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1.
Changes in low and high flows in the Vistula and the Odra basins: Model projections in the European‐scale context 
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下载免费PDF全文 Mikołaj Piniewski Mateusz Szcześniak Zbigniew W. Kundzewicz Abdelkader Mezghani Øystein Hov 《水文研究》2017,31(12):2210-2225
A number of extensive droughts and destructive floods have occurred in Poland in the last 25 years; hence, projections of low and high river flows are of considerable interest and importance. In the first part of this paper, projections of low and high flows in the rivers of the Vistula and the Odra basins (VOB region), for two future time horizons, are presented. Projections are based on the Soil and Water Assessment Tool (SWAT) hydrological model simulations driven by results of the EURO‐CORDEX experiment under Representative Concentration Pathways 4.5 and 8.5. The VOB region covers most of Poland and parts of five neighboring countries, giving this study an international relevance. In the second part of the paper, a review of projections of low and high flows in rivers in Central and Eastern Europe is presented. Despite a substantial spread of flow projections, the main message of the modelling part is that increases of both low and high flows are dominating. The magnitude of increase of low flow is considerably higher than that of high flow. In other words, future streamflow droughts are projected to be less severe, whereas, in contrast, river floods are projected to increase, which is a challenge for flood risk reduction, water management, and climate change adaptation. There is an overall agreement of our findings for the VOB region with projections of hydrological extremes from large‐scale models forced by EURO‐CORDEX results in the European‐scale studies. 相似文献
2.
简要介绍了地球介质各向异性研究的发展历程,重点介绍了国内外有关上地幔各向异性的研究工作及成果;阐述了上地幔各向异性的起源及其地球动力学意义;较详细地分析了上地幔各向异性研究的各种方法及其优缺点;论述了川滇地区各向异性研究的意义和目的,并提出了整个研究工作的内容和步骤. 相似文献
3.
土壤中的含汞量与土壤中岩石粒径大小的关系 总被引：8，自引：0，他引：8
为弄清土壤中的含汞量与土壤中岩石粒径大小的关系，采集了内蒙古通辽市的130个第四系松散地层土样，用热释法测量了土壤中的含汞量，结果表明，土壤含汞量的大小主要受区域地质条件和构造活动强度的控制，同一地质区域内土壤含汞量的高低受岩石颗粒粒径大小的影响，岩石颗粒小，土壤含汞量高，反之，则相反。 相似文献
4.
D. M. Pechersky A. A. Lyubushin Z. V. Sharonova 《Izvestiya Physics of the Solid Earth》2012,48(1):42-60
The data on geomagnetic reversals, organic changes, and lower-mantle plume magmatism in the Phanerozoic are collected and
correlated. No direct relationship is revealed between the geomagnetic reversals, plumes, and biozones. However, the frequency
of geomagnetic reversals is found to correlate to the frequency of biozonal alterations. We relate this inconsistency to the
coupling of the two processes, which are mutually independent, with the long-term changes in the Earth’s rotation. The plumes
are formed at the core-mantle boundary and, thus, the reversals should have a different source. We hypothesize that the change
in the geomagnetic polarity is due to the nonuniform rotation of the inner core relative to the mantle in combination with
the changes in the axial tilt of the Earth’s rotation. 相似文献
5.
The contamination by polychlorinated biphenyls (PCB) and hexachlorobenzene (HCB) in sea waters and sediments of Tiber River estuary has been studied in 1976 and 1977.PCBs have been detected in all the samples analysed at mean levels of 0.297 ppb (1976) and 0.135 ppb (1977); these levels are much higher than those proposed as acceptable for surface waters. Contamination increases with increasing distance from the shore.HCB has been identified in only 16% of the water samples analysed and it was found absent in sediment samples.The results are discussed relative to both the levels of PCB in other sea waters and the toxicity of these products to the aquatic animals. 相似文献
6.
Trends in the timing and magnitude of floods in Canada 总被引：2，自引：0，他引：2
This study investigates trends in the timing and magnitude of seasonal maximum flood events across Canada. A new methodology for analyzing trends in the timing of flood events is developed that takes into account the directional character and multi-modality of flood occurrences. The methodology transforms the directional series of flood occurrences into new series by defining a new location of the origin. A test of flood seasonality (multi-modality) is then applied to identify dominant flood seasons. Floods from the dominant seasons are analyzed separately by a seasonal trend analysis. The Mann–Kendall test in conjunction with the method of pre-whitening is used in the trend analysis. Over 160 streamflow records from one common observation period are analyzed in watersheds with relatively pristine and stable land-use conditions. The results show weak signals of climate variability and/or change present in the timing of floods in Canada during the last three decades. Most of the significant trends in the timing of spring snowmelt floods are negative trends (earlier flood occurrence) found in the southern part of Canada. There are no significant trends identified in the timing of fall rainfall floods. However, the significance of the fall, rainfall-dominated flood season has been increasing in several analyzed watersheds. This may indicate increasing intensity of rainfall events during the recent years. Trends in the magnitude of floods are more pronounced than the trends in the timing of floods. Almost one fifth of all the analyzed stations show significant trends in the magnitude of snowmelt floods. Most of the significant trends are negative trends, suggesting decreasing magnitudes of snowmelt floods in Canada over the last three decades. Significant negative trends are found particularly in southern Ontario, northern Saskatchewan, Alberta and British Columbia. There are no significant trends in the magnitude of rainfall floods found in the analyzed streamflow records. The results support the outcomes of previous streamflow trend studies conducted in Canada. 相似文献
7.
Michael F. Hochella Jr.Author Vitae 《Earth and Planetary Science Letters》2002,203(2):593-605
Nanoscience and technology are not exactly new, but nevertheless rapidly expanding fields that are providing revolutions in all sciences on the scale of what genomics and proteomics have done in recent years for the biological sciences. Nanoscience is based on the fact that properties of materials change as a function of the physical dimension of that material, and nanotechnology takes advantage of this by applying selected property modifications of this nature to some beneficial endeavor. The prefix ‘nano’ is used because the property dependence on physical size is generally observed close to the nanoscale, somewhere around 10−9 m. The dimensions at which changes are observed depend on the specific material and the property in question, as well as which of the three dimensions are restricted in real space (e.g. small particles vs. thin films vs. ‘one-dimensional’ phases). Properties change in these confined spaces because the electronic structure (i.e. the distribution of electron energies) of the material is modified here in the gray area between the bulk and atomistic/molecular realms, or equivalently between the continuum and strictly quantum domains. Earth materials with at least one dimension in the nanorange are essentially ubiquitous. Many have been known for several decades and more are being discovered all the time. But the scientific emphasis has now shifted to that of measuring, understanding and ultimately predicting the property changes from the bulk to nanodomains, and to the understanding of the significant ways that Earth processes are affected by these changes. In addition, where possible, Earth scientists are using nanoscience to develop nanotechnology that should play important roles in Earth sustainability issues of the future. 相似文献
8.
Summary Statistics on sunspot leaders and followers in active regions are derived from the 50 years of Greenwich records 1905–1954. The results are combined with the probable structure of large scale solar eddies as synthesized from various relevant pieces of information. It is found that active regions tend to be located in anticyclonic ridges of the large disturbances. The statistical leader and follower populations are further subdivided, each into new and old spot classifications. The new leaders, especially, show motions different from those of other spots, suggesting the presence of a life cycle for the large disturbances. It is found that the divergence and vorticity are positive and anticyclonic, respectively, for the new active regions, the former quantity being numerically larger than the latter in this case. Various possible implications of the material are discussed. 相似文献
9.
The results of studying the finely dispersed particles in the natural and anthropogenic geosystems are briefly reviewed. The analysis is confined to the solid Earth, the troposphere, and the stratosphere. Definitions are given for the main fine-dispersed objects in geophysics (nanocrystals, nano- and microscale particles, nanoclusters, nanoporous materials, colloidal particles, aerosols, etc.). The specific mechanical properties of nanoobjects are outlined, and the limiting particle sizes at which these particularities are significant are estimated. The studies of fine-dispersed particles formed in the experiments on destruction of rocks are described. The role of fine particles in the Atmospheric Brown Clouds is discussed, and the effect of these clouds on the climatic changes is analyzed. Participation of fine particles in the interactions between the geospheres is considered by the examples of extraterrestrial dust, eruption of the Eyjafjallajökull volcano, and vortex entrainment of the fine particles from the troposphere into the stratosphere. 相似文献
10.
V. A. Petrov V. V. Poluektov R. M. Nasimov S. I. Shchukin J. Hammer 《Izvestiya Physics of the Solid Earth》2009,45(11):1012-1018
The Antey deposit in the southeastern Transbaikal region is one of the main objects of uranium ore mining. It is localized
in the Late Paleozoic granite basement of the Strel’tsovo Caldera formed during the Late Mesozoic tectono-magmatic activation
of geological structures in the region. Vein ore bodies of the deposit are controlled by steep near-meridional faults being
developed in zones of intense hydrothermal-metasomatic alterations, cataclasis, brecciation, and elevated rock fracturing.
The upper parts of the ore bodies are located at a depth of 400 m and their lower parts are traceable up to depths of 1300
m below the surface. The mining activity involves progressively deeper levels of the section, which determines the necessity
for the complex assessment of the deposit potential. The mode of rock deformation at the four lower horizons of mines occurring
at depths of 500 to 700 m is discussed. It is shown that variations in the mode of deformation are determined by a combination
of natural and technogenic factors, which should be taken into consideration in predicting the geomechanic behavior of the
rocks for safe mining works. 相似文献
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Data on water withdrawal and use in different economic branches in the Volga basin in 1970–2000 are analyzed. Time variations in the removed volumes of waste, mine, and drainage waters, as well as in their chemistry, are considered. Characteristics of water use in 2010 are forecasted based on predictions of the socioeconomic development of Russia and extrapolation of the tendencies established in the dynamics of the analyzed indices. 相似文献
13.
N. I. Tananaev 《Water Resources》2012,39(6):648-656
Regularities in the manifestation of hysteresis effect in the relationship between water discharge and suspended load in rivers in the permafrost zone of Siberia and Far East are studied for individual phases of water regime. The existing typifications of hysteresis curves, the formation mechanisms of suspended load peaks in permafrost zone rivers are considered. Data of regime observations are used to determine the predominant types of hysteresis curves discharge-sediment load for 27 gages on 16 large rivers in the region. The role of permafrost conditions and processes in the formation of the hysteresis effect is identified and a relationship between the type of the hysteresis curve and the predominant sediment source is established. 相似文献
14.
Chun-Chan Kung Ryoichi Hayatsu Martin H. Studier Robert N. Clayton 《Earth and Planetary Science Letters》1979,46(1):141-146
Nitrogen isotope fractionations have been measured in Fischer-Tropsch and Miller-Urey reactions in order to determine whether these processes can account for the large15N/14N ratios found in organic matter in carbonaceous chondrites. Polymeric material formed in the Fischer-Tropsch reaction was enriched in15N by only 3‰ relative to the starting material (NH3). The15N enrichment in polymers from the Miller-Urey reaction was 10–12‰. Both of these fractionations are small compared to the 80–90‰ differences observed between enstatite chondrites and carbonaceous chondrites. These large differences are apparently due to temporal or spatial variations in the isotopic composition of nitrogen in the solar nebula, rather than to fractionation during the production of organic compounds. 相似文献
15.
岩浆岩在青藏高原的大陆动力学研究中有着重要的作用,它既是构造演化的记录,又是重要构造-岩浆-成矿带的指示.本文主要基于冈底斯带及邻区的地面重力和航磁数据,首先进行地质-地球物理先验信息约束下的重磁2.5维交互式反演,再将2.5维反演结果作为参考模型加入到三维反演计算中,得到地下三维密度和磁化率结构.结合岩浆岩密度、磁化率统计资料和岩浆岩地球化学成果,推断研究区基性岩、I型花岗岩和S型花岗岩的三维分布图,得到如下结论:S型花岗岩主要分布在冈底斯东带和冈底斯弧背断隆带以北;北冈底斯的西部无明显的岩浆活动,而在其南侧和北侧,发现大量的隐伏基性岩和零散分布的I型花岗岩;中生代I型花岗岩在南冈底斯和冈底斯弧背断隆带广泛分布,且到新生代才出现大量的S型花岗岩.上述结果为中生代班公湖—怒江洋壳和新特提斯洋壳的双向剪刀式俯冲模式的观点提供了重要佐证,并认为班公湖—怒江洋壳在北冈底斯西部约84°E—88°E的范围内先后存在向北和向南俯冲的可能,北向羌塘地体下俯冲,南向冈底斯地体下俯冲. 相似文献
16.
城市群地震灾害特点与防震减灾对策 总被引：7，自引：0，他引：7
城市群是我国经济迅速发展的产物。我国东部地区已经涌现了大量的城市群。城市群地震灾害比单个城市的地震灾害更为复杂、严重。地震对社会经济的影响更大。本文首次对城市群的地震灾害特点、防震减灾对策进行了系统的讨论，并着重指出了城市群防震减灾研究的重点领域。 相似文献
17.
A. F. Grachev O. A. Korchagin V. A. Tselmovich H. A. Kollmann 《Izvestiya Physics of the Solid Earth》2008,44(7):555-569
Results of investigation of the cosmic matter in the transitional clay layer at the Cretaceous-Paleogene boundary in the Gams
section, Eastern Alps, are presented. A great diversity of iron microspherules and particles of different morphologies, pure
nickel spherules, awaruite (Fe3Ni) particles, and diamond crystals are discovered. Iron microspherules are also met in the overlying Paleocene deposits,
but their diversity there is not great. The discovered metallic microspherules and particles are described, their chemical
compositions are presented, and their origin is discussed. 相似文献
18.
Phase and Correlation in `Random' Seismic Fields and the Reconstruction of the Green Function 总被引：3，自引：0，他引：3
Michel Campillo 《Pure and Applied Geophysics》2006,163(2-3):475-502
We first present a summary of recent results on coda interpretation. We emphasize the observation of the stabilization of
P to S energy ratio indicating the modal equipartition of the wavefield. This property clearly shows that the coda waves are
in the regime of multiple scattering. Numerical solutions of the elastic radiative transfer equation are used to illustrate
the evolution of the wave-field towards P-to-S energy stabilization, and asymptotically to complete isotropy. The energy properties
of the coda have been widely studied but the phase properties have often been neglected. The recently observed coherent backscattering
enhancement, an expression of the so-called `weak localization', demonstrates that interference effects still persist for
multiple diffracted waves. Another manifestation of the persistence of the phase is the possibility to reconstruct the Green
function between two stations by averaging the cross correlation of coda waves produced by distant earthquakes and recorded
at those two stations. This reconstruction is directly related to the properties of reciprocity and time reversal of any wavefield.
Using broadband seismic coda waves, we show that the dominant phases of the Green function in the band 2 s–10 s, namely fundamental
mode Rayleigh and Love waves, are reconstructed. We analyze the time symmetry of the cross correlation and show how the level
of symmetry evolves with the isotropization of the diffuse field with lapse time. Similarly we investigate the correlation
in continuous ambient noise records. Whereas the randomness of the coda results from multiple scattering by randomly distributed
scatterers, we assume that the seismic noise is random mostly because of the distribution of sources at the surface of the
Earth. Surface waves can be extracted from long time series. The dispersion curves of Rayleigh waves are deduced from the
correlations. On paths where measurements from earthquake data are also available, we show that they are in good agreement
with those deduced from noise correlation. The measurement of velocities from correlation of noise along paths crossing different
crustal structures opens the way for a `passive imaging' of the Earth's structure. 相似文献
19.
20.
H.L. Kuo 《Pure and Applied Geophysics》1997,150(1):143-153
—The boundary layer flows created by the frictional dissipation of the wind speed at the surface in the atmosphere and by surface wind stress in the ocean at the equator and in the equatorial region, are obtained by taking the influence of the surface friction on the zonal velocity as being balanced by vertical transport for the long-term mean flow and by a corresponding time variation for time-dependent flow fields. Solutions are expressed in terms of the velocities in zonal and vertical directions and the divergence of the horizontal current in the two media. It is found that under the ever present easterly flow in the lower atmosphere, the boundary layer flow in the atmosphere is convergence and ascending motion in the lower troposphere, and divergence at the surface and uplift in ocean, and in reverse directions for the westerly flow. Similar results are obtained for time-dependent wind fields and they give way to the steady asymptotic solutions when the period of the variation exceeds 10 months. 相似文献