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Comparison Between Computer Simulation of Transport and Diffusion of Cloud Seeding Material Within Stratiform Cloud and the NOAA-14 Satellite Cloud Track
YU Xing,DAI Jin,LEI Hengchi,FAN Peng,
YU Xing
,DAI Jin,LEI Hengchi,FAN Peng

大气科学进展 , 2005,
Abstract: A precipitation enhancement operation using an aircraft was conducted from 1415 to 1549 LST 14 March 2000 in Shaanxi Province. The NOAA-14 satellite data received at 1535 LST soon after the cloud seeding shows that a vivid cloud track appears on the satellite image. The length, average width and maximum width of the cloud track are 301 km, 8.3 and 11 km, respectively. Using a three-dimensional numerical model of transport and diffusion of seeding material within stratiform clouds, the spatial concentration distribution characteristics of seeding material at different times, especially at the satellite receiving time,are simulated. The model results at the satellite receiving time are compared with the features of the cloud track. The transported position of the cloud seeding material coincides with the position of the track. The width, shape and extent of diffusion of the cloud seeding material are similar to that of the cloud track.The spatial variation of width is consistent with that of the track. The simulated length of each segment of the seeding line accords with the length of every segment of the track. Each segment of the cloud track corresponds to the transport and diffusion of each segment of the seeding line. These results suggest that the cloud track is the direct physical reflection of cloud seeding at the cloud top. The comparison demonstrates that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulated results are sound and trustworthy. The area, volume, width, depth, and lateral diffusive rate corresponding to concentrations 1, 4, and 10 L-1are simulated in order to understand the variations of influencing range.
The Physical and Precipitation Response to AgI Seeding from a Mesoscale WRF-based Seeding Model
碘化银播撒对云和降水影响的中尺度数值模拟研究

FANG Chungang,GUO Xueliang,WANG Panxing,
方春刚
,郭学良,王盘兴

大气科学 , 2009,
Abstract: A WRF-based AgI-seeding model has been developed and used to simulate cloud seeding effects on cloud physics and precipitation of a convective cloud system in Beijing.The effects of diffusion and transport of seeding agent under different seeding locations,seeding time and seeding amounts on cloud hydrometeor and precipitation have been discussed.The results show that the diffusion and transport of AgI agent are strongly dependent on the seeding location.AgI injected into the maximum supercooled cloud water...
Seeding Influential Nodes in Non-Submodular Models of Information Diffusion  [PDF]
Elliot Anshelevich,Ameya Hate,Malik Magdon-Ismail
Computer Science , 2013,
Abstract: We consider the model of information diffusion in social networks from \cite{Hui2010a} which incorporates trust (weighted links) between actors, and allows actors to actively participate in the spreading process, specifically through the ability to query friends for additional information. This model captures how social agents transmit and act upon information more realistically as compared to the simpler threshold and cascade models. However, it is more difficult to analyze, in particular with respect to seeding strategies. We present efficient, scalable algorithms for determining good seed sets -- initial nodes to inject with the information. Our general approach is to reduce our model to a class of simpler models for which provably good sets can be constructed. By tuning this class of simpler models, we obtain a good seed set for the original more complex model. We call this the \emph{projected greedy approach} because you `project' your model onto a class of simpler models where a greedy seed set selection is near-optimal. We demonstrate the effectiveness of our seeding strategy on synthetic graphs as well as a realistic San Diego evacuation network constructed during the 2007 fires.
Competitive Diffusion in Social Networks: Quality or Seeding?  [PDF]
Arastoo Fazeli,Amir Ajorlou,Ali Jadbabaie
Mathematics , 2015,
Abstract: In this paper, we study a strategic model of marketing and product consumption in social networks. We consider two firms in a market competing to maximize the consumption of their products. Firms have a limited budget which can be either invested on the quality of the product or spent on initial seeding in the network in order to better facilitate spread of the product. After the decision of firms, agents choose their consumptions following a myopic best response dynamics which results in a local, linear update for their consumption decision. We characterize the unique Nash equilibrium of the game between firms and study the effect of the budgets as well as the network structure on the optimal allocation. We show that at the equilibrium, firms invest more budget on quality when their budgets are close to each other. However, as the gap between budgets widens, competition in qualities becomes less effective and firms spend more of their budget on seeding. We also show that given equal budget of firms, if seeding budget is nonzero for a balanced graph, it will also be nonzero for any other graph, and if seeding budget is zero for a star graph it will be zero for any other graph as well. As a practical extension, we then consider a case where products have some preset qualities that can be only improved marginally. At some point in time, firms learn about the network structure and decide to utilize a limited budget to mount their market share by either improving the quality or new seeding some agents to incline consumers towards their products. We show that the optimal budget allocation in this case simplifies to a threshold strategy. Interestingly, we derive similar results to that of the original problem, in which preset qualities simulate the role that budgets had in the original setup.
Physical effect of cloud seeding revealed by NOAA satellite imagery
Xing Yu,Jin Dai,Hengchi Lei,Xiaohong Xu,Peng Fan,Zhengqi Chen,Changhui Duan,Yong Wang
Chinese Science Bulletin , 2005, DOI: 10.1360/03WD0650
Abstract: From 0615 to 0749 UTC, 14 March 2000, a precipitation enhancement operation with AgI using an aircraft was conducted at the middle part of Shaanxi Province, China. 80 min after cloud seeding (0735 UTC), NOAA-14 satellite data showed a vivid zigzag cloud track on the satellite image. Its length is 301 km, and its average and maximum width are 8.3 and 11 km. The cloud track is very similar in shape with, but different in position and width from that of cloud seeding line. In order to determine that the cloud track is indeed caused by cloud seeding, a three-dimensional numerical model of transport and diffusion of seeding material is used to simulate the shape of seeding material concentration distribution, the turning points, width and length of seeding line. The simulated results are compared with the features of cloud track at 0735 UTC. Every segment of the cloud track is consistent with the transport and diffusion of every segment of seeding line. The transport position, length, width and the variation trend of seeding line agree with those of cloud track. All suggest that the cloud track is the direct physical reflection of cloud seeding effect on the cloud top, which can respond to the transport and diffusion of seeding material. For this study case, the main effecting duration for every segment of seeding line is from 20 to 80 min, the time for each segment of seeding line diffusing to the maximum width is from about 50 to 70 min. This time is obtained from the appearing and disappearing time, width variation of the cloud track segments and simulated results. Also, the comparisons demonstrate that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulating results are sound and trustworthy.
Physical effect of cloud seeding revealed by NOAA satellite imagery
Xing Yu,Jin Dai,Hengchi Lei,Xiaohong Xu,Peng Fan,Zhengqi Chen,Changhui Duan,Yong Wang,
YUXing
,DAIJin,LEIHengchi,XUXiaohong,FANPeng,CHENZhengqi,DUANChanghui,WANGYong

科学通报(英文版) , 2005,
Abstract: From 0615 to 0749 UTC, 14 March 2000, a precipitation enhancement operation with AgI using an air- craft was conducted at the middle part of Shaanxi Province, China. 80 min after cloud seeding (0735 UTC), NOAA-14 satellite data showed a vivid zigzag cloud track on the satel- lite image. Its length is 301 km, and its average and maxi- mum width are 8.3 and 11 km. The cloud track is very simi- lar in shape with, but different in position and width from that of cloud seeding line. In order to determine that the cloud track is indeed caused by cloud seeding, a three-dimensional numerical model of transport and diffu- sion of seeding material is used to simulate the shape of seeding material concentration distribution, the turning points, width and length of seeding line. The simulated re- sults are compared with the features of cloud track at 0735 UTC. Every segment of the cloud track is consistent with the transport and diffusion of every segment of seeding line. The transport position, length, width and the variation trend of seeding line agree with those of cloud track. All suggest that the cloud track is the direct physical reflection of cloud seed- ing effect on the cloud top, which can respond to the trans- port and diffusion of seeding material. For this study case, the main effecting duration for every segment of seeding line is from 20 to 80 min, the time for each segment of seeding line diffusing to the maximum width is from about 50 to 70 min. This time is obtained from the appearing and disap- pearing time, width variation of the cloud track segments and simulated results. Also, the comparisons demonstrate that the numerical model of transport and diffusion can simulate the main characteristics of transport and diffusion of seeding material, and the simulating results are sound and trustworthy.
Investigation of Cloud Seeding Interval for Precipitation Enhancement by Aircraft within Stratiform Clouds
层状云中飞机人工增雨作业间距的研究

YU Xing,DAI Jing,
余兴
,戴进

大气科学 , 2005,
Abstract: Three cloud seeding intervals frequently used in precipitation enhancement by aircraft within stratiform clouds are designed to investigate their effects on effective range by using numerical simulation. The simulated seeding lines deviate from the designed line due to transport by horizontal wind fields. The different seeding interval leads to diversified projective effective area and duration, whose tempo spatial distribution and corresponding surface position are variable. Enlargement or reduction of seeding interval does not mean to simply and synchronously amplify the effective area and duration, but amalgamation of seeding lines can extend the effective duration. Also a mathematical formula of benefit for precipitation enhancement is developed. Under the same operational conditions, the benefit of 8 km interval is 31 percent higher than that of the 20 km, and 23 percent higher than that of the 4 km. Finally, a set of mathematical expression of seeding interval is formulated for cross and parallel seeding schemes from the view of physical cause.
Diffusion and Contagion in Networks with Heterogeneous Agents and Homophily  [PDF]
Matthew O. Jackson,Dunia Lopez-Pintado
Computer Science , 2011,
Abstract: We study how a behavior (an idea, buying a product, having a disease, adopting a cultural fad or a technology) spreads among agents in an a social network that exhibits segregation or homophily (the tendency of agents to associate with others similar to themselves). Individuals are distinguished by their types (e.g., race, gender, age, wealth, religion, profession, etc.) which, together with biased interaction patterns, induce heterogeneous rates of adoption. We identify the conditions under which a behavior diffuses and becomes persistent in the population. These conditions relate to the level of homophily in a society, the underlying proclivities of various types for adoption or infection, as well as how each type interacts with its own type. In particular, we show that homophily can facilitate diffusion from a small initial seed of adopters.
Modelling Electrical Car Diffusion Based on Agents  [PDF]
Lei Yu,Tao Zhang,Peer-Olaf Siebers,Uwe Aickelin
Computer Science , 2014,
Abstract: Replacing traditional fossil fuel vehicles with innovative zero-emission vehicles for the transport in ci ties is one of the major tactics to achieve the UK government 2020 target of cutting emission. We are developing an agent-based simulation model to study the possible impact of different governmental interventions on the diffusion of such vehicles. Options that could be studied with our what-if analysis to include things like car parking charges, price of electrical car, energy awareness and word of mouth. In this paper we present a first case study related to the introduction of a new car park charging scheme at the University of Nottingham. We have developed an agent based model to simulate theimpact of different car parking rates and other incentives on the uptake of electrical cars. The goal of this case study is to demonstrate the usefulness of agent-based modelling and simulation for such investigations.
A case study of stratus cloud base height multifractal fluctuations  [PDF]
K. Ivanova,H. N. Shirer,E. E. Clothiaux,N. Kitova,M. A. Mikhalev,T. P. Ackerman,M. Ausloos
Physics , 2001, DOI: 10.1016/S0378-4371(02)00554-X
Abstract: The complex structure of a typical stratus cloud base height (or profile) time series is analyzed with respect to the variability of its fluctuations and their correlations at all experimentally observed temporal scales. Due to the underlying processes that create these time series, they are expected to have multiscaling properties. For obtaining reliable measures of these scaling properties, different methods of statistical analysis are used herein : power spectral density, detrended fluctuation analysis, and multifractal analysis. This broad set of diagnostic techniques is applied to a typical stratus cloud base height (CBH) data set; data were obtained from the Southern Great Plains site of the Atmospheric Radiation Measurement Program of the Department of Energy from a Belfort Laser Ceilometer. First, we demonstrate that this CBH time series is a nonstationary signal with stationary increments. Further, two scaling regimes are found, although the characteristic laws are quite similar ones. Next, the multi-affine scaling properties are confirmed. The scaling properties of the cloud base height profile of such a continental stratus are found to be similar to those of the marine cloud base height profiles studied by us previously. Some physical interpretation in terms of anomalous diffusion (or fractional random walk) is given for the continental case.
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