水环境模拟中多孔介质非均质性空间变异最优估计模型

在生产实践中,经常要求对含水介质渗透性参数的空间分布数值作出可靠的估计.如何利用已知数据对指定点处的渗透性参数作出令人满意的估计,历来是水文地质工作者和应用数学工作者都关心的问题.文章应用能够刻画区域化变量随机性与结构性特征的地质统计学的理论和方法对能够反映多孔介质非均质特性的参数进行了分析,通过分析结果得出了参数空间变异性局部最优估计模型--普通克里格法.     

METHODOLOGIES FOR CALIBRATION AND PREDICTIVE ANALYSIS OF A WATERSHED MODEL1

ABSTRACT: The use of a fitted parameter watershed model to address water quantity and quality management issues requires that it be calibrated under a wide range of hydrologic conditions. However, rarely does model calibration result in a unique parameter set. Parameter nonuniqueness can lead to predictive nonuniqueness. The extent of model predictive uncertainty should be investigated if management decisions are to be based on model projections. Using models built for four neighboring watersheds in the Neuse River Basin of North Carolina, the application of the automated parameter optimization software PEST in conjunction with the Hydrologic Simulation Program Fortran (HSPF) is demonstrated. Parameter nonuniqueness is illustrated, and a method is presented for calculating many different sets of parameters, all of which acceptably calibrate a watershed model. A regularization methodology is discussed in which models for similar watersheds can be calibrated simultaneously. Using this method, parameter differences between watershed models can be minimized while maintaining fit between model outputs and field observations. In recognition of the fact that parameter nonuniqueness and predictive uncertainty are inherent to the modeling process, PEST's nonlinear predictive analysis functionality is then used to explore the extent of model predictive uncertainty.     

缺失烟囱参数估算及其应用对空气质量模拟结果的改进

针对源清单中部分点源烟囱参数缺失而采用源排放模型SMOKE(Sparse Matrix Operator Kernel Emissions)默认的烟囱参数对空气质量模型模拟结果造成的不利影响,综合考虑气象观测数据、空气质量监测数据、源排放强度以及相关标准和规范对烟囱设计的要求,分别基于最大落地浓度法和基于统计方法对2009年珠三角地区源清单中缺失烟囱参数点源的烟囱参数进行了估算,并将估算烟囱参数用在WRF/SMOKE-PRD/CMAQ空气质量模型系统分析其对模型模拟的改善情况.相比于采用SMOKE默认烟囱参数,基于最大落地浓度估算烟囱参数对NO2、NOx、SO2、PM10及O3的模拟结果均具有一定改善作用,而基于统计方法估算烟囱参数仅对SO2、O3的模拟结果有所提高.结果表明,使用基于最大落地浓度法估算得到的烟囱参数更为合理,使污染物的垂直排放分配更加合理,可以应用于空气质量模型输入源清单中缺失烟囱参数点源的估算,从而一定程度上改善空气质量模型的模拟效果.     

GIS环境下大区域工程场地地震液化势的二维概率评价方法

用具有概率意义的饱和砂土抗液化强度经验公式来对大区域场地进行地震液化势二维概率评价;在GIS软件ArcGIS的支持下,将取样钻孔处的液化势评价结果等价于数字高程模型(Digital Elevation Model,DEM)中的高程,利用ArcGIS空间分析模块中的Kriging插值法估计大区域场地的地震液化范围。研究表明:将Kriging法应用于岩土工程地质特征的统计推断,有助于揭示勘探孔以外的地层信息,对于大区域场地地震液化范围的判别是一个较好的手段;利用ArcGIS空间分析模块中的Kriging法,通过已勘察点的信息(液化势)来估计未勘测点的土层液化势,能够较好地区划出场地地震液化势的空间分布特征。     

前沿技术进步、技术效率和区域经济差距

采用1998-2009年中国30个省市的人均GDP与当年全国人均GDP的差值作为区域经济差距指标,运用核密度估计方法观察了我国区域经济差距的变动状况。从核密度图可知,我国区域经济呈现出收敛的态势;通过随机前沿模型从全要素生产率中分解出前沿技术进步和技术效率,利用1998-2009年28个省市的面板数据,检验了全要素生产率对区域经济差距的影响。实证结果显示,前沿技术进步能够显著的缩小区域经济差距,其中对于东部地区的效果较为显著,技术效率则能够扩大东部地区的经济差距,对于中部和西部地区的影响不显著。政策含义是缩小东部地区经济差距的主要途径是加大对科技创新领域的投入,加强对欠发达地区的技术支持;对于中部地区和西部地区而言,则应该是加大市场化水平、对外开放水平和地方支出比重。     

DEVELOPMENT AND TESTING OF A SNOWMELT-RUNOFF FORECASTING TECHNIQUE1

ABSTRACT: The snowmelt-runoff model (SRM) was used to produce accurate simulations of streamfiow during the snowmelt period (April-September) for ten years on the Rio Grande Basin (3419 km²) near Del Norte, Colorado, U.S.A. In order to use SRM in the forecast situation, it was necessary to develop a family of snow cover depletion curves for each elevation zone based on accumulated snow water equivalent on April 1. Selection of an appropriate curve for a particular year from snow course measurements allows input of the daily snow cover extent to SRM for forecast purposes. Data from three years (1980, 1981, and 1985) were used as a quasi-forecast test of the procedure. In these years forecasted snow cover extent data were input to SRM, but observed temperature and precipitation data were used. The resulting six-month hydrographs were very similar to the hydrographs in the ten simulation years previously tested based on comparisons of performance evaluation criteria. Based on this result, the Soil Conservation Service (SCS) requested SRM forecasts for 1987 on the Rio Grande. Using the same procedure but with SCS estimated temperature and precipi-tation data, SRM produced a forecast hydrograph that had a r²= 0.82 and difference in seasonal volume of 4.4 percent. To approximate actual operational conditions, SRM computed daily flows were updated every seven days with measured flows. The resulting forecast hydrograph had a R²= 0.90 and a difference in volume of 3.5 percent. The method developed needs to be refined and tested on additional years and basins, but the approach appears to be applicable to operational runoff forecasting using remote sensing data.     

RUNOFF VOLUME ESTIMATION USING GIS TECHNIQUES1

ABSTRACT: Rainfall runoff of six watersheds was modeled via the Soil Conservation Service runoff curve number model in two ways: conventionally (manually) and via a geographic information system (GIS). Input data (elevation, soils, and landcover) were digital for the latter method. In contrast to previous studies, the GIS was ised for all phases of the modeling process, including watershed delineation and routing of runoff. A comparison between the two methods was consistent with results reported by others and indicates that the use of a GIS is an acceptable alternative to the conventional method for watersheds lacking relatively flat terrain. Given this limitation, the GIS method may prove advantageous over manual methods when study areas are large or numerous, runoff is modeled repetitively, alternative landcover scenarios are explored, or a digital database already exists for the study area.     

Application of cleaner production technology in chemical industry: a near zero emission

The main objective of this study is to investigate and evaluate opportunities for implementation of pollution prevention and waste minimization in a chemical industrial company producing poly sulfonated naphthalene formaldehyde which is used as a super plasticizer for concrete. Environmental problems encountered were mainly the highly polluted wastewater and a semi-solid cake containing considerable amount of the final product. Possible modules for remedial measures and their cost estimation were investigated. The proposed remedial modules included recycling of retained water discharge in filter press, recycling of washing water of reaction vessels (reactors), closed circuit cooling system for high-pressure pump, good housekeeping through control of leakage of raw material, products and water and finally utilization of retained residual product from the solid waste. The implemented pollution control measures proved to be cost effective and have short payback periods. Also, minimization of the hydraulic and organic loads in the final effluent was achieved.     

黄、东海污染物越界通量的估算研究

对黄、东海污染物越界通量估算方法进行了研究。黄、东海污染物SPM、Cu、Pb、Zn、Cd、Hg的越界通量估算值分别为82 1742 75± 10 0 70 3 0 0 4kg/h、5 883 31± 5 35 5 47kg/h、5 6 3 2 5± 45 2 2 2kg/h、17895 93± 15 6 96 45kg/h、1113 45± 85 0 0 8kg/h、35 32± 37 93kg/h。     

核电站事故对上海地区影响的快速估算

为了能快速估算上海周围某核电站发生事故并伴有放射性物质泄漏时,上海地区可能受到的放射性污染情况,选用了一种基于拉格朗日动态烟团模式的剂量估算方法,模拟计算表明,在某些天气和核电站事故等级的条件下,上海地区将出现500mSv以上的高剂量区,因此需要制定应急预案以备用。