Wednesday, June 27, 2012



Prof.T.Shivaji Rao,
Director, Center for Environmental Studies,
GITAM University, Visakhapatnam.

[ view cloud seeding process explanation through  2Video presentations] and also the following web sites for reading materials on sciencwe of cloud seeding for people's sake]

(Text Book with figures)  
(Text Book without figures)


Why BMC is taking so long for cloud seeding experiment ?/it is already confirmed that it has rained properly. Are the Shiv Sena and BJP leaders want to delay this experiment deliberatelly since by september the cloud density will be less and they can earn more money in the experiment which will not create  the result. BMC should have done this work in July when cloud cover was adequate also . BJP and Shiv Sena will earn lots of money through tanker mafia. it is corruption which is going on for a long time in Maharastra .it is done by Pawar familly as well-----AMIT[Mumbai]


Prof.T.Shivaji Rao, Director, Centre for Environmental Studies, Gitam University
And Expert Member Cloud Seeding Project of Government of Andhra Pradesh

The key role played by a good water supply as an engine of economic growth and as a yard stick of public welfare and national prosperity has been well recognized by the intellectuals of the developed countries like USA who aptly named water as the “Blue Gold”. The more the water wealth of a nation the higher will be the opportunities for  achieving high rates of progress in the fields of agriculture production and industrial growth that help in promoting economic wealth, employment opportunities and higher standards of living. Hence the advanced countries are constantly upgrading their water resources by harnessing not only all the ground and surface waters but also by tapping a renewable, virtually unlimited and unexploited sky water resource in the atmosphere in the form of innumerable clouds. Enlightened scientists, bureaucrats, industrialists and statesmen in about 50 countries are frequently using cloud seeding operations for over 40 years for various purposes like
1. Increase of annual rainfall for drinking and agricultural purposes,
2. dispersal of fog in airports and metropolitan city roads
3. Increase of hydro-power generation at the cheapest cost
4. Suppression of hail storms to reduce damage to life, crops and properties
5. mitigation of devastating impacts of recurring droughts
6. mitigation of damaging impacts of global warming and summer temperatures
7. increase of annual rain fall for improving the forests, wildlife and the environment
Several progressive countries like USA, Australia, China, Thailand, European states, former states of USSR, Latin American states, Arab states, Indonesia and Pakistan are gettinghighly benefited by employing the advanced cloud seeding technologies for the above purposes.. Several Indian states interested in promoting economic growth, agriculture development and public welfare are eager to learn from the successful experiences of other countries like China and USA and adopt those technologies by making necessary modifications to suit the local meteorological, topographical, geographical and other environmental conditions.
Cloud seeding is done to make some clouds to grow and give rain, and some clouds which give only about 10% to 20% of their water content as rainfall to increase the rainfall by seeding by 30 to 50% at a cost benefit ratio of 1:20 by using aeroplanes and 1:60 by using ground generators. Due to the heat from the Sun the water in the rivers, lakes and Oceans becomes water vapour.  As this hot moist water vapour in the air rises into  the sky the  temperature gets reduced at 7oC per km height in the sky, the water vapour condenses over smoke and dust particles to form cloud droplets of 20 microns in diameter [micron is a millionth of a meter]  A million cloud droplets must join together to form a raindrop of 1mm size to fall over the earth as rainfall or snowfall
Rain Formation:  If a warm cloud does not contain sufficient number of giant size water drops or hygroscopic particles  the cloud cannot give 10% to 20% of its moisture as rainfall. In cold clouds whose tops attain freezing level in the sky, insufficient number of ice-nuclei prevents the clouds from giving  more than 20% of the water content as in the form of rainfall or snowfall.
How Cloud Seeding Helps?: If warm clouds have to give more rain we have to inject into them chemicals like hygroscopic common salt or Calcium powder into such clouds We have to inject  Silver Iodide particles into cold clouds which extend into the freezing zone for about  15km into the sky.  So the  injection of seeding  chemicals into the clouds causes them to produce additional rainfall upto 25 %
Why Cloud Seeding Is Unavoidable?:  In Modern Times Urbanization, industrialization and deforestation are increasing the environmental pollution and global warming which are preventing the clouds from giving the normal rainfall and consequently drinking water supply and agriculture production, hydro power generation and employment opportunities are adversely effected.  Hence cloud seeding must be undertaken to supply more water to correct the above man made problems.
What is scientific secret for warm clouds to produce about 25%  additional rainfall?:
When hygroscopic chemicals like common salt are sprinkled into the warm clouds the water molecules with their negative oxygen ends interact with the positive sodium ions and the positive ends of hydrogen surround the negative chloride ions.  Consequently the water molecules pull out sodium ions and chloride ions one by one from the salt crystal and in the process Giant Condensation Nuclei (GCN) of over 40 microns are formed.  These Giant nuclei help to transform lakhs of smaller cloud drops into big rain drops of about 1 mm in size.  Due to the chemical reaction heat is liberated within the cloud and consequently more moist air is sucked into the cloud that grows in its size and thereby rainfall is also increased.   Depending upon the geographical, topographical and meteorological conditions the additional rain varies from 10% to 25% in a given area.  Some warm clouds of about 1km height do not give rain and due to insufficient number of giant size nuclei (GCN) some larger clouds give only10% to 20% of their water content as rain while the remaining water content dissipates as moisture into the atmosphere Hence we  have to inject optimum number of chemical nuclei to extract more water than what the clouds give in their natural course. See the following figure.
(animation for dissolution of salt in water - warm cloud seeding)

What is scientific secret for Cold clouds to produce by about 30% additional rainfall?:
At temperatures below freezing, the saturation vapour pressure of ice is less than that over a droplet of water. Water evaporates from droplet and deposits on ice.The water droplet droplet dissipates while ice crystal grows into a snowflake. .  Due to the chemical reaction heat is liberated within the cloud and consequently more moist air is sucked into the cloud that grows in its size and thereby rainfall is also increased.    Depending upon the geographical, topographical and meteorological conditions the additional rain varies from 15 to 30%.  Due to insufficient number of ice nuclei some cold clouds do not give rain and some larger clouds give only10% to 20% of their water content as rain while the remaining water content dissipates as moisture into the atmosphere. Hence we have to inject optimum number of ice nuclei or their equivalent nuclei in the form of silver iodide to extract more water than what the clouds give in their natural course.  
Does cloud seeding promote the stealing of one region’s water by people of another region?
According to one expert ,the amount of moisture that falls "naturally" as rain at any point in the world is a very, very small fraction of the total amount of water (actually water vapor) that is moving over that point at any time. So if you cause more rain to fall from a thunderstorm through weather modification than what would fall normally, the additional amount of water vapor it removes would be insignificant and hard to detect. The churning in the atmosphere that occurs as the winds push it along would quickly replenish the water vapor that was removed. Thus there would be little or no discernable difference in available water vapor downwind from where the precipitation fell out. Also, you need to realize that the extra rain caused by cloud seeding is not removed from the system but rather moves back into the atmosphere through evaporation or transpiration from plants, and is then available to help produce more clouds down wind. This is part of the hydrological cycle, which is what drives most of the weather on this planet. If you would like to learn more, try out the following web sites at:,
China Is World Leader In Cloud Seeding:  In China 37,000 technicians are employed to produce additional annual rainfall of  about 60 billion cubic meters or about 1800  TMC (Thousand Million Cubic ft) which is equivalent to the annual river flow in Krishna River in South India. The cost benefit ratio is estimated at 1:29.
Cloud seeding is done in more than 40 countries like United States, Japan, China, Thailand, South Africa, Canada, Australia, Pakistan, Indonesia, Latin America, Arabian States, Russia etc.,    during the last 50 years. India must take up cloud seeding to fight the recurring droughts and also to resolve the interstate water disputes in the Cauvery, Krishna and other rivers and also to fight the damaging impacts of global warming.  Although several doubts have been raised by scientists in USA and other countries Chinese Meteorologists have researched  and established that cloud seeding is not only highly scientific but is also a proven technology, if done on scientific lines.
Presently cloud seeding operations are proposed to be conducted by the state Governments of Karnataka, Tamil Nadu, Uttar Pradesh and other states due to the prevailing large scale water scarcity.  The hydro-power generation in Karnataka can be increased by augmenting water availability by squeezing the sky water by cloud seeding.  The annual flows in all the rivers like Cauvery, Krishna , Penna and their tributaries can be increased by about 20% so that the additional rainfall can be used to resolve the inter –state river water disputes in South India.
Precipitation in India : The summer monsoon from the South West starts from the equatorial belt and crosses over India in two distinct currents known as the Arabian sea branch and theBay of Bengal branch. According to National Commission of Agriculture, during the 4 rainy monsoon months of June to September the Arabian branch carries moisture amounting to about 770 Mham (7700 BCM) and the Bay of Bengal branch, about 340 Mham (3400 BCM). Of the monsoon moisture content about 25% to 30% precipitates in the form of rainfall. There is a substantial amount of moisture over the country during the remaining 8 months, contributing a precipitation of about 100 Mham (1000 BCM) a small part being snowfall. About 3000 rain gages are set up for recording the rainfall by the Indian Meteorological Department and the state Governments. The national annual average rainfall of about 120 cm provide annual precipitation of about 390 to 400 Mham (4000 BCM) including snowfall which is not yet fully recorded.

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Born in 1932 at Mudinepalli, near Gudivada, Krishna Dist. Andhra Pradesh, received Bachelors degree in Civil Engg., from Viswesaraiah Engineering College, Banglore (1956) and Masters Degree in Environmental Engineering from Rice university, Houston, Texas, (USA) (1962), Ph.D (Hony). Former Head of the Department of Civil Engineering and principal of College of Engineering, Andhra university.Formerly Hony.Professor in Andhra University,Manonmanian Sundarnar University,JNT University. Fellow of the Institution of Engineers,India Recipient of the University Grants Commissions National Award "Swami Pranavananda Award on Ecology and Environmental Sciences" for the year 1991. Recipient of Sivananda Eminent Citizen Award for 2002 by Sanathana Dharma Charitable Trust, Andhra Pradesh state. Presently Working as Director, centre for Environmental Studies, GITAM University,