Science, and transportation united states senate

Over the years the National Science Foundation has provided support

to various parts of the program, and the U.S. Air Force became an

active participant in the late 1960 , s. Since the Defense Department's

decision to discontinue joint sponsorship in 1973, the program has been

conducted primarily by the Commerce Department. 5 Aircraft from the

Air Force and from the National Aeronautics and Space Administra-

tion (NASA) are available for future experiments and storm moni-

toring.

cumulus cloud towers just outside of the eyewall of the hurricane

causes these clouds to develop vertically until they replace the original

eyewall. The effect is to increase the diameter of the eye, reducing the

maximum winds in the new eyewall.

Under this program, four storms have actually been seeded between

1961 and 1971; the tracks of these storms are shown in figure 15. In

the first storm, Hurricane Esther, clouds near the eyewall were seeded

with relatively small amounts of silver iodide on September 16 and

17, 1961. After the experiment of September 16 there was an apparent

10-percent recorded reduction in maximum wind speed, but little

change was observed on Septemlxu- 17, owing perhaps to seeding in a

3 Ibid.

4 Sheets, Robert C, "Project Stormfury : Questions and Answers." U.S. Department of

Commerce, National Oceanic and Atmospheric Administration, Environmental Research

Laboratories, National Hurricane and Experimental Meteorology Laboratory, Coral Gables,

Fla.. 1077, p. 1.

° Ibid.

cloud-free zone. Similar single-seeding experiments were conducted

on August 23 and 24, 1963, in Hurricane Beulah, with similar results;

that is, an apparent 10- to 14-percent reduction in wind speed on

AujTust 24, but little change on August 23. Errors in delivery of the

seeding agent were subsequently attributed to the poor radar systems

used at the time. 6

Figure 15. — Tracks of all hurricanes which have been seeded from 1961 to 1971.

Times and locations of seedings are indicated. (From Sheets, 1977.)

The greatest apparent success was achieved in experiments on Hur-

ricane Debbie on August 18 and 20, 1969, when maximum wind speed

reductions of 30 and 15 percent, respectively, were observed. The reduc-

tion on August 18 followed five seeding events at 2-hour intervals

over an 8-hour period. Debbie was not seeded on August 19 and

regained strength ; and the observed reduction on August 20 followed

the same seeding procedure used on August 18. Although the results

were exciting, an evaluation problem is that the observed changes fol-

lowing seeding are within the natural hurricane variability. Such

-ccurrences are statistically unlikely, however, since a 15-percent reduc-

;ion would occur less than 10 percent of the time naturally, and a

30-percent reduction is less than 5 percent likely to occur. 7

The last storm to have been seeded under Stormfury was in 1971 on

Hurricane Ginger, a storm which did not have suitable structure for

eye modification experiments. Clouds were seeded well away from the

storm center, and only local effects were detected. Consequently, the

experiment on Ginger ought not to be included with the Esther, Beu-

6 Ibid., pp. 1-2.

7 Ibid., p. 2.

298

lah, and Debbie cases. 8 Results of all known hurricane seeding experi-

Ginger in 1971, results from which are much less definitive than those

of the other cases, are discussed in footnotes to the table.

To minimize the possibility that a populated region might experi-

ence adverse effects from a hurricane seeding experiment, many safe-

guards have been built into Stormfury. Although all results to date

have been either positive or neutral, strict guidelines are maintained

in selection of storms to be seeded. 9 To be eligible for seeding, a hurri-

cane must be predicted to be within 700 nautical miles (1,100 kilome-

ters) of the operating base — Miami or San Juan — for at least 12 hours

and have maximum winds of at least 65 knots. There will be no seed-

ing if the predicted track of the hurricane has more than a 10-percent

chance of approaching within 50 miles of a populated land area with-

in 24 hours after the seeding. 10 Consequently, few opportunities have

TABLE 16.— RESULTS OF EXPERIMENTS IN SEEDING HURRICANE CLOUDS NEAR THE EYEWALL* 2

Approximate

Silver iodide maximum

Number of used 3 wind speed

Nane and date seedings (number, kilogram) change (percent)

Huiricane Esther:

Sept. 16, 1961 1 8/35.13 -10

Sept. 17, 1961 1 8/35.13 <0

Hurricane Beulah:

Aug. 23, 1963 1 55/219.96 <0

Aug. 24, 1963 1 67/235.03 -14

Hurricane Debbie:

Aug. 18, 1969 5 976/185.44 -30

Aug. 20, 1969 5 978/185.82 -15

1 In addition, a hurricane was seeded Oct. 13, 1947, and Hurricane Ginger was seeded Sept. 26 and 28, 1971. The clouds

seeded in these storms were far different and the seedings were done in a different fashion than for the storms listed above.

- From sheets. Project Stormfury : (Questions and Answers. 1977.)

3 Values in column are for totil number of units and total kilograms of silver iodide used each day (based on records

kept by Sheldon D. Elliot, Ji.). Test results indicate the smaller seeding pyrotechnic units make more efficient use of the

silver iodide.

4 Pyrotechnics dropped outside seedable clouds.

been afforded by nature for these experiments. Furthermore, analyses

of past cases, particularly the Debbie experiments, have shown the

need for more sophisticated aircraft and instrumentation, so that-

actual field experiments were discontinued in 1972, while state-of-the-

art aircraft and instrumentation were procured.

Several alternatives have been considered for increasing the number

of suitable experimental situations over a given time period. One ap-

proach would be to move the project to an area where nature provides

more opportunities statistically, such as the western Pacific Ocean. Or,

operations could be combined for a number of areas, such as the North

Atlantic and the eastern North Pacific or the North Atlantic and Aus-

tralian storm areas. Another possibility is to relax selection criteria,

but this does not seem to be a desirable choice for the near future. 11

« Ibid., p. 3.

8 Ibid., p. 4.

10 U S Department of Commerce News. "Stormfury — 1977 to Seed One Atlantic Hurri-

cane." news release, NOAA 77-248. Kockville, Md., Sept. 20, 1977, p. 1.

11 Sheets, "Project Stormfury : Questions and Answers," 1977, p. 5.

299

typhoons of the western Pacific in view of the greater frequency of

suitable storms in that region. These plans were canceled, however,

when protests were received from the Governments of Japan and main-

land China, although the Philippines had been favorable to such ex-

periments. Meteorological satellite observations have shown that hur-

ricanes and tropical storms in the eastern North Pacific (to the west of

Central America) occur more frequently than thought previously, the

number in that region exceeding those in the western North Atlantic in

recent years. Hence, a significant increase in opportunities for hur-

ricane research can be achieved by including eastern Pacific storms. 12

This would require a formal agreement with Mexico, with whose of-

ficials bilateral consultations have begun, and with other countries that

may be directly affected by the hurricanes which are eligible for seed-

ing. 13

In the interim since 1972, new instrumentation has been developed,

especially in the field of cloud physics, and NOAA's instrumented air-

craft has been updated and augmented in preparation for research ex-

periments in 1977 if suitable storms become available. During the 1976

hurricane season, XHEML personnel utilized two new aircraft for the

first time in research hurricane reconnaissance. The complement of five

aircraft now available for Stormfury include three from the NOAA

Research Facilities Center and one each from the Air Force and

NASA.

tional programs to provide data on hurricane structure and microphys-

ical processes and on analytical and theoretical studies to improve

their description and understanding. There has been a major emphasis

on development of mathematical models to simulate the development,

structure, and behavior of hurricanes in the natural state and when

seeded. A more explicit seeding hypothesis has been denned from the

results of this research, which will also benefit evaluation of future

seeding experiments. 14

Plans were formulated for one hurricane seeding experiment in the

Atlantic in 1977, if conditions were suitable, as a rehearsal for full-

scale resumption of multiple experiments during 1978, using the five

newly instrumented aircraft. For hurricanes not suitable or eligible for

such experiments, emphasis will be on acquisition of further informa-

tion on the structure and natural variability of hurricanes on the 24-

to 36-hour timescale characteristic of the seeding experiments. 15

The purpose of Stormfury is the establishment of a modification

hypothesis at a confidence level high enough that the techniques can

be taken from the experimental stage and used operationally. 16 It is

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

pheric S-ienre*. •'National Atmospheric Sciences Program : Fiscal Year 1977." ICAS 20-

FY77, May 1976, p. 89.

13 Epstein. Edward S.. in testimony before the Subcommittee on the Environment and the

Atmosphere, House Committee on Science and Technology. U.S. House of Representatives,

on NOAA's atmospheric and oceanic environmental research and development, Mav 18. 1977.

" Ibid.

mental Committee for Atmospheric Sciences. ICAS 21-FY78. 1977, p. 88.

16 Sheets, "Project Stormfury : Questions and Answers." 1977. p. 10.

300

Stormfury hypothesis, taking at least two or three full hurricane sea-

sons to realize sufficient seeding opportunities. 17

Research Facilities Center {RFC)

The NOAA Research Facilities Center, formerly the Research

Flight Facility, is an operational and technical support organization

whose mission is to provide instrumented aircraft to meet the cloud-

seeding and airborne measurements needs of NOAA and other gov-

ernmentally sponsored research programs. 18

A program of modernization for this facility was begun in fiscal

year 1973 and completed in fiscal year 1977. In fiscal year 1973 three of

the then existing NOAA aircraft (an RB-57 and two DC-6's) were

deactivated, but the C-130 was retained. Two new P-3 aircraft were

acquired in the following years and, with the C-130, were instru-

mented with the most modern and sophisticated meteorological and

oceanographic research measurement systems available. 19 Instrumen-

tation includes inertial/omega/doppler navigation systems, data re-

cording/processing/display systems, dropwindsonde systems, cloud

physics measurement devices, radar systems, cloud-seeding equipment,

gust probes, and photographic systems. 20

Global Monitoring for Climatic Change (GMCC)

This program, considered as part of NOAA's total weather modifi-

cation research effort, is designed to provide quantitative data needed

to understand and predict climatic changes. Data are derived from

measurements of existing amounts of natural and manmade trace con-

stituents in the atmosphere, from which are determined the rates of

increase or decrease in these trace amounts and their possible effects

on climate change. 21

Measurements are made at a network of baseline observations at

four stations — Point Barrow, Alaska ; Mauna Loa, Hawaii ; American

Samoa; and South Pole, Antarctica. Measurements at these baseline

observatories include determination of concentrations of carbon diox-

ide, carbon monoxide, and surface and total ozone; of solar-terrestrial

radiation ; of atmospheric aerosols ; of precipitation chemistry ; and of

standard meteorological variables — wind, temperature, humidity, pre-

cipitation, and pressure. The program also includes the development

of new and improved measurement systems for atmospheric trace con-

stituents for observatory use, data reduction and quality control of

observations, and analysis of the data in terms of climatic variations. 22

17 Epstein, testimony before the Subcommittee on the Environment and the Atmosphere,

House Committee on Science and Technology, U.S. House of Representatives, May 18.

1977.

mental Committee for Atmospheric Sciences, ICAS 21-FY78, 1977, p. 8S.

19 Ibid.

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

phere Sciences, ICAS 20-FY77. 1976. pn. 89-90.

21 Federal Coordinating Council for Science, Engineering, and Technology, Interdepart-

mental Committee for Atmospheric Sciences, ICAS 21-FY78, 1977, pp. 88-89.

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

pheric Sciences. "National Atmospheric Sciences Program : Fiscal Year 197o," ICAS 18-

FY75, May 1974, p. 79.

301

In the past there have been cooperative projects with the University of

the U.S. Energy Research and Development Administration.

The program also includes a seven station network in the continuous

United States for measuring total atmospheric ozone. An eighth sta-

tion is planned for installation in California during fiscal year 1978.

The world standard ozone spectrophotometer is maintained by the

GMCC program, and during fiscal year 1977 an intercomparison of

seven secondary standards of various countries with the NOAA stand-

ard was conducted at Boulder, Colo. 23

During fiscal year 1978 the GMCC program plans are as follows : 24

A careful analysis of a number of atmospheric parameters important in

climatic assessment will be continued and expanded. Global surface and tropo-

spheric temperature records will be updated and interpreted in terms of possi-

ble causes for the observed variability. Total ozone, and the vertical distribution

of ozone, and stratospheric water vapor measurements will be analyzed to detect

trends and further understand the causes for their fluctuations. The dura-

tion of sunshine, probably reflecting cloudiness over the United States will be

studied with updated information. The size of the 300-millibar (ten-kilometer

altitude) circumpolar vortex will be followed ; this quantity shows some promise

of being a monthly or seasonal climatic predictive tool. Fluorocarbon-11 and

-12 measurements at Adrigole, Ireland, will be analyzed in the light of the source

of the air mass reaching that location. Finally, work will continue on the use

of tetroons to delineate boundary layer air trajectories in urban areas and else-

where. This research is of use in certain air pollution problems.

L ig lit hi g suppression

In recent years NOAA has conducted a small experimental effort

in lightning suppression, using fine metalized nylon fibers — or chaff —

as a seeding agent. Based on a theoretical model, a field program was

initiated in 1972 to test the chaff seeding concept and to determine the

effect of such seeding on the electric fields of thunderstorms. Storms

are seeded from below, and, based on data from 10 seeded storms and

18 unseeded control storms, the number of lightning occurrences was

about 25 percent of those observed in the control storms. The experi-

ments were not strictly randomized; however, the observed differ-

ences between seeded and control storms was statistically significant. 25

' During the 1975 Apollo-Soyuz launch, aircraft were on standby

for possible lightning-suppression flights at Cape Canaveral. Re-

search on thunderstorm electrofication at the Kennedy Space Center is

a cooperative program with NOAA, NASA, the Department of De-

fense, and several universities. 26

M odification of extratropical severe storms

Research has been conducted by NOAA on the possibilities of mod-

erating and modifying mesoscale cloud systems associated with severe

storms, including thunderstorms, tornadoes, and cyclonic storm sys-

23 Federal Coordinating Council for Science, Engineering, and Technology, Interdepart-

mental Committee for Atmospheric Sciences, ICAS 21-FY78, 1977, p. 89.

2 * Ibid.

25 Townsend, John W., Jr., in U.S. Congress, House of Representatives, Committee on Sci-

ence and Technology, Subcommittee on the Environment and the Atmosphere, "Weather

Modification." hearings, 94th Cong., 2d sess., June 15-18, 1976. Washington, D.C., U.S.

Government Printing Office, 1976, p. 171.

16 Ibid., p. 172.

34-857 O - 79 - 22

302

atmospheric chemistry that are aimed at understanding the role of

particular materials as condensation and ice-freezing nuclei and in

influencing the dynamics and structures of clouds. 27 Research objec-

tives of this program of NOAA's Atmospheric Physics and Chemis-

try Laboratory ( APCL) include : 28

1. Expanding current knowledge and documenting descriptions

of the behavior of extratropical weather systems ;

2. Improving the accuracy and detail in short-range predic-

tions — 24 hours or less — of both natural and modified severe

weather systems through development, verification, and refine-

ment of numerical mesoscale models ;

3. Identifying and testing, through numerical experiments

using the recently mesoscale model, modification hypotlieses, and

procedures that appear to inhibit or suppress severe attending

extratropical weather systems ;

4. Establishing data requirements for field programs including

observations needed for developing an understanding and a pre-

diction capability through numerical modelling ; and

5. Designing field modification experiments to test the most

promising hypotheses.

Research at APCL includes efforts to measure and define relation-

ships between numbers and chemical composition of natural and man-

made nuclei and aerosols and to determine their impact on cloud and

precipitation mechanisms. Nuclei inventories are made prior to, dur-

ing, and after cloud-seeding experiments to permit evaluation of the

efficiency of artificial nuclei generating techniques, their efficiency in

cloud glaciation, and atmospheric residence times. Research is also

directed toward optimization of cloud-seeding techniques and existing

analysis methods. 29

DEPARTMENT OF DEFENSE

Introduction

The weather modification research, development, and operations

carried on by the Department, of Defense are intended primarily to

protect men and materials from environmental hazards and to be

aware of current and developing weather modification technologies

in order to avoid technological surprise by potential adversaries. 30 31

Recent and planned expenditures by Defense for both operational and

research efforts in weather modification for fiscal year 1977 through

fiscal year 1979 are shown in table 17.

Air Force fog dispersal operations

The U.S. Air Force conducts the only operational weather modifi-

cation activities in the Department of Defense and the only regular

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

phric Seines. ICAS 18-FY75. 1974. pp. 77-78.

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

pheric Sciences, ICAS 20-FY77, 1976. p. 89.

: » Ibid.

80 Ruggles, Kenneth \V., briefing on Department of Defense weather modification programs

for the Weather Modification Advisory Board. Washington. D.C.. May 31. 1977, p. 1.

yl See app. B for a statement of the current official position of the Department of Defense

on weather modification.

303

identifiable federally sponsored operational program. This Air Force

bases — Fairchild AFB, Washington, and Elmendorf AFB, Alaska —

permitting use of these airfields and improvement of flight safety dur-

ing cold fog conditions. At these installations a ground-based disper-

sion system is used for spraying liquid propane into the atmosphere

upwind of the target area to be cleared. Vaporization of the propane

induces local cooling, with attendant formation and growth of ice

crystals at the expense of water droplets, dissipating the fog. 32

A capability is also maintained by the Air Force for dispersal of

crushed dry ice from TTC-130 weather reconnaisance aircraft if the

need should arise for dissipation of cold fog at locations not equipped

with ground-based systems.

TABLE 17.— DEPARTMENT OF DEFENSE PLANNED EXPENDITURES FOR WEATHER MODIFICATION OPERATIONS

AND RESEARCH, FISCAL YEAR 1977 THROUGH FISCAL YEAR 1979

•fin thousands of dollars]

Fiscal year—

1977

1978

Operations: Air Force 1

53

82

Research and development: 2

Army: Cold fog dispersal..

237 .

226

Air Force:

Cold fog and stratus dispersal

Warm fog dispersal 3

550

1,400

2, 200

1,200

2,413