断流河道间断输水两岸地下水的运动模型及其解法--以塔里木河下游断流河段生态输水为例

以塔里木河下游断流河段生态输水为背景,根据间断性输水河道充水和停水2个阶段周期性交替重复出现的特征,建立了断流河道间断输水两岸地下水运动的一维非稳定流模型,并通过水位与流量边界条件相互转换的一种方法实现模型的求解,最后应用该模型分析了塔里木河下游断流河段生态输水两岸地下水位恢复状况,其结果比较满意,表明了模型的实用性。     

地层温度场下地下开采矿山斜坡道内氡运移数值模拟研究

开展伴生放射性矿的氡运移研究有利于开采过程中的氡污染治理,对矿山的安全生产有重要意义。引入温度梯度函数进行地层温度模拟,通过建立对流-扩散-衰变数学模型与斜坡道三维几何模型,对地层温度场下伴生放射性矿斜坡道进行了数值模拟研究,探索了地层温度场和通风流场对氡累积与运移的影响。研究表明:流场特征很大程度上决定氡浓度场的空间分布特征,而温度场同样也影响各区域的氡浓度大小。采用通风降氡时,流场中气流组织更好的区域氡浓度变化更大,地层温度场对硐室氡浓度影响更为敏感,本次模拟中温度升高1 K斜坡道氡浓度增加14.7 Bq/m³,硐室增加约22.0 Bq/m³。     

正交曲线坐标系准三维全沙数学模型

为了定量地预测规划河道特别是规划河堰附近的河床冲淤情况,做好拦河堰与河道的规划工作,建立了一个能考虑各泥沙粒径组的级配、流线曲率与流路曲率的差异以及能同时对推移质与悬移质泥沙进行计算的正交曲线坐标系准三维全沙数学模型.用正规划重建倒伏式拦河堰的某河的现有河道实测资料对该模型进行了验证.验证结果表明,冲淤计算结果与实测结果基本一致.以该河规划重建的倒伏式拦河堰为讨论对象,取其上下游一定的规划河道区间为计算河段,对设计洪水时的冲淤情况进行了模拟预测.预测结果表明:该模型的水位计算结果与一维非均匀流模型的计算结果基本一致并更符合河道的地形特征,河道冲淤趋势符合河道及水流的特征;规划堰上下游附近的河床冲刷量最大为3.0 m,整个计算河段的冲淤量也在-3.0~3.0 m范围内.可见,规划河道具有较好的稳定性,规划堰的选址是比较合适的.     

塔里木河河道自净需水量

在一维水质模型基础上,根据河道断面流速与流量的关系,建立了计算河道自净需水量的试算模型,分析了塔里木河各河段的水质控制目标.根据不同历史时期监测的塔里木河西大桥、阿拉尔、新渠满水文站、新和和沙雅干排的水质资料,计算了塔里木河河道新渠满水文站断面的自净需水量.结果表明:新渠满水文断面年自净需水量6.39×108m3,3,4,11,12月自净缺水0.97×108m3.     

碧流河水库下游河道的现状防洪能力

针对缺乏实测流量资料的水库下游河道,利用一维河网模型系统MIKE11,采用多种工况组合,模拟计算并分析了碧流河水库下游河道主要断面的现状防洪能力。建模过程考虑水库调度与潮位等因素的影响:使用水库下游河道最新实测断面数据与网上遥感数据,参考设计资料,并结合计算经验综合确定计算模型参数。研究成果可为碧流河水库及其下游河道组成的联合调度系统提供决策支持。     

太原市西山岩溶区汾河与地下水相互作用研究

通过对汾河西山岩溶区段的河道下垫面背景分析,将汾河干流汾河水库至兰村区间分为7个区段,识别出了4个汾河与岩溶地下水相互作用积极的地段。以地下水系统理论为指导,将兰村泉和晋祠泉岩溶水系统概化为双输入(大气降水与人工开采)单输出(泉流量)模型,在此基础上,基于岩溶水天然资源量与大气降雨入渗量、河流渗漏量关系推算出了汾河与各岩溶水系统岩溶地下水的作用强度,即汾河对各岩溶水系统的渗漏补给量。研究成果对于指导太原市水资源综合利用,缓解太原市水资源供需矛盾,有效保护岩溶地下水等提供了科学参考依据。     

大通至长江口整体水动力模型

为更好研究长江大通以下河段的水动力特性,建立了大通至长江口感潮河段的二维水动力数学模型,模拟了径流和潮汐共同作用下的河道水位与流量、河汊分流比及长江口水域的流态.在整体水动力模型的基础上,采用嵌套技术建立了镇扬河段工程区局部数学模型,整体模型为局部模型提供边界条件,局部模型采用精细网格进行工程计算.以高资港区码头工程为例,对工程建设前、后不同水文条件下水位、流场变化进行了数值模拟.计算结果表明,工程建设对河段的水利规划、堤防和行洪安全、河势不会带来明显不利的影响.     

数值模拟法与传统水力学法在导流围堰设计中的联合应用

水利水电工程施工大多选择围堰隔离河道水流来创造干地作业的条件,导流围堰的修筑关系到主体工程的施工是否能顺利展开.通过对雅口水利枢纽坝址区气象、水文和地质条件的分析研究,采用水动力学数值模拟法建立了流量与围堰的水动力数值模型,在流量为13 500m3/s、3 980m3/s、1 940m3/s 3种不同流量下,对一期导流围堰分别进行水力计算;获得了3种不同流量下,围堰处的上下游水位、进出口流速以及各断面的最大流速;并采用经验水力学法对计算结果进行了复核,从而得出了导流围堰设计的各项参数,并设计了导流围堰的断面形式.通过数值模拟法计算,使得导流计算过程更简便,结果更准确,设计更合理.     

先进安注箱热工水力特性研究

为了研究先进安注箱的热工水力特性,建立了其数学模型,包括基本守恒方程、传热模型、传质模型和阻尼器模型。开发了先进安注箱计算模块,并将其嵌入到RELAP5/MOD3.3程序中。通过与CFD模拟结果的比较分析,验证了文中模型和求解方法的合理性。针对某先进安注箱,研究了其热工水力特性,并开展了参数敏感性分析,结果表明:各参数的变化趋势合理,先进安注箱能实现从大流量到小流量段的过渡;小流量阶段的出口质量流量随阻尼器直径的增大而减小;整个阶段的出口质量流量随大流量水体积与氮气体积比的增大而减小;当立管形阻系数在一定的变化范围内时,大流量阶段的出口质量流量随立管形阻系数的减小而增大。该研究将为我国先进安注箱的设计和实验研究提供理论依据。     

中国半湿润流域WRF-Hydro模型参数敏感性分析

为提高WRF-Hydro模型在中国半湿润流域的模拟预报精度,以半湿润的陈河流域为研究对象,选取了WRF-Hydro模型中土层厚度乘子、水箱模型指数、土层渗透系数、地表截留深乘子、地表糙率乘子和河道糙率乘子6个参数进行敏感性分析。通过数据模拟这6个参数在合理取值范围内的不同取值对洪水模拟及各评价指标的影响,定性分析了各参数的敏感性,并采用修正的Morris筛选法定量判断各参数的敏感性。结果表明:土层厚度乘子、土层渗透系数及河道曼宁糙率非常敏感,根据目标函数与典型洪水分析,建议分别在0.1~1.0、0.0~1.0、0.5~1.5内取值。     

Characteristics of U-pattern distribution of highconcentration <Superscript>210</Superscript>Pb in surface air at central Guizhou,China

A better understanding of the variation of ²¹⁰Pb concentrations in the surface air is the key to trace lake sedimentation and catchment erosion, to establish and validate the global diffusion model of contaminants, and to assess the impact of natural radiation on the ecological system. Basing on the study progresses of the sedimentation, the atmospheric model and the unique environmental background in the Yunnan-Guizhou Plateau, and starting from December 20, 2001, we made use of a 500 NE Type aerosol sampler to collect filter samples, once a week in the past consecutive two years, in the surface air at Mt. Guanfeng, Guiyang City, China. Synchronous detailed γ-energy spectrometric observations of ²¹⁰Pb concentrations at both Chinese and U.S. laboratories have shown that the average monthly ²¹⁰Pb concentration displays a regular U-patterns distribution of annual variations, with high values appearing in winter and low values in late spring and summer. The average annual ²¹⁰Pb concentrations are estimated to be 2.77±0.63 mBq/m³, about 4 times the average maximum concentrations reported from quite a number of monitoring stations throughout the world. The possible factors affecting the sources of ²¹⁰Pb in the surface air in the central part of Guizhou Province are: Release of ²²²Rn from the U-Ra series enriched in the soils; chemical weathering of carbonate rocks; the exploitation, processing and utilization of coal and phosphorous resources. The principal factor controlling the high ²¹⁰Pb concentrations in the surface air in the central Guizhou and their annual U-pattern distribution is the release of ²²²Rn. The average monthly ²¹⁰Pb concentrations show a good negative powerfunction relationship with increasing precipitation and also show a good negative linear-function relationship with the rise of air temperature in month grouping. Group No.1 (June to November) reflects a relatively low release of ²²²Rn from soils in relatively high temperature seasons; Group No.2 (December to May) mirrors a relatively high release of ²²²Rn from soils in relatively low temperature seasons. The average monthly ²¹⁰Pb concentrations simulated in terms of the precipitation and air temperature are in good consistency with the measured values, revealing that the regular U-pattern distribution characteristics of ²¹⁰Pb concentrations in the surface air in the central Guizhou are controlled predominantly by regional precipitation and air temperature. Meanwhile, it is also indicated that the magnitude of variation of air temperature and precipitation within the same year also constrains the ratio of high values over low values of average monthly ²¹⁰Pb concentrations. On a month time scale, precipitation and air temperature are a main factor affecting the release of ²²²Rn from soils (rocks). In this aspect strong evidence has been obtained.     

河水与地下水耦合模型的建立与应用

建立了真正意义上的河水和地下水耦合模拟模型，采用普列斯曼隐式差分格式和有限元方法对河水和地下水流模型分别进行了离散，最后采用迭代法对耦合模型进行求解。以西北黑河流域下游为研究区域对地下水流进行了数值模拟，针对不同的地表河水和地下水开采状况对地下水位进行了预报，为水资源管理提供了科学根据。     

基于多变量时间序列（CAR）模型的洞庭湖区域地下水资源量预测

为了预测洞庭湖区域地下水资源量的变化趋势,制定应对地下水资源量较低年份的有效措施,通过分析洞庭湖区域河川天然径流量、长江三口入水量、城陵矶出水量与地下水资源量的变化趋势和相关性,运用多变量时间序列CAR模型,建立了洞庭湖区域地下水资源量的预测模型,验证了模型的预测效果;并运用该模型对洞庭湖区域地下水资源量的变化进行了预测。研究结果表明,洞庭湖区域河川天然径流量、长江三口入水量和城陵矶出水量的变化是引起地下水资源量变化的主要因素;本研究所建的模型模拟值与实测值相对误差的最大值为-7.47%,平均值为3.63%,表明该模型的预测精度高、效果好;通过对未来10年洞庭湖区域的地下水资源量进行预测可知,其平均值下降了0.49亿m3,最低值下降了0.66亿m3,表明该区域地下水资源量仍将持续降低;据不同方案下的地下水资源量预测结果可知,通过增加长江三口入水量,可以有效提高洞庭湖区域的地下水资源量。     

Oxygen isotope variation in the water cycle of the Yamzho lake Basin in southern Tibetan Plateau

Given the potential use of stable isotope in the paleoclimate reconstruction from lacustrine records as well as in the local hydrology cycle, it is crucial to understand the processes of stable isotope evolution in catchment in the Tibetan Plateau region. Here we present a detailed study on the water oxygen isotope based on 2 years observation including precipitation, river water and lake water in the Yamzho Lake, south of the Tibetan Plateau. Temporal variation of local precipitation 5180 shows an apparent ＂monsoon cycle＂. In monsoon season, 5180 in waters is lower. In non-monsoon season, δ^18O in precipitation and lake water is higher and higher river δ^18O exists in spring, probably reflecting the effect of land surface evaporation, together with the higher δ^18O values in spring precipitation. It is also found that the surface lake water δ^18O varies seasonally and annually. The lower lake water δ^18O in the late summer is apparently related to the summer monsoon precipitation. The mean δ^18O value of lake water in 2007 is 1.2‰ higher than that in 2004, probably due to the less monsoon precipitation in summer of 2007, as can be confirmed from the precipitation data at the Langkazi meteorological data. It is also found that an obvious shift of vertical lake water δ^18O reflects the fast mixture of lake water. δ^18O values of lake water are over 10‰ higher than those of precipitation and river water in this region due to the evaporation fractionation. The modeled results show that the evaporation process of the lake water is sensitive to relative humidity, and the present lake water δ^18O reflects a relative humidity of 51% in the Yamzho Lake. It shows that the lake will take 30.5 years to reach present lake water δ^18O given a large shift in the input water δ^18O. The modeled results also reveal that surface lake water temperature and inflow δ^18O have slight effect on the isotopic balance process of lake water in the Yamzho Lake.     

Indian monsoon influences altitude effect of δ~(18)O in precipitation/river water on the Tibetan Plateau

The δ^18O variation in precipitation acquired from 28 stations within the network of Tibetan Observation and Research Platform （TORP） is studied, with the focus on the altitude effect of δ^18O in river water during monsoon precipitation in an effort to understand the monsoon influence on isotopic composition in annual river water. It is found that δ^18O in precipitation on the Plateau is influenced by different moisture sources, with significant Indian monsoon influence on δ^18O composition in plateau precipitation and river water. The δ^18O of water bodies in the monsoon domain is generally more depleted than that in the westerly domain, suggesting gradual rainout of southwesterly borne marine moisture in the course of long-distance transportation and lifting over the Himalayas. The lapse rate of δ^18O in river water with altitude is the largest during monsoon precipitation, due to the increased temperature vertical gradient over the southern Plateau region controlled by monsoon circulation. The combination of δ^18O in river water in monsoon （wet） and non-monsoon （dry） seasons shows a larger lapse rate than that in non-monsoon （dry） season alone. As the altitude effect of δ^18O in precipitation and river water on the Tibetan Plateau results from the combined effect of monsoon moisture supply and westerly moisture supply, the δ^18O composition and its altitude effect on the Plateau during monsoon seasons should be considered in the reconstruction of paleoelevation of the Tibetan Plateau.     

The mean residence time of river water in the Canada Basin

Seawater was collected from the western Arctic Ocean for measurements of 18О, ^226Ra and ^228Ra. The fractions of river runoff and sea ice melt-water in water samples were estimated by using δ^18О-S-PО^＊ tracer system. The mean residence time of river water in the Canada Basin was calculated based on the relationship between ^228Ra/^226Ra）A.R. and the fractions of river runoff in the shelf and deep ocean. Our results showed that the river runoff fractions in the Canada Basin were significantly higher than those in the shelf regions, suggesting that the Canada Basin is a major storage region for Arctic river water. ^228Ra activity concentrations in the Chukchi shelf and the Beaufort shelf ranged from 0.16 to 1.22 Bq/m^3, lower than those reported for shelves in the low and middle latitudes, indicating the effect of sea ice melt-water. A good positive linear relationship was observed between ^228Ra/^226Ra）A.R. and the fraction of river runoff for shelf waters, while the ^228Ra/^226Ra）A.R. in the Canada Basin was located below this re-gressive line. The low ^228Ra/^226Ra）A.R. in the Canada Basin was ascribed to ^228Ra decay during shelf wa-ters transporting to the deep ocean. The residence time of 5.0-11.0 a was estimated for the river water in the Canada Basin, which determined the time response of surface freshening in the North Atlantic to the river runoff into the Arctic Ocean.     

常州市城市污水潜没排江流场 浓度场研究

海洋和大江(河)从整体上看蕴藏着较大的环境容量,特别离岸水体还没有得到合理利用。长江是我国第一大江,水深、流速大。常州市城市污水有条件地潜没、多孔排入长江不仅能解决常州市水环境问题,而且治理费用也将降低。本文分别用二维潮变流动方程、二维潮变扩散方程建立常州市城市污水排放江段流场、浓度场数学模型。在实测资料的基础上进行了流场计算;根据近、远期规划的污染物发生量。对COD浓度分布进行了预测,由模拟计算结果,得出城市污水排江方案是可行的结论。本文应用隐式破开算子法进行流场、浓度场数值计算。计算结果表明,该方法具有较好的稳定性和重现性。     

~(99)Tc靶件中子学特性及释热率特点的初步研究

99Tc是一种重要的长寿命裂变产物,半衰期长,极易随地下水迁徙扩散.将99Tc嬗变为短寿命或稳定核素,可有效降低其对环境的危害.99Tc在热中子谱下具有较大的吸收截面,采用PWR嬗变99Tc是一种可行途径.为了评估99Tc嬗变靶件对PWR堆芯中子学参数的影响,并为含嬗变靶件的PWR组件热工水力计算提供数据,本文对含99Tc的17×17 PWR组件进行模拟计算,给出了99Tc靶件加入前后,燃料温度系数、慢化剂温度系数的变化规律;计算了稳态工况下99Tc靶件的轴向释热率.相关结论可为PWR嬗变99Tc研究提供参考.     

Study of altitudinal lapse rates of δ18O in precipitation/river water with seasons on the southeast Tibetan Plateau

Seasonal δ^18O variation in water on the southeast Tibetan Plateau has been studied, showing the consistent variation pattern of δ^18O with altitude indicative of relevant atmospheric circulation processes. Study shows a similar variation pattern of fixed-site river water δ^18O with that of the precipitation δ^18O in southeast Tibet. δ^18O in regional rivers in southeast Tibet demonstrates a gradual depletion with increasing altitude, though the rates vary seasonally. The most depleted river ^18O occurs during the monsoon period, with the lowest δ^18O/altitude lapse rate. The river ^18O during the westerly period is also depleted, together with low δ^18O/altitude lapse rate. The pre-monsoon rivers witness the most enriched ^18O with least significant correlation coefficient with the linear regression, whilst the postmonsoon rivers witness the largest δ^18O/altitude lapse rate. Different coherence of seasonal δ^18O variation with the altitude effect is attributed to different moisture supplies. Though sampling numbers vary with seasons, the δ^18O-H linear correlation coefficients all reach the 0.05 confidence level, thus witnessing the variation features of δ^18O in seasonal river water due to the influence of atmospheric general circulation and land surface processes revealed from the altitudinal lapse rates.     

改性河砂过滤处理高锰地下水

 以改性河砂为除锰滤料,对模拟地下水进行过滤处理,研究了水力停留时间、pH值、溶解氧含量、Mn²⁺质量浓度等对除锰效率的影响。结果表明,水力停留时间为24min、溶解氧为7mg／L、中性及弱碱性、原水Mn²⁺质量浓度不大于2mg／L等条件下,改性河砂过滤可使出水Mn²⁺质量浓度持续稳定在0.1mg／L以下,符合国家饮用水标准。通过对改性河砂表面滤膜的电镜扫描和X射线能谱分析,初步确定了改性河砂表面滤膜对除锰发挥了重要作用,主要机理为吸附和自催化作用。