陆地水水质全球变化研究进展

对陆地水水质全球变化研究中的几个问题进行了讨论，包括:陆地淡水水质的全球参比值问题;水质监测的发展及全球淡水水质监测计划;全球淡水水质变化趋势分析。
       

运用H、O同位素分析石阡地区地热水来源

通过对贵州省石阡地区地热水、冷泉及河流的地热地质条件、水化学成分及氢氧同位素分析,对该地区的地热水、冷泉及河流的水化学特征、来源及石阡地区的补给模式进行了研究.温泉水属于低中矿化度的弱碱性水;温泉群中阳离子以Ca2+、Mg2+为主,阴离子以SO42-和HCO3-为主,研究区水化学类型主要为HCO3-Ca和SO4.HCO...     

面临21世纪的中国水资源问题

新中国成立后,水利建设成绩巨大,面临２１世纪,中国水资源的除害兴利,出现了一些新情况和新问题;我国是缺水严重的国家,工农业和城市生活都缺水,而用水十分浪费,水污染很严重;我国又是洪水灾害频发的国家,因此迫切需要组织多学科研究水利建设的新战略;将建立节水型社会作为基本国策,防治江河洪水灾害。     

Water and power in Santiago de Chile: Socio-spatial segregation through network integration

The analysis of the history of the management and distribution of electricity, water and sanitation networks in Santiago de Chile throws light on a problem which is central to thinking on the relationship between urban services management and territorial splintering: what is the impact of urban policy, in particular housing policy and urban planning, on access to services and on the potential levels of social segregation and institutional splintering of metropolises?The Chilean example is eminently anchored in its political and institutional history. We shall see, for example, that the authoritarian urban policy of the military government, associated with early liberal reform, enabled the improvement of access to networks in every municipality of the Greater Santiago area. However, this success, leading to the integration by urban services of a large territory, does not signify that networks remained neutral as regards the process of spatial segregation. Inversely, we can defend the theory that the presence of an integrated service was a necessary condition and a reinforcing factor of the process of urban spread and residential segregation. This paradoxical argument is a result of the ambivalent liberal network and urban policies of the military government. Urban expansion was largely sustained by the development of integrated infrastructures and universal services. The processes of liberalising land and urban services were mutually sustaining and provided the necessary conditions for the birth of an extremely intense movement of urban sprawl and segregation between 1985 and 2000.     

基于L-BFGS算法和同时激发震源的频率多尺度全波形反演

全波形反演可以利用叠前地震波场的运动学和动力学信息重建地下速度结构,具有揭示复杂地质背景下构造与岩性细节信息的潜力。然而,庞大的计算量和存储空间需求,限制了全波形反演的发展。在频率多尺度全波形反演中将L BFGS数值优化算法与同时激发震源技术相结合的方法来改善这一现状。首先,对Marmousi模型进行了速度反演：在计算过程中明显发现对计算机内存的占用减少,最终反演结果与实际Marmousi模型的拟合误差为0.095 9,较小;采用10个频带单炮震源正演384炮所需时间约为32 640 s,而采用同时激发震源（384炮）正演一次所需时间仅约为700 s。然后,基于高速楔形体模型进行了抗噪能力研究：原始含噪地震记录信噪比为11.147 3 dB;对反演得到的速度模型进行正演,其地震记录信噪比为22.251 8 dB。最后,基于逆冲断层模型进行了反演速度扰动能力研究,反演得到的最终模型很清晰,与具有速度扰动特性的实际模型非常接近,拟合误差仅为0.036 0。数值模拟试验结果表明：此方法反演精度高,内存开销较小,能够显著提高计算效率,并且具有良好的抗噪能力,能够反演出具有速度扰动特性的介质。     

Probability of scour depth exceedance owing to hydrologic uncertainty

The average risk of a bridge over water in the USA collapsing from scour during its 75 years design life is estimated at 3.7×10^?3. This risk makes scour of foundations the number one cause of bridge collapse and 3 times larger than the next cause of bridge collapse, which is collisions. The current paper presents a site specific method to estimate the probability that a certain scour depth will be exceeded during the life of a bridge. The methodology is limited to some uncertainties associated with the randomness of hydrologic conditions. It does not include uncertainties associated with other input parameters, such as geometry and soil erodibility or uncertainties associated with the scour prediction model. The SRICOS–EFA method is used as the reference method to predict the scour depth. This method requires three inputs: the hydraulic parameters (e.g. velocity hydrograph), the geometry parameters (e.g. pier size) and the soil erodibility parameters (e.g. erosion function). The input is used together with the program to generate the scour depth versus time over the period of interest. The final scour depth is that reached at the end of the specified period. This paper proposes a probabilistic framework to present the final scour depth as a cumulative density function. The cumulative density function of the flow is sampled randomly to give a future hydrograph, which has the same mean and standard deviation as the original hydrograph. For this synthetic hydrograph a final scour depth is obtained by using SRICOS–EFA. Thousands of equally likely hydrographs are generated and the corresponding final scour depths are organized in a distribution. That final scour depth distribution gives the probability that a chosen scour depth will be exceeded.     

Atmospheric sulfur deposition and streamwater quality in Finland

The correlation between sulfate concentrations in Finnish headwater streams and atmospheric sulfate deposition has been studied by using data from the streamwater chemistry in August–September 1990 and computed S deposition from the anthropogenic emissions. The sulfate concentrations and acidity in water are interpolated and smoothed into a deposition model grid. These data are compared with geological and pedogeochemical (glacial till) background information. The areas where the streamwater SO₄ concentrations are mainly controlled by either anthropogenic S deposition or sulfur in till is estimated by applying the fuzzy Gustafsson-Kessel algorithm, which provides a soft clustering suitable for overlapping control factors. Residual areas can be well explained by the SO₄-rich Littorina clay deposits. The higher overall background SO₄ concentrations in streams in south Finland compared with central and northern Finland are an indisputable consequence of the heavier S deposition load in the south. However, anthropogenic sulfur deposition has a clear correlation with the sulfates in streamwaters only in northeastern Lapland impacted by the large industrial emissions in the Kola Peninsula. The secondary sulfide and sulfate minerals of marine Littorina sediments are dominating sources in the broad coastal belts, as are the primary sulfide minerals locally in the Pori-Vammala area, at the eastern end of the main sulfide ore belt between Lake Ladoga and the Gulf of Bothnia, in the Outokumpu area, and in the Peräpohja and central Lapland schist belts. Consequently, in addition to the anthropogenic deposition, there are natural sources of sulfur which cause acidity of streamwaters.     

修正的内梅罗指数法及其在城市地下饮用水源地水质评价中的应用

为了克服内梅罗指数法和平均指数法存在的不足,对内梅罗指数法进行了修正。将公式中的算术平均修改为加权平均,各评价指标的权重是根据污染因子的危害性与该污染因子的排放标准呈反比例关系来确定的。并将修正后的公式用于西安市地下饮用水源地的水质评价中。结果表明,改进后的方法更能客观地评价水质状况,既突出了最大污染因子,又增强了危害性较强因子的作用,是合理的。     

山东省聊城市水资源演变形势初步探讨

以地处华北平原的缺水城市——聊城市为代表,从降水、地表水资源、地下水资源分析了该市水资源演变情势,对影响水资源变化情势的主要人类活动如城市化、水利工程拦蓄、调、引水、地下水开采等进行分析,最后得出结论：由于人类活动对区域水资源下垫面基础条件及地下水补给能力的影响改变,致使聊城市地表水,地下水资源的数量、质量及时空分布规律发生了显著变化。     

山东烟台地区苹果果园土壤中DDTs和HCHs残留分布特征与来源解析

为研究不同土壤类型中有机氯农药的残留特征、降解程度和来源途径,采集了山东烟台9个不同地质单元苹果园根系土壤和剖面土壤样品,用电子捕获检测器气相色谱法测定其中的滴滴涕(DDTs)和六六六(HCHs)。结果表明,研究区所有类型根系土壤中DDTs和HCHs均未超出《土壤环境质量标准》的二级土壤限值(500 ng/g);土壤中DDTs的残留量及检出率均高于HCHs,DDTs检出率为100%,平均残留量为71.7ng/g,而HCHs的检出率为19.70%,平均残留量为7.9 ng/g;根系土壤中DDTs各异构体平均浓度依次为p,p’-DDT>p,p’-DDE>o,p’-DDT>p,p’-DDD,而HCHs大部分以α-HCH形式存在,部分以β-HCH、γ-HCH存在。不同类型土壤中有机氯农药残留分布特征明显不同:DDTs在棕壤土(臧家庄)中最高(145.5 ng/g),在中粗粒砂土(武宁)中最低(24.1 ng/g);而HCHs在细砂质壤土(蛇窝泊)中最高(27.9ng/g)。各剖面土壤DDTs均在<20 cm层位中残留最高。DDTs和HCHs来源解析表明:研究区土壤为好氧条件;麻砂棕壤(官道和桃村)、黏细壤土(牟平)、细砂质壤土(蛇窝泊)和棕壤土(臧家庄)近年来仍有新的DDTs输入;大部分根系土壤均未发现HCHs新来源,但麻砂棕壤(桃村)在HCHs禁用后可能仍存在林丹的使用。