基于卫星资料的北京陆表水体的热环境效应分析

应用不同分辨率的卫星资料对北京水体类别、密云水库及城区典型水体的热环境特性及城区水体对其周围热环境影响进行研究分析.利用2006年的MODIS卫星地表温度产品对北京不同类型的地表温度研究显示:就北京四季平均状态来说,水体类别在白天具有降温作用,在秋季和冬季夜晚具有保温作用,在春季和夏季夜晚具有降温作用.利用NOAA/AVHRR卫星资料对密云水库的研究分析显示:密云水库在夏季白天具有"冷湖效应",夜晚具有"暖湖效应";密云水库在冬季未结冰时白天和夜间具有"暖湖效应",在结冰时白天具有"冷湖效应"而晚上无冷暖效应.利用FY-3A/MERSI、NOAA/AVHRR和Landsat-TM卫星资料对北京城区典型水体监测结果显示:城区水体不会有热岛现象出现,大面积的水体易出现"冷岛效应".利用2008年夏季Landsat-TM卫星资料对城区典型水体和天坛公园绿地500 m范围内的建筑地温研究分析显示:城区水体温度明显低于天坛公园绿地.城区各水体周边100 m范围内建筑区地温平均下降1.2℃;100～200 m内下降0.6℃;200～300 m内下降0.4℃,300 m范围外无明显变化.天坛公园绿地周边仅100 m内的建筑区地温下降,下降值为0.4℃.这些研究结果表明:卫星资料能有效监测水体的热环境效应,大面积的水体是降低城市地表热岛效应的重要来源,北京城区水体对周边最大300 m范围内的建筑区地表温度具有降温效应.     

Catchments of German surface water bodies

The European Water Framework Directive demands to assess and report the chemical and ecological status of water bodies (WB). Linking their status to drivers and pressures and deriving suitable mitigation measures require knowledge of the shape and area of WB catchments. We derived a network of 26 570 WB catchments in Germany using the hydrologically-defined drainage basins of the German federal states. We established a network of 338 149 drainage basins. This network underwent plausibility checks and a validation with the catchment areas of 348 monitoring stations across Germany. To this network, we assigned the longest intersecting or the next downstream WB code. To account for geometric inaccuracies we revised spurious intersections resulting in splittings and cycles in the WB network. As WB may be ecologically but not hydrologically well defined, we split them at confluences and intersections. The network of drainage basins matched the monitoring stations with a Nash-Sutcliffe efficiency of 1.00. The final WB network contained 11 005 out of the 11 586 original WBs longer than 1 m. The corresponding local catchment areas range from <<0.0001 to 446 km², with a median of 10 km². The dataset combines the requirements of hydrological and ecological modelling applications at basin or national scales with the needs of the EU reporting which can foster their acceptance by state authorities and river-basin management.     

Vibration of finite water bodies with free surface

Summary The study deals with expansion waves in fluids, with particular reference to hydrodynamic earthquake effects. The current assumption of steady harmonic motion is compared with the assumption that the motion is discontinuous in the sense that it starts from the initial condition of rest. A numerical example shows that the impulsive start may have a considerable influence on the dynamic water pressure.     

Hydrochemical and microbiological characteristics of the Gusino-Ubukunskaya group of water bodies

Results of hydrochemical and microbiological studies of five largest water bodies belonging to the Gusino-Ubukunskaya group are presented. Present-day environmental state of the ecosystem subject to anthropogenic load is described. The possibility of using water quality parameters of the investigated lakes as indicators of the degree of contamination of waters flowing into the Baikal Lake is shown.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 79–84.Original Russian Text Copyright © 2005 by Khakhinov, Namsaraev, Ulzetueva, Barkhutova, Abidueva, Banzaraktsaeva.     

Comprehensive evaluation of continental surface water quality

Two main groups of methods used for comprehensive evaluation of continental surface water quality are analyzed. A new method of comprehensive evaluation of the degree of continental surface water contamination, developed by the authors of this paper based on a combination of the differentiated and comprehensive approaches, is described in detail.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 61–69.Original Russian Text Copyright © 2005 by Nikanorov, Yemelyanova.     

梁子湖水质时空格局分析

基于大样本监测数据,从点位、湖区、全局3个层次,对梁子湖水质的季节变化和空间差异进行综合分析,发现梁子湖水质存在显著的季节差异和较大的空间差异:(1)季节上,夏、秋、冬季污染相对较重,春季污染相对较轻;夏、秋季主要污染指标为高锰酸盐指数(COD_(Mn)),冬季为总氮(TN);(2)空间上,东梁子湖和牛山湖污染相对较重,西梁子湖污染相对较轻;东梁子湖主要污染指标为COD_(Mn)、总磷(TP)和TN,牛山湖为COD_(Mn)、TN和氨氮,西梁子湖为COD_(Mn)和TN.研究结果有助于更好地了解梁子湖水质的时空变化特点,进而制定有针对性的保护措施和管理对策.     

生态补水对白洋淀流域地表水和地下水水化学特征的影响

生态补水是维持和改善白洋淀生态环境的重要途径.为研究生态补水对白洋淀水环境的影响,分别在补水前与补水后采集淀水、河水及地下水样品,分析区域地表水和地下水水化学特征.结果表明：（1）白洋淀补水前、后地表水与地下水的水化学组成中Na⁺为主要阳离子,补水后阴离子以HCO₃^-为主,淀区南部地表水电导率高;补水后地表水与地下水Ca²⁺、Mg²⁺和HCO₃^-浓度显著增加,水体电导率降低.（2）补水前地下水为Na-HCO₃型水,地表水主要为Na-Cl·SO₄及Na-Cl·HCO₃类型;补水后地表水与浅层地下水向Ca·Mg-HCO₃型演化,深层地下水水化学类型基本保持不变.（3）生态补水使白洋淀水位升高,淀区水面积增大,缓解了水资源短缺的问题;同时也使浅层地下水水化学组成发生改变,而深层地下水暂未受到影响.生态补水后,受稀释和混合作用的影响,水体Na⁺、Cl^-和SO₄^2-浓度显著下降,Ca²⁺、Mg²⁺及HCO₃^-浓度增加.在白洋淀生态补水中应"先治污,后补水",以减少补水过程中污染物向淀区的运移,还应注意区域地下水位上升过程中的阳离子交换及水岩相互作用,为合理调配生态补水及改善白洋淀生态环境提供科学依据.     

Method of ecological standardization of the impact on water bodies that cannot be standardized by bioassay: Case study of water bodies in Don basin

The work is focused on studying the possibility to ecologically standardize the characteristics that are not concentrations of chemical substances, i.e., water abundance; water temperature; and pH, which does not belong to standardized characteristics. The initial data include the data of biological (water quality classes by characteristics of plankton, periphyton, and zoobenthos) and physicochemical monitoring in 1975–1991 in water bodies of the Lower Don, as well as data on fish catches and yield in the Lower Don. The values of ecologically tolerable levels are obtained for three factors, such that going above these levels causes the environmental ill-being of the appropriate biological indicator. Nonchemical impacts, represented by water abundance and temperature have almost no effect on the deterioration of ichthyological estimates of the state (the only exception is the correlation between water abundance and sabrefish catches). At the same time, planktonic and benthic estimates appear to be more sensitive indicators of water quality decline in all three factors under consideration. The pH exponent affects all ecological groupings of Don ecosystems. The strictest upper boundaries of ecologically tolerable levels of water abundance were recorded for the sabrefish catches. On the other hand, insufficient water abundance during spring and summer deteriorates the state of planktonic and benthic organisms.     

Predicting quantiles of water quality from catchment characteristics

Water quality is often highly variable both in space and time, which poses challenges for modelling the more extreme concentrations. This study developed an alternative approach to predicting water quality quantiles at individual locations. We focused on river water quality data that were collected over 25 years, at 102 catchments across the State of Victoria, Australia. We analysed and modelled spatial patterns of the 10th, 25th, 50th, 75th and 90th percentiles of the concentrations of sediments, nutrients and salt, with six common constituents: total suspended solids (TSS), total phosphorus (TP), filterable reactive phosphorus (FRP), total Kjeldahl nitrogen (TKN), nitrate-nitrite (NO_x), and electrical conductivity (EC). To predict the spatial variation of each quantile for each constituent, we developed statistical regression models and exhaustively searched through 50 catchment characteristics to identify the best set of predictors for that quantile. The models predict the spatial variation in individual quantiles of TSS, TKN and EC well (66%–96% spatial variation explained), while those for TP, FRP and NO_x have lower performance (37%–73% spatial variation explained). The most common factors that influence the spatial variations of the different constituents and quantiles are: annual temperature, percentage of cropping land area in catchment and channel slope. The statistical models developed can be used to predict how low- and high-concentration quantiles change with landscape characteristics, and thus provide a useful tool for catchment managers to inform planning and policy making with changing climate and land use conditions.     

Assessing surface water quality of the Yangtze Estuary with genotoxicity data

The present study investigated the genotoxicity of the surface water samples from the Yangtze Estuary with the Ames test in three seasons. Several important chemical parameters, such as COD inorganic nitrogen, active phosphate and heavy metals, were also analyzed at the same time. According the results, surface water samples from the south branch and a few of samples at the seaward end of the Yangtze Estuary show positive genotoxicity in some seasons. Chemical analysis revealed that the Yangtze Estuary was seriously polluted by inorganic nitrogen and by active phosphate. However, chemical parameters could not demonstrate the spatial variation of water quality of the estuary, and they could not assess adverse effects of chemicals in mixtures as well. Therefore, it is recommended that genotoxicity data, mutation rate of the Salmonella typhimurium strain TA98 at the dose of 1 l per plate, be taken as a new parameter assessing surface water quality of the Yangtze Estuary. Our studies also suggested that genetic toxicology assays, such as the Ames test, could be applied as a routine measure to monitoring marine environment in China. The paper proposes a development of the National Seawater Quality Standard of China.     

Basic physicochemical characteristics of the state of Upper Amur surface water

The present-day ecological state of the Upper Amur is assessed. Specific features of water quality formation are demonstrated. Local sources of aquatic environment pollution are identified. The distributions of metals in dissolved and suspended forms in the river reach are examined.     

The role of land surface versus drainage network characteristics in controlling water quality and quantity in a small urban watershed

The processes that control run‐off quantity and quality in urban watersheds are complex and not well understood. Although impervious surface coverage has traditionally been used to examine altered hydrologic response in urban watersheds, several studies suggest that other elements of the urban landscape, particularly those associated with urban infrastructure and the drainage system, play an equally important role. The relative importance of impervious surfaces, stormwater ponds, expansion of the drainage network, and drainage network structures in controlling hydrologic response was examined in the subwatersheds of the Kromma Kill, an urban watershed located in Albany County, NY. In this study, geographic information systems was used to compute geospatial land surface and drainage network properties of 5 Kromma Kill subwatersheds. In these same subwatersheds, water quantity (rainfall and run‐off) and quality (macroinvertebrates, nitrate, total nitrogen, dissolved oxygen, total dissolved solids, and nonpurgable organic carbon) parameters were measured. Strong and significant correlations were identified between land surface and drainage network properties and field observations. Causal relationships were then tested using the Environmental Protection Agency's Stormwater Management Model. Field and model analyses suggest that whereas percent imperviousness is a dominant control on water quality, drainage density and slope are equally important. However, for water quantity, whereas imperviousness is positively correlated with increased run‐off volumes, drainage network properties and slope are the dominant controls on run‐off volumes. Results have important implications for stormwater management plans, especially those aimed at reducing the effective impervious surface coverage of urban watersheds. Reducing the percentage of effective imperviousness in a watershed is not a “one size fits all” solution and can help to meet some management objectives, such as reducing nitrogen concentrations and improving water quality, but may not serve as the most effective, and therefore economical, solution for every management objective including reducing run‐off volumes.     

Concerning the occurrence of water in the planetary bodies

The study of the cosmic chemical abundance of the elements suggests that water (which is a combination of the first and second most abundant chemically active elements) is likely to be the most abundant chemical compound in the solar system.It is found that water indeed appears to be a common constituent of planetary bodies even though its presence is not always directly detectable. The amount involved, and the form it takes, varies from one object to another. The Earth has surface liquid water and crustal hydrate materials and only Mars of the terrestrial planets is also likely to have non-atmospheric water and that in frozen form near the surface. The mantles of the icy satellites, and particularly those of Jupiter and Saturn, are the most extended locations of water in the solar system although Uranus and Neptune are likely to have substantial mid-mantle internal water components. Only Mercury and Moon appear to be devoid of water. The smaller bodies such as comets are excluded from the discussion even though they are now known to be composed largely of water-ice.     

Importance of soil surface characteristics on water erosion in a small grazed Sahelian catchment

This study concerns the problem of water erosion in the Sahel. Surface water and sediment yields (suspended matter and bedload) were monitored for 3 years (1998–2000) at the outlet of a small grazed catchment (1·4 ha) in the northern part of Burkina Faso. The catchment consists of about 64% sandy deposits (DRY soil surface type), which support most of the vegetation, and about 34% of crusted bare soils (ERO soil surface type). The annual solid‐matter export is more than 90% suspended sediment, varying between 4·0 and 8·4 t ha^?1. The bedload represents less than 10% of soil losses. In a single flood event (10 year return period), the sediment yield can reach 4·2 t ha^?1. During the period studied, a small proportion (20 to 32%) of the floods was thus responsible for a large proportion (80%) of the solid transport. Seasonal variation of the suspended‐matter content was also observed: high mean values (9 g l^?1) in June, decreasing in July and stabilizing in August (between 2 and 4 g l^?1). This behaviour may be a consequence of a reorganization of the soil surfaces that have been destroyed by trampling animals during the previous long dry season, vegetation growth (increase in the protecting effect of the herbaceous cover) and, to a lesser extent, particle‐supply limitation (exhaustion of dust deposits during July). The particle‐size distribution in the suspended matter collected at the catchment outlet is 60% made up of clay: fraction ≤2 µ m. The contribution of this clay is maximum when the water rises and its kaolinite/quartz ratio is then close to that of the ERO‐type surfaces. This indicates that these surfaces are the main source of clay within the catchment. Copyright © 2003 John Wiley & Sons, Ltd.     

泄流量对动水位观测影响的分析

利用深井动水位观测资料预报地震,已经被国内外地震学家进行深入研究,并得到了许多珍贵的震例资料。从多年的观测实践认识到,观测装置系统对动水位记录地震信息量是关键环节,泄流量的调节也是提高动水位观测质量的重要因素。     

Hydrogeochemical characteristics of surface water and groundwater in the karst basin,southwest China

Groundwater is a very significant water source used for irrigation and drinking purposes in the karst region, and therefore understanding the hydrogeochemistry of karst water is extremely important. Surface water and groundwater were collected, and major chemical compositions and environmental isotopes in the water were measured in order to reveal the geochemical processes affecting water quality in the Gaoping karst basin, southwest China. Dominated by Ca²⁺, Mg²⁺, HCO₃^? and SO₄^2?, the groundwater is typically characterized by Ca? Mg? HCO₃ type in a shallow aquifer, and Ca? Mg? SO₄ type in a deeper aquifer. Dissolution of dolomite aquifer with gypsiferous rocks and dedolomitization in karst aquifers are important processes for chemical compositions of water in the study basin, and produce water with increased Mg²⁺, Ca²⁺ and SO₄^2? concentrations, and also increased TDS in surface water and groundwater. Mg²⁺/Ca²⁺ molar ratios in groundwater decrease slightly due to dedolomitization, while the mixing of discharge of groundwater with high Mg²⁺/Ca²⁺ ratios may be responsible for Mg²⁺/Ca²⁺ ratios obviously increasing in surface water, and Mg²⁺/Ca²⁺ ratios in both surface water and groundwater finally tending to a constant. In combination with environmental isotopic analyses, the major mechanism responsible for the water chemistry and its geochemical evolution in the study basin can be revealed as being mainly from the water–rock interaction in karst aquifers, the agricultural irrigation and its infiltration, the mixing of surface water and groundwater and the water movement along faults and joints in the karst basin. Copyright © 2009 John Wiley & Sons, Ltd.     

密云水库东西库区的水质与浮游藻类分析

湖泊生态工程因其净化效果好、投资小、运行简单等优点,近十多年来在我国受到了广泛关注,并得到了越来越多的应用.本文介绍了云南洱海污染治理的工程技术之一--桃溪河口净化工程的设计思路.该工程基于暴雨径流输送污染物的特征,将水力工程、土石工程与生物工程有效结合,通过在桃溪河口建立溢流堰,将桃溪正常来水导截入由桃溪河口9个废弃鱼塘改造而成的净化池进行净化.工程运行的水质监测表明,该工程已发挥一定的净化效果,对TN的去除率达55.2%-86.9%,其中对NO3-N和NH4 -N的去除率都较高,对P的去除率达76.4%-88.2%,对悬浮物的去除率达29.4%-49.5%.     

Studies on finite amplitude waves in bounded water bodies

The problem treated here is the dynamics of a bay where water is driven through its opening periodically in time. The basic equations are expressed in the two horizontal coordinates and time and they are obtained by an integration of the Navier-Stokes equations in the vertical coordinate. The equations are nonlinear because of the convective terms in the acceleration. The problem of harbor dynamics provides a natural parameter as the ratio of mass of water entering the bay through the waves to the total mass of water in the bay. This small parameter multiplies the nonlinear terms and thus the problem is ideally suited for a perturbation analysis. The nonlinear terms are responsible for the generation of secondary flows and are particularly important near resonant frequences. The analysis further indicates the existence of a time independent flow analogous to acoustic streaming, known from solutions of the Navier-Stokes equations. The question of vorticity is studied and is seen that: a constant dissipation coefficient precludes the generation of vorticity even for the nonlinear case: and that only a weak (second order) vorticity can exist in the case of a variable dissipation term expressed through the Chezy coefficient. The study suggests also a semi analytic-numerical scheme with savings of 0(10²) for irregular geometries through the separation of the various order harmonics as opposed to the usual integration in time.