Download Atmosphere

The Atmosphere: Structure and
Temperature
What is Meteorology?

The study of
weather, climate,
and atmospheric
processes
How Does
Weather differ
from Climate?


Weather is constantly changing
and it refers to the state of the
atmosphere at any given time
and place
Climate is based on
observations of weather that
have been collected over many
years to help describe a place or
region
Composition of the Atmosphere
 Main
Components
Nitrogen – 78%
 Oxygen – 21%

CO2 < 1%
 Argon < 1%

What is the
significance of Water
Vapor?

Water vapor - source of
all clouds and
precipitation.
Ozone
Ozone is a form of
oxygen that
combines three
oxygen atoms into
each molecule (O3)
• Ozone filters and
absorbs harmful
UV radiation by
the sun
•
Human Influences and
Primary Pollutants



Air pollution is airborne
particles and gases that
occur in concentrations
large enough to endanger
the health of organisms
Primary Pollution:
emitted directly from
identifiable sources
Secondary Pollutions: not
emitted directly into air
(agriculture)
Primary Pollutants
and Sources

Primary Pollutants





Carbon monoxides
Nitrogen oxides
Volatile Organics
Sulfur oxides
Particulate matter
Sources




Transportation
Stationary Source
Fuel Combustion
Industrial Processes
Solid Waste
Pressure and
Temperature Changes


The atmosphere rapidly
thins as you travel away from
Earth until there are too few
gas molecules to detect.
Pressure Changes


As you increase in altitude, or
travel away from Earth, pressure
decreases
Temperature Changes

As you increase in altitude in the
Troposphere the temperature
decreases.
Layers of the Atmosphere

The Troposphere - the
bottom layer




Temperature decreases with an
increase in altitude.
Where weather occurs
Tropopause: boundary of the
troposphere
The Stratosphere




Above the troposphere
Temperature remains constant,
then gradually starts to increase
Contains the ozone layer
Stratopause: boundary of the
stratosphere

The Mesosphere




Above the stratosphere
Temperature decreases with
height
Mesopause: boundary of the
mesosphere
The Thermosphere:
Upper layer of the
atmosphere

Temperature increase with
height


Auroras occur here
Fades into space
Heating the Atmosphere
Heat: the energy
transferred from
one object to
another because of
a direct difference in
their temperature
 Temperature:
measure of the
amount of heat

Ways Heat Can be
Transferred
 Heat
transfer from
HOT to COLD objects
 Conduction
The transfer of heat
through matter by
molecular activity
 Transfer by touching

 Convection

The transfer of heat
by a mass movement
or circulation within a
substance
 Radiation
Travels out in all
directions
 Solar energy reaches
earth by radiation

What Happens to Solar Radiation?
Reflection vs. Scattering

Reflection



occurs when light
bounces off an object.
30 % of all radiation is
reflected back to
space
Scattering produces
a larger number of
rays that travel in
many directions.

Absorption:
50 % of the solar
energy that strikes
the top of the
atmosphere
reaches the
Earth’s surface
 20% is absorbed in
the clouds
 30% is reflected
back to space

Why Do
Temperatures Vary?

Factors:
Heating of land
 Heating of water
 Altitude
 Geographic
position
 Cloud cover
 Ocean currents

Land and Water Temperatures
Land heats and cools more rapidly
and to higher temperatures than
water
 Water – heats up longer and will
retain the heat longer

Albedo
the fraction of total
radiation that is
reflected by any
surface.
Daylight Cloud Cover



Clouds reflect solar
radiation back to space
Temperatures are lower
than on a clear day
Nighttime Cloud
Cover


Clouds absorb radiation
from land and reradiates
some of it back to Earth
Temperatures are higher
than on a clear night
World
Distribution and
Temperatures
Isotherms - lines
on a weather
map that connect
points that have
the same
temperatures