| A Three-Dimensional Model of Transport and Diffusion of Seeding Agents within Stratus |
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| 作者姓名： | Yu Xing Dai Jin Jiang Weimei Fan Peng |
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| 作者单位： | Yu Xing，Dai Jin (Center of Weather Modification of Shaanxi Province，Xi'an 710015) Jiang Weimei (Department of Atmospheric Sciences，Nanjing University. Nanjing 210093) Fan Peng (Center of Weather Modification of Shaanxi Province，Xi'an 710015) |
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| 摘 要： | 1. IntroductionMany projects and experiments of rain enhancement are carried out abroad. Most seeded cloud bodies are the convective or topographic clouds. The seeding agents are usually released near their bases and brought into the clouds by the updrafts. Whether the seeding material can reach the areas where cloud liquid water presents is emphasized. Tzivion et al.(1989) demonstrated that effective dispersal of seeding material strongly depends on the seeding altitude and the stage (time) …
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A Three-Dimensional Model of Transport and Diffusion of Seeding Agents within Stratus |
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| Yu Xing,Dai Jin,Jiang Weimei,Fan Peng.A Three-Dimensional Model of Transport and Diffusion of Seeding Agents within Stratus[J].Advances in Atmospheric Sciences,2000,17(4):617-635. |
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| Authors: | Yu Xing Dai Jin Jiang Weimei and Fan Peng |
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| Institution: | Center of Weather Modification of Shaanxi Province; Xi'an 710015,Center of Weather Modification of Shaanxi Province; Xi'an 710015,Department of Atmospheric Sciences; Nanjing University. Nanjing 210093,Center of Weather Modification of Shaanxi Province; Xi'an 710015 |
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| Abstract: | It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorpo-rating a mesoscale nonhydrostatic model has been formulated, and is applied to simulating the transporting and diffusive characteristics of multiple line sources of seeding agents within super-cooled stratus. Several important factors are taken into consideration that affect the diffusion of seeding materials such as effects of topography and vertical wind shear, temporal and spatial variation of seeding parameters and wet deposi-tion. The particles of seeding agents are assumed to be almost inert, they have no interaction with the particles of the cloud or precipitation except that they are washed out by precipitation. The model validity is demonstrated by the analyses and comparisons of model results, and checked by the sensitivity experiments of diffusive coefficients and atmospheric stratification. The advantage of this model includes not only its exact reflection of heterogeneity and unsteadiness of background fields, but also its good simulation of trans port and diffusion of multiple line sources.The horizontal diffusion rate and the horizontal transport distance have been proposed that they usual-ly were difficult to obtain in other models. In this simulation the horizontal diffusion rate is 0.82 m s-1 for average of one hour, and the horizontal average transport distance reaches 65 km after 1 h, which are closely related to the background fields. |
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| Keywords: | Puff trajectory model Transport and diffusion Multiple line sources of seeding agents Heterogeneity and unsteadiness Diffusion rate and transport distance Super-Cooled stratus |
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