R 15 The...
Transcript of R 15 The...
15 The Atmosphere C
HA
PT
ER
Charging Toward Cleaner Air in London
• More than 4000 people in London died during a “killer smog” event in 1952.
• In 2003, London started charging a fee to people who drove into the city during the week.
• Since the program began, traffic congestion in London has decreased by 30%, but there is not a lot of evidence that air quality has improved.
Talk About It What are the pros and cons of a
congestion-charging program?
Lesson 15.1 Earth’s Atmosphere
The air we breathe and all the weather we see is contained in the lowest 1% of the Earth’s atmosphere.
N2
NOT A GREENHOUSE GAS!!!
Non atmospheric nitrogen is part of some pollutants like NO2, N2O, or NO (NOx) which can cause smog, acid rain, or global warming
21% O2
78%
Properties of the Atmosphere
• Temperature: Varies
and location
• Pressure: In general,
air pressure decreases
with altitude; can be
measured using a
barometer.
Lesson 15.1 Earth’s Atmosphere
Barometer
Relative Humidity
• The ratio of water vapor in air
to the maximum amount the
same air could contain at the
same temperature
• Is affected by temperature and
location; in general, warm air
holds more water.
• When air cools, water vapor
may condense to liquid (dew or
rain) or to ice (frost or snow).
Water vapor can only
condense on surfaces, such
as a petal or a dust particle.
Lesson 15.1 Earth’s Atmosphere
Hoarfrost on leaves
Convection Currents
• Warm air is less dense than cool air.
• When air near the surface heats up, it rises; as it rises, it cools and then sinks.
• Rising and sinking fluids generate convection currents.
• Cause wind and heat to move through the atmosphere
Lesson 15.1 Earth’s Atmosphere
QuickTime™ and a decompressor
are needed to see this picture.
Heat Transfer in the Troposphere
Lesson 15.1 Earth’s Atmosphere
• Radiation: The
transfer of energy
through space,
such as heat from
the sun to Earth’s
atmosphere
• Conduction:
The transfer of
heat directly
between two
objects that are
in contact
• Convection: The
transfer of heat by
the movement of
currents within a
fluid (liquid or gas)
Layers of Atmosphere
Lesson 15.1 Earth’s Atmosphere
• Troposphere: 0–11 km;
movement of air, weather
• Stratosphere: 11–50 km;
ozone layer, absorbs and
scatters UV rays
• Mesosphere: 50–80 km;
meteoroids burn up
• Thermosphere: 80+ km;
disturbances produce
aurora borealis
Did You Know? The stratosphere and mesosphere are cold, but the upper thermosphere can be hotter than 1500°C.
The earth is surrounded by
all kind of gases. This layer
is called the earth's
Atmosphere.
•Without this atmosphere
life on earth isn't possible.
It gives us air, water, heat,
and protects us against
harmful rays of the sun and
against meteorites.
•This layer around the earth
is a colorless, odorless,
tasteless 'sea' of gases,
water and fine dust.
•The atmosphere is made
up of different layers with
different qualities. It
consists of
•78 percent nitrogen,
•21 percent oxygen,
•0.93 percent argon,
•0.03 percent carbon
dioxide
The Sky Meets The Space
Fig. 18-3, p. 467
Atmospheric pressure (millibars)
0
Temperature 110
Thermosphere
65 100
1,000
90 55
80
70 Mesosphere 45
60 35
50
Alt
itu
de (
miles)
Alt
itu
de (
kilo
mete
rs)
40 Stratosphere
25
30
20 Ozone layer 15
10 Pressure
Troposphere 5
(Sea
level) –80 –40 0 40 80 120
Pressure =
1,000 millibars
at ground level
200 120 75
0
Temperature (˚C)
400 800 600
Thermosphere (52 – 300 miles)
Thinnest gas layer Where the space shuttle orbits Temp increases rapidly due to gamma rays, X rays, and
radiation hitting molecules and converting the kinetic energy to heat Molecules broken into ions by ejecting electrons – heated
by solar energy – causes ions to glow (aurora borealis – northern lights) Extremely high temps +3000 F – but because air so thin –
would feel cold since so few molecules contacting skin and transferring heat Radio waves reflected - makes communication possible
Aurora Borealis(in north) /Aurora
Australis(in south), a luminous
atmospheric phenomenon that
generally appear as bright colorful
bands of light commonly referred to
as the southern and northern lights,
occur in the ionosphere.
•Stratosphere
•Stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler higher up and warmer farther down.
•Almost completely free of clouds and weather
•Area where most long distance flights take place so they can avoid weather disturbances and take advantage of the strong and steady winds.
•Stratosphere (13-30 miles)
•Temperature increases with altitude because the ozone traps high energy radiation and holds heat.
•Ozone layer is found here –
•O3 formed by UV radiation and lightning
•Protects earth from UV radiation
•CFC’s caused “hole” over the poles seasonally – ozone layer is the thickest over the poles and thinnest over the equator
• Mesosphere (31-50 miles) • Temperature decreases with altitude.
• This is due to decreasing solar heating and increasing cooling by CO2 radiative emission.
• Coldest of all atmospheric layers – freezes water vapor into ice clouds
• Noctilucent clouds clouds visible after sunset
• Meteors burn up in this layer. Most melt or vaporize as a result of collisions with the gas particles contained there.
• The mesosphere lies above the maximum altitude for aircraft and below the minimum altitude for orbital space craft. As a result, it is the most poorly understood part of the atmosphere.
TROPOSPHERE
•0-7 miles
•75% of the mass of the atmosphere is found here
•Temperature decreases as altitude increases
•Convection currents redistribute heat and moisture around the globe
•Creates weather
•Greenhouse effect takes place here due to CO2 in the atmosphere.
Air Masses and Fronts
• Air masses: Large bodies of air with similar properties
• Fronts: Boundaries between air masses of different properties
Lesson 15.1 Earth’s Atmosphere
Warm front
• Boundary along which a mass of warmer,
moister air pushes against a mass of
cooler, drier air
• Can produce light precipitation
Cold front
• Boundary along which a mass of cooler,
drier air pushes against a mass of
warmer, moister air
• Can produce heavy precipitation
Core Case Study: Different Climates Support Different Life Forms
• Climate -- long-term temperature and precipitation patterns – determines which plants and animals can live where
• Tropical: equator, intense sunlight
• Polar: poles, little sunlight
• Temperate: in-between tropical and polar
Solar Energy and Global Air Circulation: Distributing Heat
• Global air circulation is affected by the uneven heating of the earth’s surface by solar energy, seasonal changes in temperature and precipitation.
Figure 5-3
Fig. 5-3, p. 102
Spring
(sun aims directly
at equator)
Fall
(sun aims directly at equator)
Summer
(northern hemisphere
tilts toward sun)
Solar
radiation
23.5 °
Winter
(northern hemisphere
tilts away from sun)
Coriolis Effect Global air circulation is
affected by the rotation of the earth on its axis.
Figure 5-4
7-1 What Factors Influence Climate?
• Concept 7-1 Key factors that determine an area’s climate are incoming solar energy, the earth’s rotation, global patterns of air and water movement, gases in the atmosphere, and the earth’s surface features.
The Earth Has Many Different Climates (1)
• Weather • Temperature, precipitation, wind speed, cloud cover
• Hours to days
• Climate • Area’s general pattern of atmospheric conditions over decades and
longer
Fig. 7-2, p. 149
Natural Capital: Generalized Map of the Earth’s
Current Climate Zones
Fig. 7-2, p. 149
Polar (ice) Subarctic (snow) Cool temperate Highland Warm ocean current River
Warm temperate Dry Tropical Major upwelling
zones
Cold ocean current
Arctic
Circle
Tropic of
Cancer
Tropic of
Capricorn
Antarctic
Circle
The Earth Has Many Different Climates (2)
• Air circulation in lower atmosphere due to 1. Uneven heating of the earth’s surface by sun
2. Rotation of the earth on its axis
3. Properties of air, water, and land
• Ocean currents • Prevailing winds
• Earth’s rotation
• Redistribution of heat from the sun
• Surface currents and deep currents
Fig. 7-3, p. 149
Global Air Circulation
Fig. 7-3, p. 149
Moist air rises,
cools, and releases
moisture as rain
Cold deserts
60°N Evergreen coniferous forest The highest solar
energy input is at
the equator. Hot desert
Northeast trades 30°N
Temperate deciduous forest and grassland
Westerlies
Air cools and
descends at lower
latitudes.
Tropical deciduous forest Warm air rises
and moves
toward the poles.
Solar
energy Equator 0°
Tropical rain forest
Tropical deciduous forest
Southeast trades Hot desert
30°S Westerlies
60°S
Cold deserts
Temperate deciduous forest and grassland
Air cools and
descends at
lower latitudes.
Polar cap
Polar cap
Fig. 7-4, p. 150
Cool,
dry air
Condensation and
precipitation
Heat released radiates to space
LOW
PRESSURE
HIGH
PRESSURE
Falls, is
compressed,
warms
Rises,
expands,
cools
Warm,
dry air
Hot,
wet air Flows toward low
pressure, picks up
moisture and heat
HIGH
PRESSURE Moist surface
warmed by sun
LOW
PRESSURE
Fig. 7-4, p. 150
Energy Transfer by Convection
in the Atmosphere
Fig. 7-5, p. 150
Connected Deep and Shallow Ocean Currents
Fig. 7-5, p. 150
Warm, less salty, shallow current
Cold, salty,
deep current
The Earth Has Many Different Climates (3)
• El Niño-Southern Oscillation • Every few years
• Prevailing winds in tropical Pacific Ocean change direction
• Affects much of earth’s weather for 1-2 years
• Link between air circulation, ocean currents, and biomes
Figure 4, Supplement 7
Normal and El Niño Conditions
•El Niño is characterized
by warm temperatures,
and La Niña is
characterized by are
cooler temperatures in
the Eastern Pacific.
•Occurs when a change
in the direction of
tropical winds warms
the coastal surface
water, suppresses
upwelling, and alters
weather.
Figure 3 . World-wide climatic impacts of warm ENSO events
The upper half (3a)
corresponds to the
northern hemisphere winter
(October to March) and the
lower half (3b) covers
impacts during April to
September. D indicates
drought, R stands for
unusually high rainfall (not
necessarily unusually
intense rainfall) and W
indicates abnormally warm
periods. The figure is
modified from two
illustrations given by
Pacific Marine
Environmental Laboratory
WWW home page (NOAA,
USA).
Florida El Niño Effects
• Rainfall - Above average rainfall
• Severe Weather - During El Niño the jet stream is oriented from west to east over the northern Gulf of Mexico and Northern Florida. Thus this region is most susceptible to severe weather
• Temperatures - Below normal temperatures
• Winter Storms - Increased cyclogenesis (low pressure systems) in the Gulf of Mexico
• Hurricanes - El Niño almost always reduces the frequency of storms.
Florida La Niña Effects
• Rainfall -Generally dry conditions
prevail during La Niña's in late fall, winter and early spring.
• Wildfires - Increased risk of Wildfires in Spring/summer months.
• Temperatures - Temperatures average slightly above normal during La Niña events.
• Hurricanes - According to research, the chances for the continental U.S. and the Caribbean Islands to experience hurricane activity increases substantially during La Niña.
Drought in Southern Africa, Southern India, Sri Lanka,
Philippines, Indonesia, Australia, Southern Peru, Western
Bolivia, Mexico, Central America
Heavy rain and flooding in Bolivia, Ecuador, Northern
Peru, Cuba, U.S. Gulf States
Hurricanes in Tahiti, Hawaii
Reduced upwelling can adversely affect local bird
and fish populations off the coasts of Ecuador and
Peru.
Effects of El Nino http://www.usatoday.com/weather/resources/graphics/2008-09-25-el-nino-la-
nina-affect-us-weather_N.htm
Figure 5, Supplement 7
Impact of El Nino-Southern Oscillation
Greenhouse Gases Warm the Lower Atmosphere
• Greenhouse gases • H2O
• CO2
• CH4
• N2O
• Natural greenhouse effect
•Gases keep earth habitable
• Human-enhanced global warming
Fig. 3-4, p. 57
Flow of Energy to and from the Earth
Earth’s Surface Features Affect Local Climates
• Differential heat absorption by land and water • Land and sea breezes
• Rain shadow effect
•Most precipitation falls on the windward side of mountain ranges
•Deserts leeward
• Cities create microclimates
Fig. 7-6, p. 152
Rain Shadow Effect
Fig. 7-6, p. 152
Prevailing winds
pick up moisture
from an ocean.
On the windward side
of a mountain range,
air rises, cools, and
releases moisture.
On the leeward side of the
mountain range, air
descends, warms, and
releases little moisture,
causing rain shadow effect.
Microclimates – usually created around cities due to heat absorbing building materials like
concrete and brick. High buildings trap radiant heat and block wind flow. This can also
increase and trap pollution causing haze and smog.
URBAN HEAT ISLAND - REASONS
MOTOR
EXHAUSTS
FACTORY &
OTHER
POLLUTION
DOMESTIC HEATING DARK AND
DRY TARMAC
SURFACES
SMOG RESULTS
FROM POLLUTION
Human heat sources (domestic heating,
cars, factories) all warm the air.
Pollution by exhausts, factories and
other dusts absorb radiation and
prevent heat loss during the night. Dark
surfaces have a low albedo. Dry
surfaces reduce latent heat loss by
evaporation
In humid conditions, this may result in
smog (a mixture of fog and smoke)
which was common in pre-war London
and still is in LA, Rome, Athens,
Mexico City etc where surrounding
hills prevent the escape of polluted air.
RUSH
HOUR
TRAFFIC
THROUGH
A HAZE OF
FUMES
Are living / green roofs the solution?
• can help act as insulation
• promote cooling in cities
• can be used as an urban garden to grow crops or
small amounts of food for a community
Lesson 15.2 Pollution of the Atmosphere
Air pollution is estimated to cause 2 million premature deaths worldwide every year.
Sources of Air Pollution
Lesson 15.2 Biomes
• Natural processes: Windblown dust, particles in volcanic
eruptions, smoke and soot from fire
• Human sources: Most come directly or indirectly from
the burning of fossil fuels.
Did You Know? Humans can increase the hazards of natural air pollution. For example, by removing trees, humans expose soil, which can dry out and add to huge dust storms when picked up by wind.
Dust storm approaching a U.S. farm during the 1930s
Types of Air Pollutants
Lesson 15.2 Pollution of the Atmosphere
• Primary air pollutants:
Released directly into the
atmosphere; example: soot
• Secondary air pollutants:
Formed when primary
pollutants react chemically
with other substances;
example: sulfuric acid
Sources and Types of Air Pollutants
Fig. 18-5, p. 469
METHANE (VOC)
• Agricultural sources
• Cows
• Rice paddies
• Energy Related
• Landfills
• Oil recovery/drilling
• Liquid used for industrial purposes
• offgassing
Rice paddies are one
of the largest man-
made sources of
methane, and rice is
the world’s second-
most produced staple
crop.
As more carbon
dioxide enters the
atmosphere, rice
plants grow faster, the
experimental data
showed. This growth,
in turn, pumps up the
metabolism of
methane-producing
microscopic
organisms that live in
the soil beneath rice
paddies. The end
result: More methane.
Methane and
permafrost • https://www.youtube.com/wat
ch?v=2w4UQfJHD-A
How Air Pollutants Affect Your Health
Lesson 15.2 Pollution of the Atmosphere
• Lung irritation and respiratory
illnesses, such as asthma
• Carbon monoxide interferes with
body’s ability to use oxygen.
• Trace amounts of some air
pollutants, such as benzene or
soot, may contribute to cancer.
How Pollutants Are Formed from Burning Coal and Oil, Leading to Industrial Smog
Fig. 18-9, p. 474
Smog
Lesson 15.2 Pollution of the Atmosphere
• A mix of air pollutants that forms over cities
• “Smog” is a combination of the words smoke and fog.
• Industrial smog (soot, sulfur, and water vapor) comes from
industrial sources. GREY smog
• Photochemical smog is mostly tropospheric ozone created
when primary pollutants from vehicle exhaust react to
sunlight. BROWN CLOUDS
Charging Toward Cleaner Air in London
• More than 4000 people in London died during a “killer smog” event in 1952.
• In 2003, London started charging a fee to people who drove into the city during the week.
• Since the program began, traffic congestion in London has decreased by 30%, but there is not a lot of evidence that air quality has improved.
Talk About It What are the pros and cons of a
congestion-charging program?
• Normally, air near Earth’s surface warms and rises, carrying pollutants with it.
• When a layer of warmer air sits over a layer of cooler air, it traps pollution near Earth’s surface.
Temperature Inversions Lesson 15.2 Pollution of the Atmosphere
Did You Know? A
thermal inversion
caused London’s
“killer smog.”
QuickTime™ and a decompressor
are needed to see this picture.
Acid Deposition Lesson 15.2 Pollution of the Atmosphere
• Sulfur dioxide and nitrogen oxides can react with water,
oxygen, and other chemicals to form acids.
• Acid falls as particles or dissolves in precipitation, lowering the
pH of rain and snow.
• Acid deposition harms forest and lakes and damages human
structures.
Did You Know? Rainwater
is naturally acidic (pH 5.6),
but acid precipitation in
some parts of the U.S. has
a pH as low as 4.
For humans, touching or
walking in acid rain is not
harmful BUT the acidity
can dissolve heavy
metals and other
compounds that can
cause injury to humans
that may come into
contact with
contaminated water or
soil.
Lesson 15.3 Controlling Air Pollution
Since the Clean Air Act was first enacted in 1963, emissions of the worst pollutants in the U.S. have decreased by 57%.
The Clean Air Act
Lesson 15.3 Controlling Air Pollution
• First passed in 1963 to protect
human and environmental health
by improving air quality; has been
revised several times
• Limits emissions of pollutants
• Sets standards for air quality,
• Establishes a legal framework for
suing industries that break the
rules, and provides funding for
pollution control
CAFÉ Standards
•Corporate average fuel economy
•An effort to reduce fuel consumption and emissions
•Avg mpg efficiency of 27.5 (cars) 22.5 (suv and trucks) – 2010 standards
The Background
On May 19, 2009, President Barack Obama proposed a new national fuel economy program which adopts uniform federal standards to regulate both fuel economy and greenhouse gas emissions while preserving the legal authorities of DOT, EPA and California. The program covers model year 2012 to model year 2016 and ultimately requires an average fuel economy standard of 35.5 miles per US gallon (6.63 L/100 km; 42.6 mpg-imp) in 2016 (of 39 miles per gallon for cars and 30 mpg for trucks), a jump from the current average for all vehicles of 25 miles per gallon.
The Argument
The evidence is overwhelming that CAFE standards result in
more highway deaths. A 1999 USA TODAY analysis of crash
data and estimates from the National Highway Traffic Safety
Administration and the Insurance Institute for Highway Safety
found that, in the years since CAFE standards were mandated
under the Energy Policy and Conservation Act of 1975, about
46,000 people have died in crashes that they would have
survived if they had been traveling in bigger, heavier cars
Major Accomplishments of the Clean Air Act
Lesson 15.3 Controlling Air Pollution
• Catalytic converters, present in all
cars since 1975, have reduced
vehicle emissions.
• Lead has been phased out of gasoline.
• Industries and power plants have reduced releases of
pollutants by using scrubbers, which remove or alter
chemicals before they leave factory smokestacks.
Did You Know? The removal of lead from gasoline has led to a 99% reduction in lead emissions since 1973.
We Can Use the Marketplace to Reduce Outdoor Air Pollution
• Emission trading or cap-and-trade program • https://www.youtube.com/watch?v=EKT_ac4LPkU
• https://www.youtube.com/watch?v=axr95YXuxPE
• Mixed reactions to program
• SO2 emissions down significantly
• NOx now in effect
• Mercury plan strongly opposed for creating toxic hotspots
• Many problems with making cap-and-trade effective
The Ozone Hole
Lesson 15.3 Controlling Air Pollution
• Ozone is a pollutant in the troposphere,
but in the stratosphere it creates a
protective barrier against UV radiation.
• Chemicals called chlorofluorocarbons
(CFC), which used to be found in
everything from aerosol cans to
refrigerators, have destroyed ozone,
causing an “ozone hole” to form over
Antarctica.
• An ozone hole allows more UV
radiation to reach Earth’s surface,
potentially increasing cases of skin
cancer.
Recovery of the Ozone Layer
Lesson 15.3 Controlling Air Pollution
• The Montreal Protocol is an international treaty signed in
1987 that has cut CFC production by 95% since the 1980s.
• Ozone levels in the stratosphere have begun to stabilize,
and the ozone hole will likely start to disappear….?????
Ozone Hole 2000
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
The Antarctic ozone hole, which
was expected to reduce in size
swiftly when manmade chlorine
emissions were outlawed 27
years ago, is stubbornly
remaining the size of North
America, new data from Nasa
suggests.
Natural Capital Degradation: Effects of Ozone Depletion
Fig. 19-22, p. 522
What Role Do the Oceans Play in Projected Climate Disruption?
• Solubility of CO2 in ocean water
• Warmer oceans • Last century: 0.32-0.67C°increase
• Absorb less CO2 and hasten atmospheric warming
• CO2 levels increasing acidity
• Affect phytoplankton and other organisms
There Is Uncertainty about the Effects of Cloud Cover on Global Warming
• Warmer temperatures create more clouds • Thick, low altitude cumulus clouds: decrease surface temperature
• Thin, cirrus clouds at high altitudes: increase surface temperature
• Effect of jet contrails on climate temperature
Enhanced Atmospheric Warming Could Have Serious Consequences
• Worst-case scenarios • Ecosystems collapsing
• Low-lying cities flooded
• Wildfires in forests
• Prolonged droughts
• More destructive storms
• Glaciers shrinking; rivers drying up
• Extinction of up to half the world’s species
• Spread of tropical infectious diseases
Permafrost Is Likely to Melt: Another Dangerous Scenario
• If permafrost in Arctic region melts • Methane, a greenhouse gas, will be released into the atmosphere
• Arctic permafrost contains 50-60x the amount of carbon dioxide emitted annually from burning fossil fuels
• Methane in permafrost on Arctic Sea floor
Sea Levels Are Rising (1)
• 0.8-2 meters by 2100
• Expansion of warm water
• Melting of land-based ice
• What about Greenland?
Agriculture Could Face an Overall Decline
• Regions of farming may shift • Decrease in tropical and subtropical areas
• Increase in northern latitudes
• Less productivity; soil not as fertile
• Hundreds of millions of people could face starvation and malnutrition
Fig. 19-16, p. 513
Collect Greenhouse Gas Emissions and Stash Them Somewhere
• Solutions 1. Massive global tree planting; how many?
2. Restore wetlands that have been drained for farming
3. Plant fast-growing perennials on degraded land
4. Preserve and restore natural forests
5. Promote biochar
6. Seed oceans with iron to stimulate growth of phytoplankton
7. Carbon capture and storage – from coal-burning plants
Governments Can Help Reduce the Threat of Climate Disruption
1. Strictly regulate CO2 and CH4 as pollutants
2. Carbon tax on fossil fuels
3. Cap-and-trade approach
4. Increase subsidies to encourage use of energy-efficient technology
5. Technology transfer