Table of Contents Formation of Precipitation 3
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Position Wind speed Date/Time Lat. (oN) Lon. (oW) (knots) ________________________________________________________ Aug 26/0600 29.2 91.3 115
Aug 27/0000  Stop! Question #5. Based how far the storm has traveled over the
last 24 hours and its direction so far, which locations would you issue hurricane warnings and watches? 
Intentional Weather ModificationWeather modification is deliberate human intervention to influence and improve the atmospheric processes and events that constitute the weather – that is, to aim the weather at human purposes. From earliest recorded times, people have used prayer, wizardry, dancing, and even black magic in attempts to alter the weather. Until modern times, however, most attempts at weather modification remained largely in the realm of the mystic. By the nineteenth century such devices as smudge pots, sprinklers, and wind machines to fight frost were in use. During the American Civil War, observations that rainfall apparently increased following some battles led to experiments in which cannons were fired into clouds to bring more rain. Unfortunately, these experiments, as well as many others, proved unsuccessful. Weather modification strategies fall into three broad subdivisions. The first relies on the injection of energy by force. The use of powerful heat sources or the intense mechanical mixing of the air (such as by helicopters) are both examples of techniques of fog dispersal attempted at some airports that fall into this category. The second subdivision involves the alteration of land and water surfaces in order to change their natural interactions with the lower atmosphere. One commonly discussed but still theoretical example of this technique is the blanketing of a land area with a dark substance. If it were done, the amount of heat absorbed by the surface would increase and lead to stronger upward air currents that, in turn, might aid cloud formation. Finally, the third subdivision involves triggering, intensifying, or redirecting the atmosphere’s natural energies. The seeding of clouds with such agents as dry ice and silver iodide for many purposes, including precipitation enhancement, represents the primary example in this category. Because it offers a relatively inexpensive and easily used technique, cloud seeding has been the main focus of modern weather modification technology. Modern weather modification is used for various purposes. First, it can be used to disperse fog and clouds to improve visibility. The US Air Force has practiced weather modification for many years at various airbases, and commercial airlines have modified weather at selected airports in the northwest US. Additionally, weather modification can be used to suppress hail and reduce the damage caused by it. Finally, weather medication can be used to prevent frost from killing crops. The first scientific breakthrough in intentional weather modification came in 1946 when Vincent J. Schaefer discovered that dry ice dropped into a supercooled cloud spurred the growth of ice crystals. Shortly after Schaefer’s discovery, it was learned that silver iodide could also be used for cloud seeding. The similarity in the crystalline structures of silver iodide and ice accounts for silver iodide’s ability to initiate the growth of ice crystals. Thus, unlike dry ice, silver iodide crystals act as freezing nuclei rather than as a cooling agent. This substance has an advantage over dry ice in that it can be supplied to clouds from burners on the ground as well as from aircraft. If either substance is to be successful, certain atmospheric conditions must exist. Clouds must be present, for seeding cannot generate them. In addition, at least the top portion of the cloud must be supercooled to below 0oC. Directory: cms -> lib6 -> NJ01001533 -> Centricity -> Domain lib6 -> Unit 6: Branding & Licensing lib6 -> Unit 11: Sports & Entertainment Communications lib6 -> Sports & Entertainment Marketing Unit Two Outline, 2014-15 School Year lib6 -> Aeneid, Book VI english and Latin Translation Passages (English by A. S. Klein) Lines 1-55, the Temple at Cumae lib6 -> The Seminar Gazette lib6 -> Tour begins at: 6pm at Somerset Borough Building 340 West Union Street Somerset, Pa 15501 Domain -> Name Period Date Domain -> Berlin Conference Activity Domain -> Art history review name of the era Download 0.49 Mb. Share with your friends:
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