| From the starting point of atmospheric physics, by the method of atmospheric science and mathematics, with computer technology forecasting space-time distribution of the atmospheric contaminant's density in a region with some pollution sources is a hot spot of research recently in the world. It is very significant to establish a forecasting system of ambient air quality with automation, visual interface, graphical output, with the function of forecasting contamination density, the management of pollution sources and enquiry together.Forecasting system of ambient air quality was established with the models of atmospheric diffusion in this paper, which was applied in the protection of the atmospheric environment in Zhangqiu. The city arrangement adjustment, the ambient air capacity of sulfur dioxide and centralized control to the point and area sources were studied. Following are the main research content and results1 .Forecasting modles of ambient air qualityPollution sources, meteorological condition and topography are main three factors which influence the ambient air quality. Gauss diffusion model at the basis of the theory of rapids statistics, i.e. Gauss model of the continuous point source in the limitless space is the foundation of forecasting system in paper. Because of the difference in actual diffusion condition and hypothetical condition on which Gauss model is derived, the models of continuous point source, area source under the condition of wind, breeze, calm, blocked and fumitory condition in the limited space, the models of abnormal emission of instant and limited time T, the models of medium and long term and urban pleophyletic diffusion models were established.2.Building and assessment of the forecasting system of ambient air quality (1) Objective and design of the forecasting systemAccording to objective of the system, the forecasting system should easily renew and maintain data of pollution sources by the automatic enquiry function and realize scientificmanagement; can realize statistics and analysis of the meteorological condition; can forecast and simulate distribution of the pollutant.At the base of the data of meteorological condition, pollution sources observed and collected and monographic maps, by the support of technique of Mapinfo5.0 Visual FoxPro.5.0 and Winsurf softs, spatial and attributive data-bases of the forecasting system of ambient air quality were established; model-bases were built with the expanding and modified Gauss models; the forecasting system of ambient air quality was established by correlating basic data-bases to model-bases with programs to realize the data input and data output.(2) Function and assessment of the forecasting systemThe analysis and assessment of system's functions with its features manifests: compared with homogeneous systems, this system is better in data management of pollution sources, friendly visual interface, the function of graphical output and statistics of meteorological data, and but it has some shortages in system integration, automatism and stability and needs further perfection, optimization and enhancement.When actual pollution data of Zhangqiu was input urban pleophyletic diffusion model, coincidence index d was gotten, and the value of d was 0.68, which indicated performance of the model was good.3. Application of the forecasting system in ambient air protection in ZhangqiuStatistical analysis of the meteorological condition in Zhangqiu in 1999 indicated: the dominant wind direction was S, and the second dominant wind direction was E ESE; the greatest sources in outflow discharge were industrial point sources, and the area sources made the greatest contribution. Some greatest industrial point sources were exactly arranged in E and ESE direction, and the domestic sources distributed all over the municipalities, which led to severe air pollution in city.From the point of environmental protection, according to the atmospheric problems in Zhangqiu, with the forecasting system of ambient air quali...
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