Artificial rain making methods seminor report

ARTIFICIAL RAIN MAKING METHODS
Dept of M.E. ACEM Page 1
1. INTRODUCTION
Rain is liquid water in the form of droplets that have condensed from atmospheric
water vapour and then become heavy enough to fall under gravity. Rainfall is responsible for
depositing most of the fresh water on the Earth. It provides suitable conditions for many types
of ecosystems, as well as water for hydroelectric power plants and crop irrigation.
1.1 Water cycle
Rainfall is a major component of “Water cycle”. The water cycle, also known as the
hydrological cycle or the hydrologic cycle, describes the continuous movement of water on,
above and below the surface of the Earth. The mass of water on Earth remains fairly constant
over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline
water and atmospheric water is variable depending on a wide range of climatic variables. The
water moves from one reservoir to another, such as from river to ocean, or from the ocean to
the atmosphere, by the physical processes of evaporation, condensation, precipitation,
infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different
forms: liquid, solid (ice) and vapour.
Fig-1: Water-cycle process
The transformation of water from liquid to gas phases as it moves from the ground or
bodies of water into the overlying atmosphere is called as “Evaporation”. The release of
water vapour from plants and soil into the air is called “Transpiration”. The transformation of
water vapour to liquid water droplets in the air, creating clouds and fog is known as
“Condensation”. Condensed water vapour that falls to the Earth's surface is known as

“Precipitation”. Most precipitation occurs as rain, but also includes snow, hail, fog drip and
sleet. Water flows vertically through the soil and rocks under the influence of gravity is
known as “Percolation”.
The water cycle involves the exchange of energy, which leads to temperature changes.
When water evaporates, it takes up energy from its surroundings and cools the environment.
When it condenses, it releases energy and warms the environment. These heat exchanges
influence climate.
The evaporative phase of the cycle purifies water which then replenishes the land with
freshwater. The flow of liquid water and ice transports minerals across the globe. It is also
involved in reshaping the geological features of the Earth, through processes including
erosion and sedimentation. The water cycle is also essential for the maintenance of most life
and ecosystems on the planet.
Due to failure in the process of water cycle the Precipitation deficiency and Dry
season will occurs and it greatly increases drought occurrence.
1.2 Drought
A drought is a natural disaster of below-average precipitation in a given region;
resulting in prolonged shortages in the water supply, whether atmospheric, surface water or
ground water. A drought can last for months or years, or may be declared after as few as 15
days. It can have a substantial impact on the ecosystem and agriculture of the affected region
and harm to the local economy.
Fig-2, 3: Effect of drought on environment and wild life

There are many ill effects of droughts, they are
i. Destruction of crops
ii. Forest fires
iii. Famine caused by crop destruction
iv. Wildlife destruction
v. Hydroelectric plants lose source of power
vi. Hunger and famine
vii. Death of farm animal
viii. Tree destruction and damage
ix. Diseases caused by lack of clean water, etc.....
By lack of water resources the crops are not growing to maturity stage, it causes the
huge loss to farmers and it is main reason to increase the cost of living. The lack of clean
water causes the harmful diseases like Diarrheal, Cholera, Typhoid fever, and Guinea worm
disease. Water related diseases cause more than 3.4 million deaths each year. The forest fires,
wildlife destruction, death of farm animals and humans due to hunger. To drain these
disasters the artificial Rainmaking methods are invented.
1.3 Rain making
Rainmaking, also known as artificial precipitation, artificial rainfall and pluviculture,
is the act of attempting to artificially induce or increase precipitation, usually to stave off
drought. According to the clouds' different physical properties, this can be done using
airplanes or rockets to sow to the clouds with catalysts such as dry ice, silver iodide and salt
powder, to make clouds rain or increase precipitation, to remove or mitigate farmland
drought, to increase reservoir irrigation water or water supply capacity, or to increase water
levels for power generation.
2. HISTORY OF DEVELOPMENT
Louis Gathmann in 1891 suggested shooting liquid carbon dioxide into rain clouds to
cause them to rain. During the 1930s the Bergeron-Findeisen process theorized that
supercooled water droplets present while ice crystals are released into rain clouds would
cause rain. While researching aircraft icing, General Electric (GE)'s Vincent Schaefer and
Irving Langmuir confirmed the theory. Schaefer discovered the principle of cloud seeding in

July 1946 through a series of serendipitous events. Following ideas generated between him
and Nobel laureate Langmuir while climbing Mt Washington in New Hampshire, Schaefer,
Langmuir's research associate, created a way of experimenting with supercooled clouds using
a deep freeze unit of potential agents to stimulate ice crystal growth, i.e., table salt, talcum
powder, soils, dust, and various chemical agents with minor effect.
Dry ice and silver iodide agents are effective in changing the physical chemistry of
super-cooled clouds, thus useful in augmentation of winter snowfall over mountains and
under certain conditions, in lightning and hail suppression. While not a new technique,
hygroscopic seeding for enhancement of rainfall in warm clouds is enjoying a revival, based
on some positive indications from research in South Africa, Mexico, and elsewhere. The
hygroscopic material most commonly used is table salt. It is postulated that hygroscopic
seeding causes the droplet size spectrum in clouds to become more maritime (bigger drops)
and less continental, stimulating rainfall through coalescence. From March 1967 until July
1972, the US military's Operation Popeye cloud-seeded silver iodide to extend the monsoon
season over North Vietnam, specifically the Ho Chi Minh Trail. The operation resulted in the
targeted areas seeing an extension of the monsoon period an average of 30 to 45 days. The
54th Weather Reconnaissance Squadron carried out the operation to "make mud, not war".
An attempt by the United States military to modify hurricanes in the Atlantic basin
using cloud seeding in the 1960s was called Project Stormfury. In Australia, the
Commonwealth Scientific and Industrial Research Organisation (CSIRO) conducted major
trials between 1947 and the early-1960s:
 1947 – 1952: CSIRO scientists dropped dry ice into the tops of cumulus clouds. The
method worked reliably with clouds that were very cold, producing rain that would
not have otherwise fallen.
 1953 – 1956: CSIRO carried out similar trials in South Australia, Queensland and
other states. Experiments used both ground-based and airborne silver iodide
generators.
 Late-1950s and early-1960s: Cloud seeding in the Snowy Mountains, on the Cape
York Peninsula in Queensland, in the New England District of New South Wales, and
in the Warragamba catchment area west of Sydney.

Only the trial conducted in the Snowy Mountains produced statistically significant rainfall
increases over the entire experiment.
In India,
 1951- Tata firm over Western Ghats using ground based silver iodide generators.
 1957-1966 National physical Laboratory (NPL) conducted experiments using ground
based generators, in North India.
 1973-1974, 1976 and 1979-1986 IITM, experiments with clouds seeding shows 24%
increase in the rainfall.
 1983-1994 Tamil nadu Govt. Carried out cloud seeding.
 1990-2000 witnessed many advances in the airborne instrumentation, radars, flares
and software. They got imported to India in new millennium.
 2003 Karnataka Govt. has initiated cloud seeding with modern gradates like radars
and aircrafts Maharashtra Govt. followed a month later.
 2003-2009 A.P. Govt. has conducted cloud seeding operations perhaps the longest
and biggest programme in south East Asia.
3. THE PRINCIPLE OF ARTIFICIAL RAIN
In the troposphere, the temperature of the atmosphere descends with altitude.
Therefore the clouds in the troposphere are lower in temperature as they rise in altitude and
vice versa. When the temperature of a cloud is above 0 °C, the cloud is called a warm cloud;
when it is below 0 °C it is called a cold cloud. Inside a warm cloud, small water drops will
become large ones through collision and coalescence, and will finally break the buoyancy of
the cloud and fall out of its bottom to become rainfall to the ground. Likewise, inside a cold
cloud, ice crystals can also grow to a size where they can break the buoyancy and fall out of
the cloud's bottom, and when they pass through a temperature of 0 °C they will melt and
become rain drops, also providing the ground with rain. When the water drops in a cloud are
too small or there are not enough ice crystals to create rainfall, we can use artificial ways to
create ice crystals or help small water drops grow, and thereby facilitate the formation of
precipitation. This human influenced weather phenomenon is called artificial rain. There are
many ways to make rain in a warm cloud, e.g. spraying water drops, hygroscopic powder or
liquid (sodium chloride), etc, and letting the water drops grow though collision and

coalescence to finally become rain. There are also many ways to make rain in a cold cloud,
but the most common way is to use dry ice or silver iodide.
Fig-4: Principle of artificial rain
This is mainly because the temperature of dry ice is -78 °C. Spreading dry ice in a
cold cloud lacking ice crystals will rapidly reduce its temperature. Therefore we directly
transform super cooled water into ice crystals, which will eventually become rain without the
help of ice-crystal nuclei. Silver iodide, on the other hand, is a very effective ice-crystal
nucleus. By adding it to a cloud, silver iodide acting as an ice-crystal nucleus can facilitate
the solidification of water drops below -5 °C into ice crystals. Through the growing process
the ice crystals under the coexistence of water drops, the rain will be formed.
4. THE EFFECTIVINESS OF ARTIFICIAL RAIN
According to the evaluation by meteorological researchers with years of experience in
rainmaking, artificial rainmaking by long-term planning of ground silver iodide burning can
on average increase precipitation by 10%; whereas using aerial artificial rainmaking, by
spreading silver iodide to appropriate convective thunderstorm cells, can increase
precipitation by 20%. However, the effectiveness of artificial rain is still influenced by
complicated factors such as weather conditions in each region, implementation skills, and
administrative coordination, and is therefore still uncertain in some areas and also increases
the effective precipitation.

4.1 Effective Precipitation
Effective Precipitation (EP) is the amount of precipitation that is actually added and
stored in the soil. During drier periods less than 5mm of daily rainfall would not be
considered effective, as this amount of precipitation would likely evaporate from the surface
before soaking into the ground. Effective precipitation enters the soil and becomes available
to the plant. The moisture deficit is calculated by subtracting the effective precipitation from
the calculated evapotranspiration.
4.2 How Effective Precipitation is calculated
During extended warm dry periods rainfall less than 5 mm may not add any moisture
to the soil reservoir as most of it is evaporated before entering the soil. Therefore, if rainfall is
less than 5mm the Farmwest calculator does not enter a value for effective precipitation. In
addition, only 75% of the rainfall over 5mm is considered to be effective precipitation.
The equation used in the Farmwest calculator is:
Effective Precipitation (mm) = (RAIN - 5) x 0.75
5. TYPES OF ARTIFICIAL RAIN METHODS
Mainly there are 3 methods to produce artificial rainfall, they are
5.1. Cloud seeding method.
i. Static cloud seeding.
ii. Ground generator seeding.
iii. Rocket cloud seeding.
Fig-5: Cloud seeding methods
5.2. Cloudbuster.
5.3. Bioprecipitation.

5.1. Cloud seeding
5.1.1. Introduction
Cloud seeding is a type of weather modification that aims to change the amount or
type of precipitation that falls from clouds by dispersing substances into the air that serve as
cloud condensation or ice nuclei, which alter the microphysical processes within the cloud.
The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are
also widely practised in airports where harsh weather conditions are experienced. Cloud
seeding also occurs due to ice nucleates in nature.
5.1.2. Methodology
The most common chemicals used for cloud seeding include silver iodide, potassium
iodide and dry ice (solid carbon dioxide). Liquid propane, which expands into a gas, has also
been used. This can produce ice crystals at higher temperatures than silver iodide. After
promising research, the use of hygroscopic materials, such as table salt, is becoming more
popular.
In cloud seeding, increase in snowfall takes place when temperatures within the
clouds are between −4 and 19 °F (−20 and −7 °C).Introduction of a substance such as silver
iodide, which has a crystalline structure similar to that of ice, will induce freezing nucleation.
In mid-altitude clouds, the usual seeding strategy has been based on the fact that the
equilibrium vapour pressure is lower over ice than over water. The formation of ice particles
in super cooled clouds allows those particles to grow at the expense of liquid droplets. If
sufficient growth takes place, the particles become heavy enough to fall as precipitation from
clouds that otherwise would produce no precipitation. This process is known as "static"
seeding.
Seeding of warm-season or tropical cumulonimbus (convective) clouds seeks to
exploit the latent heat released by freezing. This strategy of "dynamic" seeding assumes that
the additional latent heat adds buoyancy, strengthens updrafts, ensures more low-level
convergence, and ultimately causes rapid growth of properly selected clouds.
Cloud seeding chemicals may be dispersed by aircraft or by dispersion devices
located on the ground (generators or canisters fired from anti-aircraft guns or rockets). For

release by aircraft, silver iodide flares are ignited and dispersed as an aircraft flies through the
inflow of a cloud. When released by devices on the ground, the fine particles are carried
downwind and upward by air currents after release.
An electronic mechanism was tested in 2010, when infrared laser pulses were directed
to the air above Berlin by researchers from the University of Geneva. The experimenters
posited that the pulses would encourage atmospheric sulphur dioxide and nitrogen dioxide to
form particles that would then act as seeds.
5.1.3. Effectiveness
Whether cloud seeding is effective in producing a statistically significant increase in
precipitation is still a matter of academic debate, with contrasting results depending on the
study in question, and contrasting opinion among experts.
In 2003 the US National Research Council (NRC) released a report stating, "Science
is unable to say with assurance which, if any, seeding techniques produce positive effects. In
the 55 years following the first cloud-seeding demonstrations, substantial progress has been
made in understanding the natural processes that account for our daily weather. Yet
scientifically acceptable proof for significant seeding effects has not been achieved".
A 2010 Tel Aviv University study claimed that the common practice of cloud seeding
to improve rainfall, with materials such as silver iodide and frozen carbon dioxide, seems to
have little if any impact on the amount of precipitation. A 2011 study suggested that airplanes
may produce ice particles by freezing cloud droplets that cool as they flow around the tips of
propellers, over wings or over jet aircraft, and thereby unintentionally seed clouds. This could
have potentially serious consequences for particular hail stone formation.
5.1.4. Conspiracy theories
Cloud seeding has been the focus of many theories based on the belief that
governments manipulate the weather in order to control various conditions, including global
warming, populations, military weapons testing, public health, and flooding.

i. Static cloud seeding method
In this the army planes or aircrafts are used for seeding.
Planes used in this process
 Hawker 400.
 Beech craft king air B350.
 Bombardier Lear jet 35A.
 Piper.
 Cessna 340.
Mainly used aircrafts are
a. Hawker 400
Table-1: Specifications of Hawker 400
Fig-7: Side view of Hawker 400
Fig-8: Top view of Hawker 400
Length 48 ft 5 in
Height 13 ft 11 in
Wing Span 43 ft 6 in
Horsepower per Engine 2,965 shp
Maximum Gross Weight 16,300 lbs
Typical Empty Weight 13,000 lbs
Typical Useful Load 5,515 lbs
Maximum Fuel Capacity 733 US gal
Maximum Cruise Speed 465 kts
All-Engine Service Ceiling 43,465 ft
Single-Engine Service Ceiling 20,600 ft
All-Engine Rate Of Climb 2,414 ft/min
Single-Engine Rate Of Climb 350 ft/min
Fig-6:Seeding aircraft

b. Beech craft king air B350
The Beech craft King Air B350i surpasses its predecessor’s high-caliber performance
with more payload capability and range, a quieter interior with standard Wi-Fi, and Pro Line
Fusion avionics with full touch-screen simplicity. The King Air is the world’s most popular
business turboprop aircraft – a title never simply granted, but earned again and again with
continuous enhancement over five decades. The Specifications of king air B350 shown below
Table-2: Specifications of King air B350
Length 46 ft 8 in
Height 14ft 4 in
Wing Span 57 ft 11 in
Horsepower per Engine 1,050 shp
Maximum Gross Weight 15,000 lbs
Typical Empty Weight 12,500 lbs
Maximum Fuel Capacity 539 US gal
Maximum Cruise Speed 312 kts
All-Engine Service Ceiling 35,000 ft
Single-Engine Service Ceiling 21,500
All-Engine Rate Of Climb 2,731 ft/min
Single-Engine Rate Of Climb 780 ft/min
Fig-10: Top view of King air B350 Fig-11: Side view of King air B350

For clear understanding it can be explained in three stages:
Fig-12: Aircraft Fig-13: Stages in Static cloud seeding method
I. Agitation:
The first stage includes the usage if certain chemicals like calcium oxide, compound
of urea and ammonium nitrate or chloride calcium carbide, in order to stimulate air mass of
the target area to rise high and to form rain clouds. The chemicals mentioned above are
capable of absorbing water vapour present in the air mass and thus helpful in stimulating the
condensation process.
II. Building up stage:
It is the second stage and in this stage the cloud mass is built up using various
chemicals like urea, dry ice, ammonium nitrate, kitchen salt and sometimes even calcium
chloride to increase nuclei which further increases the density of clouds.
III. Seeding:
In the final stage, super cool chemicals such as dry ice and iodide are used which are
helpful in building up vast beads of water (nuclei) and makes them to fall on the earth as rain
drops.
The aircraft that contain rain making chemicals can be directly fired into clouds.
Those rain making chemicals are usually shot from a largely pressurized canister into the
base of the clouds which normally hangs above the top of the mountain to cluster up and to
rain on the mountain.

ii. Ground generator seeding
This method is same as static cloud seeding, but aircrafts are replaced by ground
generator.
Fig-14: Ground generators Fig-15: Steps in Ground generator seeding
There are two types of ground-based generators: Remote Controlled Ground-Based
Generators and Manual Ground-Based Generators. These solution-burning ice nuclei
generators are most often used to seed orographic clouds in areas of rugged topography.
iii. Rocket cloud seeding
The rockets are aimed at cloud seeding by using silver iodide in rain-bearing clouds,
resulting in the showers. A bunch of rockets has to be fired within minutes, aiming at the eye
of the clouds to yield the precipitation reaction to induce rainfall. Once the rockets are fired,
rain is expected within 50 minutes.
Fig-16 Stages in Rocket seeding Fig-17, 18: Launcher and loading rockets

This technology is much cheaper than using aeroplanes for the job. Job is aimed at
hitting the yellow spot of the cloud from clouds from the ground anywhere between 4 and
10kms from the surface. It has a success ratio of 80% as against 40% ratio in the static
seeding method.
5.2. Cloudbuster
A cloudbuster is a pseudoscientific device designed by Austrian psychoanalyst
Wilhelm Reich (1897–1957), which Reich said could produce rain by manipulating what he
called "orgone energy" present in the atmosphere.
The cloudbuster was intended to be used in a way similar to a lightning rod: focusing
it on a location in the sky and grounding it in some material that was presumed to absorb
orgone, such as a body of water would draw the orgone energy out of the atmosphere,
causing the formation of clouds and rain. Reich conducted dozens of experiments with the
cloudbuster, calling the research "Cosmic orgone engineering".
Fig-19: Cloud buster Fig-20: Side view of cloud buster
5.2.1. History
The first cloudbuster were built by Wilhelm Reich in the U.S. during the 1950s and
must be seen in relation to his orgone accumulators. They allegedly draw "orgone energy",
Reich postulated, from the atmosphere and dissipates it into earth. In recent years,
instructions for building cloudbuster are being circulated in the internet which partly differ

from Reich's constructions and are based on the ideas of American businessman and esoteric
Don Croft, who claims he discovered the device by using a pendulum.
5.2.2. Principle
In principle, a cloudbuster of newer design consists of several long copper tubes
which are mounted in a parallel way. At one end the tubes are directed to the sky, at the other
end they are fixed to a container in which a two-component adhesive or polyester resin is
mixed with iron or aluminium scrap. This substance is called orgonite. Crystals are added and
connected to each tube.
5.2.3. Construction
A cloudbuster consists of an array of parallel hollow metal tubes which are connected
at the rear to a series of flexible metal hoses which are equal or slightly smaller in diameter to
the parallel tubes. Alternatively, the rear of the tubes is joined together to a single large
diameter pipe and flexible metal hose. The open ends of these hoses are placed in water,
which Reich believed to be a natural orgone absorber. The pipes can be aimed into areas of
the sky to draw energy to the ground like a lightning rod.
Fig-21: Line diagram of metal tube Fig-22: Metal tubes

5.2.4. Negative incidents occurs while using Cloudbuster
 A young fellow in Canada built and erected a large cloudbuster. He later left town,
leaving the apparatus operating, haphazardly pointing to the sky. Several months went
by without rains. The cloudbuster was later discovered by accident, by other persons
who knew about the dangers and dismantled it. Rains resumed shortly thereafter.
 A young man in Ireland built a cloudbuster and operated it while in a "trance state".
Major devastating coastal storm occurred; boats were sunk and people were killed.
 Another mystic in the south-eastern USA, skeptical about the cloudbuster, built one
and generated a huge thunderstorm with a funnel cloud. In a panic, he destroyed the
instrument. After his death, his wife began selling ineffective "cloudbuster" to
desperate farmers, for thousands of dollars.
5.2.5. Negative Biophysical Effects on Cloudbuster Operators
 Several of Reich's assistants were immobilized and greatly sickened by the field
effects surrounding his laboratory during the oranur experiment. Later on, similar
reactions occurred in the surroundings of operating cloudbuster, particularly during
desert and drought operations.
 A man using a cloudbuster in a California desert touched the pipes with his bare
hands. He was paralyzed on one side of his body, and never completely recovered.
 A cloudbuster operator developed a walnut-sized tumor one day after handling a
cloudbuster during a drought. The tumor was eventually eliminated through
orgonomic first-aid, involving therapy, use of the accumulator, dor-buster, and
detoxification techniques.
 A medical doctor in Germany used a medical dor-buster on his patients for many
years. The apparatus resembles a minature cloudbuster, and functions similarly. He
developed a paralysis in the arm he used to work the apparatus, which later spread to
his shoulder and the side of his face, after which he died.
 A man who used a manually operated cloudbuster for many years in droughty
situations became quite ill, in spite of many precautions. He eventually developed
scleroderma and cancer, which killed him.

 A man with a history of high blood pressure and a stroke had another debilitating
stroke a few days after working as an informal helper on a cloudbuster operation,
where his exposure was limited to no more than 15 minutes per day over three days.
All the usual precautions had been taken.
 Other cloudbuster operators have been made very ill from standing too close to the
instrument. The biological effects of overcharge, and of what Reich called dor-
sickness, have included high fever, muscle cramps, nausea, and diarrhea. Severe skin
rashes, hives, and "flu" symptoms have also been observed. Reich noted that effect of
the toxic field around the cloudbuster tends to hit a person at their weakest spot,
causing old health problems to flare-up.
5.3. Biopricipitation
Biopricipitation is the concept of rain-making bacteria and was proposed by David
Sands from Montana State University before 1983. The formation of ice in clouds is required
for snow and most rainfall. Dust and soot particles can serve as ice nuclei, but biological ice
nuclei are capable of catalyzing freezing at much warmer temperatures. The ice-nucleating
bacteria currently known are mostly plant pathogens. Recent research suggests that bacteria
may be present in clouds as part of an evolved process of dispersal.
Ice-nucleating proteins derived from ice-nucleating bacteria are used for snowmaking.
Fig-23: Bioprecipitation cycle

Fig-24: Growth and Photosynthesis Fig-25: Bioprecipitation
6. ADVANTAGES OF ARTIFICIAL RAIN MAKING METHODS
 It creates rain.
 It makes all areas more hospitable in dry seasons.
 It could regulate the weather.
 It would allow for economic improvement.
 It can reduce crop damage and it can provide relief to those drought-stricken areas.
 It is used to increase plant life.
 The water quantity increases in dams and reservoirs.
 Decreases diseases caused by lack clean water.
 Reduces pollution.
7. DISADVANTAGES OF ARTIFICIAL RAIN MAKING METHODS
 High cost.
 Difficult to operate.
 The chemicals which are used in these methods may cause residual injuries to humans
and mammals.
 Due to some mistakes in these methods leads to Thunderstorms, Hurricanes and
floods. It causes huge damage to population and wealth.
 Difficult to aim targets.

8. CONCLUSION
After doing an extensive research for this topic I have a wider knowledge of this
artificial rain making methods, learnt useful information about different types mechanical and
biological methods to produce rainfall.
These methods mainly works for precipitation and although it used for to reduce the
pollution and also for weather modifications.
These having the minor disadvantages, but there eliminated using proper materials
and having giving training to the operator to reduce the mistakes.
Artificial rain making methods help to increase the green life and oxygen and
decreasing the pollution.
Thus these methods plays major role in reducing drought and increasing the quantity
of drinking water in future.

Artificial rain making methods seminor report

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