基于实测数据的鄱阳湖悬浮泥沙粒度遥感反演模式分析

水体悬浮泥沙粒度是重要的水质参数之一,影响着水体的遥感反射率。研究两者之间的关系对于内陆湖泊水环境遥感监测具有重要意义。基于鄱阳湖实测数据,采用相关分析方法,用不同数学模型进行鄱阳湖悬浮泥沙粒度反演研究。研究结果表明:(1)浑浊区适合采用体积百分比众数粒径建立反演模型,清水区适合采用数量百分比中值粒径建立反演模型;(2)浑浊区悬沙粒度的敏感单波段是环境卫星Ⅳ波段,在清水区悬沙粒度的敏感单波段有环境卫星Ⅱ和Ⅲ波段,而环境卫星Ⅱ,Ⅲ波段比组合是整个研究区水域的敏感波段;(3)单波段反演模型中,幂函数适用于鄱阳湖粒度遥感反演;波段比反演模型中,多项式模型适于鄱阳湖粒度遥感反演。     

水体悬浮泥沙含量遥感的模拟研究

本文利用地面模拟研究对水体悬浮泥沙含量遥感中的一些关健问题进行了深入的探讨.在0.38～1.10微米波段内测定了含有悬浮泥沙水体的反射光谱特性,确定了反射光谱特性与泥沙含量之间的关系.利用曲线拟合法,求得了光谱反射比、波段的平均反射比与水体悬浮泥沙含量之间的最佳拟合函数(即最佳回归方程).结果表明,波段不同则最佳回归方程的函数形式亦不同.回归分析的结果指出,水体悬浮泥沙含量的最佳遥感波段是ERTS和LANDSAT-D的5波段,最佳遥感波长是0.60微米.此外,还研究了拟合优度不同的回归方程对最佳遥感波段选择和泥沙含量遥感探测准确度的影响.计算证明,拟合优度非最佳的回归方程不但会导致最佳波段的错误选择,而且亦将造成水体泥沙含量的遥感探测准确度的严重下降.本文的模拟研究不仅为水体悬浮泥沙含量的航空和卫星遥感提供了有价值的理论依据,而且在模拟实验的基础上提出了一种利用光谱辐射计对地表水体悬浮泥沙含量进行地面遥测的新设想.     

黄东海悬浮泥沙输运结构及其形成机制

选取典型的水色遥感反演得到的悬浮泥沙浓度资料,并配合同期海表面温度遥感资料,对特定年份黄东海冬季悬浮泥沙的平面分布及其动力成因进行了分析,得出了黄东海冬季悬浮泥沙的平面分布主要是由本海域的环流结构所决定的结论;同时利用悬浮泥沙浓度和海表面温度的相关性得出了东中国海冬季清晰的环流结构,并给出了各主要环流分量的悬浮泥沙浓度特征值和温度特征值.利用1998-2002年表层悬浮泥沙浓度的月平均资料,结合卫星风场资料,研究了南黄海和东海北部悬浮泥沙浓度与局地风速在季节尺度上的相关关系.得出在季节变化尺度上,悬浮泥沙浓度与风速的关系密切并存在一定的时间滞后,约1-2个月;悬浮泥沙浓度季节内变化与风速的关系不明显.     

黄河三角洲附近海域悬浮泥沙浓度估算

基于黄河口附近海域水体悬浮泥沙浓度及光谱信息同步测量数据,设计了使用MODIS Band1波段反射率进行悬浮泥沙浓度定量反演的模型.以MODIS产品MOD09GQ陆地反射率数据为数据源,进行了黄河三角洲附近海域悬浮泥沙浓度反演,获得了2009年夏季黄河入海口悬浮泥沙浓度分布图,结果表明:悬浮泥沙浓度分布的基本趋势是由岸向海逐渐降低,但在黄河入海口南北两侧浓度梯度表现出较大差异;浓度大于300 mg/L的悬浮泥沙主要分布在清水沟流路以南的莱州湾西岸,而黄河清8汊以北区域仅在特定潮流及天气情况下在河口以外区域有较宽分布;浓度为10 ～ 300mg/L的中、低浓度悬浮泥沙主要分布在入海口南侧莱州湾中部海域、高浓度悬浮泥沙分布区以外;浓度小于10 mg/L的极低浓度悬浮泥沙主要分布在上述区域之外远离岸线的地区.     

长江口深水航道海域悬浮泥沙光谱特性研究

 长江口深水航道治理和维护的核心问题为泥沙问题。对长江口深水航道 7 个浮标所在海域进行了不同浓度含沙水体的反射光谱测量,并且结合“长江口深水航道水文、泥沙、波浪自动遥测系统”遥测数据和野外现场取样数据,对其光谱特性进行了分析,发现这些海域悬浮泥沙的敏感波段在 730 ～ 930 nm 之间,并且 731 nm 附近的一阶微分与悬浮泥沙浓度相关性较好。在对其光谱特性进行分析的基础上,分别建立了悬浮泥沙光谱反射率、光谱反射率均值和反射率一阶微分的指数反演模型和二次反演模型,结果显示 900 nm 波长的指数模型可以较准确地定量反演出悬浮泥沙浓度。     

Ⅱ类水体悬移质泥沙含量遥感反演综述

悬移质泥沙是水环境的重要参数之一,其含量的变化对流域生态环境有着多方面的影响。传统研究方法能够实现悬移质泥含量的精确分析,但存在布点有限、时效不足等问题,而遥感技术可弥补传统研究方法的不足,实现大面积水域的同步观测。基于悬移质泥沙含量遥感反演的4类模型:物理模型、半分析模型、经验模型、人工智能算法模型,总结了Ⅱ类水体悬移质泥沙含量遥感反演的研究进展,探讨了反演研究中存在的离水辐亮度提取难度大、混合像元不易分解等问题,并针对我国内陆山区河流,提出山区Ⅱ类水体悬移质泥沙含量遥感反演发展面临的关键问题。     

卫星数据表达的悬沙回归模式及其应用

本文从水体具有的多光谱特性出发,利用陆地卫星 CCT 数据和现场悬浮泥沙浓度测量值,得到了多元非线性回归模式。波段比值作为相关模式的变量既具有能消除光照变化、太阳高度角、扫描角以及水面波动等变化影响的特点,又可以省略遥感数据需要绝对辐射标定的过程。根据在卫星 MSS-7波段图象上接收不到清净水体向上辐射的能量特征,对程辐射作了近似的订正。除此之外,根据回归方程,通过数字图象处理,取得了长江口、吕泗近海悬浮泥沙浓度等值图,并对该区域的泥沙运动及其分布状况作了分析判读。文章最后利用珠江口伶仃洋赤湾近海悬浮泥沙浓度资料,对多元回归模式进行了验证计算,误差是合理的。     

长江口水体表层泥沙含量遥感监测研究

利用近年长江口地区的SPOT遥感影像,对长江口表层悬浮泥沙浓度的空间分布和动态变化规律进行分析,绘制了长江口表层水体含沙浓度分级图.结合同步监测数据,对长江口表层悬浮泥沙扩散规律、高混浊水域的范围、河流泥沙入海形态等方面进行了深入的探讨,为长江口泥沙现状调查和近期运动规律反演和预测提供一条新的研究途径.     

基于遥感信息的杭州湾表层悬沙浓度变化趋势研究

采用杭州湾1988-2014年的Landsat-TM/OLI遥感影像,结合实测水体光谱和同步悬沙取样数据,构建表层悬沙浓度遥感定量反演模式,开展表层悬沙浓度反演并讨论其时空变化特征。结果表明：构建的定量反演模式精度良好,揭示了杭州湾表层悬沙浓度的时空多变性;年际趋势显示,洪季近二三十年来杭州湾湾口北部水域表层悬沙浓度减少约40%～50%,其他水域相对较稳定;与洪季不同,枯季表层悬沙整体呈现减小态势,减小幅度为30%～40%;长江入海泥沙减少、滩涂围垦、沿岸水流以及长江口外泥沙源的共同作用是表层悬沙浓度年际变化的主要影响因素。     

基于归一化水体指数及其阈值自适应算法的水体遥感反演效果分析

归一化水体指数（NDWI）是水体遥感反演的一种重要指标，其阈值及修正直接影响反演结果的精度。基于Landsat-8与GF-1光学多光谱影像，使用归一化水体指数法阈值0（TH₀）、最大类间方差法（OTSU）自适应阈值（TH_otsu）与均值漂移聚类算法（Mean-Shift）自适应阈值（TH_MS）分别对典型正常水体、云雾覆盖水体、富营养化水体、高含泥沙水体进行水体遥感提取与效果分析，结果表明：正常水体以TH₀为阈值提取精度最高，THMS提取精度次之，TH_otsu提取精度最差；而云雾覆盖水体、富营养化水体以及含泥沙水体使用THMS提取精度最高，尤其少量云雾覆盖下的水体，TH_MS具有更明显的优势，TH₀提取精度次之，TH_otsu提取精度最差；对于不同的阈值，Land?sat-8比GF-1总体表现出更高的水体提取精度。Mean-Shift算法应用于NDWI阈值修正与水体遥感反演具有快速、水质适应性强、效果稳定的优势，对尤其是复杂条件下的水体信息遥感反演具有较好的提取效果。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam,lower Kaskaskia River,Illinois, USA

Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd.     

浅谈优化Vray渲染在制作三维场景的应用研究

用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要.     

固结、渗流和沉积控制方程研究

本文从两相流体动力学的守恒方程出发，考虑固相、液相的相对运动，推导了可以考虑场的不均匀性和流体压缩性的统一形式的控制方程，并对方程所基于的物理概念和相互联系进行了必要的分析。通过对方程适当形式的表达，可导出用于大、小变形固结、渗流和沉积的简化方程，显示了在不同领域的三个理论存在一定的统一性。方程推导过程并未对本构关系加以限制，适用范围较广。依据实际问题的要求，作了不同形式的简化。     

四川省及重庆市中型水电站效益分析

该文分析了四川省及重庆市几座中型水电站的调查材料表明：四川省及重庆市中型水电站不仅在川渝主网和地方电网中起着很大的作用，并具有巨大的社会效益，同时还有综合利用效益，说明修建中型水电站的优越性．     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

掺MgO混凝土的宏细观试验研究

利用MgO膨胀剂的延迟微膨胀效应能显著提高大体积混凝土的力学性能,产生的预压应力还能有效提高大体积混凝土抵抗温度开裂的能力,但目前对其微观机理研究不多。采用宏观与微观相结合的方式,研究了不同活性指数、不同掺量的MgO混凝土的力学性能,利用SEM/EDS微观分析手段揭示了MgO对混凝土性能影响的作用机理。试验结果表明：MgO取代部分水泥掺入混凝土中,混凝土的力学性能降低;掺量为4%~5%时,活性指数为100s的MgO混凝土的膨胀率大于活性指数为50 s的MgO混凝土;MgO混凝土的膨胀特性与Ca,Si,Mg,Al等元素的分布情况有关,掺入的MgO将改变界面区Ca,Si,Mg元素的富集特性,Ca元素和Mg元素更易于在界面区富集,导致混凝土宏观力学性能的降低。