Short‐term discharge and suspended sediment fluctuations in the proglacial Skeldal River,north‐east Greenland     

T. A. Stott  J. R. Grove 《水文研究》2001,15(3):407-423

The summer discharge pattern of the Skeldal River, which drains a 560 km² partly glacierized catchment in north‐east Greenland, is dominated by diurnal oscillations reflecting variations in the melt rate of snow and ice in the basin. Superimposed on this diurnal pattern are numerous short‐lived discharge fluctuations of irregular periodicity and magnitude. The larger fluctuations are described and attributed to both rainfall events and periodic collapse of the glacier margin damming flow from beneath the Skelbrae glacier. Other minor fluctuations are less readily explained but are associated with changes in the channelized and distributed reservoirs and possibly temporary blockage of subglacial conduits caused by ice melt with subsequent damming. Fluctuations in suspended sediment concentration (SSC) are normally associated with discharge fluctuations, although examples of ‘transient flushes’ were observed where marked increases in SSC occurred in the absence of corresponding discharge variations. A strong relationship between the event discharge increase and event SSC increase for rainfall‐induced events was established, but no such relationship existed for non‐rainfall‐induced events. There is some evidence for an exhaustion effect in the SSC patterns both at the event time‐scale and as the month proceeds. A mean suspended sediment load of 1765 ± 0·26 t day^?1 was estimated for the study period, which would be equivalent to a suspended sediment yield of 732 ± 4 t km^?2 year^?1. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

VARIATIONS OF THE SUSPENDED MATTER AND THE PARTICULATE ORGANIC CARBON IN THE ENTRY OF THE GIRONDE ESTUARY, FRANCE     

林荣根  EtcheberHenri 《中国海洋湖沼学报》1994,(1)

The effects of using different types of glass fiber filters (GF/F, GF/C) and of sample treatments evaluated. Studies on the variation of suspended matter (SM) and particulate organic carbon (POC) showed that: 1) the transversal and day to night variations are important and must be taken into account in order to get a corrcet river flux; 2) no regular seasonal variations of SM and POC observed, as they are controlled essentially by the climatological, hydrologic, physiochernical, biological, and geological conditions of the drainage area.  相似文献   

Circulation and sedimentation in a tidal-influenced fjord lake: Lake McKerrow,New Zealand     

R.A. Pickrill  J. Irwin  B.S. Shakespeare 《Estuarine, Coastal and Shelf Science》1981,12(1):23-37

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Chemical determination of particulate nitrogen in San Francisco Bay. Nitrogen: chlorophyll a ratios in plankton     

S.W. Hager  D.D. Harmon  A.E. Alpine 《Estuarine, Coastal and Shelf Science》1984,19(2):193-204

Particulate nitrogen (PN) and chlorophyll a (Chla) were measured in the northern reach of San Francisco Bay throughout 1980. The PN values were calculated as the differences between unfiltered and filtered (0·4 μm) samples analyzed using the UV-catalyzed peroxide digestion method. The Chla values were measured spectrophotometrically, with corrections made for phaeopigments. The plot of all $\text{PN}\text{Chl}\text{a}$ data was found to be non-linear, and the concentration of suspended particulate matter (SPM) was found to be the best selector for linear subsets of the data. The best-fit slopes of $\text{PN}\text{Chl}\text{a}$ plots, as determined by linear regression (model II), were interpreted to be the N: Chla ratios of phytoplankton. The Y-intercepts of the regression lines were considered to represent easily-oxidizable detrital nitrogen (EDN). In clear water ( < 10 mg l^?1 SPM), the N: Chla ratio was 1·07 μg-at N per μg Chla. It decreased to 0·60 in the 10–18 mg l^?1 range and averaged 0·31 in the remaining four ranges (18–35, 35–65, 65–155, and 155–470 mg l^?1). The EDN values were less than 1 μg-at N l^?1 in the clear water and increased monotonically to almost 12 μg-at N l^?1 in the highest SPM range. The N: Chla ratios for the four highest SPM ranges agree well with data for phytoplankton in light-limited cultures. In these ranges, phytoplankton-N averaged only 20% of the PN, while EDN averaged 39% and refractory-N 41%.  相似文献   

Cyclic shear response of channel-fill Fraser River Delta silt   总被引：2，自引：0，他引：2  

M.V. Sanin  D. Wijewickreme   《Soil Dynamics and Earthquake Engineering》2006,26(9):854-869

The cyclic shear response of a channel-fill, low-plastic silt was investigated using constant-volume direct simple shear testing. Silt specimens, initially consolidated to stress levels at or above the preconsolidation stress, displayed cyclic-mobility-type strain development during cyclic loading without static shear stress bias. Liquefaction in the form of strain softening accompanied by loss of shear strength did not manifest regardless of the applied cyclic stress ratio, or the level of induced excess pore water pressure, suggesting that the silt is unlikely to experience flow failure under cyclic loading. The cyclic shear resistance of the silt increased with increasing overconsolidation ratio (OCR) for OCR>1.3. The silt specimens that experienced high equivalent excess cyclic pore water pressure ratios (r_u>80%) resulted in considerable volumetric strains (2.5%–5%) during post-cyclic reconsolidation implying potentially significant changes to the particle fabric under cyclic loading.  相似文献   

黄河口水体光谱特性及悬沙浓度遥感估测   总被引：10，自引：1，他引：10  

樊辉  黄海军  唐军武 《武汉大学学报(信息科学版)》2007,32(7):601-604

通过黄河口含沙水体野外遥感光谱反射率的观测实验，探讨了黄河口水体表观光谱特性，分析了悬浮体中有机颗粒含量和悬沙粒度对光谱特性的影响。针对Landsat TM／ETM^＋影像波段特性，对黄河口含沙水体在其可见光至近红外4个波段的光谱特性进行了模拟分析，并结合表观光谱观测数据建立了经验回归函数，以估测不同时相黄河口水体表层悬沙的浓度。  相似文献   

浅析饱水淤泥和粘性土的粘聚力     

黄丽珊 《矿产与地质》2005,19(2):201-203

以汕头地区普遍存在的饱水淤泥土和粘性土为例，研究饱水粘性土与淤泥土的粘聚力和土体的含水量、液限之间的关系，指出饱水粘性土的粘聚力是变量，而不是常量，粘聚力与液限和含水量之差呈近正比关系。  相似文献   

黄河下游河道悬移质泥沙与床沙交换计算研究   总被引：5，自引：0，他引：5       下载免费PDF全文

赵连军  谈广鸣  韦直林  张红武  江恩惠 《水科学进展》2005,16(2):155-163

在前人研究成果的基础上,根据挟沙水流任一粒径组泥沙在输移过程中质量守恒原理,建立了一维非恒定挟沙水流悬移质泥沙和床沙交换基本方程;通过引入平衡冲淤物粒径的概念,建立了河床处于淤积与冲刷时冲淤物粒径的计算公式,并提出了一套完整的一维非恒定挟沙水流悬移质泥沙和床沙交换计算方法。将该成果引入黄河下游一维扩展泥沙数学模型中,采用黄河下游1977年高含沙洪水与1999年汛后至2002年汛前冲刷系列进行了验证。结果表明,该方法能较好地模拟悬沙与床沙的交换过程,克服分组挟沙力方法的缺陷,使得非均匀沙计算理论上更加完善,应用上更加方便。  相似文献   

深圳湾浅海相淤泥固结变形特性研究   总被引：3，自引：0，他引：3  

张长生  张伯友  江辉煌 《水文地质工程地质》2005,32(3):35-37

深圳—香港西部通道填海及地基处理中,主固结沉降采用压缩模量Es计算的结果比实测沉降量小30%左右,采用压缩指数Cc计算的结果比较符合实际。淤泥的沉降比在20%～32%,总平均值达到26%,超过以往15%～20%的经验值。淤泥在满载一定时间后沉降速率下降缓慢,在达到0 5mm d左右时,各项指标就满足设计要求,因而卸载时的沉降速率标准定为0 5mm d。  相似文献   

AYX2型积时式悬沙采样器进水管路优化设计     

雷玉勇 万霞张尚权  代文良 《水文》2005,25(5):23-27

积时式悬沙采样器进口管路的结构和几何参数是影响采样器管嘴进口流速的关键因素之一。为保证所采水样的真实和准确性，一般要求采样器进口流速接近河流的天然流速。本文通过建立采样器进口流速的数学模型，对采样器进口管路进行了参数优化。研究表明，通过优化结构参数，在水深0-40m。天然流速0-5m／s的范围内，采样器的进口流速系数K在[0．9，1．1]区间的概率可达98％。  相似文献