It is a scientific procedure of weather manipulation that alters a cloud’s capability to produce rainfall by dispersing cloud condensation agents into the air. The most common chemicals used for cloud seeding include silver iodide, potassium iodide and dry ice (solid carbon dioxide). He acknowledges the potential for misuse, but argues that this is an idea that should be seriously considered. Let us know if you have suggestions to improve this article (requires login). After promising research, the use of hygroscopic materials, such as table salt, is becoming more popular. Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... A Cessna 441 Conquest II fitted with cloud-seeding pods on its wings, at Hobart International Airport, Tasmania, Australia, 2008. Silver iodide is a highly photosensitive as a reaction of iodide solution with silver ions. There are three types of cloud seeding techniques: Environmental scientist David Keith makes a case in favor of cloud seeding and solar engineering as a potential solution to Climate Change. Natural Climate Change vs. Man-made Climate Change, Volcanoes and their effect on global climate, Early English Forest wildlife protection laws, Looking for Climate Change in world’s oldest trees, From Traditional to Sustainable to Regenerative, Top 5 ways to increase our vegetation index, Top 5 ways to creatively re-use leftover water, The basic principle of this technique is to increase the precipitation efficiency of the clouds. Background The vast majority of modern attempts at modifying weather involve cloud seeding, which is the intentional treatment of individual clouds or cloud systems to achieve a desired effect (WMA, 1996). Silver iodides are examples of inorganic compounds with chemical formula Agl. Cloud seeding, deliberate introduction into clouds of various substances that act as condensation nuclei or ice nuclei in an attempt to induce precipitation. Quite often a chemical reaction at the surface is needed to deposit the atoms.…. Both aircraft and ground generators have been employed, but the techniques are typically beyond the means of an individual farmer. Attempts have been made to use these substances in cloud seeding operations that minimize damage to crops and buildings from hailstones. Black Friday Sale! The process of dispersing silver iodide to bring about rain is called. Silver Iodide; The main compound of cloud seeding for artificial rain is silver iodide. Results suggest that cloud modification is entirely possible, but…, Seeding for rain—accomplished by dropping silver iodide crystals from airplanes—is known to induce precipitation. The resulting water vapour deposits into ice crystals, which build quickly as water droplets attach themselves. While many different chemicals can be used for cloud seeding, such as solid carbon dioxide (dry ice), silver iodide is the most commonly used. As the second driest state in the U.S., the goal of cloud seeding programs in Utah has Chemicals like silver iodide can act as a seeding agent and provide a nucleus for the moisture already inside the clouds to condense, thus rendering the clouds more efficient in precipitating their water content. In clouds at temperatures above freezing, calcium chloride particles provide the condensation nucleii around which raindrops form. Updates? Then silver iodide falls from the sky. The crystalline structure of AgI is similar to that of ice, allowing it to induce freezing in cloud seeding for the purpose of rainmaking. This can produce ice crystals at higher temperatures than silver iodide. Many substances have been used, but solid carbon dioxide (dry ice) and silver iodide have been the most effective; when used in supercooled clouds (composed of water droplets at temperatures below freezing), they form nuclei around which the water droplets evaporate. The process of dispersing silver iodide to bring about rain is called static cloud seeding. Cloud seeding releases dangerous silver iodide into the air. Cloud droplets form when atmospheric water vapour condenses on small particles in the atmosphere called cloud condensation nuclei (CCN). © 2020 Climate Change Explained. Silver iodide. Liquid propane, which expands into a gas, has also been used. Premium Membership is now 50% off! effects from cloud seeding with silver iodide. Our editors will review what you’ve submitted and determine whether to revise the article. Built using WordPress and OnePage Express Theme. In the laboratory, vapour growth is usually accomplished by flowing a supersaturated gas over a seed crystal. This article was most recently revised and updated by, https://www.britannica.com/science/cloud-seeding, Resources in Atmospheric Sciences - Cloud seeding. Corrections? Silver iodide (AgI) is a yellow, inorganic, photosensitive iodide of silver used in photography, in medicine as an antiseptic, and in rainmaking for cloud seeding.