Science, and transportation united states senate

1,914

ing on Department of Defense weather modification programs for the Weather Modification Advisory Board, May 31, 1977.

■ Data for basic research on weather modification differs from entries in table 2, based on 1977 inputs to ICAS; data

above on research and development were received Apr. 27, 1978, from Col. Elbert W. Friday, Office of the Under Secretary

of Defense for Research and Engineering.

3 Includes costs for engineering development of a warm fog dispersal system as well as expenditures for basic research

n warm fog dispersal.

The dry ice particles falling through the fog sublimate, causing a

large temperature decrease in their vicinity, so that the resulting ice

particles which form and grow at the expense of supercooled fog drop-

lets will fall out as snow. This capability has not been used since fiscal

year 1976, and the dry ice crushers are currently stored at Keesler

AFB, Miss. The Air Force plans continued use of these techniques,

however, to reduce adverse weather effects due to fog on airfield opera-

tions and flight safety. 33

Army research and development

Research and development efforts in weather modification are con-

ducted by all three services in the Department of Defense to some

extent. Although the Army has terminated its technical base program,

one equipment item, a mobile cold fog dissipator, is in the engineering

32 Ruggles. briefing on Department of Defense weather modification programs for the

Weather Modification Advisory Board, 1977. p. 1.

33 Ibid., p. 2.

304

dissipating supercooled fog at Army airfields, helipads, and artillery

sites, employs the propane dispenser technology to remove fog in local

areas. The system is to be field tested in Alaska during 1978. 35 Army

research on warm fogs, now terminated, had been directed toward

dispersal through a variety of possible techniques, including helicopter

downwash, use of hygroscopic materials, and application of heat.

Navy research and development

The research weather modification effort of the Navy is now con-

cerned with evaluation of weather modification experimental data and

of state-of-the-art techniques in order to avoid technological surprise.

Instruments and methods have been developed to study fog, clouds,

and natural weather processes, utilizing measurements of dewpoint,

liquid water distribution, cloud and fog droplet and ice particle sizes,

and number of cloud condensation nuclei. Recent investigations have

been directed toward generation, characterization, and evaluation of

active agents to inhibit or enhance the formation, growth, coalescence,

removal, and frequency of cloud and fog water droplets and toward

understanding the mechanisms and theories applicable to these proc-

esses. Numerical modeling of the fog or cloud system has been used to

design experiments and to define and evaluate the physical processes

which occur in field experiments. 36

The principal ongoing Navy research program in weather modifica-

tion has been a statistical analysis to evaluate data from the Santa

Barbara cold cloud modification experiments. 37 While not a large

effort, it is an important attempt to examine alternatives for reducing

uncertainty in evaluating weather modification experiments. No fur-

ther field experiments are currently planned by the Navy. 38

In the recent past, the Navy has also sponsored major projects

related to warm fog modification. Field experiments were conducted

by the Naval Weapons Center, China Lake, Calif. ; computer simula-

tion studies have been underway at the Navy Environmental Predic-

tion Research Facility. Monetery, Calif.; the Naval Research Labo-

ratory, Washington, D.C., has been developing instrumentation and

conducting studies related to cloud particle and cloud nuclei prop-

erties; a standard evaluation site near Macon. Ga., was under develop-

ment; and the Office of Naval Research has provided support for a

variety of investigations. 39

Air Force research and development

Air Force research projects in weather modification are currently

directed toward dispersal of warm fog and stratiform clouds. Devel-

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

pheric Sciences. ICAS 20-FY77. 1976. p. 91.

35 Ruggles. briefing on Department of Defense weather modification programs for the

Weather Modification Advisory Board. 1977. p. 2.

38 Federal Council for Science and Technology. Interdepartmental Committee for Atmos-

pheric Sciences. ICAS 20-FY77. 1976. p. 91.

37 Ruggles. "Briefing on Department of Defense Weather Modification Programs for the

Weather Modification Advisory Board." 1977. p. 2. (The second Santa Barbara randomized

seeding project was conducted by North American Weather Consultants from 1967 through

1970. under contract to the Naval Weapons Center, China Lake, Calif.)

38 Ibid.

39 Moschandreas. Demetrios J.. "Present Capabilities To Modify Warm Fog and Stratus."

Geomet. Inc.. technical report for the Office of Naval Research and the Naval Air Systems

Command, contract No. N00014-71-C-0271, Geomet report No. EF-300, Jan. 18, 1974, p. 5.

305

tual installation at an Air Force base is underway. The system devel-

opment tests will be conducted at Otis AFB, Mass., and the field pro-

gram will be supplemented with modeling studies in order to develop

relationships between windspeed and the heat and thrust requirements

of the dispersal system. 40

The system includes a number of combustors positioned along a

runway and its approaches. The burn rate of the combustors is to be

controlled precisely by a computer which monitors meteorological

instruments in the runway area. 41 Such a system, using both heat and

thrust, is termed a thermokinetic system. The expected warming of

the air over runway and approaches by 2° to 3° C above ambient

temperature should result in lowering the relative humidity and

evaporation of the fog droplets. Figure 16 shows the expected clear-

ing geometry for the system. Upon successful completion of the field

tests in 1979, it is expected that an operational warm fog dispersal

system will be designed and installed at an Air Force base by 1982. 42

The bulk of the Air Force research funding shown in table 17 covers

development and testing of this system at Otis Air Force Base. 43

Figure 16. Clearing Geometry of the Warm Fog Dispersal System, Under De-

velopment by the U.S. Air Force. (From Kunkel. The Design of a Warm Fog

Dispersal System. 1977.)

Another Air Force project is directed toward development of an

operational technique for dispersal of supercooled stratus clouds. Field

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

pheric Sciences. ICAS 20-FY77. 1976. p. 91.

41 Ruggles, "Briefing on Department of Defense Weather Modification Programs for the

Weather Modification Advisory Board, ' 1977, p. 3.

42 Kunkel. Bruce A.. "The Design of a Warm Fog Dispersal System," Sixth Conference on

Plannpd and Inadvertent Weather Modification, American Meteorological Society, Cham-

paign-Urbana, 111., Oct. 10-13, 1977, pp. 174-176.

43 Ruggles, "Briefing on the Department of Defense Weather Modification Programs for

the Weather Modification Advisory Board, 1977, p. 3.

306

ties and types of seeding materials suitable for dispersal under a wide

range of meteorological conditions. 44 Under the auspices of the Air

Force Geophysics Laboratory, field tests on supercooled stratus dis-

persal were conducted during February 1977 in Michigan, using a

dispensing system which deployed silver iodide. The objective of these

tests was to produce clearing over a predetermined ground target. In

all cases, except when the minimum cloud temperature was greater

than —6° C, clearings were effected. The tests demonstrated that such

clearings can be produced with a small lightweight delivery system

adaptable for use on tactical aircraft and that targeting is not a

serious problem. At a steep elevation angle ground targets were clearly

visible after clearing, but they were obscured by residual glaciated

clouds in the clearings when the look angle was more shallow. It is

considered possible that some of the residual might have been due to

overseeding. In another planned series of tests, attempts will be made

to optimize the seeding rate to improve visibilities in the cleared area.

Other seeding materials such as formaldehyde and propane, which are

active in the 0° C to — 6° C temperature range, will also be tested,

since silver iodide is not active above —6° C. A theoretical study is

also planned to determine the effects various forms of radiant energy

could have on dispersal of warm stratus clouds. 45

verseas operations

In recent years there had been much concern on the part of the

Congress and the American public over the use of weather modifica-

tion as a weapon of war in the war in Vietnam. A full disclosure of

these activities and a discussion of their effectiveness were provided

by the Defense Department in hearings before the Senate Committee

on Foreign Relations in 1974. 46 In a recent briefing before the U.S.

Commerce Departments National Weather Modification Advisory

Board, it was stated that the current weather modification activities of

the Department of Defense ' ; are in accord with the provisions of the

Convention on the Prohibition of Military or Any Other Hostile Use

of Environmental Modification Techniques, signed at Geneva on May

18, 1977. ?; 47 ' 48

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

pheric Sciences. ICAS 20-FY77, 1976, p. 91.

4 " Ruggles. "Briefing on Department of Defense Weather Modification Programs for the

Weather Modification Advisory Board, ' 1977, pp. 3—4.

46 U.S. Congress. Senate. Committee on Foreign Relations, Subcommittee on Oceans and

International Environment. "The Need for an International Agreement Prohibiting the Use

of Environmental and Geophysical Modification as Weapons of War and Briefing on Depart-

ment of Defense Weather Modification Activity.' hearing, 93d Cong.. 2d sess.. Jan. 25 and

Mar. 20. 1974. Washington. U.S. Government Printing Office. 1974. 123 pp. (Contains

the top secret hearing held on Mar. 20. 1974. which was made public on May 19. 1974.)

*' IUiggles. "Briefing on Department of Defense Weather Modification Programs for the

Weather Modification Advisory Board." 1977. p. 4.

48 A full discussion of the developments leading to the signing of this convention is con-

tained in ch. 10 of the report, entitled "International Aspects of Weather Modification."

The full text of the draft treaty is in app. C

307

Perhaps less well known than the use of weather modification in

purposes carried out by the U.S. Air Force in the Philippine Islands at

the request of the Philippine Government, This rain enhancement

project, named GROMET II, was conducted from April through

June of 1969, using airborne pyrotechnic seeding devices. The Air

Force had operational responsibility for the project, while the Naval

Weapons Center provided technical direction, and cooperation was

also provided by Philippine agencies. Although precise determination

of increased rainfall resulting from seeding was not possible, it was

concluded, nevertheless, that rainfall augmentation from tropical

cumulus clouds was accomplished in a simple operational manner.

Benefits derived from the project included improvement in the agri-

culture, increased sugar production, and augmented crops of rice and

corn. In addition, local personnel were trained in seeding operations,

and, owing to the success of GROMET II, the Government of the

Philippines conducted similar operations in subsequent years. 49 Other

operational attempts to assist in drought mitigation were conducted by

the Air Force in Panama, Portugal, and Okinawa.

DEPARTMENT OF TRANSPORTATION

The weather modification research and development activities of the

Department of Transportation have been conducted by the Federal

Aviation Agency (FAA), whose interest has been focused on warm

fog dispersal and the development of systems for the removal of such

fogs from airport runways. The current modest effort by the FAA is

concerned with monitoring the U.S. Air Force development program

for a warm fog dispersal system 50 and with considerations of imple-

menting recommendations of a major FAA-sponsored warm fog

dispersal systems study which was completed recently. 51

The FAA engineering report was completed in November 1975, fol-

lowing a 2-year study by an in-house task force that was charged with

determining the feasibility of a ground-based warm fog dispersal

system for a selected U.S. airport. The study included preparation of

a conceptual design and cost estimates for the proposed system. Given

that the actual mechanisms to be used for fog clearings had to be both

theoretically and operationally sound, the task force eliminated a

number of more exotic schemes and concentrated on design and cost

estimates for two candidate fog dispersal approaches — (1) a modified

passive thermal fog dispersal system and (2) a thermokinetic fog dis-

49 St. Amand. Pierre. D. W. Reed. T. L. Wright, and S.D. Elliott, "GROMET II : Rainfall

Augmentation in the Philippine Islands," Naval Weapons Center, NWC TP 5097, China

Lake. Calif.. May 1971. 110 pp.

50 See discussion of weather modification research and development activities of the De-

partment of Defense, beginning on p. 303.

51 FAA Systems Research and Development Service, fog dispersal task team, "Ground-

based Warm Fog Dispersal Systems: Technique Selection and Feasibility Determination

with Cost Estimates," Federal Aviation Administration, report No. FAA-RD-75-126. Final

report. Washington, D.C, November 1975, 67 pp.

308

result of a small temperature rise; however, whereas in the one case

the natural convective forces of the heated atmosphere and the winds

are relied upon to mix and transport the heat energy throughout the

fog, the thermokinetic technique uses jet engines to transport the

heated air into the fog by thrust. The latter technique produces some

turbulence but not to a disqualifying degree. 52 In selecting an airport

it was thought important that there be a high annual occurrence of

fog and a high air traffic density during the hours of fog for the sys-

tem to be cost-effective. From 38 U.S. airports that were screened as

potential candidates, Los Angeles International Airport (LAX) was

selected as the airport which, in 1981, would gain the highest poten-

tial benefit from a fog dispersal system located along one of its run-

ways. 53 Figure 17 shows the preliminary configuration of a single

line of burners for a fog dispersal system installed along runway 25L

at LAX. Costs for such an installation are of the order of $10 million,

but would vary, depending on the kind of system selected and the cate-

gory of landing clearance for which the system is designed. Cost-to-

benefit ratios vary accordingly, but the study showed that 15 U.S. air-

ports turned out to have at least a 1 :1 cost /benefit ratio.

NORTH

LAX - RUNWAY 25L

A - 5000 ft. 5 to 30

B - 1847 ft. 9 to 55

C - 1847 ft. 17 to 100

D - 1856 ft. 20 to 120

E - 814 ft. 13 to 80

D.H. = Decision Height

TOTAL HEAT GENERATOR LINE LENGTH - 19274 ft. for CAT I, line sections A, B, C, D.

14504 ft. for CAT II, line sections A, B. E.

Figure 17. — Preliminary configuration of proposed single line of burners for

warm fog dispersal system for runway 25L at Los Angeles International Air-

port. (From Department of Transportation report FAA-RD-75-136, by FAA

Fog Dispersal System Task Team, 1975.)

The FAA has contemplated participation in a joint warm fog dis-

persal demonstration project with Los Angeles International Airport

and the U.S. Air Force; however, such a project has not yet been

■ Ibid., p. 6.

63 Ibid., pp. 10-13.

309

agreed upon. In discussions with the Air Transport Association on

tion about increased landing fees to finance the system. 54

DEPARTMENT OF AGRICULTURE

The Forest Service within the Department of Agriculture has car-

ried on weather modification research aimed at development of meth-

ods for suppressing cloud-to-ground lightning activity as a means

of reducing forest fires in the intermountain west. Forest protection

agencies developed early interest in possible application of weather

modification to the forest-fire problem, first by considering the possi-

bility of increasing moisture through rainfall on dry forests or on the

fires directly and, later, by examining the potential for reducing di-

rectly the fire-starting capabilities of lightning itself.

The Forest Service established in 1953 a long-range program of

lightning research, called Project Skyfire, as part of its overall fire

research program. Project Skyfire has been the oldest continuously

performed weather modification program in the United States until its

recent demise. 55 Two broad objectives of the project were (1) to obtain

a better understanding of the occurrence and characteristics of light-

ning storms and lightning fires in the northern Rocky Mountain region

and (2) to investigate the possibility of preventing or reducing the

number of lightning fires by applying techniques of weather modifica-

tion. 56

After several years of gaining basic information about mountain

thunderstorms, the first cloud seeding experiments were conducted

under Skyfire in 1956 in the San Francisco peaks area of Arizona, 57

Beginning in 1960 field programs were conducted for a number of

summer seasons in the mountainous areas of western Montana. These

programs included both experiments designed to test the effects of

seeding on lightning frequency and the development of techniques for

observation and careful measurement of the characteristics of light-

ning strokes. A portion of the research during the 1960's was jointly

sponsored by the Forest Service and the National Science Founda-

tion. 58 Other participants in Skyfire have included the National

Weather Service, the National Park Service, the Bureau of Land

Management, several universities, and commercial contractors. Results

of these experiments were encouraging but have not been conclusive.

Field and laboratory experiments have shown the relationship of ice

crystals to the lightning process. Skyfire field experiments seemed to

show about one-third fewer cloud-to-ground lightning strokes for

54 Bromley. Edmond. briefing on the Department of Transportation weather modification

program before the Department of Commerce National Weather Modification Advisory

Board. May 31. 1977.

55 Barrows. J. S., "Preventing Fire From the Sky." Yearbook Separare No. 3589 (reprinted

from the 1968 Yearbook of Agriculture), U.S. Department of Agriculture, Washington, U.S.

Government Printing Office. 1968. p. 219.

58 Fuquay, Donald M. and Robert G. Baughman, "Project Skyfire Lightning Research,"

U.S. Department of Agriculture. Forest Service, final report to National Science Foundation,

Missoula. Mont. December 1969. p. 3.

57 Barrows, "Preventing Fire From the Sky," 1968. p. 221.

58 Fuquay and Baughman, "Project Skyfire Lightning Research," 1969, p. 3.

310

seeded clouds. Later experiments were carried out in Alaska in 1973 in

Montana had been concentrated on the long continuing current light-

ning stroke which seemed to be the most destructive, results in Alaska

indicated that fires could be started there with shorter strokes because

the ground cover was more combustible. Thus, the Montana results

were not transferable. 59

All field experiments in weather modification under Project Sky-

fire were terminated in 1973, since they were not considered to be cost-

effective, and work subsequent to that time has been concentrated on

analysis of data from previous experiments and on reporting to fire

protection agencies on the prospects for lightning suppression. With

conclusion of this wrap-up work during 1977, the Forest Service pro-

poses no further research in weather modification in the immediate

future. 60

DEPARTMENT OF ENERGY

Weather modification research in this Department is concerned only

with inadvertent changes to weather and climate as a result of man's

activities related to energy development and consumption. Reporting

of this research through the Interdepartmental Committee for Atmos-

pheric Sciences (ICAS) as weather modification was begun with

fiscal year 1975 funding by the former Energy Research and Develop-

ment Administration (ERDA), recognizing that a significant amount

of research on inadvertent modification of weather and climate had

been part of their agency effort. 61

Within the former agency's atmospheric science program, pertinent

studies address atmospheric chemistry of energy production pollutants,

removal processes, interactions with atmospheric processes, radioactive

properties of the atmosphere, and the effects of waste heat and moisture