I recently watched a documentary where scientists claimed they could create rain in the desert. I was skeptical at first. In my conception, it was not possible for man to make rain. I am very skeptical about the traditional folk tales in traditional communities that narrate of leaders who had the power to make rain. The scientists in today’s contemporary society stand a better chance of making compared to the traditional rainmakers. Even then, I reserved my skepticism about the possibility of artificially manipulating the clouds in order to create rain. It is after watching the entire documentary that I learnt of the concept of cloud seeding. I was very fascinated by the concept. I reckoned that this could be the solution to the perennial desertification and the resultant food insecurity in many areas of the world. Owing to my investigative nature I set out to carry out further research on cloud seeding as a concept, its mechanism, and effectiveness. This paper describes the mechanism of cloud seeding, areas where it has been employed and the reported effectiveness.
The Mechanism of Cloud Seeding
Cloud seeding entails the alteration of the weather in order influence not only the amount, but also the type of precipitation coming forth. Cloud seeding is done through the alteration of the microphysical processes that take place in the clouds. In order to achieve this alternation of the microphysical processes, scientists inoculate the clouds with particular substances. The substances inoculated into the atmosphere act as the ice nuclei upon which the alterations occur (Christner et al. 1214). Whenever cloud seeding has been performed, the intention has been to increase the quantity of rain or snow falling. However, cloud seeding has also been used for auxiliary purposes such as suppressing fog and hail in sports stadia and airports.
Various chemicals are employed as agents for freezing nucleation. Some of the common chemicals used include solid carbon dioxide, silver iodide, liquid propane, and potassium iodide (Hill and Ming, 15). These elements are used because of they have crystalline properties. These properties are alike those of ice, by that inducing freezing nucleation in the clouds. The principle that scientists exploit is that of equilibrium vapor pressure. The equilibrium vapor pressure is different in various compounds. For instance, it is lower over ice when it is compared to water. Owing to this, the freezing nucleation which occurring in clouds that are much cooled causes the particles of the chemicals inoculated into the clouds to grow. The growth of the crystalline particles of the chemicals over time causes the particles to increase in density. The increase in density causes the particles to precipitate. The fact that the precipitation comes forth from clouds that would not have produced rainfall had they not been seeded makes the concept very interesting.
The seeding can be done either from the ground or aerially. The inoculation of the clouds from the ground is done using canisters that are propelled into the sky to release the chemical particles. Aircraft are used to seed the clouds aerially by flying through the selected clouds while dispersing the chemical particles. Recent developments in the methodology of seeding selected clouds have led to the development and testing of electronic mechanisms. These mechanisms entail the use of infrared laser pulses to direct the chemical particles into the selected clouds (Barras 1).
Applications of Cloud Seeding
The most prevalent use of seeding is done in Asian countries, particularly in China where the most elaborate cloud seeding system globally exists. Rockets packed with silver iodide are propelled into the sky where they seed selected clouds to create rain in various arid areas. China reportedly used cloud seeding prior to the Olympic Games which were held in the City of Beijing in order to rid it of pollutants in the air. Cloud seeding was also used in 2009 in the City of Beijing to create rainfall after the occurrence of a drought spanning four months (British Broadcasting Corporation 1). Cloud seeding has also been employed in Dubai, particularly in Abu Dhabi in order to create rainfall and counter the effects of prolonged drought (Sanburn 1).
Effectiveness of Cloud Seeding
For a long time, cloud seeding was thought to be a fringe science. Developments of the concepts have changed this perception. Cloud seeding is a popular contemporary tool through which the precipitation in an area can be improved (Weiser 1). The sustained research into the concept and the development of new technology has enabled cloud seeding to rise in stature to a probable source of water for many arid areas. Even though its effectiveness, particularly the cost effectiveness aspect is still debated in academic realms, the concept has been used successfully to not only create precipitation, but also to improve the quality of air by riding the atmosphere of pollutants.
The documentary I watched and my inquisitive nature led me to perform more research on the concept. As described in this paper, cloud seeding entails the artificial manipulation of condensation through freezing nucleation. This is achieved inoculating selected clouds with chemicals whose particles have crystalline properties. The increase in density causes the crystalline particles to fall, and as they meet higher temperature zones, they melt to fall as rainfall. The paper has highlighted the usage of cloud seeding in many areas. The effectiveness of the approach has also been indicated.
Barras, Colin. Laser creates clouds over Germany. New Scientist. 2 May. 2010. Web. 4 Jul. 2015
British Broadcasting Corporation. China Lets it Snow to End Drought. British Broadcasting Corporation. 19 Feb. 2009. Web. 4 Jul. 2015
Christner, Brent, Morris, Cindy, Foreman, Christine and Cai, Rongman, Sands, David. Ubiquity of biological ice nucleators in snowfall. Science 319, 5867 (2008): 1214.
Hill, Spencer. and Ming, Yi. Nonlinear climate response to regional brightening of tropical marine stratocumulus. Geophysical Research Letters 39 (2012): L15707.
Sanburn, Josh. Scientists create 52 artificial rain storms in Abu Dhabi desert. Time News Feed. 3 Jan. 2011. Web. 4 Jul. 2015
Weiser, Matt. Cloud seeding, no longer magical thinking, is poised for use this winter. Sacramento Bee, 11 Nov. 2013. Web. 4 Jul. 2015