An Environmental Risk Evaluation Method Employing Atmospheric Dispersion Models and GIS

This study aims to develop a method for evaluating the environmental risk of harmful chemical substances released from specific sources, using two atmospheric dispersion models and GIS (Geographic Information Systems). In the first stage of evaluation, ADMER was used to conduct a wide-area evaluation which covered the entire area of the evaluation target region. In the second stage, METI-LIS was used to conduct a detailed limited-area evaluation which targeted the vicinity of sources. In this study, incinerators were selected as sources and dioxins were selected as harmful chemical substances. The area selected for evaluation was the Tokyo Metropolis in Japan, and the evaluation method proposed in this study was used to evaluate environmental risk. Through the use of atmospheric dispersion models and GIS, the behavior of dioxins emitted into the atmosphere from incinerators was estimated. By superimposing atmospheric levels and population data, the amounts of dioxins that humans exposed to were found. Additionally, by superimposing deposition amounts and land use data, the amounts of dioxins accumulated in each land environment were found. Conducting these steps enabled the impact of dioxins on humans and the environment to be grasped quantitatively and visually, and the risk that dioxins emitted from incinerators pose to the environment to be evaluated.

Simplified Atmospheric Dispersion Model andModel Based Real Field Estimation System ofAir Pollution

The atmospheric dispersion model has been well developed and applied in pollution emergency and prediction. Based on thesophisticated air diffusion model, this paper proposes a simplified model and some optimization about meteorological andgeological conditions. The model is suitable for what is proposed as Real Field Monitor and Estimation system. The principle ofsimplified diffusion model and its optimization is studied. The design of Real Field Monitor system based on this model and itsfundamental implementations are introduced.

A Dynamic Bayesian-Based Comprehensive Trust Evaluation Model for Dispersed Computing Environment

Dispersed computing is a new resourcecentric computing paradigm.Due to its high degree of openness and decentralization,it is vulnerable to attacks,and security issues have become an important challenge hindering its development.The trust evaluation technology is of great significance to the reliable operation and security assurance of dispersed computing networks.In this paper,a dynamic Bayesian-based comprehensive trust evaluation model is proposed for dispersed computing environment.Specifically,in the calculation of direct trust,a logarithmic decay function and a sliding window are introduced to improve the timeliness.In the calculation of indirect trust,a random screening method based on sine function is designed,which excludes malicious nodes providing false reports and multiple malicious nodes colluding attacks.Finally,the comprehensive trust value is dynamically updated based on historical interactions,current interactions and momentary changes.Simulation experiments are introduced to verify the performance of the model.Compared with existing model,the proposed trust evaluation model performs better in terms of the detection rate of malicious nodes,the interaction success rate,and the computational cost.

Study on Conventional Atmospheric Dispersion Models in China,America and Canada

The conventional atmospheric dispersion models used in China (CRADM), America (HPDM) and Canada (AMS) are investigated. The main differences between the three models are described, and the various aspects of CRADM, HPDM and AMS for same input are compared and discussed. Some problems in application of atmospheric dispersion models to environmental impact assessment are analyzed and suggestions for rivision are proposed. Results show that the Briggs plume rise formula in neutral condition overestimates the real rise due to the fact that the accumulative effect of ambient turbulence on plume is not considered in his model.

Modeling the Dispersion and Atmospheric Mitigation of Pollutants in the Dibamba-Douala Thermal Power Plant

This work simulates the dispersion and atmospheric attenuation of pollutants from the Dibamba-Douala thermal power plant. The objective of this research is to study the dispersion of air pollutants and mitigate the impact of pollutants on the populations living around the power plant. The methodology used is as follows: the Gaussian model is used for the representation of the dispersion in the form of a plume, the finite difference method for digital resolution. Finally, dispersion charts are constructed which allow the heights of the chimneys to be fixed for which the concentrations of pollutants discharged comply with ambient air quality standards. The results obtained using the simulation made in the MATLAB software version 2016 show that, for a wind regime of 1.5 m/s;we have a predicted distance of 150 m at which the concentration is canceled out. Then, for the wind speed of 2 m/s;we had a predicted distance of 125 m and finally for a wind speed of 2.5 m/s;we observed the 120 m distance at which the concentration is canceled. In addition, for the same wind regimes, the attenuation of pollutants at ground level is obtained for a height of 60 m.

Random walk modeling of wake dispersion for the exhaust tower of an underground tunnel in urban area

In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.

Review of Air Dispersion Modelling Approaches to Assess the Risk of Wind-Borne Spread of Foot-and-Mouth Disease Virus

Foot-and-mouth disease virus (FMDV) is one of the most economically serious veterinary pathogens due to its negative effects on livestock and its highly infectious nature via a variety of transmission paths through oral and inhalation routes. Measures to enhance outbreak management can be designed according to analytical results predicted by mathematical models for wind-borne dispersion, an important path of virus transmission. Accurate atmospheric dispersion models are useful tools for properly determining risk management plans, while inaccurate models may conversely lead to accidental loss in two possible ways. Overly strict measures, e.g., slaughter for too wide an area, can cause severe economic difficulties, including irreversible loss of business operations for a number of farms. On the contrary, inestimable loss potentially caused by lax controls is a persistent threat. In this paper, available modelling procedures for forecasting the spread of FMDV, which have been used since the 1970s, each having its advantages and limitations, are reviewed for the purpose of ensuring suitable application in various conditions of any future emergency cases.

A Support Vector Machine-based Evaluation Model of Customer Satisfaction Degree in Logistics

This paper presents a novel evaluation model of the customer satisfaction degree (CSD) in logistics based on support vector machine (SVM). Firstly, the relation between the suppliers and the customers is analyzed. Secondly, the evaluation index system and fuzzy quantitative methods are provided. Thirdly, the CSD evaluation system including eight indexes and three ranks based on one-against-one mode of SVM is built. Last simulation experiment is presented to illustrate the theoretical results.

A Fast Version of LASG/IAP Climate System Model and Its 1000-year Control Integration

A fast version of the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）/Institute of Atmospheric Physics （IAP） climate system model is briefly documented. The fast coupled model employs a low resolution version of the atmospheric component Grid Atmospheric Model of IAP/LASG （GAMIL）, with the other parts of the model, namely an oceanic component LASG/IAP Climate Ocean Model （LICOM）, land component Common Land Model （CLM）, and sea ice component from National Center for Atmospheric Research Community Climate System Model （NCAR CCSM2）, as the same as in the standard version of LASG/IAP Flexible Global Ocean Atmosphere Land System model （FGOALS_g）. The parameterizations of physical and dynamical processes of the atmospheric component in the fast version are identical to the standard version, although some parameter values are different. However, by virtue of reduced horizontal resolution and increased time-step of the most time-consuming atmospheric component, it runs faster by a factor of 3 and can serve as a useful tool for longterm and large-ensemble integrations. A 1000-year control simulation of the present-day climate has been completed without flux adjustments. The final 600 years of this simulation has virtually no trends in global mean sea surface temperatures and is recommended for internal variability studies. Several aspects of the control simulation＇s mean climate and variability are evaluated against the observational or reanalysis data. The strengths and weaknesses of the control simulation are evaluated. The mean atmospheric circulation is well simulated, except in high latitudes. The Asian-Australian monsoonal meridional cell shows realistic features, however, an artificial rainfall center is located to the eastern periphery of the Tibetan Plateau persists throughout the year. The mean bias of SST resembles that of the standard version, appearing as a ＂double ITCZ＂ （Inter-Tropical Convergence Zone） associated with a westward extension of the equatorial eastern Pacific cold tongue. The sea ice extent is acceptable but has a higher concentration. The strength of Atlantic meridional overturning is 27.5 Sv. Evidence from the 600-year simulation suggests a modulation of internal variability on ENSO frequency, since both regular and irregular oscillations of ENSO are found during the different time periods of the long-term simulation.

The comparison of ensemble or deterministic dispersion modeling on global dispersion during Fukushima Dai-ichi nuclear accident

Ensemble forcasting,originally developed for weather prediction,is lately being extended to atmospheric dispersion applications,which is a new,effective methodology for improving the atmospheric dispersion numerical modeling.In March 2011,due to the massive 9.0 earthquakes and ensuing tsunami that struck off the northern coast of the island of Honshu,the Fukushima Nuclear Plant I had the substantial leak of radioactive materials into surrounding environment and atmosphere.To aim at the global dispersion modeling of atmospheric radionuclides from Fukushima Nuclear Accident,this paper presents two approaches of atmospheric dispersion forecasting:ensemble dispersion modeling(EDM) and deterministic dispersion modeling(DDM),conducts the globally dispersion modeling cases for Fukushima nuclear accident,and analyzes and evaluates the simulation results using observation data.In this paper,EDM includes three different perturbation methods:meteorological perturbation method,turbulence perturbation method,and physical parameterization ensemble forecasting method.The simulation results show that the trajectories from EDM have a better performance,which is in better agreement with the atmospheric circulation and observation data; the spread from DDM is slower and not as far as EDM.Additionally,the results from EDM display a better performance in the modeling of transport from Japan to China East Sea on April 4.The reasons for these results are:the techniques of MET and TUR are performed by adding perturbations on mean wind and turbulent velocity,respectively; the various different flow fields will result in far spreading in horizontal and the simulation results closer to observation; PHY is performed by using different diffusion physical parameterizations and produces the perturbations on vertical wind,which results the spreading in smaller range and discontinuous in horizontal.Finally,the comparative analysis between modeling results and observation data shows that all cases results are in good agreement with trends of observed radionuclides surface concentration; however,the modeling surface concentration is smaller than observation,especially in DDM and PHY.Furthermore,the EDM results show that MET and TUR are of more evolutionary advantage than PHY in modeling of average and maximum concentration.Therefore,this study can serve as a reference to atmospheric dispersion and environmental emergency response(EER).

Development and evaluation of a regional ocean-atmosphere coupled model with focus on the western North Pacific summer monsoon simulation:Impacts of different atmospheric components

A regional ocean atmosphere coupled model (ROAM) is developed through coupler OASIS3,and is composed of regional climate model RegCM3 and CREM (Climate version of Regional Eta Model) as its atmospheric component and of a revised Princeton ocean model (POM2000) as its oceanic component.The performance of the ROAM over the western North Pacific summer monsoon region is assessed by the case simulation of warm season in 1998.Impacts of different atmospheric model components on the performance of ROAM are investigated.Compared with stand-alone simulation,CREM (RegCM3) produces more (or less) rainfall over ocean area with inclusion of the air-sea coupling.Different biases of rainfall are caused by the different biases of SST derived from the coupled simulation.Warm (or cold) SST bias simulated by CREM_CPL (RegCM3_CPL) increases (or decreases) the evaporation at sea surface,then increases (or decreases) the rainfall over ocean.The analyses suggest that the biases of vertical profile of temperature and specific humidity in stand-alone simulations may be responsible for the SST biases in regional coupled simulations.Compared with reanalysis data,the warmer (or colder) and moister (or dryer) lower troposphere simulated in CREM (RegCM3) produces less (or more) sea surface latent heat flux.Meanwhile,the more unstable (or stable) lower troposphere produces less (or more) cloudiness at low-level,which increases (or decreases) the solar radiation reaching on the sea surface.CREM (RegCM3) forced by observed SST overestimates (or underestimates) the sea surface net heat flux,implying a potential warm (or cold) heat source.After coupling with POM2000,the warm (or cold) heat source would further increase (or decrease) the SST.The biases of vertical profile of temperature and specific humidity may be ascribed to the different representation of cumulus convection in atmospheric models.

基于政策建模一致性(PMC)指数模型的中美人工智能政策比较研究

对人工智能政策文本,特别是从人工智能专项政策的角度开展相关研究,能够为进一步完善中国人工智能政策体系提供决策支持。为此,以中美两国在顶层设计、职能部门两个层面共74份人工智能政策文本作为研究对象(中国51份、美国23份),通过文本挖掘方法识别出两国人工智能政策的关注重点,用政策建模一致性(PMC)指数模型建立人工智能政策评价指标体系,并结合PMC指数值和PMC曲面图,对两国各6份具有代表性的政策文本进行量化评价和对比分析。研究发现在总体上,中美两国的人工智能政策表现较好,能够较为准确地把握当前人工智能的发展前景,具有一定价值导向性和前瞻性;政策制定设计较为合理、政策协同性较高;在政策制定过程中都注重对智能化、科技创新、成果应用等方面的研究,而对于政策领域和效力级别方面则重视程度较低。同时发现两国在政策对象、政策内容和保障措施等方面的差异化显著:美国的政策扎根于技术研发、人才队伍建设、标准体系构建和基础研究投资等方面,在政策内容、保障措施等方面比中国更完善,但政策对象覆盖程度不够广;中国的政策对象兼顾宏观和微观的视角,涉及国家、产业和企业等层面,但在伦理规范、合作发展、核心技术优势等方面存在缺陷。基于此,进一步从保障措施、政策内容与政策领域3个方面提出完善中国人工智能政策的发展对策,强调中国人工智能政策的整体优化路径应为“保障措施→政策内容→政策领域”。

基于不同气象数据的山地城市大气环境敏感性评估对比

以典型低纬高原山地城市云南省德宏州为例,利用WRF_CALPUFF模型开展大气环境敏感性评估并以此为依据进行敏感区识别,分别采用WRF模拟结果和地面气象站观测资料作为模型输入地面气象数据,通过对比分析基于两种不同数据的评估结果,讨论适用于山地城市大气环境敏感性评估的数据和方法。结果表明:2种方法模拟计算的扩散指数均能反映出地形差异所致的扩散能力空间差异性,弱扩散区识别均较可靠。气象背景场采用WRF高空模拟数据和地面气象站观测数据相结合的方法,评估结果可靠,具有基础数据获取较难、技术难度较低、时间成本较低的特点,若能获取站点数据则推荐此法。气象背景场均采用WRF模拟结果的方法,在识别布局敏感区时不确定性较高,主要因地形复杂地区风场模拟不确定性较高所致,但此法具有基础数据获取较容易、技术难度较高、时间成本较高的特点,若采用此法,需提高模拟准确性以保障评估结果的可靠性。

基于熵权法—PSR模型的重庆市大气污染治理政策效果评价

采用PSR模型构建重庆市大气污染治理政策效果评价指标体系,通过熵权法与综合指数法对政策效果综合评价,并引进障碍度模型进行障碍因子判断。结果表明,重庆市大气污染治理政策效果显著提升,大气环境质量得到明显改善,压力、状态、响应层面总体上取得了较满意的效果;工业废气排放持续有效控制尚需加强和人均机动车保有量持续增加,NO_(2)、O_(3)污染物排放控制力度需要加强;缺乏较为完善的大气环境污染协同防治体系,是制约重庆市大气污染治理政策效果的重要障碍因素。因此,加强工业氮氧化物和挥发性有机物的深度治理、加强新生产和在用汽车排放管理和完善“政-企-民”协同防治体系,是进一步提升大气污染治理政策效果主要着力点。

JRODOS模拟核事故时核素扩散及剂量时空分布

核事故时核素扩散范围和造成的辐射剂量是核电厂事故应急措施制定的重要参考,利用JRODOS软件模拟了不同气象源和大气扩散模型对核电厂核素浓度和辐射剂量时空分布的影响。结果表明:WRF气象场情景下核素的扩散范围广,FNL气象场情景下核素浓度和有效剂量区域均值较高。不同大气扩散模型中LASAT模型模拟的有效剂量最高。这为核事故后果评价数据来源和大气扩散模型选择提供了依据。

城市地下空间资源地质环境适宜性评价方法对比分析

为了选择最优的地下空间资源地质适宜性评价模型,对地下空间进行资源科学、合理的评价,给地下空间开发提供合理的规划支持,笔者等选取了3种不同的模型,对其进行对比分析,总结其优缺点及适用条件,并以深圳市南山区为例进行地下空间资源地质适宜性评价,利用ArcGIS生成了南山区地下空间资源地质适宜性评价分区图。评价结果表明,最不利等级判别法评价模型较为适用于南山区的地质适宜性评价,突出了敏感因子对于南山区地下空间开发的制约性作用。笔者等的研究对未来地下空间资源地质适宜性评价的模型选择具有一定借鉴意义,为深圳市南山区的地下空间规划提供一定的参考。

缓黏结预应力抗浮灌注桩设计方法分析

缓黏结预应力技术作为一种新的预应力技术,在抗浮灌注桩中的应用仍处于初步探索阶段,需进一步研究其设计方法。文章首先提出了三种设计验算方法及设计验算流程,阐述了三种方法的区分要素,然后结合案例给出了设计验算过程,并对结果进行了分析,最后结合方案的经济性及施工便捷性提出了方案比选模型。

城市型石化企业大气环境风险防护区域划定研究

随着城市化进程日益加快,城市用地范围由中心城区向外扩张,原本位于郊区的石化企业开始与城市融合,石化企业周边的空地被开发成住宅区、商业区和生活区等人员密集的场所,导致城市型石化企业的出现。城市型石化企业与周边居民的矛盾日益突出,因此城市型石化企业急需设置足够的风险防护区域。本研究以华北某石化企业新建120 t/h酸性水汽提装置为例,依据《建设项目环境风险评价技术导则》(HJ 169—2018)的环境风险模拟程序和要求,对该项目环境风险进行预测。根据预测结果,以半径为960 m的范围作为大气环境风险防护区域进行重点防护。本研究可为城市型石化企业的风险防范措施落实、应急预案编制及生态环境部门的风险管理提供参考。

黄百铁路白石岩隧道段线路方案因素评价体系及目标优选

以黄桶至百色铁路白石岩隧道段线路方案为例,分析该段线路方案的控制性因素,以地形条件、地质条件、工程条件和环境条件为一级影响因子,下分二级因子,建立线路方案因素评价体系,在此基础上基于偏最小二乘法通径方法,建立方案比选模型,并对该段方案进行比选,确定较优方案。结果表明:方案因素评价体系能够较好地进行因素分级和评判方案,建立的模型能较好进行方案比选,对铁路线路选线具有一定的参考价值和辅助功能。

Evaluation of Spring Persistent Rainfall over East Asia in CMIP3/CMIP5 AGCM Simulations

The progress made fi＇om Phase 3 to Phase 5 of the Coupled Model Intercomparison Project （CMIP3 to CMIP5） in simulating spring persistent rainfall （SPR） over East Asia was examined from the outputs of nine atmospheric general circulation models （AGCMs）. The majority of the models overestimated the precipitation over the SPR domain, with the mean latitude of the SPR belt shifting to the north. The overestimation was about 1mm d-1 in the CMIP3 ensemble, and the northward displacement was about 3°, while in the CMIP5 ensemble the overestimation was suppressed to 0.7 mm d-i and the northward shift decreased to 2.5°. The SPR features a northeast-southwest extended rain belt with a slope of 0.4°N/°E. The CMIP5 ensemble yielded a smaller slope （0.2°N/°E）, whereas the CMIP3 ensemble featured an unre- alistic zonally-distributed slope. The CMIP5 models also showed better skill in simulating the interannual variability of SPR. Previous studies have suggested that the zonal land-sea thermal contrast and sensible heat flux over the southeastern Tibetan Plateau are important for the existence of SPR. These two ther- mal factors were captured well in the CMIP5 ensemble, but underestimated in the CMIP3 ensemble. The variability of zonal land-sea thermal contrast is positively correlated with the rainfall amount over the main SPR center, but it was found that an overestimated thermal contrast between East Asia and South China Sea is a common problem in most of the CMIP3 and CMIP5 models. Simulation of the meridional thermal contrast is therefore important for the future improvement of current AGCMs.