So much

1. THE
ATMOSPHERE
C O M P O S I T I O N ,
S T R U C T U R E ,
& T E M P E R AT U R E

2. COMPONENTS OF THE ATMOSPHERE
Nitrogen and Oxygen
• the most plentiful components of
• significant to life on Earth
• has minor importance in affecting
weather phenomena
Carbon Dioxide
• present in only minute amounts
(0.037%)
• an important constituent of air
• an efficient absorber of energy
emitted by Earth
• influences the heating of the
atmosphere
Variable Components:
Aerosols, Water Vapor, Ozone

3. WATER VAPOR
• Amount varies from 0-4% by volume
• the source of all clouds and precipitation
• has the ability to absorb heat given off by Earth as
well as some solar energy

4. AEROSOLS
• solid and liquid particles suspended in air for considerable amount of time
• Origin:
– Sea salts from breaking waves
– fine soil blown into air
– smoke and soot from fires
– pollen and microorganisms blown by wind
– ash and dust from volcanic eruptions
• act as surfaces on which water vapor can condense (an important function in the
formation of fog and clouds)
• Can absorb, reflect, and scatter incoming solar radiation
• Contributes to an optical phenomenon we have all observed– the varied hues of red
and orange sunrise and sunset

5. OZONE
• O3, not the same as the oxygen we breathe
• concentrated in the stratosphere (altitude between 10-50 km)
• absorbs UV radiation emitted by the sun (UV is also needed
to form Ozone)
• If ozone did no filter a great deal of the UV radiation, and if
the UV rays reached the surface of the Earth undiminished,
our planet would be uninhabitable for most life.
• Anything that reduces the amount of Ozone in the
atmosphere could affect the well-being of life on earth

6. OZONE DEPLETION: A GLOBAL ISSUE
• Over the past 60 years, people have placed the ozone layer in jeopardy
by POLLUTING the atmosphere.
• Most significant pollutants:
– chlorofluorocarbons (CFCs)
Uses of CFCs – coolants for air-condition and refrigeration equipment, cleaning
solvents for electronic components, propellants for aerosol sprays, and the
production of certain plastic foams
• CFS are practically inert in the lower atmosphere so these gases escapes
to the ozone layer, where sunlight separates the chemicals into their
constituents atoms. CHLORINE ATOMS break up some of the ozone
particles.

7. OZONE DEPLETION: A GLOBAL ISSUE
• A decrease in ozone concentration permits more harmful
wavelengths to reach Earth’s surface.
• Threats of exposure to UV radiation:
– increased risk of skin cancer
– can impair the human immune system
– promote cataracts
– reduced vision leading to blindness

8. • In 2009 the ozone hole covered an area about the size of North America.
(NASA)
Ozone Distribution in the Southern Hemisphere
ozone hole

9. SOURCES AND TYPES OF AIR
POLLUTION
• Air pollutants – airborne particles and gases that occur in concentrations that endanger
the health and well-being of organisms or disrupt the orderly functioning of the
environment.
• Primary Pollutants – emitted directly from identifiable sources (industrial processes,
electrical generation, solid waste disposal, and transportation)
– Carbon monoxide (CO)
– nitrogen oxides (NO2)
– sulfur dioxides (SOx)
– volatile organic compounds (VOCs)
– particulate matters (PM)
• Secondary Pollutants – forms in the atmosphere when reactions take place among
primary pollutants (ex: SO2 forming sulfuric acid, VOCs forming photochemical smog)

10. CONCEPT CHECK
• What are the 2 major components of clean, dry air?
• Why are water vapor and aerosols important constituents of
Earth’s atmosphere?
• What is Ozone? Why is it important to life on Earth?

11. VERTICAL STRUCTURE OF THE
ATMOSPHERE
• Where does the atmosphere end and the outer space begin?
There is no sharp boundary; the atmosphere rapidly thins as
you travel away from Earth, until there are too few gas
molecules to detect.

12. ATMOSPHERIC
VARIATION WITH
ALTITUDE
• The rate of pressure
decrease with an increase
in altitude is not constant.
• Pressure decreases rapidly
near Earth’s surface and
more gradually at greater
heights.

13. THERMAL
STRUCTURE OF
THE ATMOSPHERE

14. Radiosondes supply data on vertical
changes in temperature, pressure,
and humidity.
A lightweight package of
instruments, the radiosonde, is
carried aloft by a small weather
balloon.
The orange object beneath the
balloon is a small parachute that
deploys after the balloon bursts.
(Photo by Michael Burnett/Photo Researchers,
Inc.)

15. TROPOSPHERE
• The bottom layer in which we live
• temperature decreases with an increase
in altitude
• the chief focus of meteorologists,
because it is in this layer that essentially
all important weather phenomena
occur
• Thickness varies with latitude and the
season
• atmospheric properties like
temperature and humidity are readily
transferred by large-scale turbulence
Environmental Lapse Rate
• The temperature decrease in
the troposphere
• average value is 6.5°C per
kilometer
• can be highly variable, and
must be regularly measured
Radiosoundes attached to a
balloon transmit data (ex: vertical
changes in pressure, wind, and
humidity) by radio as it ascends
through the atmosphere
Tropopose
• the outer boundary of the
troposphere

16. STRATOSPHERE
• the temperature remains constant
to a height of about 20 kilometers
(12 miles) and then begins a
gradual increase that continues
until the stratopause, at a height of
nearly 50 kilometers (30 miles)
above Earth’s surface
• Temperatures increase in the
stratosphere because it is in this
layer that the atmosphere’s ozone
is concentrated

17. MESOSPHERE
• Temperatures again decrease with
height until, at the mesopause,
more than 80 kilometers (50
miles) above the surface
• accessibility is difficult
• one of the least explored regions
of the atmosphere
• cannot be reached by the highest
research balloons nor is it
accessible to the lowest orbiting
satellites

18. THERMOSPHERE
• extends outward from the
mesopause and has no well-defined
upper limit
• a layer that contains only a tiny
fraction of the atmosphere’s mass
• temperatures again increase, owing
to the absorption of very short-
wave, high-energy solar radiation by
atoms of oxygen and nitrogen
• Temperatures (or the average speed
at which molecules move ) rise to
extremely high values of more than
1000°C

19. CONCEPT CHECK
•

20. EARTH-SUN RELATIONSHIPS
• nearly all of the energy that drives Earth’s variable weather and
climate comes from the Sun
• It is the unequal heating of Earth that creates winds and drives
the ocean’s currents
• These movements, in turn, transport heat from the tropics toward
the poles in an unending attempt to balance energy inequalities.
• If the Sun were “turned off,” global winds and ocean currents
would quickly cease.
• the variations in solar heating are caused by the motions of Earth
relative to the Sun and by variations in Earth’s land–sea surface

21. EARTH’S MOTION
Rotation
• Earth’s spin about an axis
• produces the daily cycle of day
and night
• Circle of Illumination – line
separating the dark half of the
Earth from the lighted half
Revolution
• Earth’s orbital movement
around the Sun
• Earth travels an elliptical orbit
around the Sun at 113, 000 km
per hour

22. SEASONS
• depends on the length
of daylight and altitude
of the Sun

23. Changes in the Sun’s angle cause variations in the amount of solar energy reaching Earth’s
surface.
The higher the angle, the more intense the solar radiation

28. ENERGY, HEAT, AND TEMPERATURE
• The universe is made up of a combination of matter and energy.
• Energy – the capacity to do work; thermal
– Types of energy: chemical, nuclear, radiant (light), and gravitational energy
– Kinetic energy - energy of motion
• Heat – a term that is commonly used synonymously with thermal energy.
– refers to the quantity of energy present
• Temperature – is related to the average kinetic energy of a material’s
atoms or molecules
– refers to the intensity, that is, the degree of “hotness”
• Heat is the energy that flows because of temperature differences. In all
situations, heat is transferred from warmer to cooler objects.

29. MECHANISMS OF HEAT TRANSFER
• Conduction - the transfer of heat through matter by molecular
activity; Energy is transferred through collisions from one molecule to
another, with the heat flowing from the higher temperature to the
lower temperature
• Convection - the transfer of heat by mass movement or circulation
within a substance; It takes place in fluids (e.g., liquids like the ocean
and gases like air) where the atoms and molecules are free to move
about.
• Radiation - heat-transfer mechanism by which solar energy reaches
our planet

30. FATE OF INCOMING SOLAR RADIATION
Reflection and Earth’s Albedo
• Energy is returned to space
from Earth in two ways:
reflection and emission of
radiant energy.
• About 30% of the solar energy
reaching the outer
is reflected back to space.
• The fraction of the total
radiation that is reflected by a
surface is called its albedo.
Radiation may be absorbed, transmitted, or redirected (reflected or scattered).
Scattering
• scattering accounts for the
brightness and even the blue
color of the daytime sky
• half of the solar radiation
that is absorbed at Earth’s
surface arrives as diffused
(scattered) light

31. Absorption
• Nitrogen, the most abundant constituent in the atmosphere, is a poor absorber of all
types of incoming radiation.
• Oxygen and ozone are efficient absorbers of ultraviolet radiation. Oxygen removes
most of the shorter ultraviolet radiation high in the atmosphere, and ozone absorbs
most of the remaining ultraviolet rays in the stratosphere.
• The absorption of UV radiation in the stratosphere accounts for the high
experienced there
• For the atmosphere as a whole, none of the gases are effective absorbers of visible
radiation. This explains why most visible radiation reaches Earth’s surface and why we
say that the atmosphere is transparent to incoming solar radiation
FATE OF INCOMING SOLAR RADIATION
Radiation may be absorbed, transmitted, or redirected (reflected or scattered).

32. THE GREENHOUSE EFFECT

33. AIR TEMPERATURE DATA
• At a weather station, the temperature is read on
a regular basis from instruments mounted in an
instrument shelter
• The shelter protects the instruments from direct
sunlight and allows a free flow of air.
• In addition to a standard mercury thermometer,
the shelter is likely to contain a thermograph to
continuously record temperature and a set of
maximum–minimum thermometers.
• Max.-Min. Thermometers record the highest and
lowest temperatures during a measurement
period, usually 24 hours

34. The daily maximum and minimum temperatures are the bases for many of
the temperature data compiled by meteorologists:
1. By adding the maximum and minimum temperatures and then dividing by
two, the daily mean temperature is calculated.
2. The daily range of temperature is computed by finding the difference
between the maximum and minimum temperatures for a given day.
3. The monthly mean is calculated by adding together the daily means for
each day of the month and dividing by the number of days in the month.
4. The annual mean is an average of the 12 monthly means.
5. The annual temperature range is computed by finding the difference
between the highest and lowest monthly means.

35. WHY TEMPERATURES VARY
The Controls of Temperature:
• Land and Water
• Altitude
• Geographic Position
• Cloud Cover and Albedo

38. WEATHER & CLIMATE
• Weather – refers to the state of the atmosphere at a
given time and place; constantly changing,
sometimes from hour to hour and at other times
from day to day
• Climate - climate is the sum of all statistical weather
information that helps describe a place or region

39. BASIC ELEMENTS OF WEATHER AND CLIMATE
• (1) air temperature,
• (2) humidity,
• (3) type and amount of cloudiness,
• (4) type and amount of precipitation,
• (5) air pressure, and
• (6) the speed and direction of the wind
- quantities or properties that are measured regularly

40. END OF CHAPTER 16