声学多普勒流速剖面仪应用浅析

对声学多普勒流速剖面仪在实际应用中进行了分析.通过在白山水库采用走航式及定点测流(垂向代表线法)两种方式,对白山水库测流断面进行了流量测验、流速分布及流向测量.声学多普勒流速剖面仪既适用于自由水面又适用于封冻期测量,最后对声学多普勒流速剖面仪进行了讨论.     

声学多普勒流速剖面仪近底有效流速数据处理初步研究

通过分析声学多普勒流速剖面仪(Acoustic Doppler Current Profiler,ADCP)的声强垂向剖面分布特征,利用数学极值定理,确定床面边界位置,进而确定出ADCP记录的所有在水中的流速单元,将ADCP处理软件"丢弃"的部分近底流速数据或由于底跟踪丢失而损失的流速数据确定出来。利用"六点法"同时、同高度的电磁海流计流速数据对提取出来的ADCP近底流速数据进行验证。验证结果表明,提取出来的ADCP近底流速数据可信、可用。     

应用声学多普勒流速仪进行冰期流量测验的比测研究

水利部松辽委黑龙江水文水资源勘测局、黑龙江省水文局和美国SonTek／YSI水文仪器公司合作，在黑龙江黑河地段的卡伦山水文站进行了冰期流量、流速和水深的比测研究。比测研究采用了SonTek／YSI的1．5MHz河猫Mini—ADP进行实测，并与先期采用机械式旋杯流速仪的实测资料进行比对。比测研究的目的是通过声学多普勒定点测流技术与标准的机械流速仪测量技术进行对比，验证声学多普勒剖面流速仪定点流量测量的精度，推广应用声学多普勒测流技术在封冰期测流的方法。     

声学多普勒流速剖面仪垂线平均流速计算模型研究及应用

以湖南省桃江水文站为研究对象,提出声学多普勒流速剖面仪（ADCP）垂线平均流速计算模型,通过对比分析表明ADCP施测的流速与转子速仪施测的垂线平均流速存在很好的一致性。因此该模型具有较好的适用性及推广应用价值,为水文缆道自动测流系统的建设提供技术支撑。     

定点式横向声学多普勒流速剖面仪应用研究

介绍了应用定点式横向声学多普勒流速仪进行实时流量在线监测方面的比测率定研究工作。主要从设备选型、安装位置、代表流速计算、单元流速区间选择、关系率定、精度评定、测点流速分析等方面进行了分析研究。通过设备选型、安装位置、单元流速区间选择等多方面的比较分析,选择最佳方案,进行比测分析,率定出代表流速与断面平均流速的关系。重点对设备安装位置、单元流速区间的选择、流速横向分布等进行比较分析,对于其他测站的类似H-ADCP监测方案有一定的指导意义。     

声学多普勒流速仪在浙江水文中的应用

本文介绍了声学多普勒流速仪在浙江省水文系统中的应用情况.声学多普勒测验技术解决了钱塘江河口感潮地区流量测验的难题,在平原河网应用的稳定性也得到验证,时于无稳定水位～流量关系的测站也提供了解决方案,但也存在一些应用上的限制.     

激光粒度仪转速对河流砂质沉积物测量的影响

激光粒度仪是沉积物粒度测量中常用的仪器,通过对河流沉积物的粒度测量发现,激光粒度仪的转速会影响粒度测量结果。实验结果表明:被测样品的颗粒易受撞击而破碎,激光粒度仪转速对样品遮光度有影响;转速太大会使大颗粒的破碎严重,转速太小又会导致样品颗粒不能均匀分散于溶液中,综合分析得出河流砂质沉积物应用Mastersizer 2000激光粒度仪测量的较适宜转速为1 900~2 000 r/min左右,且不宜加超声波震荡。     

浅地层剖面仪SEGY型数据文件的读取

浅地层剖面仪(GeoChirpⅡ)是英国GeoAcoustics Ltd生产的一种浅地层剖面仪,该仪器采集的原始数据以二进制形式保存在SEYG型数据文件中。为了读取该仪器记录的原始数据,除了解数据文件的记录格式外,最关键的一步是获取数据文件的重要参数(如道数、点数、数据样点格式等)。这里研究了浅地层剖面仪(GeoChirpⅡ)的SEYG型数据文件的格式,在难以按照常规方式获取重要参数的情况下,首先充分利用GeoPro软件上显示的相关信息获取了剖面的道数及每道的采样点个数等重要参数,数据样点格式则根据说明书确定。然后利用所获取的重要参数编写相应程序以读取该数据文件的原始数据及把处理过的数据写成SEYG型数据文件,数据处理实例则证实了该方法可有效读取原始数据和写入目标数据。最后对读取GeoChirpⅡ的SEYG型数据文件过程中遇到的问题作了初步探讨。     

ADCP声波流速流向剖面仪在海洋环境监测与评价中的应用

在简述ADCP声波流速流向剖面仪基本原理的基础上,结合几个典型的环境监测工程实例,简单地介绍了该技术在香港特别行政区海洋环境质量监测、海洋工程环境评价等方面的应用成果.工程应用的实际结果表明,采用ADCP技术能够获得良好的环境监测效果,阐明了这一技术在环境质量监测应用方面的重要性和有效性.     

基于浅地层剖面仪的鄱阳湖水下沉积地形探测与分析

鄱阳湖是我国重要的淡水和砂石资源提供地,其水下沉积地形现状一直是学术界研究的重点。该文借助浅地层剖面探测手段对鄱阳湖水下地形与沉积特征进行了探测,通过分析32条浅地层剖面测线资料发现,鄱阳湖水深变化幅度为0.16~23.71 m,入江水道与主湖区西北部相对较深;松散沉积物厚度变化范围为0~8.73 m,主湖区中部松散沉积物较厚,估算松散沉积物总体积约3.02 km3。为检验浅地层剖面探测数据的可靠性,2022年9月在主湖区开展了浅钻探测工作。通过与前人的相关研究对比发现,大规模采砂活动能够对鄱阳湖水下地形产生显著影响。该文较全面地揭示了鄱阳湖水下地形现状与沉积特征,得出的结论与建议对相关研究与管理工作具有重要的参考价值。     

Evaluating the support vector machine for suspended sediment load forecasting based on gamma test

Due to the various influencing factors on river suspended sediment transportation, determining an appropriate input combination for developing the suspended sediment load forecasting model is very important for water resources management. The influence of pre-processing of input variables by Gamma Test (GT) was investigated on performance of Support Vector Machine (SVM) with two kernels; Radial Basis Function (RBF) and polynomial in order to forecast daily suspended sediment amount in the period between 1983 and 2014 at Korkorsar basin, northern Iran. The best input combination was identified using GT and correlation coefficient analysis. Then, the SVM model was developed and the suspended sediment amount was forecasted with RBF and polynomial kernels. The obtained results in testing phase showed that GT-SVM (RBF kernel) model can estimate suspended sediment more accurately with the lowest RMSE (14.045 ton/day), highest correlation coefficient (0.88) and highest NSEC coefficient (0.88) than SVM (RBF kernel) model (RMSE?=?18.36ton/day, \( {R}^2=0.79, \) \( NSEC=0.73 \)) and had a better performance than the other models. The results indicated that in forecasting the first nine maximum values of suspended sediment load, GT-SVM (RBF) had a higher capability than the other models and could provide a more accurate estimation from the maximum rate of suspended sediment. The results of this study showed the capability of identifying the priority of the input parameters can change GT to a useful and technical test for input variables pre-processing to forecast the amount of suspended sediments.     

基于遥感方法反演悬浮泥沙分布

基于遥感理论,采用地物光谱仪与光电测沙仪对同一水样同步测量的方法,确保建立相关关系数据的同步性;由地物光谱仪测得的光谱值推算出遥感反射率,并等效计算ETM₊图象相应波段的遥感反射率;由光电测沙仪测出悬浮泥沙浓度;通过对等效算出的ETM₊各个波段遥感反射率和悬浮泥沙浓度这两组数据的相关分析,得到4种形式的经验模型.结果表明,TM₄与TM₁波段光谱值的比值与悬浮泥沙浓度之间的相关系数最高,故应用该模式进行研究区域悬沙浓度反演.     

Simulation of suspended sediment based on gamma test,heuristic, and regression-based techniques

In the present study, four different heuristic techniques viz. multi-layer perceptron (MLP), radial basis function (RBF), self-organizing maps (SOM), and co-active neuro-fuzzy inference system (CANFIS) with hyperbolic tangent and sigmoid transfer functions and two regression-based techniques, i.e., multiple linear regression (MLR) and sediment-rating curve (SRC), were used for suspended sediment modeling. Gamma test (GT), correlation function (CF), M test, and trail–error procedure were applied for estimation of appropriate input variables as well as training data length. The results of the GT and CF suggested the five input variables (Q_t, Q_t?1, Q_t?2, S_t?1, and S_t?2, where Q_t?1 and S_t?1 indicate the discharge and sediment values of one previous day) as the best combination. The optimal training data length (75% of total data) was estimated by M test and trail–error procedure for development of the applied models. The MLP with sigmoid transfer function (M-2) performed better than the all other models. The results of sensitivity analysis indicated that the present-day discharge (Q_t), 1-day lag discharge (Q_t?1) and 1-day lag suspended sediment (S_t?1) are the most influenced parameters in modeling current day suspended sediment (S_t).     

平衡悬沙剖面的新指数公式

基于扩散理论,分析了国内外主要平衡悬沙剖面公式自由面边界条件内在的不合理性及其原因,并结合常数型和线性型悬沙扩散系数的分布特征,应用几何平均法建立了平方根型的悬沙扩散系数表达式,推得了平衡悬沙剖面的新指数公式。通过收集、整理与分析大量水槽与河流实测悬沙资料,对提出的悬沙扩散系数和平衡悬沙剖面公式与van Rijn公式、张红武公式进行了分析比较。研究结果表明,新指数公式不仅对平衡悬沙剖面的刻画精度较高,而且具有表达式特别简洁、床面含沙量为有限定值和可直接解析积分的特点,既利于理论分析,又便于工程应用。     

Multibeam bathymetric and sediment profiler evidence for ice grounding on the Chukchi Borderland, Arctic Ocean

Multibeam bathymetry and 3.5-kHz sub-bottom profiler data collected from the US icebreaker Healy in 2003 provide convincing evidence for grounded ice on the Chukchi Borderland off the northern Alaskan margin, Arctic Ocean. The data show parallel, glacially induced seafloor scours, or grooves, and intervening ridges that reach widths of 1000 m (rim to rim) and as much as 40 m relief. Following previous authors, we refer to these features as “megascale glacial lineations (MSGLs).” Additional support for ice grounding is apparent from stratigraphic unconformities, interpreted to have been caused by ice-induced erosion. Most likely, the observed sea-floor features represent evidence for massive ice-shelf grounding. The general ESE/WNW direction of the MSGLs, together with sediment, evidently bulldozed off the Chukchi Plateau, that is mapped on the western (Siberian) side of the plateau, suggests ice flow from the Canada Basin side of Chukchi Borderland. Two separate generations of glacially derived MSGLs are identified on the Chukchi Borderland from the Healy geophysical data. The deepest and oldest extensive MSGLs appear to be draped by sediments less than 5 m thick, whereas no sediment drape can be distinguished within the resolution of the sub-bottom profiles on the younger generation.     

Mineralogy of suspended sediment in three karst springs

Springs in karstic carbonate rocks frequently carry a sediment load as well as a dissolved load. Analysis of morphology and mineralogy of suspended sediment from three contrasting karst springs reveals a suite of clastic particles that reflect both source areas and processes that take place within the aquifer. Nolte Spring in Lancaster County, Pennsylvania, USA, discharges sediment of apparently precipitated calcite, indicating that at some point in the aquifer or vadose zone, water exceeds saturation with respect to calcite. Sediment morphologies and chemical conditions in the aquifer point to two different scenarios for this precipitation. The other two springs, Arch Spring in Blair County, Pennsylvania and Bushkill Spring in Northampton County, Pennsylvania, show no evidence of calcite precipitation. Arch Spring discharges mainly layer silicates, while Bushkill Spring discharges mainly silica.

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Resumen Los manantiales en rocas carbonatadas karstficadas tienen frecuentemente una carga de sedimentos y de sólidos disueltos. Los análisis de la morfología y mineralogía de los sedimentos suspendidos de tres manantiales kársticos contrastados revela un conjunto de partículas clásticas que reflejan ambas áreas fuente y los procesos que tienen lugar dentro del acuífero. Nolte Spring en el Condado de Lancaster, Pennsylvania, USA, descarga sedimento de calcita aparentemente precipitada indicando que en cierto punto del acuífero o en la zona vadosa, el agua supera la saturación con respecto a la calcita. La morfología de los sedimentos y las condiciones químicas en el acuífero apuntan a dos escenarios diferentes para esta precipitación. Los otras dos manantiales, Arch Spring en el Condado de Blair, Pennsylvania y Bushkill Spring en el Condado de Norhtampton, Pennsylvania, no muestran evidencia de precitación de calcita. Arch Spring descarga principalmente filosilicatos mientras que Bushkill Spring descarga fundamentalmente Sílice.

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Résumé Les sources situées en contexte carbonaté karstique charrient fréquemment, outre les matières dissoutes, une charge solide. La morphologie et la minéralogie des sédiments en suspension issus de trois sources karstiques de caractéristiques distinctes ont été analysées : une série de particules clastiques, reflétant à la fois les secteurs des sources et les processus internes de l’aquifère, en ressort. Les sédiments issus de Nolte Spring (Comté de Lancaster, Pennsylvanie, Etats-Unis) sont constitués de calcite apparemment précipitée: ceci indique que l’eau atteint la sursaturation vis-à-vis de la calcite à un certain point de l’aquifère ou de la zone non-saturée. La morphologie des sédiments et les conditions chimiques au sein de l’aquifère mènent à deux scénarii différents pour expliquer cette précipitation. Les deux autres sources, Arch Spring (Comté de Blair, Pennsylvanie) et Bushkill Spring (Comté de Northampton, Pennsylvanie), ne présentent aucun indice de précipitation de calcite. Arch Spring exporte essentiellement des phyllosilicates, alors que la silice est majoritaire à Bushkill Spring.

     

Effects of concentration-dependent settling velocity on non-equilibrium transport of suspended sediment

In this study, non-equilibrium transport of suspended sediment from one equilibrium state to another is investigated. Based on a convective-diffusion equation, a numerical model for flow with suspended sediment is developed by considering the effect of concentration-dependent settling velocity. The numerical model is validated by comparing analytical solutions and experimental results. The concentration profiles, mean concentrations and distance necessary to reach a new equilibrium state are examined by comparing them with the results of constant settling velocity. For a high concentration flow, the results indicate that evident differences between the above three indicators can be determined with and without concentration-dependent settling velocity. Additionally, the effects of concentration-dependent settling velocity are sensitive to the sediment mobility parameter (or Rouse number), although they are nearly independent of the diffusion Reynolds number.     

基于Landsat-8数据南海近岸悬浮泥沙与叶绿素a浓度定量反演

为了对南海近岸海域海水悬浮泥沙与叶绿素a进行浓度估算,基于Landsat-8数据确定悬浮泥沙与叶绿素a的敏感波段并构建估算模型。结果表明,Landsat-8数据第一、二、四波段对悬浮泥沙浓度较为敏感,第一、二、三波段对叶绿素a浓度较为敏感,而以上单波段仍不能单独用于准确提取该区悬浮泥沙与叶绿素a,故建立多种形式的统计模型。由第一、二、四波段线性组合形成的悬浮泥沙浓度反演模型的相关系数达到0.904,平均相对误差为10.24%,反演精度为89.76%。由第一、二、三波段线性组合形成的叶绿素a浓度反演模型的相关系数达到0.886,平均相对误差为11.27%,反演精度为88.73%。     

Impact of suspended sediment load on the silting of SMBA reservoir (Algeria)

The phenomenon of suspended sediment load is very complex in Mina River basin because of its important soil heterogeneity, vegetation deficiency and rainfall variability in time and space. The methodological approach adopted in this paper consists of finding a regressive power model, which may explain better the suspended sediment discharge as a function of the flow discharge collected at Wadi El-Abtal and Sidi AEK Djilali hydrometric stations by studying this relation at various temporal scales: daily, annual, monthly and seasonal. The obtained monthly power relations, explaining the greatest part of the variance, lead to interpolate, extrapolate and analyse suspended and bed loads deposited on Sidi M’hamed Ben Aouda (SMBA) reservoir since being in service in 1977/1978. These allow authors to find relations between specific erosion and effective rainfall and propose some solutions for river basin managers and policy makers to reduce the silting of SMBA reservoir.