (ice, liquid, vapor)
Hydrologic cycle recycles fresh water for the
biosphere.
Atmosphere protects earth from UV, meteorites,
solar wind.
“Ocean of air” is very thin; we can’t breathe
above 10 km.
Air is absolutely necessary for life:
Eat 3 x per day, can survive without
food for 40 days.
Drink 6 x per day, can survive without
water for 7 days.
Breathe 22,000 x per day, can live
without air only 3-5 min.
1022 molecules in every breath of air
1044 molecules in the entire atmosphere
1022 breaths of air in the atmosphere.
Composition (major constituents)
Nitrogen
78.08%
Oxygen
20.95%
Water Vapor
0 to 4%
Argon
0.93%
CO2
0.0387% = 387 ppm
Weather Elements
Air Temperature
Air Pressure
Humidity
Clouds
Precipitation
Visibility
Wind
Air Quality
Thermometer
Barometer
Psychrometer
Types and amounts
Liquid or Frozen
For Aviation
Speed and Direction
Pollution Load
Definitions
Weather: The state of the atmosphere at a given
place and time. Weather elements: T, P, humidity,
clouds, precipitation, visibility, wind, air quality.
Meteorology: Scientific study of the weather.
Ancient meaning (Aristotle) was much broader.
Climate: Aggregate of regional weather
conditions over time. Usually a 30-year average
over a region plus a statement about frequency of
extreme conditions, such as lightning strikes,
tornadoes, hurricanes or drought.
Climatology: Scientific study of climate.
Includes fields such as applied climatology,
climate modeling, and climate dynamics.
Physical Oceanography: Chemistry and
dynamics of oceans, including currents, waves,
air-sea interaction, and topics such as El Niño
and La Niña.
Atmospheric Science: Umbrella term covering
proliferation of research specialties since the
mid-1950s. Meteorology, Climatology, Cloud
Physics, Atmospheric Chemistry, Numerical
Weather Prediction, Satellite and Radar
Meteorology, etc.
Global Change or Earth System Science:
Umbrella term for study of the complex
interactions of the atmosphere, lithosphere,
hydrosphere, and biosphere on all temporal and
spatial scales plus the human or social
dimensions of environmental change.