Spatial Calibration and Temporal Validation of Flow for Regional Scale Hydrologic Modeling1

Abstract: Physically based regional scale hydrologic modeling is gaining importance for planning and management of water resources. Calibration and validation of such regional scale model is necessary before applying it for scenario assessment. However, in most regional scale hydrologic modeling, flow validation is performed at the river basin outlet without accounting for spatial variations in hydrological parameters within the subunits. In this study, we calibrated the model to capture the spatial variations in runoff at subwatershed level to assure local water balance, and validated the streamflow at key gaging stations along the river to assure temporal variability. Ohio and Arkansas‐White‐Red River Basins of the United States were modeled using Soil and Water Assessment Tool (SWAT) for the period from 1961 to 1990. R² values of average annual runoff at subwatersheds were 0.78 and 0.99 for the Ohio and Arkansas Basins. Observed and simulated annual and monthly streamflow from 1961 to 1990 is used for temporal validation at the gages. R² values estimated were greater than 0.6. In summary, spatially distributed calibration at subwatersheds and temporal validation at the stream gages accounted for the spatial and temporal hydrological patterns reasonably well in the two river basins. This study highlights the importance of spatially distributed calibration and validation in large river basins.     

安全仪表系统的开发与要求

综述安全仪表系统的发展过程;对其主要组成、特点以及其各自要求进行研讨;给出安全仪表系统开发的简化流程;探讨安全仪表系统的经济性分析和仪表选择方法;对安全仪表系统整体生命周期中的计划编制、设计、实施、运行、维护和确认等各阶段活动的关键要求进行了讨论和研究。该研究对安全仪表系统的深入理解有指导作用,并为安全仪表系统的分析、设计、实施、运行和维护等活动提供参考。     

An enhanced environmental multimedia modeling system based on fuzzy-set approach: II. Model validation and application

Part I of this study develops an enhanced environmental multimedia modeling system (EMMS) based on fuzzy-set approach. Once the model development is complete, the composite module and the entire modeling system need to be tested and validated to ensure that the model can simulate natural phenomena with reasonable and reliable accuracy. The developed EMMS is first tested in a complete case study. And then verification results are conducted to compare with extensively researched literature data. In the third step, the data from an experimental landfill site is used for a pilot-scale validation. The comparisons between EMMS outputs and the literature data indicate that the EMMS can perform accurate modeling simulation. The modules of EMMS could support the entire environmental multimedia modeling system. Further field-scale validation is finished. The results are satisfactory. Most of the modeling yields closely match the monitoring data collected from sites. In addition, with the aid of fuzzy-set approach, EMMS can be a reliable and powerful tool to address the complex environmental multimedia pollution problems and provide an extensive support for decision makers in managing the contaminated environmental systems.     

反硝化滤池的数值模拟与模型校正

建立了反硝化滤池中试系统,在滤速8m/h,进水C/N分别为4和5两种工况条件下运行,考察其反硝化处理效果,结果表明在进水C/N=5条件下,出水TN浓度由14.52mg/L下降为7.14mg/L.应用BioWin软件,构建了反硝化滤池中试系统的模型,基于滤速8m/h,进水C/N=5条件下的运行数据,应用常规灵敏度分析法(Si,j)和均方根灵敏度分析法( ),对BioWin软件中的412个参数进行了灵敏度分析,结果表明,对反硝化滤池中试系统模拟结果影响最为显著的两类参数为:与甲基营养菌有关的计量学参数及与生物膜有关的参数.根据灵敏度分析结果,选取5个灵敏度最高的参数,通过调整参数值对所构建的反硝化滤池模型进行了校正,应用于滤速8m/h,进水C/N=5条件下的运行模拟取得了较好的效果.最后应用校正模型对滤速8m/h,进水C/N=4条件下的运行结果进行模拟,结果表明模拟值与实测值同样能够较好地吻合.由此得出结论,本研究所构建的反硝化滤池中试系统模型及基于灵敏度分析的模型校正方法是有效的,可用于实际反硝化滤池工艺的模拟.     

某地铁多层车站的防排烟系统设计及模拟研究

在分析地铁车站火灾烟控和乘客疏散要求的基础上,分析了地铁防排烟设计的基本思路和模式,结合某多层结构地下车站,给出了通风排烟系统的设计方案。利用模拟仿真的方法对通风排烟系统火灾事故情况下的运行效果进行了验证评估。计算表明,隧道烟控流速、楼扶梯开口流速、可用安全疏散时间等指标均可达到规范的要求。提出的设计方案和事故运行模式可提供作为一种地下车站通风排烟系统设计的模式。     

有机污染物土壤吸附预测模型及其影响因素

以701种有机化合物的土壤吸附系数作为数据集,选取594种有机化合物作为训练集,剩余107种作为测试集.根据训练集化合物建立土壤吸附系数Koc与辛醇/水分配系数Kow的线性和非线性模型,应用平均残差(AE),平均绝对残差(AAE)和均方根误差(RMSE)来检验模型的预测能力,模型具有良好的预测能力.同时,比较不同类型的化合物的实测值与预测值,发现部分同系物的预测值与实测值存在系统的偏差,这些偏差主要是由吸附机理,溶解度,水解作用,挥发作用,实验误差等原因造成,这些因素均会对土壤吸附系数的预测产生影响.     

RegCM3模式模拟我国春季气溶胶光学厚度及检验

利用区域气候模式RegCM3模拟了我国2005~2007年春季每月的气溶胶光学厚度及沙尘气溶胶光学厚度(AOD),并利用站点观测资料检验了模拟结果,探讨了沙尘气溶胶和人为活动排放气溶胶对春季AOD的贡献与影响.结果表明,模拟的我国春季AOD主要有3个高值区:南疆盆地和北疆部分地区,河西走廊地区,以及四川盆地和临近的中南部分地区.前两者AOD高值主要由沙尘气溶胶引起,后者主要受人为活动排放的气溶胶影响.观测资料检验表明模拟结果具有一定的可信度,模式对人类活动影响较少区站点的模拟效果优于对人类活动频繁区站点及城市和沿海站点的模拟,对城市和沿海站点的模拟结果偏低,对最偏远的阜康、海北、拉萨和西双版纳等站点的模拟结果与实际观测差别较大.     

Modelling concentrations of airborne primary and secondary PM10 and PM2.5 with the BelEUROS-model in Belgium

The Eulerian Chemistry-Transport Model BelEUROS was used to calculate the concentrations of airborne PM₁₀ and PM_2.5 over Europe. Both primary as well as secondary particulate matter in the respirable size-range was taken into account. Especially PM_2.5 aerosols are often formed in the atmosphere from gaseous precursor compounds. Comprehensive computer codes for the calculation of gas phase chemical reactions and thermodynamic equilibria between compounds in the gas-phase and the particulate phase had been implemented into the BelEUROS-model. Calculated concentrations of PM₁₀ and PM_2.5 are compared to observations, including both the spatial and daily, temporal distribution of particulate matter in Belgium for certain monitoring locations and periods. The concentrations of the secondary compounds ammonium, nitrate and sulfate have also been compared to observed values. BelEUROS was found to reproduce the observed concentrations rather well. The model was applied to assess the contribution of emissions derived from the sector agriculture in Flanders, the northern part of Belgium, to PM₁₀- and PM_2.5-concentrations. The results demonstrate the importance of ammonia emissions in the formation of secondary particulate matter. Hence, future European emission abatement policy should consider more the role of ammonia in the formation of secondary particles.     

稻麦作物净初级生产力模型研究:模型检验与情景预测

利用我国若干代表性区域98组稻麦作物生产力的试验数据,对所建立的稻麦作物净初级生产力模型进行了检验.结果表明,该模型能根据常规的气象和土壤资料、化肥施用量等数据资料较好地模拟我国主要区域稻麦作物的净初级生产力.模拟值(y)与观测值(x)的线性关系为:y=1.05p-16.8(r²=0.771,p<0.001,n=98).对南京地区的情景预测结果表明:大气CO₂浓度升高促进稻麦作物的固碳能力;气温升高会降低水稻和小麦的碳固定,但对小麦的影响要小于水稻;在当前情景及未来情景(CO₂浓度为540μmol·mol^-1,温度增加1～4℃)下,氮肥施用对小麦碳固定的促进作用大于水稻,氮肥施用量高于150 kg·hm^-2时对2种作物的碳固定没有显著的促进作用,甚至降低水稻的净初级生产力.     

飞行器防空间静电放电设计和试验技术

结合某飞行器的特点,以及产品在轨飞行期间遭遇的空间静电放电(SESD)环境,研究了在没有可借鉴的条件下,如何通过分析提出大型天线及本体的空间静电放电防护设计目标,根据产品实际情况设计了分段实施的措施,运用等效理念设计了试验子样和测试方案,策划了设计元器件、原材料、天线系统、飞行器等不同层面的试验验证技术和方法.