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Weather and Climate
Air Pollution issues
Chapter 17 & 18
Weather – short-term atmospheric
conditions. Climate – 30 year averages of
atmospheric conditions.
Temperature & Moisture most important
considerations. Climate influences
include: Latitude, Elevation, Topography
(Orographic Lifting/Rain Shadow Effect),
Vegetation, Distance from Ocean, Position
on Continent.
6 Climate zones, subdivided into climate
types.
Zones are:
Humid Equatorial; Dry; Humid Temperate;
Humid Cold; Cold Polar; and Highland
3
Variations in Earth surface temperatures &
climate are due to; Inclination of Earth’s
axis in relation to the Sun and the Unequal
Distribution of Land vs. Water & Differential Thermal Characteristics of Land &
Water. Long-term changes may be due to
variations in Solar activity & Earth orbit.
Pp. 510 - 511
Lower angle of Sun’s rays hitting Earth =
more surface area coverage/less
concentration.
Seasonal changes are largely due to Earth’s
axial inclination in relation to the Sun.
4
Axial inclination – responsible for Seasonal
Variations.
5
Atmosphere – Dry atmosphere composed
of 78% Nitrogen (N2) & 21% Oxygen (O ).
Remaining 1% composed of Argon,
Carbon Dioxide, Neon, Helium, and other
trace gases.
Important atmospheric functions include
shielding Earth’s surface from UV, X-rays,
cosmic rays from space, while allowing
visible and infrared wavelengths to
penetrate atmosphere. Greenhouse Effect
shields Earth from excessive diurnal
temperature variations (day to night
temperature variations).
6
Atmospheric Layers – Most important are
Troposphere (surface to 11 miles) &
Stratosphere (11 to 16 miles).
Troposphere – “Weather maker”, turbulent,
rich in water vapor/droplets.
Stratosphere – “Ozone shield”, steady wind,
but little turbulence. Ozone not present as
a “layer”, but is more prevalent from 11 to
16 miles above Earth’s surface. Oxygen
(O2) and Ozone (O3) both block UV radiation, but Ozone is more dense, more efficient, but is also unstable. Thinning
seems seasonal, greatest in September.
7
Atmospheric Circulation – caused by:
• Earth’s Rotation
• Uneven Distribution of Land Mass
• Properties of Heat Transfer between
air/water/land
• Solar Energy
Horizontal/Latitudinal Wind “Belts” –
Rossby Regime.
• 00 to 300 North – Northeast Trade Winds
• 300 to 600 North – Westerlies Wind Belt –
Jet Stream
• 600 to 900 North – Polar Easterlies
8 Vertical atmospheric circulation – Hadley cells –
Driven by Equatorial Heating (Equatorial Low
Pressure Zone). Pg. 479
Polar Cell
Ferrel Cell
Hadley Cell
Low Pressure Zones
= Rising Air,
Counter-clockwise.
High Pressure
Zones = Falling Air,
Clockwise.
The vertical air movements of the Hadley
Cells lead to:
A persistent Low Pressure Zone at the
Equator (00)
A persistent Mid-Latitude High Pressure
Zone at 300
A weaker, persistent Low Pressure Zone at
600
And a strong, persistent Polar High
Pressure Zone at 900 called the Polar
Vortex
10
The combined actions of the Horizontal
Wind Belts, the Hadley Cells, & the Earth’s
rotation lead to the Coriolis Effect, i.e.,
clockwise rotation of ocean currents in
Northern Hemisphere. Example – Gulf
Stream carries heat from sub-tropics
northward, warms Scandinavia, British Isles.
The North Pacific Drift carries enough heat
to warm the NW coastline of North America.
The wind-driven surface circulation patterns,
called gyres, are influenced by landmass
locations and coastline shapes.
11
Major Surface Ocean Currents
12
The varying density of sea water largely affects
vertical ocean currents. Colder, saltier water
tends to sink, while warmer, less salty water
remains near the oceans surface. Pg. 511
Present-day circulation
13
There is evidence of past changes in the
ocean “conveyor belt”, but all of the
reasons are not known. Weakening of the
North Atlantic – Gulf Stream component
may bring about another ice age.
El Niño – Southern Oscillation – periodic
changes in wind/oceanic current patterns
in Pacific Ocean. May be driven by solar
activity. Under normal conditions – NE
Trade Winds & SE Trade Winds combine
to form E to W moving winds along InterTropical Convergence Zone across Pacific
Ocean. Every 3 to 7 years, these winds
weaken.
14
Under normal conditions – Convergence of
Trade Winds push surface water to the west,
causing an upwhelling of cold, organic-rich
bottom water along the West Coast of South
America.
Under El Niño
Pacific
Ocean
conditions –
weakening of
trade winds =
weakening of
South
America upwhelling,
affecting E.
Pacific ecosystems &
weather.
El Niño/Southern Oscillation (pp. 510 – 511)
Warm tropical waters in Western Pacific
(Indonesia) generate a persistent low
pressure system in the area.
The Southern Oscillation refers to the
alternating El Niño and La Niña events. A
12,000 yr history suggests faster
oscillations during colder time periods.
ENSO History Other research suggests
ENSO and Atlantic Oscillations are driven
by solar activity.
16 Global
weather changes due to El Niño, may
cause temperature spikes, e.g., 1998 El Niño.
ENSO - Solar Activity Model
La Niña – stronger trade winds
17
The Hydrologic Cycle is the dynamic movement of water through the atmosphere,
over & below the land surface, through the
life cycles of plants and animals, and to
and from the oceans & other water bodies.
Components:
• Evaporation/Transpiration
• Condensation
• Precipitation
• Runoff/Infiltration
18
El Niño wind currents are thought to interfere with Atlantic Hurricanes by preventing
the vertical growth of cumulonimbus
clouds in developing hurricanes.
Why Does It Rain? Condensation of Water Vapor &
Condensation Nuclei (minute particulates) needed
Mechanisms for Atmospheric Uplift –
•Cyclonic – Counter-clockwise rotation, uplift of air
•Convection – Uplift by heat
•Orographic Effect – Uplift by mountains
Cooling
Warming
Remember –
Low pressure – counterclockwise, rising air currents,
convergence at surface. Most favorable for rain/snow.
High pressure – clockwise, falling air currents, divergence
at surface.
Ocean Currents – Northern Hemisphere
Earth’s Rotation and prevailing winds produce clockwise
circulation in Northern Atlantic and Northern Pacific
Oceans – Coriolis Effect. Example – Gulf Stream and
Kuroshio Currents. In addition, there are drift currents and
eddy currents that produce local current variations (next
slide).
Other factors influencing Oceanic Currents–
•Fresh Water vs. Different Salinities
•Differing Water Temperatures
•Shape of Coastlines
•Presence of Large Islands
Other oceanic currents include vertical “upwhellings”,
particularly along coastlines, that bring nutrient-rich
bottom water to the surface and complex “thermohaline”
currents, that may play a major role in global climate.
21
Ocean Currents Redistribute Heat
North Pacific Summer
North Pacific Winter
North Pacific Summer
Current Details
North Pacific Winter
Current Details
North Atlantic Ocean North
Atlantic Summer and North
Atlantic Winter
Seasonal Winds and Monsoons
Best examples of Monsoon Season Rains
occur with summer heating of large Asian
landmass, generating intense convection
that “draws” warm, moist air inland from
the Indian Ocean. Orographic lifting
caused by Himalayan Mts. results in
flooding of Ganges River. Ganges Delta
includes most of Bangladesh.
Smaller continents may generate lesser
“Monsoon” effects.
CLIMATE CHANGE - The Sun provides
the energy that drives the Earth’s climate.
Variations in Solar activity and the Earth’s
orbit affect primarily affect the climate.
Compiled by R. S. Bradley and J. A. Eddy based on J. T. Houghton et al., Climate
Change: The IPCC Assessment, Cambridge University Press, Cambridge, 1990
and published in EarthQuest, vol 5, no 1, 1991. Courtesy
of Thomas
Crowley.
Ice core data over periods of 160,000 yrs. and
420,000 yrs. suggest a correlation between
atmospheric CO2 and global temperatures.
Disagreements between scientists focuses
on the connection between CO2 and
temperature.
Which one leads and which one follows?
Recent studies suggest that temperature
leads by several hundred years or more.
Human-Caused Global Climate Change
Greenhouse heating first hypothesized by Svante
Arrhenius (1896), concerns over effects of burning coal.
In the larger scale – we have been undergoing global
warming since the end of the last ice age (end of
Pleistocene Epoch – 8,000 to 12,000 years ago).
In the smaller scale – we have been undergoing global
warming since the end of the Little Ice Age (1350 to 1850
AD).
The Industrial Revolution began about 200 years ago.
Mona Loa CO2 changes 1957 – 2002 = 315 ppm to 372 ppm
315 ppm = 0.0315% 372 ppm = 0.0372% 744 ppm = 0.0744%
Evidence exists that increased CO2 = increased plant vitality
= more photosynthesis = negative feedback loop.
Kyoto objections
Chirac: Kyoto "First Step Toward Global Governance“
Link to article
Some believe the Kyoto Treaty is an attempt to plan the
world’s energy use for the next century.
This includes the use of taxes, rationing, and economic
sanctions to punish “non-attainment”.
Taxes and rationing will hurt economies of developed
world, hinder Research & Development by Free Market.
Other concerns: Loss of Sovereignty; Exemption of China,
India, Brazil, and Mexico; Failure to include alternative
scientific views; Over-reliance on models; Too much
politics, etc…
Remember – the UN is not elected.
Compiled by R.S. Bradley and J.A.
Eddy based on J.T. Houghton et al.,
Climate Change: The IPCC
Assessment, Cambridge University
Press, Cambridge, 1990 and published
in EarthQuest, vo. 1, 1991. Courtesy of
Thomas Crowley, Remembrance of
Things Past: Greenhouse Lessons
from the Geologic Record 1.
(notice differences in time scales vs.
previous diagram (slide 10).
(Graph on right): Based on data from
J. Imbrie, J.D. Hays, D.G. Martinson,
A. McIntyre, A.C. Mix, J.J. Morley,
N.G. Pisias, W.L. Prell, and N.J.
Shackleton, in A. Berger, J. Imbrie, J.
Hats, G. Kukla, and B. Saltzman,
eds., Milankovitch and Climate,
Dordrecht, Reidel, pp. 269-305,
1984.Courtesy of Thomas Crowley
Global Warming: A Chilling Perspective
29 CLIMATE SKEPTICS
Water Vapor Rules the Greenhouse –This is the one to
study.
Most-serious greenhouse gas is increasing
Table 9.3 doesn’t even mention Water Vapor as a
Greenhouse Gas
Water Vapor vs. Carbon Dioxide as Greenhouse Gases
Water Vapor in the Climate System
Water Vapor as a Greenhouse Gas
Carbon dioxide is a Greenhouse Gas
and it is more efficient at trapping heat
than water vapor/clouds, but the
current amount is 385 ppm = 0.0385%
Source: Prof. Richard Lindzen, Massachusetts
Institute of Technology, U.S. Senate Hearing, May 6,
1992.
30
Convection Uplift
Current Evidence of Climate Change
Laundry list of predictions and problems
blamed on Global Warming.
“Around the world, coral reefs are bleaching
because of higher water temperatures.”
CLIMATE AND AIR POLLUTION
U.S. releases 147 million metric tons of air
pollutants (not including carbon dioxide
or wind-blown soil).
Since the 1970s, there has been progress in
reductions of major pollutants, except
Nitrogen oxides.
Lack of progress noticeable, especially in southern Asia –
“Asian Brown Cloud” – dust, smoke, dirt, volcanic ash,
other particulates, rises above Asian cities and drifts
southward over Indian Ocean after monsoon season, may
be affecting ENSO system.
Major Kinds of Pollutants
Primary Pollutants – from the original source – volcanoes,
motor vehicles, factory combustion, dust, open burning,…
Secondary Pollutants – form from chemical reactions
between primary pollutants. Chemical reactions may
include photochemical reactions (triggered by sunlight) –
Ground level ozone of most concern.
Fugitive emissions – non-smokestack emissions – dust,
soot and ash from open burning, hydrocarbons from
pipelines, wells, refinery leaks, etc..
Conventional (criteria) pollutants – Sulfur dioxide, carbon
monoxide, particulates, volatile organic compounds (VOCs),
nitrogen oxides, ozone, and lead. 1970 Clean Air Act
mandated EPA to monitor and limit concentrations of these
pollutants within the ambient air (existing air conditions).
Unconventional pollutants – less volume, greater toxicity
than conventional pollutants, e.g., asbestos, benzene,
mercury, PCBs, and vinyl chloride.
Sources and Problems of Major Pollutants
Sulfur dioxide – with water forms sulfurous acid. When
oxidized to form sulfur trioxide with water turns to sulfuric
acid.
Hydrogen sulfide – Highly toxic in larger amounts, produces
rotten egg odor assoc. with some oil wells and refineries,
when combined with oxygen, also produces sulfuric acid.
Nitrogen oxides – by-products of fuel combustion, some
of which is from catalytic converters. Various nitrogen
oxide gases are referred to as NOx gases. These are
precursors of ground level ozone which combine with
various hydrocarbons (VOCs) through photochemical
reactions. Scotch pine trees can release nitrogen
oxides when exposed to UV radiation.
Carbon monoxide – product of incomplete combustion,
combines with hemoglobin in blood, prevents
absorption of oxygen. EPA Info - Carbon Monoxide May
be a precursor of ground-level ozone.
Particulate material – dust, ash, soot, lint, smoke, pollen,
spores, algal cells, aerosols (minute droplets),
asbestos,…
Volatile Organic Compounds (VOCs) – organic gases, e.g.,
isoprenes (C5H8), terpenes (C10H15), and methane (CH4),
oxidize to carbon monoxide and carbon dioxide.
Brown air smog – combination of primary and secondary
pollutants – most common to US cities.
Gray air smog – results from burning of heavy, sulfur-rich
fuel oil and coal. Formerly a problem in US cities, now
more of a problem in some Eastern European and Asian
cities.
Metals – Pb, Zn, Ni, Hg, U. May be present in emissions
from smelters, coal-burning power plants.
Indoor air pollution – issues – outgassing from synthetic
materials (formaldehyde, chloroform, benzene, styrene),
rebreathing of cigarette smoke, dust mites, carpet
fibers, mold, spores,…
INTERACTION BETWEEN CLIMATE PROCESSES AND
AIR POLLUTION
Long range transport – China dust to Hawaii and western
US, Sahara dust to Miami, industrial contaminants,…
Stratospheric Ozone Depletion – Not a hole, but rather a
thinning. Worst during Antarctic spring (September),
recovers during Antarctic Summer (our Winter).
The debates over: Are variations normal? How much of the
chloride ion is coming from CFCs and how much from
volcanoes?
Chloride repeatedly cycles through the system, acting as a
catalyst, possibly speeding up the breakdown of the
already unstable ozone molecules.
Tracking the Ozone Layer Good article – 16 pages long.
April 2001 Report on Ozone
Urban Climates – Inversions – usually triggered by rapid
nighttime cooling in valleys or basins where air movement
is restricted. Overlying warm layer w/out convection traps
pollutants – El Paso, Mexico City, LA, Denver.
Heat Island Effect – Concentration of heat within cities due
to vehicles, factories, paving and building materials that
absorb solar energy, lack of tree cover, buildup of dust,
other particulates, concentration of ground-level ozone
precursors.
Asphalt, concrete, brick, etc. absorb solar energy –
reradiate energy as infrared (heat).
Trees provide cooling effect through evapotranspiration –
emitting water vapor from their leaves.
Evidence suggests that ground level ozone damages crops.
Visibility loss in Blue Ridge Mts., Grand Canyon, elsewhere
due to the migration of pollution from cities.
Acid Deposition (acid rain) – results from the combination
of rain and carbon dioxide, rain and nitrogen oxides, rain
and sulfur gases. In dry climate, sulfate and nitrate
particles can settle as particulates.
Worst acid rainfall in areas associated with smelting of
sulfide minerals (pyrite and related metallic ores).
Sudbury, Ontario and Copperhill, Ga./Ducktown, Tenn. –
examples.
NAPAP – National Acid Precipitation Assessment Program
– 10 year study (1980-1989), $537 million, almost 700
scientists, issued 28 volume report. Conclusion was that
in most places in US, acid precipitation was a nuisance,
not a crisis. EPA vs. Ed Krug
Damage to Appalachian trees was due to aphids. Upstate
New York lakes were acidic due to natural conditions.
NAPAP study focused on United States, other nations with
different fuels (more coal use, heavy fuel oils, less
environmental regulations) may have more acid-rainfallrelated damage to buildings, forests, etc..
AIR POLLUTION CONTROL
Past attempts at dilution and dispersion were only shortterm solutions to the problem.
Most US air pollution is related to transportation and
energy generation. Improvements in technology, fuel
and fuel efficiency, and conservation are all viable
strategies.
Even though we have our problems – Re: the Eastern Bloc
– “…a rigid bureaucracy, and lack of democracy have
created ecological disasters. Where governments own,
operate, and regulate industry, there are few checks and
balances or incentives to clean up pollution.”