Science, and transportation united states senate

is true for the hail mass and all other response variables considered,

regardless of the method of analyzing the data. 57

In a recent paper by Knight, Foote, and Summers it was concluded

that "at the present state of knowledge of hail formation in storms, it

would appear to be premature to start another major statistical seeding

experiment. There is no new, very promising technique in the offing, as

the Soviet method appeared to be when NHRE started." 58 The authors

further state that scientific research necessary for a solid foundation

for new attempts to modify the precipitation from convective storms is

underway and provide the following summary of positive results from

N HRE :

The National Hail Research Experiment included a first attempt at mounting

a hail suppression test with a strict randomized design and evaluation based

upon physical measurement of hail rather than crop damage. The results have

l»een analyzed in detail, with extensive evaluation of data quality and of opera-

tional success, facets not generally treated in such detail in previous programs.

Tlie outcome was that the seeding may have had a variety of non-zero effects or

no effects at all. The one conclusive result was to rule out very large increases or

decreases of hail or rain by the seeding. The physical research portion of NHRE

led to advances in knowledge of hail and of storms, and contributed substantially

to the development of the research tools . . . needed to derive answers to the

oul standing, practical problems. 50

Figure 11 shows the components of the Portable Automated Mesonet

(PAM) data network. There were 15 of the remote PAM stations in

the. XHRE observing network during the 1976 field season. Each

PAM station measures pressure, temperature, moisture, precipitation,

and wind direction and speed. Data are telemetered to a central collec-

tion point, in real time if needed, or they are stored at the PAM

station and collected at the central collection point daily.

fi ' Crow, et al.. "Final Report — National Hail Research Experiment : Randomized Seeding

Experiment : 1972-74." vol. 1. 1976. p. iii.

Knight. Charles A.. G Brant Foote, and Peter W. Summers, "Physical Research and

General Conclusions from the National Hail Research Experiment." preprints from the

"Sixth Conference on Planned and Inadvertent Weather Modification." Champaign-Urbana,

111.. Oct. 10-13, 1977. American Meteorological Society, Boston, Mass., p. 165.

59 Ibid.

280

PORTABLE AUTOMATED MESONET (PAM)

Figure 11. — Components of the Portable Automated Mesonet (PAM) data col-

lection system, used in the National Hail Research Experiment (NHRE). Each

PAM station measures pressure, temperature, moisture, and wind speed and

direction; data are then telemetered to a central collection point. (Courtesy

of the National Science Foundation.)

A typical remote field installation of the portable automated mesonet (PAM)

system. (Courtesy of the National Science Foundation.)

282

Weather modification technology development

to utilize predictive models, advanced measurement systems, and

statistical analyses to improve the experimental design and evaluation

of weather modification investigations. Part of the demand for some

of the long, costly weather modification experiments is due to the

large natural variability of atmospheric processes, which is a major

obstacle to successful field tests of weather modification technology.

It is expected that improvements achieved through the high priority

research incorporating the combined use of the three research tools

listed above will not only aid in the logistic design of experiments,

but will also reduce the predicted natural variability of weather

events, thus reducing the overall time required for conducting a de-

finitive experiment. 60

The NSF-supported Climax experiments (conducted by Colorado

State University from 1960 to 1970) first demonstrated the efficacy

of wintertime orographic precipitation enhancement. Results of these

experiments have provided the basis for a number of subsequent dem-

onstration experiments. 61 The following examples of weather modifi-

cation technology development projects have received NSF research

support in recent years : 62

1. Evaluation of the Florida area cumulus experiment (FACE),

where cloud motion has been found to be a significant covariate in the

data evaluation.

2. Development of new techniques for the evaluation of convective

precipitation in the metropolitan meteorological experiment (Metro-

mex).

evaluation of operational cloud-seeding programs.

4. Research on various ice nucleants which might be used instead of

silver iodide and on development of delivery systems for organic

nucleants.

5. Assessment of Midwest cloud characteristics for weather modifi-

cation, by compiling and analyzing sample statistics of variables im-

portant in cloud development and precipitation processes as well as in

their modification as a function of mesoscale and macroscale atmos-

peric conditions.

6. Exploration of the feasibility of artificially generating cirrus

clouds as a weather modification tool and numerical modeling of ef-

fects of cirrus clouds on the troposphere and mesoscale weather.

7. Maintenance and operation of a testing and calibration facility for

seeding materials, cloud-seeding generators, and ice nucleus measur-

ing instrumentation, for use by research projects of Federal agencies

and by the commercial cloud-seeding industry (at Colorado State

University).

Other specific research projects designed to improve the technology

of weather modification are found in the list of recent RANN awards

for weather modification research in table 14. In the past, the NSF

program in weather modification has made significant contributions to

80 Federal Council for Science and Technology, Interdepartmental Committee for Atmos-

pheric Sciences, ICAS 20-FY77, p. 96.

81 The Climax experiments are discussed under orographic precipitation enhancement tech-

nology, in ch. p. 77.

62 Downie and Dirks, "National Science Foundation Weather Modification Program," 1976.

p. 560 ; and Currie S. Downie, personal communication.

283

the initial phases of major weather modification projects of other Fed-

and Project Skyfire (Department of Agriculture) .

Instrumented aircraft, operated by the Research Aviation Facility of the National

Center for Atmospheric Research (NCAR), whose primary mission in the 1976

summer field season of the National Hail Research Experiment (NHRE), was

to assess the feasibility of on-top cloud seeding. (Courtesy of the National

Science Foundation.)

Inadvertent weather modification

The objective of this portion of the NSF/RANN weather modifica-

tion research program is "to delineate the mechanisms whereby, and

the extent to which, an agricultural region modifies its own climate

and an urban area modifies its surrounding weather, precipitation, and

aerosol." 63 Most of the NSF research on inadvertent weather modifi-

cation is concentrated in the metropolitan meteorological experiment

(METROMEX) in the neighborhood of St. Louis. The research seeks

to provide better definition of the causes for anomalies in precipitation

and other atmospheric properties observed as a result of the urban in-

fluence. In addition to METROMEX other inadvertent weather modi-

fication research in which NSF has interest includes studies on the ef-

fees of energy development, expanded agricultural production, and

growing urban sprawl. 64

One current NSF-sponsored project is being conducted by the Uni-

versity of Washington on inadvertent effects induced by coal-fired

electric powerplants. The objective of this research is to determine

63 National Science Foundation, "Summary of Awards : 1976," Division of Advanced En-

vironmental Research and Technology, Washington, D.C. (no publication date), NSF-RA-

760219, p. 97.

64 Federal Council on Science and Technology, Interdepartmental Committee on Atmos-

pheric Sciences, ICAS 20-FY77, pp. 96-97.

284

modern coal powerplants. Such effects may be considerable since the

plants emit much heat, moisture, particulates, and gaseous material

into the atmosphere. Results from the project are expected to aid in

evaluation of environmental effects of these generators and to assist in

the siting of new powerplants. Principal users of the results include

regional, State, and Federal agencies concerned with energy develop-

ment, research, ecology, and land development, as well as engineering

firms involved with air pollution impact studies and control systems. 65

The subject of another inadvertent weather modification study is

the influence on the climates of the Great Plains by widespread irriga-

tion. The main objective of this research is to determine the effects on

precipitation; also of concern are influences on other meteorological

parameters. Results show the existence of rainfall anomalies over an

area comparable in size to the irrigated area, and the effects are most

detectable during wet summer months. 66

METROMEX is a multi-institutional, multiyear research project

sponsored by the NSF and several other Government agencies, at-

tempting to discover causes for, and to assess consequences of, urban-

ind'uced eather effects at St. Louis and vicinity. Primary goals of

METROMEX are the systematic investigation of : 67

The effects of a large urban complex on the frequency, amount,

intensity, and duration of clouds, precipitation, and related severe

weather; and

The conditions whereby the urban complex modifies the precip-

itation process.

Application related goals of the experiment are investigation and

activities : 68

To study and develop techniques for translating the results of

the scientific goals to other urban areas so as to predict the urban-

related changes in other cities ;

To translate relevant results to a wide variety of users in the

scientific, government, and business communities ;

To provide the basis for studies of the potential changes in cli-

mate relating to megalopolis and to major land use changes.

A wide variety of potential users of the information from METRO-

MEX include urban and regional planners, meteorologists, hydrol-

ogists, airport planners and operators, and air quality scientists. The

study is relevant to impacts of increased use of coal, large concentra-

tions of electrical energy generators in power parks, and long range

consequences of air pollution on climate. 69

METROMEX is the world's first major field program planned to

link urban land use with modification of the surrounding weather. The

selection of St. Louis as the site for the experiments was based on the

relatively simple topography of the city and its surroundings, the

existence of farmlands downwind to the east in the "shadow" of the

85 National Science Foundation. Division of Advanced Environmental Research and Tech-

nology, "Summary of Awards : 1976," p. 99.

w Downie and Dirks, "National Science Foundation Weather Modification Program," 1976.

p. 559 .

m "Principal Investigators of Project Metromex. Metromex Update." Bulletin of the

American Meteorological Society, vol. 57, No. 3, Mar. 1976, p. 304.

" Ibid.

» Downie and Dirks, "National Science Foundation Weather Modification Program," 1976.

p. 559.

285

tered airspace above the city which permitted research flights and

atmospheric experiments, and the patterns of urbanization which are

typical of other areas in midlatitude North America. 70

Most of the METROMEX field activities were conducted during the

summer months in a 2,000-square-mile area about 56 miles in diameter

which includes St. Louis and the Alton-Wood River industrialized area

to the northeast. A larger 3,800-square-mile area which includes St.

Louis and extends downward contained the world's largest rain-gage

network. 71 These two areas are shown in figure 12.

O STANDARD WEATHER OBSERVATION SITE

Figure 12. — METROMEX field experiment area, centered in St. Louis, and ex-

tended "downwind" area containing network of rain gages and other instru-

mentation. (From Changnon ad Simonin. Studies of selected precipitation

cases from METROMEX. Illinois State Water Survey, Urbana, 1975.)

70 National Science Foundation, "Do Cities Change the Weather?" Mosaic, vol. 5, No. 3,

summer 1974, p. 30.

1 1bid.

286

been made of the speeds and direction of winds at different heights and

locations, of temperatures, cloud dynamics, precipitation, the nature

and intensity of pollutants, number and sizes of storms, and the quality

and quantity of ground water under different weather conditions. 72

Planning for METKOMEX was initiated in 1969-70 by scientists

from the Illinois State Water Survey, the University of Chicago, the

University of Wyoming, and Argonne National Laboratory. The ex-

perimental field program was launched in 1971, supported in part by

the Atomic Energy Commission, the Department of Health, Educa-

tion, and Welfare, and the State of Illinois, as well as the National Sci-

ence Foundation. Other research groups which later participated in the

project include Stanford Research Institute, Battelle Pacific North-

west Laboratories, the University of Missouri, Sierra Nevada Corp.,

and the University of California at San Diego. 73 Field measurements

in METROMEX were essentially completed during 1976; although

the final METROMEX project report is expected to be published in

the near future, the analysis of the large amount of collected data

should continue for some years.

In a 1976 review of project accomplishments, the following findings

from METROMEX were summarized : 74

1. There is a summer precipitation anomaly at St. Louis, varying

between a 10 and 30 percent excess above background, the location

and intensity of which vary with the prevailing seasonal storm motions

and general character of summer weather.

2. Some individual rain intensity centers of showers or thunder-

storms that develop or pass over St. Louis and over the Alton-Wood

River industrial area appear to be enhanced significantly (94 and 73

percent, respectively) .

3. The major precipitation changes in and east of the urban indus-

trial area seem to occur during squall line or squall zone conditions

when nature is capable of producing moderate to heavy rains, result-

ing in a 60 percent or greater increase in heavy rain (greater than or

equal to 3 cm.) days, a 25 percent increase in thunderstorm activity,

and an 80 percent increase in hailstorms and hail intensities in and

just east of the city. Radar shows a region of maximum development

of large thunderstorms extending to 100 kilometers northeast from

the city.

4. Like most large cities, St. Louis has a marked heat island and an

identifiable minimum in specific humidity. These effects are most

marked at the surface, but often show height-averaged temperature

excesses of 1 degree K and moisture deficits of 1 gram of water vapor

per kilogram of air, relative to nearby rural areas, extending through

the mixing layer to cloud bases.

5. The low-level air flow under light wind conditions is markedly

perturbed by the city and often results in distinct convergence over

and just downwind of the city center.

6. The pattern of production of Aitken condensation nuclei (ACN)

and cloud condensation nuclei (CCN) has been developed for the

area. Elemental emission rates have been measured.

" Ibid.

73 Principal investigators of Project Metromex. Metromex update, 1976, p. 304.

71 Ibid., pp. 304-305.

287

for removal and deposition of urban pollutants.

Mechanisms which, in varying degrees, may be responsible for ob-

served downwind increases in summer precipitation, heavy rain occur-

rences, and hail activity include the large quantities of particulate

and gaseous matter injected by industries and motor vehicles into the

atmosphere, the heat added and heat island effects of the urban area,

the anomalous moisture patterns over the city, and the increased

turbulence and wind perturbation caused by the roughness of the

city's surface and the heat island. 75 It has further been observed that

the 10 to 30 percent increase in summer rainfall over the 2,000-square-

mile area east of St. Louis produces a 15-percent average increase in

streamflow and increased infiltration of ground water. 76

Societal utilization activities

The purposes of this portion of the NSF/RANN" program, con-

cerned with social, legal, environmental, and economic impacts of

weather modification, are "to evaluate societal reaction to weather

modification, to determine societal expectations, and to identify the

needs for the scientific base necessary to bring about successful appli-

cation of weather modification." This research "extends across the

disciplines of political, social, legal, economic, ecological, and physi-

cal sciences in an effort to investigate the impact of weather modifi-

cation technology on man." 77 A number of studies have been sup-

ported by the Foundation in this category, in which these aspects of

weather modification are examined.

A study group on the societal consequences of weather modification

was formed in 1973 at the request of the Interdepartmental Commit-

tee for Atmospheric Sciences (ICAS). This study, sponsored by the

NSF, was designed to examine needs of the Nation for a weather modi-

fication capability and to determine if the present Federal weather

modification program is directed toward meeting those needs. Results

of this investigation, now nearing completion, should be useful in

identifying the alterations or redirections of the Federal program

required to meet societal goals. 78

Studies in social, legal, economic, and ecological aspects of weather

modification that are currently underway or have recently been com-

pleted include the following :

1. Preparation of a compendium on economic impacts of weather

variability, by the University of Missouri. This report was designed

to present quantified relations between weather and certain basic

human activities, such as agriculture and energy use. 79

2. A comparative analysis of public response to weather modifica-

tion, by Human Ecology Research Services, Inc. Building on results

of 6 years of sociological study of public response to weather modifi-

cation, this research will examine social response to weather modifica-

tion in South Dakota and test preliminary hypotheses on acceptance

and rejection processes. Validation of the preliminary hypotheses and

75 Downie and Dirks, "National Science Foundation Weather Modification Program,"

1976. p 559.

7 « Ibid.

77 National Science Foundation. Division of Advanced Environmental Research and Tech-

nology, "Summary of Awards : 1976," p. 101.

78 Downie and Dirks, "National Science Foundation Weather Modification Program," 1976,

p. 560.

288

causal model of the acceptance/rejection process. 80

3. Field experiment to test a hypothesis of the reality, characteris-

tic, and magnitude of extended area effects from weather modification,

by Colorado State University. With increasing evidence that planned

weather modification projects may have effects that extend over broad

geographic areas, this research is an investigation of "downwind''

effects of past experiments in the Rocky Mountains and the Great

Plains of the United States and in Israel, extending an earlier 3-year

study of such effects. Physical and statistical analyses are combined

to determine such extended area effects and to develop hypotheses de-

scribing processes which produce the effects. The project also includes

design of a field experiment based on results of these post hoc analyses

and on current results from modeling studies and physical experi-

ments. This research is intended to provide a basis for evaluating

extended-area effects on societal activities and should be valuable in

formulation of policies on public issues in weather modification. 81

4. Management of nucleating agents used in weather modification

and development of microbial threshold toxicity criteria, by Colorado

State University. The purpose of this research is to provide informa-

tion on possible long-term effects of weather modification nucleating

agents on microbial ecosystems, concentrating on soil and aquatic eco-

systems, which are the most critical areas for accumulation of the

agents. Results of this study will be used to prepare environmental

impact statements for silver iodide seeding in various experimental

and operational cloud seeding programs. 82 In the final phase of this

study, a workshop on the environmental impacts of cloud seeding

materials was conducted in Vail, Colo., in November 1976. The pro-

ceedings of the workshop are expected to be published during 1978.

5. Utilization of weather modification technology : A State govern-

ment decisionmaking study, by Syracuse University. State govern-

ments have taken the lead in developing regulatory policies affecting