The history of water salinity in the Pearl River estuary,China, during the Late Quaternary   总被引：1，自引：0，他引：1  

Yongqiang Zong  Fengling Yu  Guangqing Huang  Jeremy M. Lloyd  Wyss W.‐S. Yim 《地球表面变化过程与地形》2010,35(10):1221-1233

This research reconstructed the Late Quaternary salinity history of the Pearl River estuary, China, from diatom records of four sedimentary cores. The reconstruction was produced through the application of a diatom–salinity transfer function developed based on 77 modern surface sediment samples collected across the estuary from shallow marine environment to deltaic distributaries. The statistical analysis indicates that the majority of sediment samples from the cores has good modern analogues, thus the reconstructions are reliable. The reconstructed salinity history shows the older estuarine sequence formed during the last interglacial was deposited under similar salinity conditions to the younger estuarine sequence, which was formed during the present interglacial. Further analysis into the younger estuarine sequence reveals the interplays between sea level, monsoon‐driven freshwater discharge, and deltaic shoreline movement, key factors that have influenced water salinity in the estuary. In particular, a core from the delta plain shows the effects of sea‐level change and deltaic progradation, while cores from the mouth region of the estuary reveal changes of monsoon‐driven freshwater discharge. This study demonstrates the advantages of quantitative salinity reconstructions to improve the quality of reconstruction and allow direct comparison with other quantitative records and the instrumentally observed values of salinity. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Characteristics and Influence of Phosphorus Accumulated in the Bed Sediments of a Stream Located in an Agricultural Watershed     

Adam R. Hoffman  David E. Armstrong  Richard C. Lathrop  Michael R. Penn 《Aquatic Geochemistry》2009,15(3):371-389

We investigated the accumulation and influence of bioavailable P (BAP) in sediments of a stream located in an agricultural area of the Lake Mendota watershed in Wisconsin, USA. During hydrologic events, the stream carried high concentrations of suspended sediment (up to 250 mg/l) and BAP (up to 2.5 mg/l). Bed sediments were highly enriched in BAP, as inventories of BAP in the top 10 cm of sediment ranged from 143 to 14,500 μg P/cm². Space variations in BAP inventories were related to site-specific hydrodynamics and geochemical factors, including iron (Fe; r ² = 0.71) and aluminum (Al; r ² = 0.54) concentrations. Most sites behaved as potential sinks for dissolved reactive phosphate during hydrologic events and potential sources during base-flow periods. Through the combination of site-specific factors and geochemical controls, Dorn Creek modifies the amount, timing, and composition of P delivered from the watershed to downstream sites and water bodies.  相似文献   

Erosion modelling for land management in the Tahoe basin,USA: scaling from plots to forest catchments     

M.E. Grismer 《水文科学杂志》2013,58(5):878-900

Abstract

Recent developments in hydrological modelling of river basins are focused on prediction in ungauged basins, which implies the need to improve relationships between model parameters and easily-obtainable information, such as satellite images, and to test the transferability of model parameters. A large-scale distributed hydrological model is described, which has been used in several large river basins in Brazil. The model parameters are related to classes of physical characteristics, such as soil type, land use, geology and vegetation. The model uses two basin space units: square grids for flow direction along the basin and GRU—group response units—which are hydrological classes of the basin physical characteristics for water balance. Expected ranges of parameter values are associated with each of these classes during the model calibration. Results are presented of the model fitting in the Taquari-Antas River basin in Brazil (26 000 km² and 11 flow gauges). Based on this fitting, the model was then applied to the Upper Uruguay River basin (52 000 km²), having similar physical conditions, without any further calibration, in order to test the transferability of the model. The results in the Uruguay basin were compared with recorded flow data and showed relatively small errors, although a tendency to underestimate mean flows was found.  相似文献   

Estimation of phosphorus loads with sparse data for agricultural watersheds in the Czech Republic     

Tereza Beránková  Richard M. Vogel  Daniel Fiala  Pavel Rosendorf 《水文科学杂志》2013,58(8):1417-1426

Abstract

Agricultural watersheds in the Czech Republic are one of the primary sources of non-point-source phosphorus (P) loads in receiving waters. Since such non-point sources are generally located in headwater catchments, streamflow and P concentration data are sparse. We show how very short daily streamflow and P concentration records can be combined with nearby longer existing daily streamflow records to result in reliable estimates of daily and annual P concentrations and loads. Maintenance of variance streamflow record extension methods (MOVE) can be employed to extend short streamflow records. Constituent load regressions are used to predict daily P constituent loads from streamflow and other time varying characteristics. Annual P loads are then estimated for individual watersheds. Resulting annual P load estimates ranged from 0.21 to 95.4 kg year^-1 with a mean value of 11.77 kg year^-1. Similarly annual P yield estimates ranged from 0.01 to 0.3 kg ha^-1 year^-1 with an average yield of 0.07 kg ha^-1 year^-1. We document how short records of daily streamflow and P concentrations can be combined with a national network of daily streamflow records in the Czech Republic to arrive at meaningful and reliable estimates of annual P loads for small agricultural watersheds.

Citation Beránková, T., Vogel, R. M., Fiala, D. & Rosendorf, P. (2010) Estimation of phosphorus loads with sparse data for agricultural watersheds in the Czech Republic. Hydrol. Sci. J. 55(8), 1417–1426.  相似文献   

Application of a rainfall-runoff model to three catchments in Iraq     

FAYEZ ABDULLA  LAITH AL-BADRANIH 《水文科学杂志》2013,58(1):13-25

Abstract

The capability of the Surface inFiltration Baseflow (SFB) conceptual rainfall-runoff model to simulate streamflow for three catchments selected from northern Iraq is investigated. These catchments differ in their climatic regimes and physical characteristics. Three versions of the model were tested: the original three-parameter model (SFB), the modified five-parameter model (SFB-5), and the modified six-parameter model (SFB-6). The available daily precipitation, potential evapotranspiration and runoff data were used in conjunction with a simulated annealing (SA) optimization technique to calibrate the various versions of the SFB model. A simple sensitivity analysis was then carried out to determine the relative importance of the model parameters. The study indicated that use of the original three parameter model was not adequate to simulate monthly streamflow in the selected catchments. The modified version (SFB-5) provided better runoff simulation than the original SFB model; overall a 19% increase was observed in the coefficient of determination (R²) between simulated and observed monthly runoff. The SFB-5 model performed with varying degrees of success among the catchments. The model performance in the validation stage was reasonable and comparable to that of the calibration stage. The sensitivity analysis of the SFB model for arid catchments revealed that the baseflow parameter (B) was the most sensitive one, while the S and F parameters were less sensitive than the B parameter.  相似文献   

中国各季节气候对热盐环流减弱的不同响应     

程军  刘征宇  张福颖  郭品文  杨洋 《南京气象学院学报》2011,34(6):653-661

使用CCSM3（community climate system model version 3）模式的＂淡水扰动试验＂结果,对热盐环流强度减弱后中国区域冬、夏气候的不同响应特征进行了研究。结果表明：CCSM3可较为准确地再现中国附近区域表面气温及降水量的量值和分布形态。当热盐环流年平均强度减弱约80%之后,中国区域冬、夏季的表面气温与降水量显著降低,但冬、夏季的降低幅度与空间分布形态存在显著的差异。冬季的降温幅度较大且分布较为一致,平均降温幅度可达2.2℃,最大的降温幅度可达4℃;夏季的降温幅度相对较小且南北差异较大,平均降温幅度为1.3℃,最大的降温幅度为3℃。冬、夏季降水量的降低幅度都在6%左右,但其成因及其分布形态都存在显著差异。  相似文献   

舟山海域淡水资源调查岩心钻探技术     

郑荣耀  卢秋平 《探矿工程》2013,40(5):26-30

舟山海域淡水资源调查项目DZS1孔,水深15 m、钻孔深度达202.1 m,在以粘土层和砂层为主的第四系覆盖层全孔取心、在风化基岩层取心2 m。在第四系覆盖层不下套管直接利用φ127 mm钻具进行绳索锤击取心钻探,基岩采用φ127 mm钻具作为套管、φ50 mm钻具单动双管回转取心钻探。介绍了该孔的主要施工工艺与质量控制方法,包括勘探船抛锚定位、潮汛对钻杆的影响、钻探取心过程控制、用取心钻头不取心扫孔技术、更换钻头技术、泥浆工艺等。  相似文献   

海岛淡水透镜体演变规律的室内模拟实验     

甄黎  周从直  束龙仓  曹英杰  耿海涛 《吉林大学学报(地球科学版)》2008,38(1):81-85

淡水透镜体作为海岛主要的甚至是唯一的淡水资源,对其在天然和开采条件下的演变规律研究是海岛淡水资源利用和管理的首要任务。采用自制的室内物理模型,对海岛淡水透镜体的演变过程进行了模拟实验。模拟了降雨补给条件下淡水透镜体的形成过程;在无补给条件下,开采淡水时倒锥的变化过程。结果表明：当开采量达到3.73×10^-5m³/s时,倒锥进入抽水井,淡水透镜体被击穿。  相似文献   

鄱阳湖流域蚌类环境DNA宏条形码引物的筛选验证   总被引：1，自引：0，他引：1  

陈金萍  周春花  欧阳珊  黄晓晨  吴小平 《湖泊科学》2021,33(4):1254-1264

环境DNA技术是一种非侵入、高灵敏、高效率且对环境无破坏性,对生物体无损伤的调查工具.为了筛选适合于蚌类环境DNA生物多样性研究的宏条形码引物,本研究通过对鄱阳湖流域24种常见蚌的基因组DNA进行普通扩增和高通量测序筛选了11对引物(设计了9对通用引物及从相关文献中引用了2对引物),结果显示引物cytb和16S rRN...  相似文献   

Analysis of trends in annual streamflow to the Arctic Ocean     

Martin Durocher  Ana I. Requena  Donald H. Burn  Jennifer Pellerin 《水文研究》2019,33(7):1143-1151

There is increasing interest in the magnitude of the flow of freshwater to the Arctic Ocean due to its impacts on the biogeophysical and socio‐economic systems in the north and its influence on global climate. This study examines freshwater flow based on a dataset of 72 rivers that either directly or indirectly contribute flow to the Arctic Ocean or reflect the hydrologic regime of areas contributing flow to the Arctic Ocean. Annual streamflow for the 72 rivers is categorized as to the nature and location of the contribution to the Arctic Ocean, and composite series of annual flows are determined for each category for the period 1975 to 2015. A trend analysis is then conducted for the annual discharge series assembled for each category. The results reveal a general increase in freshwater flow to the Arctic Ocean with this increase being more prominent from the Eurasian rivers than from the North American rivers. A comparison with trends obtained from an earlier study ending in 2000 indicates similar trend response from the Eurasian rivers, but dramatic differences from some of the North American rivers. A total annual discharge increase of 8.7 km³/y/y is found, with an annual discharge increase of 5.8 km³/y/y observed for the rivers directly flowing to the Arctic Ocean. The influence of annual or seasonal climate oscillation indices on annual discharge series is also assessed. Several river categories are found to have significant correlations with the Arctic Oscillation, the North Atlantic Oscillation, or the Pacific Decadal Oscillation. However, no significant association with climate indices is found for the river categories leading to the largest freshwater contribution to the Arctic Ocean.  相似文献