The influence of dependence in characterizing multi-variable uncertainty for climate change impact assessments     

Sajjad Eghdamirad  Fiona Johnson  Ashish Sharma 《水文科学杂志》2019,64(6):731-738

Few approaches exist that explicitly use the uncertainty associated with the spread of climate model simulations in assessing climate change impacts. An approach that does so is second-order approximation (SOA). This incorporates quantification of uncertainty to ascertain its impact on the derived response using a Taylor series expansion of the model. This study uses SOA in a statistical downscaling model of monthly streamflow, with a focus on the influence of dependence in the uncertainty of multiple atmospheric variables. Uncertainty is quantified using the square root error variance concept with a new extension that allows the inter-dependence terms among the atmospheric variable uncertainty to be specified. Applying the model to selected point locations in Australia, it is noted that the downscaling results differ considerably from downscaling that ignores uncertainty. However, when the effects of dependence in uncertainty are incorporated, the results differ according to the regional variations in dependence structure.  相似文献   

Exhumed hydrocarbon traps on the North Atlantic margin: Stratigraphy,palaeontology, provenance and bitumen distribution,an integrated approach     

Steven D. Andrews  Audrey Decou  Bill Braham  Simon R. A. Kelly  Paula Robinson  Andrew C. Morton  John E. A. Marshall  Fiona Hyden 《Basin Research》2020,32(5):1213-1233

Previous work has demonstrated the presence of a number of exhumed hydrocarbon traps in central East Greenland. Re-evaluation of the stratigraphy alongside detailed investigation of the occurrence of bitumen within the Mols Bjerge and Laplace Bjerg exhumed hydrocarbon traps provides new perspectives on these structures, as well as the petroleum geology of East Greenland and the wider North Atlantic. Sedimentological and stratigraphic studies, augmented with palynological and provenance investigations, have constrained the dating and correlation of the strata exposed in the Mols Bjerge and Laplace Bjerg. Petrographic analysis, alongside analysis of the bitumen identified, has highlighted a much wider distribution of hydrocarbon than previously recognized. It was previously considered that Jurassic strata formed the main reservoir interval within the Mols Bjerge and Laplace Bjerg exhumed hydrocarbon traps. It is shown here that the reservoir intervals in the Laplace Bjerg trap lie within the Late Triassic Ørsted Dal and Vega Sund members, which contain up to 18% pyrobitumen and were previously misidentified as Jurassic. The Jurassic Bristol Elv Formation is the most extensively bitumen stained unit in the Mols Bjerge trap. However, occurrences of pyrobitumen (up to 3%) are recorded throughout the Triassic stratigraphy, including the Early Triassic Wordie Creek Formation. Faults, thick calcrete development and regionally continuous mudstone units play an important role in compartmentalizing the palaeohydrocarbon accumulations.  相似文献   

Introduction to “Northern Gulf of Mexico ecosystem change and hazards susceptibility”     

John C. Brock  Dawn L. Lavoie  Richard Z. Poore 《Geo-Marine Letters》2009,29(6):343-347

The northern Gulf of Mexico and its diverse natural resources are threatened by population and development pressure, and by the impacts of rising sea level and severe storms. In the wake of the devastating 2005 hurricane season, and in response to the complex management issues facing the region, the U.S. Geological Survey organized the multidisciplinary “Northern Gulf of Mexico Ecosystem Change and Hazards Susceptibility” project. This special issue of Geo-Marine Letters hosts a few of the early results in the form of 11 papers covering three themes: (1) the control exerted by the underlying geologic framework on geomorphology and nearshore processes and features; (2) impact of human activities on nearshore water quality; and (3) hurricanes and associated effects.  相似文献   

Flood mortality in SE Asia: Can palaeo-historical information help save lives?     

Alan D. Ziegler  H. S. Lim  Robert J. Wasson  Fiona C. Williamson 《水文研究》2021,35(1):e13989

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Deglaciation and proglacial lakes          下载免费PDF全文

Fiona S. Tweed  Jonathan L. Carrivick 《Geology Today》2015,31(3):96-102

Glaciers and ice sheets are important constituents of the Earth's land surface. Current worldwide retreat of glaciers has implications for the environment and for civilisation. There are a range of geomorphic changes occurring in cold environments and it is anticipated that these will be accentuated as a consequence of climate change. In particular, the number and size of proglacial lakes is currently increasing as a result of deglaciation and their significance for the physical environment and for society is becoming increasingly apparent. This article provides an overview of the major interdependent relationships between climate change, glaciers and proglacial lake development. In particular, it describes the key processes and impacts associated with proglacial lake evolution with reference to examples drawn from the European Alps, North America, the Himalayas, the Andes, Greenland, New Zealand and Iceland.  相似文献   

Passive oil collection device     

Vitaly Vodyanoy  Oleg Pustovyy  Timothy Moore  Kenney Brock 《Environmental Earth Sciences》2013,70(4):1753-1763

A novel, efficient, economical oil collection device, which recovers oils from surface waters using physical principles has been demonstrated. This method has never been used in oil skimmers. The device contains a water-filled vessel open at one end that is positioned above the spilled oil so that the oil entrance opening is leveled with the oil layer on the water surface. The oil moves upward into the vessel displacing the water due to the lower density of the oil. The device has no moving parts. Torricelli’s discovery and Pascal’s law govern containment of the liquid in the vessel above the water level, while Archimedes’ buoyancy force moves oil in the vessel. A collection of thick and thin oil layers on calm water has been shown. This device is very durable, environmentally friendly, recovers pure oil, emits no noise, no pollution, and capable of producing a broad economic impact in the oil clean-up industry by protecting health, life, and the environment.  相似文献   

Flood and megaflood processes and deposits: recent and ancient examples,I. P. Martini,V. R. Baker and G. Garzón (eds), Special Publication 32, of the International Association of Sedimentologists,Blackwell Science,Oxford 2002 (312 pp) ISBN 0 632 06404 8     

Fiona S. Tweed 《第四纪科学杂志》2003,18(2):193-194

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Spatial and temporal perspectives on spring break‐up flooding in the Slave River Delta,NWT     

B. E. Brock  B. B. Wolfe  T. W. D. Edwards 《水文研究》2008,22(20):4058-4072

Spatial and temporal patterns of spring break‐up flooding in the Slave River Delta (SRD), Northwest Territories, are characterized during three years (2003–2005) using water isotope tracers and total inorganic suspended sediment (TSS) concentrations measured from lakewater samples collected shortly after the spring melt. Strongly contrasting spring melt periods led to a moderate flood in 2003, no flooding in 2004 and widespread flooding in 2005. Flooded lakes have isotopically‐depleted δ¹⁸O (δ²H) signatures, ranging between ? 19·2‰ (?145‰) and ? 17·1‰ (?146‰) and most have high TSS concentrations (>10 mg L^?1), while non‐flooded lakes have more isotopically‐enriched δ¹⁸O (δ²H) signatures, ranging between ? 18·2‰ (?149‰) and ? 10·6‰ (?118‰) and low TSS concentrations (<10 mg L^?1). These results, in conjunction with the isotopic signatures of Slave River water and snowmelt, are used to estimate the proportion of river‐ or snowmelt‐induced dilution in delta lakes during the spring of each study year. Calculations indicate river flooding caused dilution of ～70–100% in delta lakes, while snowmelt dilution in the absence of river flooding ranged from ～0–56%. A positive relationship exists between the spatial extent of spring flooding in the SRD and level and discharge on the Slave River and upstream tributaries, suggesting that upstream flow generation plays a key role in determining the magnitude of spring flooding in the SRD. Parallel variations in the 46‐year instrumental Slave River discharge record and flood stratigraphy in the active delta indicate that there is potential for extending the flood history of the SRD, a development that will contribute to a more robust understanding of the drivers of historic, contemporary and future flood frequency in the delta. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

A Comparison of Awareness,Attitudes, and Usage of Water Quality Conservation Practices Between Amish and Non-Amish Farmers     

Jessica D. Ulrich-Schad  Caroline Brock  Linda S. Prokopy 《社会与自然资源》2017,30(12):1476-1490

This study provides a unique examination of Amish farmers’ awareness of water quality issues and their attitudes toward and use of agricultural conservation practices compared with small non-Amish farmers in Northeastern Indiana. There is minimal research about the conservation beliefs and behaviors of this growing and highly diverse ethnoreligious minority, who have faith-based technological restrictions and are often hesitant to work with community outsiders, especially the government. We find that, compared with non-Amish farmers, Amish farmers have limited awareness of the linkages between common agricultural practices and broader water quality problems and lower levels of adoption of conservation practices, with the exception of cover crops. This information is essential for conservation practitioners who need to work with a diverse range of agricultural producers to increase the uptake of conservation practices that address critical water quality concerns.  相似文献   

Secular variations in seawater chemistry controlling dolomitization in shallow reflux systems: insights from reactive transport modelling          下载免费PDF全文

Tatyana Gabellone  Fiona Whitaker 《Sedimentology》2016,63(5):1233-1259

Dolomitization often plays a critical role in the pore network development of platform carbonates, with implications for reservoir quality distribution. Understanding both the hydrological system driving dolomitization and the chemistry of the fluids involved is fundamental to constrain predictions of the geometry and the petrophysical properties of dolomite bodies. Here, the role of secular variations in seawater Mg/Ca as a control on dolomitization and early porosity modification was evaluated using one‐dimensional reactive transport models and fluids based on modern (aragonite sea), Mississippian and Aptian (calcite sea) seawaters. The sensitivity of dolomitization to a range of extrinsic controls (brine salinity, temperature, fluid flow rate and pCO₂) and to intrinsic reactivity of the sediments (effective reactive surface area) was also explored. Simulations suggest faster calcite replacement by dolomite for seawaters with higher Mg/Ca, indicating that dolomitization potential is determined more by Mg/Ca rather than saturation index. Increasing evaporative concentration enhances reaction rate independent of the effect of enhanced density‐driven fluid flux. In addition to brine composition, effective surface area of precursor sediments and temperature exert a critical control on replacement rate, while secular variations of pH and carbonate alkalinity associated with changes in pCO₂ are only secondary controls. Above flow rates of 0·01 m yr^?1 replacive dolomitization is reaction‐limited rather than flux limited, favouring alteration of fine‐grained carbonates and suggesting that preferential alteration of grainstone units is rare unless head gradients are low. Post‐replacement dolomite cementation is flux dependent, and thus favoured in areas of high head gradient and high permeability sediments and, contrary to replacement, supersaturation is a more important driver than Mg/Ca. While uncertainties remain regarding low‐temperature dolomitization kinetics, the capability of numerical simulations to decouple individual controls provides new insights which can be used, in conjunction with traditional comparative sedimentology, to generate more rigorous conceptual models for individual reservoir settings.  相似文献