Intro to the Atmosphere

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Intro to the Atmosphere
The layers of gas that surround the other

spheres of influence on our planet
Interacts frequently with
Interacts frequently with


Hydrosphere- Clouds,Humidity,Rain
Hydrosphere- Clouds,Humidity,Rain
-
-
Lithosphere
- Weathering,Wind Erosion,Dust Particles
Lithosphere
- Weathering,Wind Erosion,Dust Particles
-
-
Exosphere
- Blocks incoming Solar Radiation
Exosphere
- Blocks incoming Solar Radiation
-
-
Biosphere
- Us!, plants, animals
Biosphere
- Us!, plants, animals
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-
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How do we know about the atmosphere?
Measuring instruments

Thermometer- temperature
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Barometer- pressure
-
Geiger Counter- radioactivity
-
Chromatograph- chemical composition
-
Space missions

satellites
-
aircraft
-
Theory

physics and chemistry
-
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Origins of atmosphere
Early on- volcanic activity is

responsible for atmospheric gases
rich in CO2 (carbon dioxide)
-
very different from todays atmosphere
-
simple plants and bacteria as planktonic life
forms (phytoplankton) changed the atmospheric
composition over 2 billion years

-
increased the oxygen content in oceans then air
Solar radiation also contributed

created other atoms by irradiating
-
existing components- ozone layer
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Composition (modern)
N
(nitrogen) 78
2
O
(oxygen ) 21
2
Ar (argon) 0.93
an inert gas
CO
(Carbon Dioxide) 0.035
2
a greenhouse gas
Aerosols and Water
dust and moisture particles small

enough to stay up in the atmosphere
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The structure of
the atmosphere
divided based on

Ionosphere
the
temperature

Composition is
unchanging here
Clouds
Ozone Layer O3
form
here
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Aurora
Ionosphere
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AURORA BOREALIS movies
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Factors associated with the atmosphere
Heat

different from temperature (avg. kinetic energy)
-
usually measured as the temperature of the air
-
F, C, K scales
-
a function of the kinetic energy (molecular
motion).
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Moisture

Measured as relative humidity
-
a function of temperature and availability
-
expressed as a percentage
-
Pressure

Measured in millibars, pascals, or inches
-
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Heat transfer
One of the big things the atmosphere does!
Conduction
contact between air and ground

Convection
mixing due to temp related density changes

Radiation- also known as radiative or
electromagnetic energy
absorbed and emitted by all objects

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Conduction
Heat transfer (2)
contact between hot cool

transfers E from hot to cool
-
solids gt liquids gt gases

atmosphere poor at
-

conduction

Convection ( Advection)
"mixing" of hot cold

Usually in currents
-
Con- is vertical Ad- is horizontal or lateral
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Radiation
Sun is the source of most radiation

visible light Moderate-wave radiation
-
infrared (heat)Longwave radiation
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X-rays, gamma rays, etc very shortwave
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Earth also gives

off radiation
Living things also

give off radiation
Angle of approach

and reflective
properties are
critical factors
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Air Pressure
The "weight" of the air pressing
down on the Earth's surface
A simple barometer
measured by a Barometer

-
inches (or mm) of mercury
rising up in a tube
adjusted according to height

above avg. sea level
less air pressing down from above at higher
-
altitudes
also takes into account motion of air

sinking vs rising
-
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Atmospheric Density
120 km
air is "thinner"


aloft- less atoms of it
Pressure is


lower aloft
Important for


heat
and
pressure
transfer
0 km
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A surface weather map
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(No Transcript)
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Moisture- the other main thing
dependent on temperature

warmer hold more water vapor
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colder holds less water vapor
-
results from

evaporation of liquid water
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cools surface and adds heat to air
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sublimation
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direct transformation from solid water
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(ice) to vapor
Acts as a trap for longwave radiation (heat)

Transports heat

Acts to transport water

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Interaction of Radiation,Pressure,Moisture at
macro or global scale
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Interaction of Radiation,Pressure,Moisture at
meso scale
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Sea Breeze- Exo, Geo, Hydro, Atmosphere
interaction at micro scale
animation