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Weather Modification
Published in William Goldfarb, Water Law, 2020
“Weather modification” is defined as “any artificially produced change in the composition, behavior, or dynamics of the atmosphere, when such change is produced with intent to alter the weather.”34 This definition excludes inadvertent weather changes such as those potentially caused by fossil fuel burning, and it implicitly excludes “climate modification” involving relatively long-term or lasting climatic changes. Seeding clouds with silver iodide or other chemicals to increase precipitation, especially to augment winter snowpack, is the most popular weather modification technique. But attempts are also made at hail and lighting suppression, hurricane diversion, and fog dissipation.35
Survey of Types of Solid Electrolytes
Published in P.J. Gellings, H.J.M. Bouwmeester, Electrochemistry, 2019
Silver iodide, AgI, adopts the wurtzite-type structure at room temperature. This β form of AgI transforms into the α form (bcc) at 147°C with a jump of conductivity over more than 3 orders of magnitude, as given in Figure 6.5. The silver ion conductivity after the transformation is ~l S cm−1, which is almost the same as that of the molten phase (m.p. 552°C) and even comparable to an H2SO4 solution. Cuprous iodide, CuI, undergoes a similar transition at 430°C and turns into a very good Cu+ conductor. A common feature of both compounds is that they are composed of extremely polarizable ions.
Atmospheric Effects
Published in Wayne T. Davis, Joshua S. Fu, Thad Godish, Air Quality, 2021
Wayne T. Davis, Joshua S. Fu, Thad Godish
Pollutants may also affect precipitation in cold cloud processes by influencing the concentration of freezing nuclei. Because atmospheric levels of freezing nuclei are frequently low, the addition of freezing nuclei in the form of pollution particles may enhance precipitation under cold cloud conditions. An application of this principle is cloud seeding with silver iodide crystals.
Study of ice nucleation on silver iodide surface with defects
Published in Molecular Physics, 2019
Rohit Goswami, Atanu K. Metya, S. V. Shevkunov, Jayant K. Singh
Among all the ice-nucleating agents, silver iodide (AgI) is widely used as cloud seeding agents because of its efficacious ice-nucleating ability [43]. Owing to this efficiency, diverse experimental and theoretical studies [29,44] have been devoted to the ice nucleation on AgI surface. Zielke et al. [38] observed that silver exposed AgI surface accelerated ice nucleation while iodide exposed surface hindered the process. Water condensation studies over β-AgI surface with defects in the form of rectangular towers [45] and pyramids [46,47] showed greater thermodynamic stability of condensate over the surface. The increased stability at the early stage of nucleation was reported to be a function of the shape and size of the nanostructure [45]. Similar condensation study over AgI surface with disordered structure observed an increase in absorption ability [48] and rupture of the hydrogen bond between molecules due to defects [46,48]. However, the influence of defective AgI surface on the liquid to solid transition mechanism of water has not been probed using molecular dynamics (MD). Recent studies have reported enhanced ice nucleation efficiency for systems with surface defects in the form of steps, cavities, and crevices [27]. The nucleation rate has been reported to increase for surface geometries which favour the formation of topological defects in ice lattice structures [49].