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1.
空气质量数值模型的构建及应用研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
综述了近年来国内外空气质量模型的发展历程、空气质量数值模型构建的关键技术以及应用研究。指出了目前空气质量数值预报及应用主要面临气象条件,尤其是大气边界层模拟、大气污染物排放源和大气物理化学过程等问题。提出,应当通过规范化制作和完善排放源清单数据,建立统一的排放源分析标准,提高排放源数据的准确性;多向发展观测手段,加大监测密度和频率,并进行实验室化学分析,提出适合我国的大气物理化学机制。就空气质量模式而言,对模式方案进行优化,以及使用气象、卫星资料同化等技术手段,将其与观测相结合,构建监测与预报系统相结合的统一体系,应用于多平台。  相似文献
2.
Fence for traffic noise control sometimes causes adverse effect on air pollution. Thus in this study, performance of porous fence as a tool for control of both air pollution and noise pollution was evaluated. A two-dimensional numerical model for flow and pollutant concentration and an analytical model for traffic noise were utilized in the analysis of a double-decked road structure with fences only at ground (Case 1) and at both ground and upper deck (Case 2). Porous fences were assumed only at the ground level since the solid fences at the upper deck usually leads to desirable result on air pollution. Effects of the variable porosity on air quality and noise level near road were evaluated. Obtained results showed: (1) flow pattern in leeward of fence was drastically changed at 40–50% porosity in Case 1 and 50% in Case 2. The porosity larger than 40% excluded presence of a circulation behind the fence. (2) Effect of porous fence on air pollution was different in Cases 1 and 2. In Case 1, the porous fence generally resulted in the reduction of air pollution at the ground level; on the other hand, in Case 2, it rather led to increase of the concentration. (3) Traffic noise level was also largely changed by the porosity of the fence; an example of simultaneous evaluation of the effects of porous fence on both air and noise pollution in Case 1 showed that the fence of 60% porosity leads to reduction of air pollution by 20% compared with solid fence case, and reduction of noise pollution by 4–6% in dB compared with no fence case, at l m high and 10 m from the road.  相似文献
3.
It is well known that the commonly used k- turbulence models yield inaccurate predictions for complex flow fields. One reason for this inaccuracy is the misrepresentation of Reynolds stress differences. Nonlinear turbulence models are capable to overcome this weakness while being not considerably more complex. However no comprehensive studies are known which analyze the performance of nonlinear turbulence models for three-dimensional flows around building-shaped structures. In the present study the predictions of the flow around a surface-mounted cube using three nonlinear two-equation turbulence models are discussed. The results are compared with predictions of the standard k- turbulence model and wind tunnel measurements. It is shown that the use of nonlinear turbulence models can be beneficial in predicting wind flows around buildings.  相似文献
4.
Most of the mesoscale models use roughness parameters to characterise the ground and to compute the surface stress. As the experimental determinations of the urban roughness parameters are rare and not very reliable, a new methodology based on microscale numerical simulations is presented here and the first results from two-dimensional simulations with different roof shapes are analysed.Firstly, it appears that the roof shape has a large influence : large difference in the Reynolds stress profile and in the roughness sub-layer thickness, enhancement of the exchanges at the roof level by buildings with attic. It also appears that the fetch necessary to obtain a constant flux layer is unrealistic compared to the real spatial homogeneity of quarters in European cities. Consequently, a new parameterisation of the urban ground-induced friction is to be developed without reference to the constant flux layer theory.  相似文献
5.
以广州省控工业污染源排放的气态污染物(SO2、NOx为主要研究对象,通过中尺度气象模式MM5与空气质量模式CALPUFF耦合,模拟11月典型气象条件下, SO2和NOx的扩散传输过程,研究其时空分布特征,并分析省控工业污染源排放对特定区域(主要针对2010年亚运场馆)空气质量的影响。结果表明,主要受典型风速的影响,SO2和NOx浓度具有明显的时空分布不均匀性。浓度高峰值主要出现在晚间至凌晨时段,而浓度低峰值主要出现在白天至中午时段。受污染源分布、排放高度和风向的影响,荔湾区和越秀区污染物浓度较高,且在广州西南部形成较明显的污染带;且这些省控污染源对南沙体育馆空气质量有较大影响。 研究结果对广州空气污染来源分析具有一定参考意义。  相似文献
6.
为验证大气中SO2的浓度对气态H2O2自动荧光法监测的影响,设置了SO2与H2O2在自动荧光过氧化氢分析仪中的反应实验;同时,利用SO2和H2O2的反应速率公式进行了模拟计算,模拟计算结果与仪器的监测结果基本相符.证明了在大气SO2浓度较高的情况下,气态SO2对H2O2的自动荧光法测定确实会有显著影响,通过模拟计算的方法可对在线监测的H2O2浓度数据进行校正.  相似文献
7.
A compact model for evaluation of acid flushing of heavy-metal-contaminated soil in a small-scale on-site treatment plant is proposed. The model assumes that the soil was re-packed in a container after excavation resulting in a soil structure with heterogeneous and random physical and chemical properties. To evaluate the effects of heterogeneity on the efficiency of contaminant removal by acid flushing, a numerical analysis of lead transport in the heterogeneous soil medium was performed. The model examines cation exchange and surface complexation reactions involving three cations (Ca, Pb, and H) and one anion (Cl) in both dissolved and exchangeable forms, two Pb surface complexes (SOPbCl and SOPbOH), and one Cl surface complex (SOH2Cl). The transport of these species during flushing with acid in a synthetically generated two-dimensional heterogeneous soil was simulated in the model. Results indicated that the flushing fluid preferentially followed pathways with large permeability. The heterogeneous cation exchange capacity (CEC) distribution and surface complexation sites had a significant effect on the transport of dissolved species. Because the CEC was set to a relatively low value, Pb was adsorbed mainly as surface complexes (SOPbCl and SOPbOH). Simulation results suggest that blocks of low hydraulic conductivity located in the upper part of the model domain greatly impede solute transport. Ponding conditions did not significantly affect the efficiency of decontamination. The model and its results are useful in the design of small-scale treatment plants for acid flushing.  相似文献
8.
再生水作为改善城市景观用水纳入河道,可其对地下水具有潜在的污染风险。通过构建区域地下水数值模型,应用质点追踪技术,计算出永定河补水区在河湖受水后地下水5 a 运移1.47 km、20 a 运移6.32 km,年均运移0.32 km。在数值模拟的基础上,依据地下水运移轨迹,结合区域水文地质条件,将研究区划分为核心监控区、二级监控区和控制监控区3个地下水监测分区,并提出各分区地下水监测井的布设原则及布设方式,实现地下水环境监测网络的优化。  相似文献
9.
利用温度反演和数值模拟的方法,对田湾核电站航天遥感测量和数值模拟结果作对比分析。结果显示:遥感监测和数值模拟结果在田湾核电站附近海域的海面温度场羽迹展布方向、不同季节大小潮型、潮态规律上都是相似的,只是在规模和数量上存在着一定差异,两者可以相互验证。  相似文献
10.
通过对比分析发现,2007年客观源清单比2001年初始源清单能够更好地反映当前长江三角洲地区的大气污染物源排放情况。基于客观源清单,利用第三代空气质量模式(Models-3/CMAQ)较好地模拟出长三角地区近地层大气浓度的日变化和空间分布,模拟结果表明,NOX与O3在空间分布上并不一致,两者之间存在非线性关系,NO2与SO2之间存在较好的线性变化相关性。  相似文献
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