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2
Contributions of the Atmospheric Sciences to the National
Well-Being
The responsibilities of the atmospheric sciences include the
advance of fundamental understanding, the prediction of weather and
climate change, and the identification of environmental threats.
This section examines four ways in which the atmospheric sciences
contribute to national well-being and the achievement of national
goals through protection of life and property, maintaining
environmental quality, enhancing economic vitality, and
strengthening fundamental understanding. Today, they contribute to
a broad range of decisions concerning individual actions, business
and economic strategies, and public policy.
Atmospheric information is valuable when it helps to clarify the
advantages and risks of alternative courses of action for private
and public decision makers, but assessing the influence of
atmospheric information on public safety and economic activities is
not straightforward. Atmospheric information is usually only one of
many factors that influence a decision, and the value of a forecast
often depends on such factors as lead time, forecast resolution,
and expected accuracy and on user constraints such as the ability
to respond or to assess realistically the costs versus benefits of
various courses of action.
Protection of Life and Property
The United States experiences a great diversity of weather, some
of it the most severe in the world. As a consequence, this nation
has been a leader in developing the understanding and technological
capability to provide forecasts of the continually changing weather
and warnings of severe weather events such as floods, tornadoes,
and hurricanes. Atmospheric information and forecasts are provided
in the United States through a four-way partnership:
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1. The government acquires and analyzes observations and issues
forecasts and warnings.
2. The government, newspapers, radio, and television all
participate in dissemination of weather forecasts and severe
weather warnings.
3. Private-sector meteorological firms use government data and
products to provide weather information for the media and special
weather services for a variety of industries and activities.
4. Government, university, and private-sector scientists develop
improved understanding of atmospheric behavior and help to turn
this advancing understanding into new capabilities and technology
for observing and predicting atmospheric events. This four-way
partnership has served the nation well; it could be nurtured to
generate even greater benefit.
Although we can do little to change the atmosphere or the
weather, we can do much to anticipate atmospheric events such as
severe weather and thus provide opportunities for protecting lives
and property. These capabilities are expanding rapidly, for both
traditional weather impacts and new ones, including applications to
environmental quality, to solar events that affect satellites in
Earth orbit, communications, to power transmission and changes in
weather patterns associated with El Niño events. Today, the
nation is reaping significant benefits from its investments in
atmospheric observations and prediction capabilities.
Need for Forecasts and Warnings
The benefits of weather forecasts and warnings as measured by
lives saved, injuries avoided, or property that has not been
damaged cannot be estimated easily. Determining the economic
benefits of long-term forecasts, such as those associated with El
Niño, is even more difficult. Nevertheless, casualties
produced by unusual weather events are substantial, both in an
absolute sense and relative to other natural disasters.
Long-term fatality statistics for tornadoes and hurricanes are
shown in Tables I.2.1 and I.2.2, using data that go back to the
1930s and 1900s. The data show remarkable progress. More detailed
information on weather-related fatalities and damage in the United
States for 1991-1995 is given in Table I.2.3. The number of
fatalities attributable to weather is typically 300-400 per year.
However, one large event, such as the extreme temperatures of 1995,
can add as many as 1,000 fatalities to that total. Similarly,
Hurricane Andrew (1992) and the floods in 1993 each caused more
damage than is attributable to all weather events in some other
years. Changnon et al. (1997) present an analysis of the effects of
recent weather events on the U.S. insurance industry.
Table I.2.4 provides worldwide statistics on deaths owing to
civil strife, natural disasters, and other environmental causes. It
shows that more than 25 percent of deaths are due to drought,
famine, and severe weather and that these
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TABLE I.2.1 Reported Fatalities from Tornadoes in
the United States
Period
Fatalities
1930s
1,945
1940s
1,786
1950s
1,419
1960s
945
1970s
998
1980s
522
1986-1995
485
SOURCE: Aviation Weather and Storm Prediction
Center, National Centers for Environmental Prediction, National
Weather Service.
TABLE I.2.2 Reported Fatalities from
Representative Hurricanes in the United States (1900-1995)
Year
Ranka
Location
Fatalities
First Half of Twentieth Century
1900
1
Galveston
>8,000
1909
6
Louisiana and Mississippi
406
1915
4
Texas and Louisiana
550
1919
9
Florida, Texas, Louisiana
287
1928
2
Florida
1,836
1935
5
Florida
414
1938
3
Southern New England
600
Second Half of Twentieth Century
1961
25
Texas
46
1965
16
Southern Louisiana
75
1969
11
Southern States to West Virginia
256
1972
14
Florida to New York
122
1979
Caribbean Islands to New York
22
1980
Texas Coast
2
1989
20
Carolinas
56
1992
Florida and Louisiana (Andrew)
23
a Among
top 30 deadliest mainland U.S. hurricanes 1900-1995.
SOURCE: Hebert et al., 1996.
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Representative terms from entire chapter:
weather events
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TABLE I.2.3A Weather-Related Fatalities in the
United States, 1991-1995
Fatalitiesa
Weather Event
1991
1992
1993
1994
1995
Total
Extreme temperatures
49
22
38
81
1,043
1,233
Convective stormsb
144
93
99
155
153
644
Floods
61
62
103
91
80
397
Otherc
75
40
62
20
51
248
Snow, ice, avalanches
45
64
67
31
17
224
Hurricanes
13
27
2
9
17
68
Marine storms
4
0
0
1
1
6
Total
391
308
371
388
1,362
2,820
Annual Average
564
TABLE I.2.3B Weather-Related Damage in the United
States, 1991-1995
Damage ($ millions)
Weather Event
1991
1992
1993
1994
1995
Total
Hurricanes
1,164
33,611
15
426
5,932
41,148
Floods
874
690
21,288
921
1,250
25,023
Otherc
1,878
1,932
5,019
893
359
10,081
Convective stormsb
1,527
1,580
1,086
1,001
2,638
7,832
Snow, ice, avalanches
516
28
602
1,143
111
2,400
Extreme temperatures
224
479
416
52
1,120
2,291
Marine storms
45
31
1
3
2
82
Total
6,228
38,351
28,427
4,439
11,412
88,857
Annual average
17,771
SOURCE: Office of Meteorology, National Weather
Service.
a The
fatalities represent only those deemed to be directly attributable
to weather and floods. Number of fatalities in which weather was a
contributing factor would be much larger.
b Term
includes tornadoes, thunderstorms, lightning, and hail.
c Includes
drought, dust storms, rain, fog. strong winds, fire weather, and
mud slides.
events account for more than 92 percent of all people affected
by all the disasters combined.
Weather fatalities and damage could be mitigated by improved
design and construction standards for buildings and critical
systems; relocation of residents from hazard prone locations; and
earlier, more accurate, and more focused warnings of severe
weather. Although it is difficult to estimate accurately the
relative effectiveness of implementing these three strategies, it
seems that improving severe weather warnings, despite requiring
investments in observational technology and forecast capabilities,
might be the least expensive and most feasible of
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TABLE I.2.4 Worldwide Disaster Statistics: Annual
Averages for 1960-1989
Classification of Disaster
Number of Events
Percent
Deaths
Percent
Percent Affected
Percent
Civil strife
4.5
5.8
97,087
62.2
3,916,454
5.6
Drought and famine
10.3
13.1
21,220
13.6
36,185,464
51.8
Weather (storms and floods)
37.0
47.1
17,894
11.5
28,182,075
40.4
Earthquakes, volcanoes
10.5
13.4
16,583
10.6
1,400,787
2.0
Fires and epidemics
16.2
20.6
3,228
2.1
160,371
0.2
Totals
78.5
100.0
156,012
100.0
69,845,151
100.0
SOURCE: Office of U.S. Foreign Disaster Assistance
(1991); adapted from Bruce (1994).
the three options and might generate the increased public
confidence that would lead to even greater response to warnings. It
is noteworthy that early warnings appear to have been effective in
limiting to 23 the number of deaths attributed to Hurricane Andrew
in 1992, even though the direct damage reached a record total of
more than $25 billion (Hebert et al., 1996).
Progress in Weather Services
In the United States, daily weather maps and forecasts were
first provided by the Army Signal Corps, starting in the 1870s.
Radiosonde networks established over much of the world in the late
1940s and 1950s, practical numerical weather prediction initiated
in the late 1950s, radar data networks also established in the
1950s, and weather satellites deployed in the 1960s all led to
measurable improvements in forecasts.
The National Oceanic and Atmospheric Administration (NOAA) and
the National Weather Service (NWS) are now completing a
historically unique technological development cycle. New facilities
include a national Doppler weather radar network, major weather
satellite improvements, the enhanced Automated Surface Observation
System (ASOS) surface network, and a computerized network of
weather display and prediction systems (Automated Weather
Interactive Processing System—AWIPS) to be distributed at
forecast centers around the country. In addition to improving
weather forecasts, these new capabilities will be used for the
study of climate and of atmospheric chemistry and physics, and for
a variety of applications and special purposes. However, the full
benefits of these new technological systems will be realized only
if there is a sustained and substantial commitment by the
government to support research efforts such as the U.S. Global
Change Research Program (USGCRP) and the U.S. Weather Research
Program.
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Maintaining Environmental Quality
The human habitability of the Earth depends on certain basic
prerequisites, including the availability of clean air and water,
food, shelter, and security from natural hazards. Natural processes
sometimes create adverse environments, and local anthropogenic
activities sometimes create life-threatening conditions. Examples
include the lethal episodes of smog in London and in Pennsylvania
valleys apparently caused by coal burning during the nineteenth and
early twentieth centuries. Local anthropogenic influences on air
quality and other aspects of the environment continue to be major
problems for individual cities, states, and countries. When the
pollution caused by one jurisdiction interferes with the economic
interests of another, governments become involved in complex
issues.
Chlorofluorocarbons and Ozone
Recent concerns have focused on threats posed by certain trace
gases that are long-lived and mix throughout the entire global
atmosphere. Important examples are the manufactured
chlorofluorocarbon (CFC) gases that were widely used in spray cans
and refrigeration systems in the middle to late twentieth century.
These gases have lifetimes of years because they have no natural
removal mechanisms in the lower atmosphere. CFCs released at the
Earth's surface diffuse in a few years to the upper atmosphere
where they are exposed to energetic solar radiation. After a series
of chemical transformations, CFCs lead to a decrease in the ozone
concentration in the stratosphere, which in turn permits an
increase in dangerous ultraviolet radiation at the Earth's surface.
As described later, scientific research produced an explanation of
the processes involved. When the cause-and-effect relationship
became known and accepted, the governments of many nations
developed and signed agreements (the "Montreal Protocol") to limit
products deemed harmful to the ozone layer.
Greenhouse Gases and Global
Change
A more complex problem is posed by the increasing concentrations
of so-called greenhouse gases, primarily carbon dioxide released by
the combustion of coal, natural gas, and petroleum. Some of the
carbon dioxide is absorbed in the terrestrial system, but a
globally dispersed residual has been accumulating in the atmosphere
at a rate of about 0.5 percent per year.
Theory suggests that increasing concentrations of greenhouse
gases will result in a warming of the planetary surface and that
the direct effects may be amplified by feedback mechanisms,
including absorption and re-emission of infrared radiation by
atmospheric water vapor, itself a greenhouse gas. The observed
concentrations of carbon dioxide (and other greenhouse gases such
as methane) have increased since the beginning of the industrial
revolution in the
Page 23
eighteenth century in parallel with the consumption of fossil
fuels. Moreover, there appears to have been an increase in the
Earth's surface temperature over the last century. Although all of
the complex interactions are not fully understood, there is enough
evidence that the climate research community has accelerated
efforts to understand the links and interactions among components
of the climate system. The federal government has responded to
these concerns with the U.S. Global Change Research Program that
brings together the efforts of many agencies in a coordinated and
comprehensive study (see USGCRP, 1997). Other governments are also
concerned and have turned to the international scientific community
for advice. In its most recent report, the Intergovernmental Panel
on Climate Change (IPCC, 1996) has stated, "The balance of evidence
suggests that there is a discernible human influence on global
climate."
Understanding and taking action on the effects of greenhouse
gases are each challenging because of the difficulty of modeling
the entire climate system and the complexity of assessing economic,
social, and political implications. Atmospheric scientists will
have to collaborate with disciplines that can delineate other
dimensions of these issues to develop an understanding that may be
useful to governments and society. Moreover, the level of public
confidence in climate change predictions will directly influence
the urgency with which the nation undertakes measures to mitigate,
or adapt to, the predicted change.
Aerosols
Anthropogenic aerosols created by the burning of some fossil
fuels are another example of environmental consequences of human
activities. These tiny particles can limit visibility, cause lung
problems, foul delicate machinery, reduce the intensity of the
sunlight reaching the Earth's surface, and contribute to acid rain.
Aerosols influence the formation of clouds and hazes. Screening of
sunlight and changes in cloud properties have potential climate
effects since they could disturb the energy balance of the
Earth-atmosphere system. An important question is the extent to
which anthropogenically produced aerosols are offsetting, delaying,
or altering the nature of global warming attributed to increasing
concentrations of greenhouse gases. Years of research will be
required in order to develop the quantitative understanding
necessary to advise policy makers about the consequences of
increasing concentrations of aerosols (see NRC, 1996a).
Role of the Atmospheric Sciences in
Environmental Issues
Atmospheric scientists often respond to an emerging
environmental problem with dynamical and chemical studies and with
analyses of the associated scientific issues. Sometimes such
studies reveal that scientific advances are required to explore and
then understand the new problem and its relation to atmospheric
processes or events.
Page 24
Studies focused solely on the scientific aspects of an
environmental issue are rarely either sufficient or satisfactory.
Environmental issues and their potential consequences must be
addressed in the context of their human implications, including
economic, social, and political aspects. Thus, the atmospheric
sciences become most effective as partners in interdisciplinary
collaborations aimed at resolving the intertwined scientific and
human aspects of an environmental issue.
To maintain the confidence of society, atmospheric researchers
must maintain high standards of scientific integrity and, in either
purely scientific or applied efforts, must concentrate on
scientific questions and rigorous analysis of causes and effects.
They must remain neutral with respect to the economic and political
considerations that swirl around all issues related to maintaining
environmental quality. Through this strategy, atmospheric
scientists will help clarify for society the consequences of a
range of alternative actions and policy options.
Enhancing National Economic
Vitality
A wide range of activities that contribute to national economic
vitality are sensitive to weather and climate variations. The
atmospheric sciences have a long and successful history of
assisting these activities in two ways:
1. The public and private weather information sectors provide
predictions of weather and its consequences—some focused on
specific activities—that allow government and industry to
reduce the economic loss and disruption of activities owing to
adverse weather or to take advantage of favorable conditions for
action.
2. The atmospheric sciences develop and disseminate a wealth of
information that contributes to reducing long-term vulnerability or
sensitivity to atmospheric conditions and climate variations and,
in some cases, specifies envelopes of opportunity for certain
activities.
The atmospheric sciences thus contribute to decision making in
both public and private domains and help lubricate the national
economic engine. A more effective contribution to enhancing
national economic vitality will require improved collaboration
between providers and users of atmospheric and environmental
information to ensure that needs, decision processes, capabilities,
and constraints on alternative actions are fully explored.
Benefits of Weather and Climate
Information
Contributions to the gross domestic product (GDP) of activities
that are weather sensitive to some extent are shown in Table I.2.5.
Other specific examples are available, including the estimate in
Table I.2.3 that damage by adverse weather averaged $17.7 billion
per year in 1991-1995. As another example, the Federal Aviation
Administration assesses the economic cost of weather-related
Page 25
TABLE I.2.5 Categories of U.S. Activities That
Display Sensitivity to Weather and Climate
Industry
Contribution to Gross Domestic Product,
1996 ($ billion)
Percent of Gross Domestic Product
Industries Sensitive to Weather and
Climate
Agriculture, Forestry, and Fisheries
115.5
1.9
Construction
222.1
3.7
Transportation and Public Utilities
529.3
8.8
Retail Trade
557.5
9.3
Finance, Insurance, and Real Estate
1106.1
18.4
Subtotal
2530.5
42.1
Industries Generally Not Sensitive to Weather
and Climate
Mining
85.2
1.4
Manufacturing
1063.0
17.7
Wholesale Trade
394.4
6.5
Services
1182.7
19.7
Government
755.7
12.6
Subtotal
3481.0
57.9
Gross Domestic Product
6011.5
100.0
SOURCE: Bureau of Economic Analysis, Department of
Commerce.
delays of U.S. airline traffic at $1 billion per year; improved
forecasts of winds aloft would lead to substantial savings in
airline costs for fuel (see NRC, 1994a). Governments spend
considerable sums on removing snow from highways and repairing
highway damage from weathering. Agricultural activities are
sensitive to weather events and air quality. The benefits of
weather information to the construction, retail, or tourism
industries are large but would be difficult to specify
precisely.
In attempting to estimate the benefits of weather, climate, and
air quality information, it is essential to distinguish those
effects that can be mitigated with timely, accurate information
from those that cannot. Although the accurate warnings of
hurricanes can reduce the loss of life, they provide little
protection against the destruction of buildings by hurricane winds
or tidal surges. Even though forecasts of precipitation rates can
assist in managing flood control facilities, the damage from severe
and widespread floods is largely independent of forecast accuracy.
Agricultural damage from an extended drought may be severe, even
though both long-term outlooks and short-term forecasts were
accurate. However, forecasts of severe winter storms allow
individuals and industries to make
Page 26
suitable advance preparations. Accurate measurements and
forecasts of air pollution could be used to mitigate pollution
through temporary decreases in emission rates. Improved
understanding, modeling, and prediction of the interactions between
solar phenomena and near-Earth space will help reduce damage to
satellites in orbit and perhaps reduce disruptions of
communications and electrical power networks.
Although weather and climate forecasts may not provide for
mitigation of all harmful effects, the use of climate data and
extreme-value statistics, along with impact assessments, design
studies, and possibly appropriate codes or standards, can
significantly reduce the adverse consequences of severe weather
events. Moreover, long-term climate records provide information
critical to urban planning, land-use planning, agricultural
strategies, and air quality standards. As skill develops in
seasonal climate forecasting on a regional scale, both governments
and industry can begin to realize further benefits in shaping
strategies to expected weather conditions. Forecasts of El
Niño are proving useful in agricultural planning in several
Latin American countries (NRC, 1996b).
Strengthening Fundamental
Understanding
The following examples illustrate how enhanced fundamental
understanding of the atmosphere leads to practical benefits and can
stimulate progress.
In the 1930s, Professor Carl-Gustav Rossby was trying to
understand the large-scale patterns of the middle and upper
troposphere being observed from 3 to 10 km above the surface by
newly developed balloon-borne instrument packages. He developed a
highly simplified version of the equations of atmospheric motion
and predicted a periodic wave structure (now known as Rossby waves)
that corresponds to some of the observations. A fundamental aspect
of large-scale, midlatitude flow was described by just a few
symbols. This work fore-shadowed and contributed to more detailed
understanding of large-scale atmospheric flow and was also a
significant stimulus for the development of numerical weather
prediction and thus for the increased success of contemporary
weather forecasts and climate models.
Evidence that state-of-the-art numerical models can reproduce
complex atmospheric processes was provided by Joseph Klemp and
Robert Wilhelmson in the mid-1970s. Their numerical simulation
successfully modeled the three-dimensional structure and dynamics
of the powerful thunderstorms common to the Great Plains and other
U.S. locations. Their work provided a foundation for the present
understanding of severe storm dynamics and perhaps for a method of
numerically predicting such events in the future.
The discovery in the last decade of the processes by which the
release of the manufactured chlorofluorocarbon gases used in spray
cans and refrigeration can damage the protective ozone layer of the
stratosphere involved laboratory experiments, theoretical process
analysis, ground-based and satellite observations, and
Page 27
for verification, instrumented aircraft measurements over the
South Pole. The success of the endeavor, and its importance to
human life and safety, was recognized by award of the 1995 Nobel
Prize in Chemistry to Sherwood Rowland, Mario Molina, and Paul
Crutzen.
A widely recognized contribution to fundamental understanding by
a meteorologist is chaos theory, pioneered by Edward N. Lorenz
beginning in the 1960s. Professor Lorenz explored the properties of
a simplified system of equations describing convection. He
discovered, through numerical experimentation, that the evolving
solutions of these equations were aperiodic and ultimately
unpredictable, even though they were clearly deterministic in the
sense that they were governed by the equations of the system. Such
chaotic behavior of nonlinear systems is now known to be common
rather than rare, and this discovery has resulted in a new paradigm
for phenomena occurring in almost every field of science. It has
also resulted in a widely accepted theory of atmospheric
predictability and has led to a deeper understanding of the
mathematical structure of atmospheric motion and the nature of
strategies required to predict the statistics that describe
climate. Of even greater significance, perhaps, is the fact that
the understanding of chaos and nonlinear dynamics that stemmed from
basic research in meteorology has now illuminated phenomena studied
in many scientific disciplines.
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