共查询到20条相似文献,搜索用时 12 毫秒
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Tanabe S 《Marine pollution bulletin》2005,50(10):1025-1026
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Hydrogeology: time for a new beginning? 总被引:1,自引:0,他引:1
Phillips FM 《Ground water》2002,40(3):217-219
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Introduction The accumulation of high precision GPS data has great significance for understanding and explaining crustal movement and establishing the geodynamical model correctly. However, it is an important basic task to study block movement with the displacement data which covers the datum influence information, as well as the deformation information of the block and abnormal deforma-tion information in the block such as fault or zone of fracture and so on. Firstly steady or com-parativel… 相似文献
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Environmental indicators are being increasingly used to emphasise the relevance of monitoring. However, indicators must also be effective. In particular, they must be able to answer management questions, be accessible to the target audience and be sufficiently precise. Here, we use a time series of mercury levels in plaice from Liverpool Bay to illustrate how specific management questions can be formulated, answered, and the precision of these answers assessed. We also show how a programme design can incorporate a series of management questions that are likely to arise over time in response to observed changes in a time series. 相似文献
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Soil piping is a widespread, although often overlooked land degradation process. So far, subsurface soil erosion studies have been focused on the importance of soil piping in hydrological and geomorphological processes, and factors controlling piping processes. Nowadays, the environmental changes being caused by the Anthropocene have clearly demonstrated that society depends on soil more than ever before, so the traditional studies of soil erosion processes need to be redefined. In that sense, geomorphologists face to overcome new piping-related problems. In this article we identify new possible areas of research: (i) soil pipes and pipe collapses (PCs) as natural hazards, (ii) role of soil piping in carbon cycle, (iii) soil pipes and PCs and their relationships with biodiversity, and (iv) piping-affected areas as geodiversity sites. Only better recognition of natural hazards driven by soil piping, such as land subsidence and degradation, landslides, flooding and off-site sediment effects may result in better prevention and control measures in piping-affected areas. Moreover, in the context of Global Change the role of soil piping in carbon cycle should be raised. Land-use and land-cover changes, as well as climate change may affect piping dynamics in different morphoclimatic regions and soil loss due to piping may lead to carbon loss. Soil pipes and PCs are closely interlinked with biodiversity, both positively and negatively. Piping erosion may directly and indirectly destroy vegetation and animals, although in some cases piping erosion may create new habitats and provide favourable conditions for some species. However, soil piping is not only an environmental and societal problem, but it may also contribute to the world geodiversity, which is clearly observed in badland sites. Piping erosion may have a significant impact on environment and society, thus further research with new questions is essential to provide knowledge for sustainable development. 相似文献
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Watershed science:Bridging new advances in hydrological science with good management of river basins
<正>Watershed science traditionally refers to the themes of hydrology and water resource management.Watershed science has been experiencing a rapid evolution that thrives on a forceful superimposition of multi-discipline and innovative earth observing and information techniques.The water and its interactions with other systems in a watershed is increasingly becoming a focus in scientific communities,and several new disciplines such as ecohydrology,ecoeconomics,environmental hy- 相似文献
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Dongxiao Wang Yinghao Qin Xianjun Xiao Zuqiang Zhang Xiangyu Wu 《Ocean Dynamics》2012,62(9):1311-1322
A new ocean reanalysis, covering the period from 1990 to 2009, is evaluated against observational sea surface temperature (SST) and sea surface height (SSH) data in reproducing the temporal characteristics of El Ni?o and El Ni?o Modoki. The new reanalysis assimilates the available SST, temperature–salinity profile, and satellite altimetry data sets into a global ocean model forced with surface boundary conditions from the National Centers for Environmental Prediction atmospheric reanalysis 2. Using the Ni?o 3 index and the improved El Ni?o Modoki index, to distinguish between El Ni?o and El Ni?o Modoki signals, our results show that the two time series in the new reanalysis are in agreement with those obtained from observations during the study period. A composite analysis method is used to demonstrate the temporal evolution of these two types of El Ni?o. The new reanalysis has the advantage of representing the strength and location of El Ni?o events better than the control run, with an increase in the spatial correlation, but El Ni?o variability in the reanalysis is weak in the eastern Pacific, particularly off the coast of South America. As for the El Ni?o Modoki events, the initiation, development, and termination of the warm SST anomalies all occur in the central Pacific. All main features associated with the warm SST anomaly pattern of El Ni?o Modoki are well represented in the reanalysis. Furthermore, using this new ocean reanalysis, we select two strong cases to investigate possible mechanisms that may lead to the different warm SST anomaly patterns. 相似文献
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C.M. Green K.M.U. Fletcher S. Cheyney G.J. Dawson S.J. Campbell 《Geophysical Prospecting》2019,67(6):1611-1619
This paper reviews the impacts of new satellite altimeter data sets and new technology on the production of satellite gravity. It considers the contribution of the increased data volume, the application of new altimeter acquisition technology and the potential for future developments. Satellite altimeter derived gravity has provided gravity maps of the world's seas since the 1980s, but, from 1995 to 2010, virtually all improvements were in the processing as there were no new satellite data with closely spaced tracks. In recent years, new data from CryoSat-2 (launched in 2010) and the geodetic mission of Jason-1 (2012–2013) have provided a wealth of additional coverage and new technology allows further improvements. The synthetic aperture radar mode of CryoSat-2 uses a scanning approach to limit the size of the altimeter sea surface footprint in the along-track direction. Tests indicate that this allows reliable data to be acquired closer to coastlines. The synthetic aperture radar interferometric mode of CryoSat-2 uses two altimeters to locate sea-surface reflection points laterally away from the satellite track. In a study to generate gravity for freshwater lakes, this mode is found to be valuable in extending the available satellite coverage. The AltiKa altimeter uses higher frequency radar to provide less noisy sea-surface signals and its new orbit mode gives potential for further improvements in satellite gravity. Future developments include the potential for swath mapping to provide further gravity improvements. 相似文献
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Kakuschke A Valentine-Thon E Griesel S Fonfara S Siebert U Prange A 《Marine pollution bulletin》2011,62(8):1891-1894
Environmental exposure to metals is believed to affect marine mammal health adversely including immunosuppression or acute as well as chronic inflammatory processes leading to hypersensitivities or autoimmune diseases. Metal-specific hypersensitivities were found in several pinnipeds of the North Sea. However, hypersensitivity is a complex phenomenon whose characteristics are still not completely understood; in particular, effects on health are not well established. In the present study, we compared basic hematological and biochemical parameters of seals with and without metal-specific hypersensitivities. We found altered hematological parameters and liver enzyme patterns in seals with a metal-induced hypersensitivity, including a reduction in macrophages, an increase in lymphocytes, and elevated levels of lactate dehydrogenase. These findings support the suggestion of a chronic influence of metal pollutants on the health of marine mammals of the North Sea. 相似文献
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Susumu Umino Kyoko Kanayama Keitaro Kitamura Akihiro Tamura Osamu Ishizuka Ryoko Senda Shoji Arai 《Island Arc》2018,27(1)
Boninites are widely distributed along the western margin of the Pacific Plate extruded during the incipient stage of the subduction zone development in the early Paleogene period. This paper discusses the genetic relationships of boninite and antecedent protoarc basalt magmas and demonstrates their recycled ancient slab origin based on the T–P conditions and Pb–Hf–Nd–Os isotopic modeling. Primitive melt inclusions in chrome spinel from Ogasawara and Guam islands show severely depleted high‐SiO2, MgO (high‐silica) and less depleted low‐SiO2, MgO (low‐silica and ultralow‐silica) boninitic compositions. The genetic conditions of 1 346 °C at 0.58 GPa and 1 292 °C at 0.69 GPa for the low‐ and ultralow‐silica boninite magmas lie on adiabatic melting paths of depleted mid‐ocean ridge basalt mantle with a potential temperature of 1 430 °C in Ogasawara and of 1 370 °C in Guam, respectively. This is consistent with the model that the low‐ and ultralow‐silica boninites were produced by remelting of the residue of the protoarc basalt during the forearc spreading immediately following the subduction initiation. In contrast, the genetic conditions of 1 428 °C and 0.96 GPa for the high‐silica boninite magma is reconciled with the ascent of more depleted harzburgitic source which pre‐existed below the Izu–Ogasawara–Mariana forearc region before the subduction started. Mixing calculations based on the Pb–Nd–Hf isotopic data for the Mariana protoarc basalt and boninites support the above remelting model for the (ultra)low‐silica boninite and the discrete harzburgite source for the high‐silica boninite. Yb–Os isotopic modeling of the high‐Si boninite source indicates 18–30 wt% melting of the primitive upper mantle at 1.5–1.7 Ga, whereas the source mantle of the protoarc basalt, the residue of which became the source of the (ultra)low‐Si boninite, experienced only 3.5–4.0 wt% melt depletion at 3.6–3.1 Ga, much earlier than the average depleted mid‐ocean ridge basalt mantle with similar degrees of melt depletion at 2.6–2.2 Ga. 相似文献
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A new network of permanently recording seismic stations in West Saxony has considerably improved detection threshold, location
accuracy and depth determination in this seismically active region. Between 2001 and 2007 more than 900 events have been located.
Seismicity mainly occurred along a band stretching north-south between Leipzig and Vogtland/NW Bohemia area with local magnitudes
ranging between −0.8 and 2.8. Seismicity clearly delineates the Leipzig-Regensburg (L-R) fault zone striking N-S, and the
Gera-Jachymov (G-J) fault zone striking roughly NNW-SSE. The hypocentral depths can be divided into two depth ranges, one
at depths below 10 km, and a second at less than 10 km depth that only extends S-N from the Vogtland until the crossing between
L-R and G-J fault zones. A small earthquake sequence that occurred near Werdau/Zwickau in August 2006 at almost the same epicenters
as an earlier sequence 1997/98 seems to confirm this finding: a relative localization of 15 events with the double-difference
technique clearly reveals two distinct subclusters at about 6 and 12–14 km depth. With the improved station coverage 33 new
fault plane solutions from events along the L-R fault zone north of the swarmquake area could be determined from P-polarities
and P/S ratios. They do not differ significantly from solutions in the Vogtland/NW-Bohemia area and are mostly compatible
with a N-S oriented fault plane. Strike slip mechanisms with or without a dip slip component dominate. 相似文献
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Kathleen C. Benison Deidre LaClair Jessica Walker 《Earth and Planetary Science Letters》2008,270(3-4):330-337
Physical sedimentology experiments have shown that sulfuric acid solutions may have formed some surface features seen on Mars. Recent data returned from Mars show the presence of jarosite, sulfate salts, hematite, phyllosilicates, and opaline silica, all of which precipitate from some terrestrial sulfuric acid solutions. There is a plethora of geochemical, mineralogical, and sedimentological data indicative of past sulfuric acid systems on Mars, but there has never been a comprehensive study published regarding sulfuric acid as a physical sedimentological agent. In the laboratory, we ran liquids of various compositions over sediments in order to test how these liquids entrain, transport, and deposit sediments. Pure water and concentrated sulfuric acid solutions produced the same general features, such as channels, gullies, and alluvial fans. However, sulfuric acid solutions yielded some distinct sedimentary features not produced by pure water runs. These features, narrow, deeply incised channels of consistent widths, rounded discrete fans, and air bubble “craters”, are similar to some Martian landscape features. These experimental results indicate that acid solutions should be considered a possible sedimentological agent on Mars. 相似文献
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Triploporella ? edgelli n. sp., a new Dasycladalean alga from the Lower Cretaceous of Lebanon
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The Dasycladalean assemblage of the Jezzinian strata (uppermost Barremian–lowermost Aptian) of Lebanon consists of two organo‐genera and eight genera with eleven species, including eight Triploporellaceae. Although Triploporella marsicana (Praturlon, 1964) was reported by Saint‐Marc from the same interval, it is not found in our material. However, a lookalike, which is herein described as Triploporella ? edgelli n. sp., is identified. This new species has cyst‐containers within the primary segments of its laterals but, because it lacks calcified secondary segments, it is left in open nomenclature. 相似文献
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《Advances in water resources》2004,27(7):707-723
A new method is presented to construct a simple and general site bond correlated 3D HYdraulic POre Network model (HYPON) of hydraulic behavior of porous media for a wide range of permeability and porosity. Pore scale microstructure in this model is captured through simple power functions of Beti's influence lines that fix both the location and the size of throat (the narrowest section of bond) by relating the important elements of microstructure such as coordination number, porebody sizes and pore wall curvature. The new element in pore-network architecture is thus, the location of throat, which is important for smooth hydraulic transitions during steady state flow conditions. Despite the reduced number of parameters in comparison with other pore-network models, the morphological characteristics of HYPON compare well to those of the process-based predictive models in literature, and these characteristics are sensitive to the variance of porebody sizes rather than to the used type of the porebody size distributions. Processes such as diagenesis and dissolution are captured implicitly through the pore wall curvature parameter. Different combinations of porosity and permeability relations are obtained if the bond curvature and porebody sizes are varied. These relations reveal that effects of diagenesis and dissolution on the permeability may be ignored as they are secondary to effects on porosity. 相似文献