Evaluating Subsurface Parameterization to Simulate Hyporheic Exchange: The Steinlach River Test Site     

Reynold Chow  Jeremy Bennett  Jürnjakob Dugge  Thomas Wöhling  Wolfgang Nowak 《Ground water》2020,58(1):93-109

Hyporheic exchange is the interaction of river water and groundwater, and is difficult to predict. One of the largest contributions to predictive uncertainty for hyporheic exchange has been attributed to the representation of heterogeneous subsurface properties. Our study evaluates the trade-offs between intrinsic (irreducible) and epistemic (reducible) model errors when choosing between homogeneous and highly complex subsurface parameter structures. We modeled the Steinlach River Test Site in Southwest Germany using a fully coupled surface water-groundwater model to simulate hyporheic exchange and to assess the predictive errors and uncertainties of transit time distributions. A highly parameterized model was built, treated as a “virtual reality” and used as a reference. We found that if the parameter structure is too simple, it will be limited by intrinsic model errors. By increasing subsurface complexity through the addition of zones or heterogeneity, we can begin to exchange intrinsic for epistemic errors. Thus, the appropriate level of detail to represent the subsurface depends on the acceptable range of intrinsic structural errors for the given modeling objectives and the available site data. We found that a zonated model is capable of reproducing the transit time distributions of a more detailed model, but only if the geological structures are known. An interpolated heterogeneous parameter field (cf. pilot points) showed the best trade-offs between the two errors, indicating fitness for practical applications. Parameter fields generated by multiple-point geostatistics (MPS) produce transit time distributions with the largest uncertainties, however, these are reducible by additional hydrogeological data, particularly flux measurements.  相似文献   

Improving sustainability of urban drainage systems for climate change adaptation using best management practices: a case study of Tehran,Iran     

Negin Binesh  Amin Sarang  Wolfgang Rauch 《水文科学杂志》2019,64(4):381-404

Although the effectiveness of best management practices (BMPs) in reducing urban flooding is widely recognized, the improved sustainability achieved by implementing BMPs in upstream suburban areas, reducing downstream urban floods, is still debated. This study introduces a new definition of urban drainage system (UDS) sustainability, focusing on BMP usage to enhance system performance after adaptation to climate change. Three types of hydraulic reliability index (HRI) plus robustness and improvability indices were used to quantify the potential enhanced sustainability of the system in a changing climate, together with a climate change adaptability index (CCAI). The sustainability of UDS for the safe conveyance of storm-water runoff was investigated under different land-use scenarios: No BMP, BMP in urban areas, and BMP inside and upstream of urban areas, considering climate change impacts. Rainfall–runoff simulation alongside drainage network modelling was conducted using a storm-water management model (US EPA SWMM) to determine the inundation areas for both base-line and future climatic conditions. A new method for disaggregating daily rainfall to hourly, proposed to provide a finer resolution of input rainfall to SWMM, was applied to a semi-urbanized catchment whose upstream runoff from mountainous areas may contribute to the storm-water runoff in downstream urban parts. Our findings confirm an increase in the number of inundation points and reduction in sustainability indices of UDS due to climate change. The results present an increase in UDS reliability from 4% to 16% and improvements in other sustainability indicators using BMPs in upstream suburban areas compared to implementing them in urban areas.  相似文献   

Dynamics and driving mechanisms of asymmetric human water consumption during alternating wet and dry periods   总被引：1，自引：1，他引：0  

Fuqiang Tian  You Lu  Hongchang Hu  Wolfgang Kinzelbach  Murugesu Sivapalan 《水文科学杂志》2019,64(5):507-524

Increases in human water consumption (HWC) and consequent degradation of the ecological environment are common in arid regions. Understanding the mechanisms behind these processes is important for sustainable development. Analyses of changes in HWC between alternating wet and dry periods are carried out in four arid inland basins in Central Asia and China (Syr Darya, Tarim, Heihe and Shulehe river basins). Based on runoff records, the presence of an asymmetric HWC response is proved (p < 0.01), with an increase in HWC during wet periods and a muted decrease during subsequent dry periods. This behaviour is interpreted by invoking theories from behavioural economics at the individual and community levels. A simple model based on these theories is shown to be able to reproduce the observed dynamics and is used to discuss the importance of strengthening institutional factors for water sustainability.  相似文献   

The Austrian node of the natural resources satellite remote sensing cloud service platform:examples of Sino-Austrian cooperation     

Wolfgang Kainz  Xinming Tang  Yucai Xue 《地球空间信息科学学报》2021,24(1):145-151

The Austrian node of the Natural Resources Satellite Remote Sensing Cloud Service Platform was established in 2016 through a cooperation agreement between the Land Satellite Remote Sensing Application Center(LASAC),Ministry of Natural Resources of the Peoples Republic of China and the University of Vienna,Austria.Under this agreement panchromatic and multi-spectral data of the Chinese ZY-3 satellite are pushed to the server at the University of Vienna for use in education and research.So far,nearly 500 GB of data have been uploaded to the server.This technical note briefly introduces the ZY-3 system and illustrates the implementation of the agreement by the first China-Sat Workshop and several case studies.Some of them are already completed,others are still ongoing.They include a geometric accuracy validation of ZY-3 data,an animated visualization of image quick views on a spherical display to demonstrate the time series of the image coverage for Austria and Laos,and the use of ZY-3 data to study the spread of bark beetle in the province of Lower Austria.An accuracy study of DTMs from ZY-3 stereo data,as well as a land cover analysis and comparison of Austria with ZY-3 and other sensors are still ongoing.  相似文献   

Late Cambrian deformation in the Lesser Himalaya     

Om N. Bhargava  Wolfgang Frank  Rufus Bertle 《Journal of Asian Earth Sciences》2011,40(1):201-212

The Tons Valley, situated in the central-easternmost part of the Himachal Lesser Himalaya, adjoining the Garhwal Himalaya, shows geological features suggestive of a strong pre-Tertiary deformational episode. The Paleoproterozoic Dharagad Group, overlain by the Mesoproterozoic Deoban and Neoproterozoic Simla groups rest as a thrust sheet over the Middle Cambrian Chilar Formation, which occurs as windows and also as tectonic slivers within the thrust sheet designated as the Dharagad Thrust Sheet (DTS). The mineral lineation, inclination of tectonic slivers and overturned beds suggest that the DTS was translated from the NE. The westernmost and southwesternmost leading edges of the DTS are exposed at Subathu and Morni WNW and WSW respectively of the Tons Valley. The position of the leading edges of the DTS vis-à-vis the windows in the Tons Valley suggest a minimum translation of about 50 km for the DTS. The Simla Group at Subathu and the Deoban at Morni, forming parts of the DTS, constitute basement for the Thanetian–Lutetian Subathu Formation of the Himalayan Foreland Basin (HFB). This stratigraphic relationship unambiguously demonstrates that the Simla and the Deoban Groups, forming leading edges of the allochthonous DTS, were already translated and emplaced at Subathu and Morni before the creation of the HFB in which the deposition commenced with the Subathu Formation in Thanetian. It implies that the DTS was translated from the NE to the present position at Subathu and Morni in pre-Thanetian time. There is no direct evidence to constrain the age of the thrusting.In view of regional regression in Late Cambrian, a distinct angular unconformity between the Cambrian and the overlying Ordovician, Early Paleozoic metamorphism and extensive development of Early Paleozoic granites and their rapid exhumation, a Late Cambrian age is suggested for the DTS thrusting. Not only the direction of movement of the DTS is same as that of the Tertiary thrust sheets but also Cambrian folds are co-axial with the Tertiary folds. This strange coincidence shows that similar kinematic field existed during two tectonic events. A ridge, like the present Central Crystalline Axis, was elevated between the Tethyan and Lesser Himalayan basins, which contributed zircons of the Early Cambrian age to both basins.  相似文献   

A stochastically and spatially adaptive parallel scheme for uncertain and nonlinear two-phase flow problems     

Ilja Kröker  Wolfgang Nowak  Christian Rohde 《Computational Geosciences》2015,19(2):269-284

  相似文献   

Ductile to brittle fault zone evolution in Austroalpine units to the southeast of the Tauern Window (Eastern Alps)     

Andreas Wölfler  Wolfgang Frisch  Harald Fritz  Martin Danišik  Anke Wölfler 《Swiss Journal of Geoscience》2015,108(2-3):239-251

  相似文献   

Catabolic and anabolic energy for chemolithoautotrophs in deep-sea hydrothermal systems hosted in different rock types     

Jan P. Amend  Thomas M. McCollom  Wolfgang Bach 《Geochimica et cosmochimica acta》2011,75(19):5736-5748

Active deep-sea hydrothermal vents are hosted by a range of different rock types, including basalt, peridotite, and felsic rocks. The associated hydrothermal fluids exhibit substantial chemical variability, which is largely attributable to compositional differences among the underlying host rocks. Numerical models were used to evaluate the energetics of seven inorganic redox reactions (potential catabolisms of chemolithoautotrophs) and numerous biomolecule synthesis reactions (anabolism) in a representative sampling of these systems, where chemical gradients are established by mixing hydrothermal fluid with seawater. The wide ranging fluid compositions dictate demonstrable differences in Gibbs energies (ΔG_r) of these catabolic and anabolic reactions in three peridotite-hosted, six basalt-hosted, one troctolite-basalt hybrid, and two felsic rock-hosted systems. In peridotite-hosted systems at low to moderate temperatures (<∼45 °C) and high seawater:hydrothermal fluid (SW:HF) mixing ratios (>10), hydrogen oxidation yields the most catabolic energy, but the oxidation of methane, ferrous iron, and sulfide can also be moderately exergonic. At higher temperatures, and consequent SW:HF mixing ratios <10, anaerobic processes dominate the energy landscape; sulfate reduction and methanogenesis are more exergonic than any of the aerobic respiration reactions. By comparison, in the basalt-hosted and felsic rock-hosted systems, sulfide oxidation was the predominant catabolic energy source at all temperatures (and SW:HF ratios) considered. The energetics of catabolism at the troctolite-basalt hybrid system were intermediate to these extremes. Reaction energetics for anabolism in chemolithoautotrophs—represented here by the synthesis of amino acids, nucleotides, fatty acids, saccharides, and amines—were generally most favorable at moderate temperatures (22-32 °C) and corresponding SW:HF mixing ratios (∼15). In peridotite-hosted and the troctolite-basalt hybrid systems, ΔG_r for primary biomass synthesis yielded up to ∼900 J per g dry cell mass. The energetics of anabolism in basalt- and felsic rock-hosted systems were far less favorable. The results suggest that in peridotite-hosted (and troctolite-basalt hybrid) systems, compared with their basalt (and felsic rock) counterparts, microbial catabolic strategies—and consequently variations in microbial phylotypes—may be far more diverse and some biomass synthesis may yield energy rather than imposing a high energetic cost.  相似文献   

Diet of Haplognathia ruberrima (Gnathostomulida) in a Caribbean marine mangrove          下载免费PDF全文

Pierre‐Yves Pascal  Claude Bellemare  Wolfgang Sterrer  Henricus T. S. Boschker  Silvina Gonzalez‐Rizzo  Olivier Gros 《Marine Ecology》2015,36(2):246-257

Haplognathia ruberrima is a cosmopolitan gnathostomulid species found in sulfur bacterial mats in mangroves in Guadeloupe (French West Indies). Haplognathia ruberrima presents a δ¹³C value lower than all measured meiofaunal grazers and lower than the available measured food sources of this environment. This low δ¹³C value can not be due to specific ingestion of ¹³C‐depleted methanogenic bacteria because abundances of those bacteria are reduced in surficial and deep sediments as revealed by δ¹³C of bacterial fatty acid. According to scanning electron microscope observations, no bacterial ectosymbionts were observed at the surface of the gnathostomulids, and transmission electron microscope views revealed the absence of bacterial endosymbionts. Energy‐dispersive X‐ray spectroscopy analysis detected low levels of sulfur (0.32%±0.8) in biological tissues of H. ruberrima, confirming the absence of thioautotrophic bacterial symbionts in these animals. Consequently, the low δ¹³C value of H. ruberrima can not be due to the presence of sulfur‐oxidizing symbionts but more probably to the selective and exclusive consumption of free‐living, sulfur‐oxidizing bacteria.  相似文献   

Late Pleistocene outburst floods from Issyk Kul,Kyrgyzstan?          下载免费PDF全文

Swenja Rosenwinkel  Angela Landgraf  Wolfgang Schwanghart  Friedrich Volkmer  Atyrgul Dzhumabaeva  Silke Merchel  Georg Rugel  Frank Preusser  Oliver Korup 《地球表面变化过程与地形》2017,42(10):1535-1548

Elevated shorelines and lake sediments surrounding Issyk Kul, the world's second largest mountain lake, record fluctuating lake levels during Quaternary times. Together with bathymetric and geochemical data, these markers document alternating phases of lake closure and external drainage. The uppermost level of lake sediments requires a former damming of the lake's western outlet through the Boam gorge. We test previous hypothesised ice or landslide dam failures by exploring possible links between late Quaternary lake levels and outbursts. We review and recompile the chronology of reported changes in lake site, and offer new ages of abandoned shorelines using ¹⁴C in bivalve and gastropod shells, and plant detritus, as well as sand lenses in delta and river sediments using Infrared Stimulated Luminescence. Our dates are consistent with elevated lake levels between ~45 ka and 22 ka. Cosmogenic ¹⁰Be and ²⁶Al exposure ages of fan terraces containing erratic boulders (>3 m) downstream of the gorge constrain the timing of floods to 20.5–18.5 ka, postdating a highstand of Issyk Kul. A flow‐competence analysis gives a peak discharge of >10⁴ m³ s^–1 for entraining and transporting these boulders. Palaeoflood modelling, however, shows that naturally dammed lakes unconnected to Issyk Kul could have produced such high discharges upon sudden emptying. Hence, although our data are consistent with hypotheses of catastrophic outburst floods, average lake‐level changes of up to 90 mm yr^–1 in the past 150 years were highly variable without any outbursts, so that linking lake‐level drops to catastrophic dam breaks remains ambiguous using sedimentary archives alone. This constraint may readily apply to other Quaternary lakes of that size elsewhere. Nonetheless, our reconstructed Pleistocene floods are among the largest reported worldwide, and motivate further research into the palaeoflood hydrology of Central Asia. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献