Ensemble modelling of ice cover for a reservoir affected by pumped‐storage operation and climate change     

Ulrike Gabriele Kobler  Martin Schmid 《水文研究》2019,33(20):2676-2690

Ensemble modelling was used to assess the robustness of projected impacts of pumped‐storage (PS) operation and climate change on reservoir ice cover. To this end, three one‐dimensional and a two‐dimensional laterally averaged hydrodynamic model were set up. For the latter, the strength of the impacts with increasing distance from the dam was also investigated. Climate change effects were simulated by forcing the models with 150 years of synthetic meteorological time series created with a weather generator based on available air temperature scenarios for Switzerland. Future climate by the end of the 21^st century was projected to shorten the ice‐covered period by ~2 months and decrease ice thicknesses by ~13 cm. Under current climate conditions, the ice cover would already be affected by extended PS operation. For example, the average probability of ice coverage on a specific day was projected to decrease by ~13% for current climate and could further be reduced from ~45% to ~10% for future climate. Overall, the results of all models were consistent. Although the number of winters without ice cover was projected to increase for all one‐dimensional models, studying individual segments of the two‐dimensional model showed that the impact was pronounced for segments close to the PS intake/outlet. In summary, the reservoir's ice cover is expected to partially vanish with higher probability of open water conditions closer to the PS intake/outlet.  相似文献   

Combined effects of pumped-storage operation and climate change on thermal structure and water quality     

Kobler  Ulrike Gabriele  Wüest  Alfred  Schmid  Martin 《Climatic change》2019,152(3-4):413-429

Climatic Change - The assessment of ecological impacts of pumped-storage (PS) hydropower plants on the two connected water bodies is usually based on present climatic conditions. However,...  相似文献   

The history of subaquatic volcanism recorded in the sediments of Lake Kivu; East Africa     

Kelly Ann Ross  Martin Schmid  Sandra Ogorka  Fabrice A. Muvundja  Flavio S. Anselmetti 《Journal of Paleolimnology》2015,54(1):137-152

  相似文献   

3-D assessment of peak-metamorphic conditions by Raman spectroscopy of carbonaceous material: an example from the margin of the Lepontine dome (Swiss Central Alps)   总被引：2，自引：0，他引：2  

Michael Wiederkehr  Romain Bousquet  Martin A. Ziemann  Alfons Berger  Stefan M. Schmid 《International Journal of Earth Sciences》2011,100(5):1029-1063

This study monitors regional changes in the crystallinity of carbonaceous matter (CM) by applying Micro-Raman spectroscopy to a total of 214 metasediment samples (largely so-called Bündnerschiefer) dominantly metamorphosed under blueschist- to amphibolite-facies conditions. They were collected within the northeastern margin of the Lepontine dome and easterly adjacent areas of the Swiss Central Alps. Three-dimensional mapping of isotemperature contours in map and profile views shows that the isotemperature contours associated with the Miocene Barrow-type Lepontine metamorphic event cut across refolded nappe contacts, both along and across strike within the northeastern margin of the Lepontine dome and adjacent areas. Further to the northeast, the isotemperature contours reflect temperatures reached during the Late Eocene subduction-related blueschist-facies event and/or during subsequent near-isothermal decompression; these contours appear folded by younger, large-scale post-nappe-stacking folds. A substantial jump in the recorded maximum temperatures across the tectonic contact between the frontal Adula nappe complex and surrounding metasediments indicates that this contact accommodated differential tectonic movement of the Adula nappe with respect to the enveloping Bündnerschiefer after maximum temperatures were reached within the northern Adula nappe, i.e. after Late Eocene time.  相似文献   

Northwest Africa 11024—A heated and dehydrated unique carbonaceous (CM) chondrite     

Samuel Ebert  Addi Bischoff  Dennis Harries  Sarah Lentfort  Jean‐Alix Barrat  Andreas Pack  Jrme Gattacceca  Robbin Visser  Peter Schmid‐Beurmann  Stephan Kimpel 《Meteoritics & planetary science》2019,54(2):328-356

Based on the high abundance of fine‐grained material and its dark appearance, NWA 11024 was recognized as a CM chondrite, which is also confirmed by oxygen isotope measurements. But contrary to known CM chondrites, the typical phases indicating aqueous alteration (e.g., phyllosilicates, carbonates) are missing. Using multiple analytical techniques, this study reveals the differences and similarities to known CM chondrites and will discuss the possibility that NWA 11024 is the first type 3 CM chondrite. During the investigation, two texturally apparent tochilinite–cronstedtite intergrowths were identified within two thin sections. However, the former phyllosilicates were recrystallized to Fe‐rich olivine during a heating event without changing the textural appearance. A peak temperature of 400–600 °C is estimated, which is not high enough to destroy or recrystallize calcite grains. Thus, calcites were never constituents of the mineral paragenesis. Another remarkable feature of NWA 11024 is the occurrence of unknown clot‐like inclusions (UCLIs) within fine‐grained rims, which are unique in this clarity. Their density and S concentration are significantly higher than of the surrounding fine‐grained rim and UCLIs can be seen as primary objects that were not formed by secondary alteration processes inside the rims. Similarities to chondritic and cometary interplanetary dust particles suggest an ice‐rich first‐generation planetesimal for their origin. In the earliest evolution, NWA 11024 experienced the lowest degree of aqueous alteration of all known CM chondrites and subsequently, a heating event dehydrated the sample. We suggest to classify the meteorite NWA 11024 as the first type 3 CM chondrite similar to the classification of CV3 chondrites (like Allende) that could also have lost their matrix phyllosilicates by thermal dehydration.  相似文献   

The Late Cretaceous Klepa basalts in Macedonia (FYROM)—Constraints on the final stage of Tethys closure in the Balkans          下载免费PDF全文

Dejan Prelević  Simon Wehrheim  Magnus Reutter  Rolf L. Romer  Blažo Boev  Milica Božović  Paul van den Bogaard  Vladica Cvetković  Stefan M. Schmid 《地学学报》2017,29(3):145-153

The waning stage(s) of the Tethyan ocean(s) in the Balkans are not well understood. Controversy centres on the origin and life‐span of the Cretaceous Sava Zone, which is allegedly a remnant of the last oceanic domain in the Balkan Peninsula, defining the youngest suture between Eurasia‐ and Adria‐derived plates. In order to investigate to what extent Late‐Cretaceous volcanism within the Sava Zone is consistent with this model we present new age data together with trace‐element and Sr–Nd–Pb isotope data for the Klepa basaltic lavas from the central Balkan Peninsula. Our new geochemical data show marked differences between the Cretaceous Klepa basalts (Sava Zone) and the rocks of other volcanic sequences from the Jurassic ophiolites of the Balkans. The Klepa basalts mostly have Sr–Nd–Pb isotopic and trace‐element signatures that resemble enriched within‐plate basalts substantially different from Jurassic ophiolite basalts with MORB, BAB and IAV affinities. Trace‐element modelling of the Klepa rocks indicates 2%–20% polybaric melting of a relatively homogeneously metasomatised mantle source that ranges in composition from garnet lherzolite to ilmenite+apatite bearing spinel–amphibole lherzolite. Thus, the residual mineralogy is characteristic of a continental rather than oceanic lithospheric mantle source, suggesting an intracontinental within‐plate origin for the Klepa basalts. Two alternative geodynamic models are internally consistent with our new findings: (1) if the Sava Zone represents remnants of the youngest Neotethyan Ocean, magmatism along this zone would be situated within the forearc region and triggered by ridge subduction; (2) if the Sava Zone delimits a diffuse tectonic boundary between Adria and Europe which had already collided in the Late Jurassic, the Klepa basalts together with a number of other magmatic centres represent volcanism related to transtensional tectonics.  相似文献   

Consistent realization of Celestial and Terrestrial Reference Frames     

Younghee Kwak  Mathis Bloßfeld  Ralf Schmid  Detlef Angermann  Michael Gerstl  Manuela Seitz 《Journal of Geodesy》2018,92(9):1047-1061

The Celestial Reference System (CRS) is currently realized only by Very Long Baseline Interferometry (VLBI) because it is the space geodetic technique that enables observations in that frame. In contrast, the Terrestrial Reference System (TRS) is realized by means of the combination of four space geodetic techniques: Global Navigation Satellite System (GNSS), VLBI, Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite. The Earth orientation parameters (EOP) are the link between the two types of systems, CRS and TRS. The EOP series of the International Earth Rotation and Reference Systems Service were combined of specifically selected series from various analysis centers. Other EOP series were generated by a simultaneous estimation together with the TRF while the CRF was fixed. Those computation approaches entail inherent inconsistencies between TRF, EOP, and CRF, also because the input data sets are different. A combined normal equation (NEQ) system, which consists of all the parameters, i.e., TRF, EOP, and CRF, would overcome such an inconsistency. In this paper, we simultaneously estimate TRF, EOP, and CRF from an inter-technique combined NEQ using the latest GNSS, VLBI, and SLR data (2005–2015). The results show that the selection of local ties is most critical to the TRF. The combination of pole coordinates is beneficial for the CRF, whereas the combination of \(\varDelta \hbox {UT1}\) results in clear rotations of the estimated CRF. However, the standard deviations of the EOP and the CRF improve by the inter-technique combination which indicates the benefits of a common estimation of all parameters. It became evident that the common determination of TRF, EOP, and CRF systematically influences future ICRF computations at the level of several \(\upmu \)as. Moreover, the CRF is influenced by up to \(50~\upmu \)as if the station coordinates and EOP are dominated by the satellite techniques.  相似文献   

Composition and pre-metamorphic geodynamic setting of the ultrahigh-pressure metabasic rocks from Dabie Shan,E-China     

U. Altenberger  R. Schmid  R. Oberhänsli 《International Journal of Earth Sciences》2008,97(6):1301-1314

As part of the Yangtze plate, segments of the Dabie Shan terrane of Central China underwent ultra-high pressure metamorphism during Triassic subduction. We studied the geochemistry of the abundant eclogites to evaluate the nature of the protoliths and their geodynamic setting. Although some previous geochemical work exists, the analyses and interpretation herein are based on a new subdivision of the ultra-high pressure sequence into basement and cover units (Changpu and Ganghe Unit), revealing new and important results. In addition, eclogites of the so-called HP Unit south of the UHP units were studied. Whereas the large ion lithophile elements indicate postmagmatic, metasomatic changes of some samples, the high-field strength elements and the rare earth elements display original magmatic trends. The geochemical characteristics of the eclogites of the ultra-high pressure areas display a strong dependence on their “structural” and geographic position. The eclogites of the basement and the Changpu Unit indicate melt intrusion and extrusion in a continental rift system, i.e. during extensional tectonics. In contrast, the Ganghe Unit is characterized by a pronounced chemical homogeneity. The composition of the eclogites indicates generation from a mantle source highly influenced by slab-derived fluids. Those of the HP Unit show similar characteristics. Magmatism of the Ganghe and HP Unit probably occurred in a continental arc setting. A similar age for both units, geographically and/or tectonically separated, is possible. The geodynamic interpretation based on the geochemistry of the four units points to a Neoproterozoic scenario in which the protoliths of the HP and the cover units could have been of similar age and deposited in one evolving geological system. A rift-related larger-scale basin might have formed, e.g. a continental back-arc basin behind a magmatic arc after or simultaneous to sedimentation and magmatism in the magmatic arc. Alternatively, magmatism occurred in independent geodynamic settings, distinct in time and space. The units were juxtaposed during exhumation, after subduction to varying depths.  相似文献   

Absolute IGS antenna phase center model igs08.atx: status and potential improvements     

R. Schmid  R. Dach  X. Collilieux  A. Jäggi  M. Schmitz  F. Dilssner 《Journal of Geodesy》2016,90(4):343-364

  相似文献   

Seepage flow in extremely thin aquifers     

Günther Schmid 《Advances in water resources》1981,4(3):134-136

  相似文献