Linkage between acoustic parameters and seabed sediment properties in the south-western Baltic Sea     

Michael Endler  Rudolf Endler  Bernd Bobertz  Thomas Leipe  Helge W. Arz 《Geo-Marine Letters》2015,35(2):145-160

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Damaging hailstorms in South Moravia,Czech Republic,in the seventeenth to twentieth centuries as derived from taxation records     

Rudolf Brázdil  Kateřina Chromá  Hubert Valášek  Lukáš Dolák  Ladislava Řezníčková 《Theoretical and Applied Climatology》2016,123(1-2):185-198

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Long-term persistence enhances uncertainty about anthropogenic warming of Antarctica   总被引：1，自引：0，他引：1  

Josef Ludescher  Armin Bunde  Christian L. E. Franzke  Hans Joachim Schellnhuber 《Climate Dynamics》2016,46(1-2):263-271

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Annual precipitation variation for the southern edge of the Gobi Desert (China) inferred from tree rings: linkages to climatic warming of twentieth century     

Feng Chen  Yujiang Yuan  Tongwen Zhang  Hans W. Linderholm 《Natural Hazards》2016,81(2):939-955

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Assessment of small-diameter shallow wells for managed aquifer recharge at a site in southern Styria,Austria     

Falk Händel  Gaisheng Liu  Johann Fank  Franz Friedl  Rudolf Liedl  Peter Dietrich 《Hydrogeology Journal》2016,24(8):2079-2091

An approach to establish the recharge component of managed aquifer recharge (MAR) has recently been proposed that uses small-diameter shallow wells installed using relatively inexpensive drilling methods such as direct push. As part of further development of that approach, a generalized procedure is presented for a technical and economic assessment of the approach’s potential in comparison to other systems. Following this procedure, the use of small-diameter wells was evaluated both experimentally and numerically for a site located in southern Styria, Austria. MAR is currently done at the site using a horizontal pipe infiltration system, and system expansion has been proposed with a target rate of 12 l/s using small-diameter wells as one possible option. A short-duration single-well field recharge experiment (recharge rate 1.3–3.5 l/s) was performed (recharge by gravity only). Numerical modeling of the injection test was used to estimate hydraulic conductivity (K). Quasi-steady-state, single-well recharge simulations for different locations, as well as a long-term transient simulation, were performed using the K value calibrated from the field injection test. Results indicate that a recharge capacity of 4.1 l/s was achievable with a maximum head rise of 0.2 m at the injection well. Finally, simulations were performed for three different well fields (4, 6 and 8 wells, respectively) designed to infiltrate a target rate of 12 l/s. The experimental and numerical assessments, supported by a cost analysis of the small-diameter wells, indicate that the small-diameter wells are a viable, cost-effective recharge approach at this and other similar sites.  相似文献   

Double trouble: subsidence and CO<Subscript>2</Subscript> respiration due to 1,000 years of Dutch coastal peatlands cultivation     

Gilles Erkens  Michiel J. van der Meulen  Hans Middelkoop 《Hydrogeology Journal》2016,24(3):551-568

Coastal plains are amongst the most densely populated areas in the world. Many coastal peatlands are drained to create arable land. This is not without consequences; physical compaction of peat and its degradation by oxidation lead to subsidence, and oxidation also leads to emissions of carbon dioxide (CO₂). This study complements existing studies by quantifying total land subsidence and associated CO₂ respiration over the past millennium in the Dutch coastal peatlands, to gain insight into the consequences of cultivating coastal peatlands over longer timescales. Results show that the peat volume loss was 19.8 km³, which lowered the Dutch coastal plain by 1.9 m on average, bringing most of it below sea level. At least 66 % of the volume reduction is the result of drainage, and 34 % was caused by the excavation and subsequent combustion of peat. The associated CO₂ respiration is equivalent to a global atmospheric CO₂ concentration increase of ~0.39 ppmv. Cultivation of coastal peatlands can turn a carbon sink into a carbon source. If the path taken by the Dutch would be followed worldwide, there will be double trouble: globally significant carbon emissions and increased flood risk in a globally important human habitat. The effects would be larger than the historic ones because most of the cumulative Dutch subsidence and peat loss was accomplished with much less efficient techniques than those available now.  相似文献   

Wetland Loss,Juvenile Salmon Foraging Performance,and Density Dependence in Pacific Northwest Estuaries     

Aaron T. David  Charles A. Simenstad  Jeffery R. Cordell  Jason D. Toft  Christopher S. Ellings  Ayesha Gray  Hans B. Berge 《Estuaries and Coasts》2016,39(3):767-780

During the transition of juveniles from fresh water to estuarine and coastal environments, the survival of Pacific salmon (Oncorhynchus spp.) can be strongly size selective and cohort abundance is partly determined at this stage. Because quantity and quality of food influence juvenile salmon growth, high rates of prey and energy acquisition during estuarine residence are important for survival. Human activities may have affected the foraging performance of juvenile salmon in estuaries by reducing the area of wetlands and by altering the abundance of salmon. To improve our understanding of the effects of wetland loss and salmon density on juvenile salmon foraging performance and diet composition in estuaries, we assembled Chinook salmon (Oncorhynchus tshawytscha) diet and density data from nine US Pacific Northwest estuaries across a gradient of wetland loss. We evaluated the influence of wetland loss and density on juvenile Chinook salmon instantaneous ration and energy ration, two measures of foraging performance, and whether the effect of density varied among estuaries with different levels of wetland loss. We also assessed the influence of wetland loss and other explanatory variables on salmon diet composition. There was no evidence of a direct effect of wetland loss on juvenile salmon foraging performance, but wetland loss appeared to mediate the effect of density on salmon foraging performance and alter salmon diet composition. Specifically, density had no effect on foraging performance in the estuaries with less than 50 % wetland loss but had a negative effect on foraging performance in the estuaries with greater than 50 % wetland loss. These results suggest that habitat loss may interact with density to constrain the foraging performance of juvenile Chinook salmon, and ultimately their growth, during a life history stage when survival can be positively correlated with growth and size.  相似文献   

Integration of stress testing with graph theory to assess the resilience of urban road networks under seismic hazards     

Nazli Yonca Aydin  H. Sebnem Duzgun  Friedemann Wenzel  Hans Rudolf Heinimann 《Natural Hazards》2018,91(1):37-68

Transportation networks daily provide accessibility and crucial services to societies. However, they must also maintain an acceptable level of service to critical infrastructures in the case of disruptions, especially during natural disasters. We have developed a method for assessing the resilience of transportation network topology when exposed to environmental hazards. This approach integrates graph theory with stress testing methodology and involves five basic steps: (1) establishment of a scenario set that covers a range of seismic damage potential in the network, (2) assessment of resilience using various graph-based metrics, (3) topology-based simulations, (4) evaluation of changes in graph-based metrics, and (5) examination of resilience in terms of spatial distribution of critical nodes and the entire network topology. Our case study was from the city of Kathmandu in Nepal, where the earthquake on April 25, 2015, followed by a major aftershock on May 12, 2015, led to numerous casualties and caused significant damage. Therefore, it is a good example for demonstrating and validating the developed methodology. The results presented here indicate that the proposed approach is quite efficient and accurate in assisting stakeholders when evaluating the resilience of transportation networks based on their topology.  相似文献   

Intergranular coesite and coesite inclusions in dolomite from the Dabie Shan: Constraints on the preservation of coesite in UHP rocks          下载免费PDF全文

Penglei Liu  Hans‐Joachim Massonne  Junfeng Zhang  Yao Wu  Zhenmin Jin 《地学学报》2017,29(3):154-161

Intergranular coesite is extremely rare in, and bears crucial information on the formation and preservation of, ultrahigh‐pressure (UHP) rocks. Here, we report the first occurrence of intergranular coesite in a metasedimentary rock, which occurs in the Ganjialing area in the Dabie Shan, east‐central China, and contains abundant coesite inclusions in both garnet and dolomite. We investigated the content of structural water in these minerals with Fourier transform infrared spectroscopy. Our new results undermine the ubiquity of the “pressure‐vessel” model and highlight the role of reaction kinetics in preserving coesite due to the availability of water in UHP rocks.  相似文献   

Holocene peatland development and hydrological variability inferred from bog‐pine dendrochronology and peat stratigraphy – a case study from southern Sweden     

Johannes Edvardsson  Hans Linderson  Mats Rundgren  Dan Hammarlund 《第四纪科学杂志》2012,27(6):553-563

Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726‐year ring‐width chronology was developed and assigned an absolute age of 7233–6508 cal a BP (5284–4559 BC) through cross‐dating with German bog‐pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog‐surface wetness. A major establishment phase at 7200–6900 cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog‐pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long‐term palaeoclimatic context. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献