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31.
Landslide susceptibility assessment using the bivariate statistical analysis and the index of entropy in the Sibiciu Basin (Romania) 总被引：13，自引：6，他引：7
Mihaela Constantin Martin Bednarik Marta C. Jurchescu Marius Vlaicu 《Environmental Earth Sciences》2011,63(2):397-406
The Sibiciu Basin is located in Romania between the Buzău Mountains and the Buzau Subcarpathians (Curvature Carpathians and
Subcarpathians). The geology of the basin consists of Paleogene flysch deposits represented by an alternation of sandstones,
marls, clays and schists and Neogene deposits represented by marls, clays and sands. The area is affected by different types
of landslides (shallow, medium-deep and deep-seated failures). In Romania, in the last decades, direct and indirect methods
have been applied for landslide susceptibility assessment. The most utilized before 2000 were based on qualitative approaches.
This study evaluates the landslide susceptibility in the Sibiciu Basin using a bivariate statistical analysis and an index
of entropy. A landslide inventory map was prepared, and a susceptibility estimate was assessed based on the following parameters
which influence the landslide occurrence: slope angle, slope aspect, curvature, lithology and land use. The landslide susceptibility
map was divided into five classes showing very low to very high landslide susceptibility areas. 相似文献
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Torben Koenigk Christof K?nig Beatty Mihaela Caian Ralf D?scher Klaus Wyser 《Climate Dynamics》2012,38(11-12):2389-2408
Decadal prediction is one focus of the upcoming 5th IPCC Assessment report. To be able to interpret the results and to further improve the decadal predictions it is important to investigate the potential predictability in the participating climate models. This study analyzes the upper limit of climate predictability on decadal time scales and its dependency on sea ice albedo parameterization by performing two perfect ensemble experiments with the global coupled climate model EC-Earth. In the first experiment, the standard albedo formulation of EC-Earth is used, in the second experiment sea ice albedo is reduced. The potential prognostic predictability is analyzed for a set of oceanic and atmospheric parameters. The decadal predictability of the atmospheric circulation is small. The highest potential predictability was found in air temperature at 2?m height over the northern North Atlantic and the southern South Atlantic. Over land, only a few areas are significantly predictable. The predictability for continental size averages of air temperature is relatively good in all northern hemisphere regions. Sea ice thickness is highly predictable along the ice edges in the North Atlantic Arctic Sector. The meridional overturning circulation is highly predictable in both experiments and governs most of the decadal climate predictability in the northern hemisphere. The experiments using reduced sea ice albedo show some important differences like a generally higher predictability of atmospheric variables in the Arctic or higher predictability of air temperature in Europe. Furthermore, decadal variations are substantially smaller in the simulations with reduced ice albedo, which can be explained by reduced sea ice thickness in these simulations. 相似文献
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Baseflow separation is important for obtaining critical parameters for hydrological models. As measuring the baseflow component directly is difficult, various analytical and empirical baseflow separation methods have been developed and tested. The recursive digital filter (RDF) method is commonly used for baseflow separation due to its simplicity and low data requirement. However, parameters used in the RDF method are often determined arbitrarily, resulting in high uncertainty of the estimated baseflow rate. A more accurate method is the conductivity mass balance (CMB) method, which is established based on the differences in physical processes between baseflow and surface runoff. In this research, the output of the CMB method was used to calibrate the parameters of an RDF model, and the calibrated RDF model was used to estimate monthly, seasonal and annual baseflow rate and baseflow index for the past 19 years using streamflow discharge records. The characteristics of the baseflow hydrographs were found to be consistent with the hydrological and hydrogeological conditions of the research area. Research results indicated that the accuracy of the RDF model has been greatly enhanced after being calibrated with the CMB method so that the RDF model can provide more reliable baseflow separation results for a long‐term study. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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James M. Dohm Robert C. Anderson Nadine G. Barlow Hirdy Miyamoto Ashley G. Davies G. Jeffrey Taylor Victor R. Baker William V. Boynton John Keller Kris Kerry Daniel Janes Alberto G. Fairn Dirk Schulze-Makuch Mihaela Glamoclija Lucia Marinangeli Gian G. Ori Robert G. Strom Jean-Pierre Williams Justin C. Ferris J.A.P. Rodríguez Miguel A. de Pablo Suniti Karunatillake 《Planetary and Space Science》2008,56(7):985-1013
The paradigm of an ancient warm, wet, and dynamically active Mars, which transitioned into a cold, dry, and internally dead planet, has persisted up until recently despite published Viking-based geologic maps that indicate geologic and hydrologic activity extending into the Late Amazonian epoch. This paradigm is shifting to a water-enriched planet, which may still exhibit internal activity, based on a collection of geologic, hydrologic, topographic, chemical, and elemental evidences obtained by the Viking, Mars Global Surveyor (MGS), Mars Odyssey (MO), Mars Exploration Rovers (MER), and Mars Express (MEx) missions. The evidence includes: (1) stratigraphically young rock materials such as pristine lava flows with few, if any, superposed impact craters; (2) tectonic features that cut stratigraphically young materials; (3) features with possible aqueous origin such as structurally controlled channels that dissect stratigraphically young materials and anastomosing-patterned slope streaks on hillslopes; (4) spatially varying elemental abundances for such elements as hydrogen (H) and chlorine (Cl) recorded in rock materials up to 0.33 m depth; and (5) regions of elevated atmospheric methane. This evidence is pronounced in parts of Tharsis, Elysium, and the region that straddles the two volcanic provinces, collectively referred to here as the Tharsis/Elysium corridor. Based in part on field investigations of Solfatara Crater, Italy, recommended as a suitable terrestrial analog, the Tharsis/Elysium corridor should be considered a prime target for Mars Reconnaissance Orbiter (MRO) investigations and future science-driven exploration to investigate whether Mars is internally and hydrologically active at the present time, and whether the persistence of this activity has resulted in biologic activity. 相似文献
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In this research the dissolved inorganic nitrogen (DIN) loadings from direct precipitation, stream flow and groundwater discharge to two small estuaries located in Prince Edward Island (PEI), Canada, were quantified over a 2‐year period. The two estuaries, like many around the world, exhibit deteriorating conditions that are believed to be related to excessive nitrogen transport from adjacent catchments. The significance of the groundwater transport pathway and the temporal variability of the loadings have not been previously investigated. The wet fraction of the atmospheric loading was quantified using available precipitation and DIN concentration records. Stream water entering the estuaries and the discharge from numerous shoreline springs, the predominate form of groundwater discharge, were monitored periodically during the study. The annual DIN loads delivered to both estuaries were dominated by streams, although groundwater discharge provided significant contributions of approximately 15–18%. Temporal variability of DIN loading was large, with monthly loads varying by a factor of 5; this variability was found to be primarily related to the variability of freshwater discharge. Concentrations of nitrate in stream water discharging to the estuaries and shoreline groundwater springs were similar in each catchment, suggesting that there was minimal differential attenuation during transport via these two pathways. The McIntyre Creek estuary had one of the highest normalized loads reported in the literature (1700 kg NO3‐N/ha estuary/year), more than four‐fold that of the Trout River estuary, and this result appears to be related to the larger percentage of land area used for potato production in the catchment. This study demonstrates that direct groundwater discharge to estuaries in PEI should not be ignored and that seasonal variations in loading may be important for managing DIN delivery to such estuaries. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Felix Borleanu Mihaela Popa Mircea Radulian Johannes Schweitzer 《Journal of Seismology》2011,15(3):431-442
The BURAR seismic array, located in Northern Romania (Bucovina region), is designed to monitor events located in an area poorly
covered by other existing seismic stations. In order to use the BURAR array for single-station locations, it is crucial to
calibrate the azimuth and slowness parameters, which are currently used in array techniques to locate earthquakes, blasts
or nuclear explosions. The goal of this study is to apply “f–k” and plane wave fit techniques in order to constrain the slowness
and azimuth parameters at BURAR for teleseismic, regional and local events. The analysis was carried out using P and S waves
recorded for events occurred between 2004 and 2008 within a radius of 50° around BURAR. The azimuth values obtained applying
both methods strongly deviated from the theoretical values for regions like Central Turkey, Bulgaria, Dodecanese Islands and
other parts of Greece, while the ray parameter deviations with respect to a 1-D IASP91 reference model are less significant.
For the local events, the anomalies are smaller, except the particular case of Vrancea intermediate-depth earthquakes for
which strong azimuth deviations (33.5°), both positive and negative, are observed. We investigate how these systematic deviations
in azimuth are explained by the structure lateral heterogeneities which characterize the study region. 相似文献
40.
Mihaela Grigore Richard Sakurovs David French Veena Sahajwalla 《International Journal of Coal Geology》2008,76(4):301-308
Degradation of coke in the blast furnace is influenced by its inherent mineral matter, the formation of which is itself dependent upon the nature of the coal mineral matter. To date few studies have been made of coke mineralogy and its relationship to the mineralogy of the parent coal. In this study the effect of carbonisation on coal mineral matter has been investigated by a detailed quantitative mineralogical examination of nine cokes and their parent coals. The quantitative analysis was performed on X-ray diffraction patterns of the mineral matter of cokes and coals, using SIROQUANT™. Coke mineralogy and its composition varied strongly between cokes, more strongly than variations in elemental composition of the ash. The mineral matter in the studied cokes consisted of crystalline mineral phases and also significant levels of amorphous phase (ranging between 44 and 75%). Decomposition of clays such as kaolinite, montmorillonite, illite and chamosite produced the amorphous phase and some of the crystalline mineral phases such as mullite, γ-alumina, spinel, cristobalite and leucite. The type of association of mineral matter in coals had an important role in how the clays decomposed. For example, association of kaolinite with silica-bearing minerals in intimate intermixture favoured formation of mullite over γ-alumina. Akermanite and diopside result from reaction of kaolinite with associated calcium bearing minerals (calcite, dolomite or ankerite). Quartz, fluorapatite and the three polymorphs of TiO2 (anatase, brookite and rutile) were the coal minerals that were least affected during carbonisation, as they were also found in the cokes, yet even they were affected in some cases. 相似文献