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Search Results: 1 - 10 of 78221 matches for " Qiuwen Chen "
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Development of 1D and 2D coupled model to simulate urban inundation: An application to Beijing Olympic Village
WeiFeng Li,QiuWen Chen,JingQiao Mao
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0208-1
Abstract: Urban inundation due to anomalous storms is a serious problem for many cities worldwide. Therefore, it is important to accurately simulate urban hydrological processes and efficiently predict the potential risks of urban floods for the improvement of drainage designs and implementation of emergency actions. However, the complexity of urban landforms and the diversity of hydraulic infrastructure pose particular challenges for the simulation and risk assessment of urban drainage processes. This study developed a methodology to comprehensively simulate inundation processes by dynamically coupling 1D and 2D hydrodynamic models. By allowing the simultaneous solution of the processes of rainfall and runoff, urban drainage, and flooding, this method can be used to estimate the potential inundation risks of any designed drainage system. Furthermore, a Geographical Information System (GIS) based platform was fully integrated with the model engine to effectively illustrate the context of the problem. The developed model was then demonstrated on the Beijing 2008 Olympic Village under the conditions of the 5-year and 50-year design storms. The sewer discharge, channel discharge, and flood propagation (inundation initiation, extent, depths, and duration) were numerically validated and analyzed. The results identified the potential inundation risks. From the study, it is found that the coupled GIS and 1D and 2D hydrodynamic models have the potential to simulate urban inundation processes, and hence efficiently predict flood risks and support cost-effective drainage design and management. It also implies promising prospects about the wide availability of high quality digital data, GIS techniques, and well-developed monitoring infrastructure to develop online urban inundation forecasts.
Soybean residues sequestration affected by different tillage practices and the impacts on soil microbial characteristics and enzymatic activities

Xiaoli Liu,Qiuwen Chen,Zhaoxia Zeng,

生态学报 , 2009,
Abstract:
Development of 1D and 2D coupled model to simulate urban inundation: An application to Beijing Olympic Village

WeiFeng Li,QiuWen Chen,JingQiao Mao,

科学通报(英文版) , 2009,
Abstract: Urban inundation due to anomalous storms is a serious problem for many cities worldwide. Therefore, it is important to accurately simulate urban hydrological processes and efficiently predict the potential risks of urban floods for the improvement of drainage designs and implementation of emergency actions. However, the complexity of urban landforms and the diversity of hydraulic infrastructure pose particular challenges for the simulation and risk assessment of urban drainage processes. This study developed a methodology to comprehensively simulate inundation processes by dynamically coupling 1D and 2D hydrodynamic models. By allowing the simultaneous solution of the processes of rainfall and runoff, urban drainage, and flooding, this method can be used to estimate the potential inundation risks of any designed drainage system. Furthermore, a Geographical Information System (GIS) based platform was fully integrated with the model engine to effectively illustrate the context of the problem. The developed model was then demonstrated on the Beijing 2008 Olympic Village under the conditions of the 5-year and 50-year design storms. The sewer discharge, channel discharge, and flood propagation (inundation initiation, extent, depths, and duration) were numerically validated and analyzed. The results identified the potential inundation risks. From the study, it is found that the coupled GIS and 1D and 2D hydrodynamic models have the potential to simulate urban inundation processes, and hence efficiently predict flood risks and support cost-effective drainage design and management. It also implies promising prospects about the wide availability of high quality digital data, GIS techniques, and well-developed monitoring infrastructure to develop online urban inundation forecasts. Supported by the National Natural Science Foundation of China (Grant No. 40601018)
Three-dimensional eutrophication model and application to Taihu Lake, China
MAO Jingqiao,CHEN Qiuwen,CHEN Yongcan,
MAO Jingqiao
,CHEN Qiuwen,CHEN Yongcan

环境科学学报(英文版) , 2008,
Abstract: Talhu Lake,the largest freshwater shallow lake in eastern China,has suffered from severe eutrophication over the past two decades. This research developed a three-dimensional eutrophication model to investigate the eutrophication dynamics.The model fully coupled the biological processes and hydrodynamics,and also took into account the effects of sediment release and the external loads from the tributaries.After sensitivity analyses,the key parameters were defined and then calibrated by the field observation data.The calibrated model was applied to study the seasonal primary productions and its regional differences.The comparisons between model results and field data in year 2000 indicated that the model is able to simulate the eutrophication dynamics in Taihu Lake with a reasonable accuracy.From the simulation experiments,it was found that the meteorological forcing have significant influences on the temporal variations of the eutrophication dynamics.The wind-induced circulation and sediment distribution play an important role in the spatial distribution of the algae blooms.
Effects of spatial resolution of remotely sensed data on estimating urban impervious surfaces

Weifeng Li,Zhiyun Ouyang,Weiqi Zhou,Qiuwen Chen,

环境科学学报(英文版) , 2011,
Abstract: Impervious surfaces are the result of urbanization that can be explicitly quantified, managed and controlled at each stage of land development. It is a very useful environmental indicator that can be used to measure the impacts of urbanization on surface runoff, water quality, air quality, biodiversity and microclimate. Therefore, accurate estimation of impervious surfaces is critical for urban environmental monitoring, land management, decision-making and urban planning. Many approaches have been developed to estimate surface imperviousness, using remotely sensed data with various spatial resolutions. However, few studies, have investigated the effects of spatial resolution on estimating surface imperviousness. We compare medium-resolution Landsat data with high-resolution SPOT images to quantify the imperviousness in Beijing, China. The results indicated that the overall 91% accuracy of estimates of imperviousness based on TM data was considerably higher than the 81% accuracy of the SPOT data. The higher resolution SPOT data did not always predict the imperviousness of the land better than the TM data. At the whole city level, the TM data better predicts the percentage cover of impervious surfaces. At the sub-city level, however, the ring belts from the central core to the urban-rural peripheral, the SPOT data may better predict the imperviousness. These results highlighted the need to combine multiple resolution data to quantify the percentage of imperviousness, as higher resolution data do not necessarily lead to more accurate estimates. The methodology and results in this study can be utilized to identify the most suitable remote sensing data to quickly and efficiently extract the pattern of the impervious land, which could provide the base for further study on many related urban environmental problems.
Development and application of a two-dimensional water quality model for the Daqinghe River Mouth of the Dianchi Lake

CHEN Qiuwen,TAN Kui,ZHU Chuanbao,LI Ruonan,

环境科学学报(英文版) , 2009,
Abstract: Water quality models are important tools to support the optimization of aquatic ecosystem rehabilitation programs and assess their efficiency. Basing on the flow conditions of the Daqinghe River Mouth of the Dianchi Lake, China, two-dimensional water quality model was developed in the research. The hydrodynamics module was numerically solved by the alternating direction iteration (ADI) method. The parameters of the water quality module were obtained through the in situ experiments and the lab analyses that were conducted from 2006 to 2007. The model was calibrated and verified by the observation data in 2007. Among the four modelled key variables that were water level, CODcr, NH3-N and PO4-P, the minimum value of the coefficient of determination (CoD) was 0.69, which mean the model performed reasonably well. The developed model was then applied to simulate the water quality changes at the downstream cross-section assuming that the designed restoration programs were implemented. According to the simulated results, the restoration programs could cut down the loads of CODcr and PO4-P about 15%, however, they would have very little effect on the NH3-N removal. Besides, the water quality at the outlet cross-section would be still in class V (3838-02), indicating more measures should be taken to further reduce the loads. The study demonstrated the capability of water quality models to support aquatic ecosystem restorations.
Flow field and dissolved oxygen distributions in the outer channel of the Orbal oxidation ditch by monitor and CFD simulation
Xuesong Guo,Xin Zhou,Qiuwen Chen,Junxin Liu,
Xuesong Guo
,Xin Zhou,Qiuwen Chen,Junxin Liu

环境科学学报(英文版) , 2013,
Abstract: In the Orbal oxidation ditch, denitrification is primarily accomplished in the outer channel. However, the detailed characteristics of the flow field and dissolved oxygen (DO) distribution in the outer channel are not well understood. Therefore, in this study, the flow velocity and DO concentration in the outer channel of an Orbal oxidation ditch system in a wastewater treatment plant in Beijing (China) were monitored under actual operation conditions. The flow field and DO concentration distributions were analyzed by computed fluid dynamic modeling. In situ monitoring and modeling both showed that the flow velocity was heterogeneous in the outer channel. As a result, the DO was also heterogeneously distributed in the outer channel, with concentration gradients occurring along the flow direction as well as in the cross-section. This heterogeneous DO distribution created many anoxic and aerobic zones, which may have facilitated simultaneous nitrification-denitrification in the channel. These findings may provide supporting information for rational optimization of the performance of the Orbal oxidation ditch.
Optimizing the operation of the Qingshitan Reservoir in the Lijiang River for multiple human interests and quasi-natural flow maintenance
Qiuwen Chen,Duan Chen,Ruiguang Han,Ruonan Li,Jinfeng Ma,Koen Blanckaert,
Qiuwen Chen
,Duan Chen,Ruiguang Han,Ruonan Li,Jinfeng M,Koen Blanckaert

环境科学学报(英文版) , 2012,
Abstract: For reservoir operation, maintaining a quasi-natural flow regime can benefit river ecosystems, but may sacrifice human interests. This study took the Qingshitan Reservoir in the Lijiang River as a case, and developed an optimization model to explore a trade-off solution between social-economic interests and nature flow maintenance on a monthly base. The objective function considered irrigation, cruise navigation and water supply aspects. An index of flow alteration degree was proposed to measure the difference between the regulated discharge and the natural flow. The index was then used as an additional constraint in the model besides the conventional constraints on reservoir safety. During model solving, different criteria were applied to the index, representing various degrees of alteration of the natural flow regime in the river. Through the model, a relationship between social-economic interests and flow alteration degree was established. Finally, a trade-off solution of the reservoir operation was defined that led to a favorable social-economic benefit at an acceptable alteration of the natural flow.
Laboratory study on ethology of Spinibarbus hollandi
基于物理模型实验的光倒刺鲃生态行为学研究

LI Weiming,CHEN Qiuwen,HUANG Yingping,
李卫明
,陈求稳,黄应平

生态学报 , 2011,
Abstract: 建立了基于天然河道的物理模型,通过控制实验研究水环境因子对鱼类行为的影响。文中选取了金沙江下游2.6 km河段建立物理模型,以南方水系的经济鱼类光倒刺鲃为研究对象,进行了鱼的行为对底质和流速的响应实验。分析得出,光倒刺鲃对砂卵石底质的选择明显大于其它底质且差异极其显著(P<0.01),光倒刺鲃2龄幼鱼期的喜好流速范围为0.3-0.6 m/s;研究同时发现水流紊动强度对光倒刺鲃行为具有重要影响。该研究结果可以为光倒刺鲃栖息地模型提供参考。
Application of lake model SALMO to the Meiliang Bay of Taihu Lake
湖泊水质模型SALMO在太湖梅梁湾的应用

GUO Jing,CHEN Qiuwen,LI Weifeng,
郭静
,陈求稳,李伟峰

环境科学学报 , 2012,
Abstract: The lake model SALMO (Simulation by Means of an Analytical Lake Model) was applied to simulate the water quality of the Meiliang Bay in Taihu Lake. The model includes 8 state variables: nitrate nitrogen, phosphate phosphorus, detritus, dissolved oxygen, biomass of three algae (Cyanophyta, Chlorophyta and Bacillariophyta) and zooplankton. Because SALMO was originally developed for non-shallow lakes (maximum depth>5 m), some improvements were made to SALMO before simulating the shallow Meiliang Bay. The data from the year 2005 were used for model calibration and the data from the year 2006 were used for model verification. The results showed that the modeled biomass of the three algae followed the observed seasonal patterns: Bacillariophyta and Chlorophyta were dominant from the end of winter to the beginning of spring, while Cyanophyta was dominant in summer and autumn. The modeled nutrient concentrations also showed a good agreement with the observations. This indicates that after improvement SALMO is applicable for Taihu Lake and can be used to study the mechanisms of algae bloom.
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