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Not Only Have Scientists Perfected Techniques To

Not Only Have Scientists Perfected Techniques To

SWATI SAXENA Story Cover

Not only have scientists perfected has played with creating artificial for a long time. In the United techniques to create Arab Emirates too artificial seeding to bring on has created rainstorms in the Dubai and Abu Dhabi deserts. In fact, faced with hard rain or snowfall, and extreme conditions, humans N the year 2008, the opening ceremony have often resorted to they have now even Iof the 29th Olympic Games to be held in various parts of the world. Common developed techniques in , China was threatened with rain. examples of weather modification include The observatory had given a rainy weather producing rain or in stricken that allow them to forecast, monitoring 90% of humidity rate. areas, suppressing that can ruin crops, prevent rainfall! How But Beijing fired over 1,000 rain dispersal or weakening hurricanes and tornados that an evening before to blow away might cause great loss of lives and property. have they achieved this the rain clouds paving the way for a Weather modification can also grand opening ceremony and a four-hour be used as a tactic in war to enhance feat? extravaganza that dazzled the world! damaging weather in the enemy territory.

SCIENCE REPORTER, JULY 2013 8 Cover Story

From left: James Espy; in his lab; John Aiken; and Vince Schaefer (right) who discovered using a cold chamber, a deep freezer lined with black velvet

In fact, Sheldon, in his 2004 thriller In 1875, the Frenchman Coulier box several times until the air was saturated novel, Are You Afraid of the Dark?, talks showed that particles floating in air served with the moisture from his lungs. The moisture of an egotistical maniac who develops as nuclei around which condensation in the box got condensed and formed a technology to control the weather and of water vapour occurs with little or no particles which are like cloud particles. But is now out to exercise that power to extort super saturation. Scottish physicist John no particles were formed. Schaefer then riches from vulnerable countries. That there Aitken using his portable expansion found an 8-inch piece of (frozen was a real possibility of nations working chamber known as Aitken nuclei counter ) with a temperature at on weather control technology to target demonstrated that there were two types of minus 79 degrees Centigrade) and thrust it enemy countries is borne out by the fact nuclei. Those with an affinity for water vapour into the supercooled box. In an instant the that in 1977, a convention was signed by on which condensation occurs before water air was full of ice crystals. The tiny crystals the United Nations to ban the use of weather saturation occurs are called hygroscopic quickly transformed into , grew modification for military or any other hostile particles and others are non-hygroscopic rapidly larger as they sucked the remaining purposes. nuclei which require some degree of moisture in the freezer box and then fell to supersaturation in order to serve as centres the bottom. Making Rain of condensation. In 1919, A. Wigan used balloon flights and measured Aitken nuclei Perhaps for the first time, in the 5th April up to about 6 km height. 1839 issue of the National Gazette and An interesting experiment was Literary Register of Philadelphia, James P. performed by Vincent J. Schaefer, a Espy proposed that large fires could create laboratory assistant to Dr. Irwing Langmuir, a a good updraft in a humid atmosphere to Nobel laureate. Schaefer obtained a home generate cumulus clouds that cause rain refrigerator unit used for food storage and fall. Almost a hundred years later, in 1939, modified it. After bringing the temperature in Gorog and Rovo of Hungary examined the box below , he breathed into the Espy’s suggestion that convective could be induced by burning large fires. Rockets being prepared, mounted and shot into the sky in By observing the fires on the lakes of oil, China to seed clouds Gorog and Rovo made calculations and concluded that the method was practical for producing rain artificially under certain conditions.

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A pilot standing beside his aircraft laden with a cylinder containing iodide

2. causes cloud 1. Silver Iodide (mixed moisture to freeze and create with acetone or Ice crystals propane) vaporized or sprayed to reach the clouds

3. Ice Crystals become The release of silver iodide was large enough to fall as rain or snow discontinued in July 1951 after the great floods in Kansas and adjacent states. It was one of the Seeding Generator most devastating floods in the area killing seventeen people. How Cloud Seeding Works Seeding Clouds Schaefer published an article on artificial weather modification have been Cloud seeding only works to the extent that these experiments in the 15 November cloud seeding to increase the rain or snow there is already water vapour present in the 1946 issue of Science magazine with the fall and hurricane seeding to mitigate its air. It has been used in several countries statement: “It is planned to attempt in the effects or turning its course. The methods to including United States of America, China, near future a large scale conversion of achieve these have been developed over and Russia. super cooled clouds in the atmosphere the years and researchers continue to look The release of silver iodide into to ice crystal clouds, by scattering small for more efficient and reliable methods to an existing super-cooled cloud (i.e., air fragments of dry ice into the cloud from a perform these phenomenon. temperature between -39 and -5 Celsius) plane.” One of the main challenges in can convert water vapour to ice crystals, In , Dr. Bernard performing weather modifications is to which is called sublimation. The ice crystals Vonnegut discovered that microscopic minimize any long-term effects on the nucleated by the silver iodide will grow, and crystals of Silver Iodide (AgI) — commonly global climate. The scientific community local water droplets will shrink. The latent used in silver-based photography – has long sought safer ways to achieve heat released by converting water vapour nucleate water vapour to form ice crystals. weather modification successfully and with to ice will increase vertical air motion inside Vonnegut chose silver iodide crystals minimal uncertainty. the cloud and aid the convective growth of because there is nearly the same distance between molecules in the crystal lattice for USA conducted a cloud seeding operation called Operation both ice and AgI, making AgI the optimum material to nucleate ice. Popeye between 1967 and 1972 during the to Vonnegut also invented a practical extend the monsoon season over Laos. way of generating tiny silver iodide particles to serve as nuclei for ice crystals. He dissolved a mixture of AgI and another iodide in acetone, sprayed the solution through a nozzle to make droplets, and then burned the droplets. In this way, one gram of Silver Iodide can produce 1016 nuclei for ice crystals. Till now, Vonnegut’s method continues to be the most common way to seed clouds. Apart from dry ice (solid carbon dioxide), liquid propane and recently hygroscopic materials such as are also being used. Liquid propane can produce ice crystals at higher temperatures than silver iodide. Some of the popular applications of SCIENCE REPORTER, JULY 2013 10 Cover Story

clouds that are generally responsible for HURRICANE HALTING producing rain. Fleet of transport aircraft at 50,000 ft drop SOOT At the time of this discovery, soot in the path of and at targeted areas of CLOUD Dr. Vonnegut worked in the research the hurricane laboratory at Company in Schenectady, , which funded the initial work on cloud seeding. General SOOT Electric rented an airplane and released CONDENSED AIR dry ice into clouds on four days during November and December 1946. The last Soot is warmed by the Sun, day of seeding coincided with the heaviest heating the cool air around snowfall of the winter in the upstate New it at the very top of the York area, which made the company hurricane. This reduces the flow of air within the hurricane management concerned about the and slows it down possibility of cloud seeding experiments causing harmful weather. MOOFED STORM Later, a General Electric and U.S. TRACK government research project released ACTUAL STORM silver iodide and dry ice in the vicinity of UPFLOW TRACK Albuquerque, New Mexico in 1948 and Depending on where 1949. Dr. Langmuir claimed that this release and when the soot caused rain all over the state of New Mexico. is dropped the now Langmuir’s group continued to release silver WARM AIR weakend hurricane will RAIN CONVERGING AIR COLD AIR change course iodide in New Mexico between November 1949 and July 1951. He claimed that the The smaller the radius of the Eye, the more intense the wind speed. release of silver iodide modified the weather, not only in the state of New Mexico but also more than thousand kilometres downwind. the cloud. Raindrops or snowflakes will grow Silver Iodide is the most common It is hard to make precise causal claims on larger by falling through a taller cloud. Also, used in cloud seeding, but it the reasons behind the weather at a large moist air from evaporated moisture in the is not the only material used. Dry ice was scale like this one, and hence Langmuir’s soil will be sucked into the base of the cloud widely used in experiments in the USA in claim was rejected by the meteorological by convection, thus increasing the total the 1950s and early 60s. Substances with community. amount of water in the cloud. temperatures less than -40 Celsius (e.g., The release of silver iodide was About thirty minutes after the silver solid carbon dioxide pellets, liquid carbon discontinued in July 1951 after the great iodide release, snow may fall below the dioxide, liquid propane, liquid nitrogen, floods in Kansas and adjacent states. It cloud. Depending on the temperature and etc.) can be dropped from airplanes was one of the most devastating floods in humidity below the cloud, the snow may into the tops of clouds to induce the area killing seventeen people, despite change to rain, or even evaporate, before formation of ice crystals. Commonly, weather forecasts and warnings. The current reaching the ground. cloud seeding is performed over cumulus consensus of meteorologists seems to be that the release of silver iodide in New Artificial rain in Dubai Moisture condenses around the charged dust. Mexico probably had no effect on the Eventually this turns to cloud which rainfall in Kansas. If there was an effect, the produces rain effect would only be a small enhancement of the total rainfall. A cloud seeding operation known as Project Cumulus was conducted by the United Kingdom between 1949 and 1952. On 16 August 1952, a severe flood occurred in the town of located in north Negatively charged ions rise with Devon, England. Salt was used for seeding the hot air and attract dust a few days before this disaster. Speculation was rife that the cloud seeding operation resulted in the Lynmouth disaster, although it could not be proved. Often in , open Ionisers produce charged burning produces that pollutes the particles into desert air environment. Cloud-seeding has been used to improve the air quality by encouraging 11 SCIENCE REPORTER, JULY 2013 Cover Story

enhance snowfall and supplement natural would be able to release large amounts of Picture of Hurricane Katrina taken from a supply of water. crystals into tropical storms and hurricanes. Hurricane Hunter aircraft in 2005 (Source: Different techniques have been used These findings and discoveries led to the Wikipedia) over the years for seeding of clouds. birth of in 1962. The team was able to decrease the sustained winds in • Aerial Cloud Seeding: Seeding clouds the storm by ten percent. using airplanes. After the creation of Project Stormfury, • Ground-Based Cloud Seeding: Seeding the team put together new ideas on how clouds by using generators, canisters to attack a hurricane. They proposed that a fired from anti-aircraft guns or rockets. hurricane could be weakened by converting • Electronic Seeding: Recently an the super-cooled water within the deep electronic mechanism was tested in 2010, clouds of the storm to ice; the hurricane’s when pulses were directed to vertical column of air would be warmed the air above by researchers from the thus weakening the storm. The team did not University of Geneva. have many opportunities to work on this new Bio-: • This method, idea over the next eight years as there were proposed around 1983, uses rain-producing not any storms that were far enough from bacteria to enhance rainfall. The biological land. They did not want to risk the lives of ice nuclei are capable of catalyzing people in case they could not reduce the freezing at much warmer temperatures. hurricane intensity (or end up worsening it). The ice-nucleating bacteria currently known In 1963, tests were conducted on are mostly plant pathogens. Many ski resorts Hurricane Beulah, a major hurricane in use a commercially available freeze-dried the , but with only marginal rainfall. In India also the Tamil Nadu preparation of ice-nucleating bacteria to success. At least 688 people were killed in government conducted cloud seeding produce snow as required. its path. Then, in 1965, the team considered operations during the years 1983, 1984– Hurricane Seeding: • Similar to cloud seeding , a tropical 87, 1993-94 when it faced severe drought seeding, hurricane seeding has also been cyclone in Atlantic basin, but due to the conditions. In the years 2003 and 2004 tested to mitigate the effect of hurricanes close proximity to Puerto Rico and other the Karnataka government initiated cloud developing in the ocean by reducing their islands, and the storm’s erratic seeding. intensity or by changing their direction. motion, the team did not go through with USA conducted a cloud seeding this idea. Betsy caused damage to property Seeding Hurricanes operation called worth more than one billion dollars and between 1967 and 1972 during the Vietnam On 13 October 1947, as part of Project around hundred casualties. War to extend the monsoon season over Cirrus the USA dropped 80 kilogrammes Laos. This was aimed to increase rainfall of dry ice into a hurricane in the Atlantic and hence obstruct the enemy military Ocean. The hurricane changed direction truck supply. Eventually, resolutions in favour A Sodium Iodide generator in , USA and traveled inland, where it did extensive Source: Arlen Huggins, Division of Atmospheric Sciences, Nevada, USA of banning environmental warfare were damage to property in the state of Georgia. passed in 1977. It was widely believed that the hurricane’s More recently, in January 2011, several change of direction was the result of the newspapers and magazines reported that cloud seeding. Subsequent analysis of the scientists backed by the government of data by meteorologists showed that this Abu Dhabi had created over fifty artificial hurricane had already begun to change rainstorms between July and August its direction when the seeding was done. 2010 near Al Ain, a city that lies close to About a decade later, scientist Dr. Mook the country’s border with Oman and is recognized that the storm’s sudden change the second-largest city in the Abu Dhabi in direction was not caused by the seeding, Emirate. The artificial rainstorms were said but rather the upper level steering winds in to have sometimes caused hail, gales and the vicinity of the hurricane. , baffling local residents. The In the early 1960s, Dr. Robert Simpson scientists reportedly used ionizers to create of the National Hurricane Research Labs the rainstorms, and although the results in Miami, , theorized that hurricanes are disputed, the large number of times it could be weakened by releasing frozen is recorded to have rained right after the nuclei or particles of silver iodide compound ionizers were switched on during a usually into the wall clouds of a hurricane or tropical dry season is supportive evidence. storm, and cause imbalance of the forces There have been ongoing cloud within the storm system. Simultaneously, seeding activities in different parts of the a group at the Navy Weapons Center in world for different applications. Several California improved seeding technology by western USA states use cloud seeding to developing new seeding generators that SCIENCE REPORTER, JULY 2013 12 Cover Story

Russians also performed sophisticated A cloud cloud-seeding in 1986 to prevent Team members of Project Cirrus seeding radioactive rain from the Chernobyl reactor operation accident from reaching Moscow. known as Project Legal Issues Cumulus was Since experiments performed at this scale conducted by can affect a large number of people and the United may cause damage, it became important to formulate laws related to weather Kingdom modification studies. Such experiments between 1949 can be conducted only when they are and 1952. On government sponsored and the residents 16 August cannot sue a private company for any 1952, a severe damages. Cloud seeding and hurricane seeding experiments may cause more flood occurred damage to the property or can claim lives in the town of which cannot be attributed to a particular Lynmouth person. Dr. Vonnegut said in 1952, while Finally in 1969, Project Stormfury had experiments on typhoons in the northwest appearing before a USA Senate committee a significant test case when Hurricane Pacific basin were explored but it generated that was considering legislation on weather Camille emerged in the 1969 Atlantic concern from China and Japan, who modification: hurricane season. Camille accelerated were worried of being impacted by the “Theory has predicted and experiments northeastward, attaining peak winds of 70 seeding. are confirming the fact that a few pounds of mph (115km/hr) as it interacted with another Other ideas have also been explored silver iodide released into the atmosphere larger Hurricane Debbie to its southeast. to weaken hurricanes including: in the form of fine particles can exercise Hurricane Debby was seeded on a couple • Using to discharge lightning in a profound influence over the weather of occasions over the two day period of storms that are likely to become hurricanes hundreds of miles away from the point of August 19 and August 20, 1969. Each time release. Clearly no private individual or • Pouring liquid nitrogen onto the sea to the storm was seeded, sustained winds were group can be permitted to carry on deprive the hurricane of heat energy reduced significantly. The first time, winds operations over thousands or hundreds of dropped 31% while the second time, they • Creating soot to absorb sunlight and thousands of square miles. The potentialities, only dropped 15%. change air temperature and hence both for good and bad, which attend convection currents in the outer wall. The apparent success with Debby silver-iodide seeding, are so large that the development and use of this technique helped fuel new projects and improvements must be placed in the hands of the Federal in technology. One of the new developments Rain, Rain… Go Away! Government.” was that aircrafts were flown into the As opposed to artificially seeding clouds hurricanes to gather weather data. The In 1975, the USA and Canada entered to induce rainfall, efforts have also been aircrew known as “Hurricane Hunters” catch into an agreement under the auspices made to delay or mitigate the rainfall to a bird’s eye view of the hurricanes helping of the United Nations for the exchange ensure smooth conduction of a particular in understanding flow development in their of information on weather modification event. China has used cloud seeding to activity. core. in 1971 was the last achieve the desired rainfall in several areas hurricane where seeding was performed Modifying weather to combat of the country. The China Meteorological problems such as drought or pollution or under Project Stormfury. Administration says 4,231 flights for cloud- for aiding agriculture is understandable. Ultimately Project Stormfury was seeding were conducted from 1995 to But considering the concerns raised over cancelled in 1980 since the team was 2003. Recently, they claimed to have widespread damages such experiments unable to clearly ascertain whether or not the devised a technique that can reduce the could cause if they go awry, it is important seeding efforts were really causing storms to size of the rain drops thus delaying the to exercise great caution while conducting weaken, or there were other natural causes. rainfall until the clouds move. these experiments. Nevertheless, the work done behind the In the 2008 Olympics held in Beijing, hurricane seeding research improved the not only did it prevent rain from spoiling the weather forecast mechanisms and several opening ceremony, the administration was of the scientific principles developed were prepared to use this technique in case rain Dr. Swati Saxena has a PhD in Aerospace applied in other fields. threatened any of its field events. China has Engineering from the Penn State University, Other than seeding hurricanes in the been working on rain mitigation techniques USA. Address in India: C/o Dr. Ashok Saxena, Atlantic Ocean under Project Stormfury, since 1950s and claim to control rain on a 204, Narain Towers, Agra-282002; Email: swati. [email protected] opportunities to perform seeding small scale. 13 SCIENCE REPORTER, JULY 2013

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