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1.
Concerns about the water–energy–food (WEF) nexus have motivated many discussions regarding new approaches for managing water, energy and food resources. Despite the progress in recent years, there remain many challenges in scientific research on the WEF nexus, while implementation as a management tool is just beginning. The scientific challenges are primarily related to data, information and knowledge gaps in our understanding of the WEF inter-linkages. Our ability to untangle the WEF nexus is also limited by the lack of systematic tools that could address all the trade-offs involved in the nexus. Future research needs to strengthen the pool of information. It is also important to develop integrated software platforms and tools for systematic analysis of the WEF nexus. The experience made in integrated water resources management in the hydrological community, especially in the framework of Panta Rhei, is particularly well suited to take a lead in these advances. 相似文献
2.
Water Resources - Aliphatic and polycyclic aromatic hydrocarbons have been studied in suspended matter and bottom sediments at the geochemical barrier the Northern Dvina–Dvina Bay during... 相似文献
3.
It is shown that the instability of turbulent flows with Ekman velocity profiles in the vicinity of the core–mantle boundary leads to the formation of horizontally oriented circulating roll structures. The geophysical implications of the presence of such structures in the liquid core are explored, namely, the formation of the hot zones with enhanced conductivity and their influence on geomagnetic reversals. 相似文献
4.
This study systematically investigates the entire parameter space of the Green–Ampt model for water infiltration and allows for arbitrary constant hydraulic head boundary conditions, any column inclination, hydrophilic and hydrophobic porous media, and a nonzero initial cumulative infiltration. There are five infiltration and five liquid-withdrawal scenarios which differ with respect to the direction of flow and the sign of the acceleration of the liquid. We present analytical solutions for these flow scenarios and 2D phase diagrams that show which flow scenario is predicted depending on the model parameters. All liquid infiltration scenarios, except accelerating downward infiltration (ADI), have already been reported by Green and Ampt. For liquid withdrawal, however, only decelerating downward flow has previously been reported, which is representative of drainage to the water table. We present experimental evidence that ADI may occur in hydrophobic media. 相似文献
5.
ABSTRACTThe literature on environmental security often stresses the complementarity between sustainability and broader security goals. Less emphasis has been placed on possible trade-offs between security objectives and aspects of sustainability. This study examines the conditions under which these synergies and trade-offs are likely to occur, and how the trade-offs can be reconciled, especially during times of peacebuilding. As a case study, we analyse the effect of Israeli security concerns on environmental infrastructure designed to treat wastewater in the West Bank. This study identifies several sustainability–security trade-offs: (1) economic—in which security concerns raise costs of wastewater infrastructure, thereby crowding-out other potentially productive investments; (2) equity—in which security concerns result in disproportionate exposure of populations to environmental hazards; and (3) environmental—in which security concerns increase ecological footprints. Yet, our case study also indicates that both sides used a variety of creative measures to reconcile these trade-offs.
EDITOR D. Koutsoyiannis GUEST EDITOR K. Aggestam 相似文献
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This paper includes an analysis of the influence of soil plasticity on the seismic response of micropiles. Analysis is carried out using a global three-dimensional modeling in the time domain. The soil behavior is described using the non-associated Mohr–Coulomb criterion. Both the micropiles and the superstructure are modeled as three-dimensional beam elements. Proper boundary conditions are used to ensure waves transmission through the lateral boundaries of the soil mass. Analyses are first conducted for harmonic loadings and then for real earthquake records. They show that plasticity could have a significant influence on the seismic response of the soil–micropiles–structure systems. This influence depends on the amplitude of the seismic loading and the dominant frequencies of both the input motion and the soil–piles–structure system. 相似文献
8.
Youhua RAN Xin LI Guodong CHENG Zhuotong NAN Jinxing CHE Yu SHENG Qingbai WU Huijun JIN Dongliang LUO Zhiguang TANG Xiaobo WU 《中国科学:地球科学(英文版)》2021,64(1):62-79
Data scarcity is a major obstacle for high-resolution mapping of permafrost on the Tibetan Plateau(TP).This study produces a new permafrost stability distribution map for the 2010 s(2005–2015)derived from the predicted mean annual ground temperature(MAGT)at a depth of zero annual amplitude(10–25 m)by integrating remotely sensed freezing degree-days and thawing degree-days,snow cover days,leaf area index,soil bulk density,high-accuracy soil moisture data,and in situ MAGT measurements from 237 boreholes on the TP by using an ensemble learning method that employs a support vector regression model based on distance-blocked resampled training data with 200 repetitions.Validation of the new permafrost map indicates that it is probably the most accurate of all currently available maps.This map shows that the total area of permafrost on the TP,excluding glaciers and lakes,is approximately 115.02(105.47–129.59)×10^4 km^2.The areas corresponding to the very stable,stable,semi-stable,transitional,and unstable types are 0.86×10^4,9.62×10^4,38.45×10^4,42.29×10^4,and 23.80×10^4 km^2,respectively.This new map is of fundamental importance for engineering planning and design,ecosystem management,and evaluation of the permafrost change in the future on the TP as a baseline. 相似文献
9.
In this study, a new model is developed for the aseismic design of a periodic viaduct when the pile–soil–structure interaction is considered. To account for the influence of the pile–soil–structure interaction, a wavenumber domain boundary element method (WDBEM) model for the periodic pile row supporting the viaduct is developed using the sequence Fourier transform as well as the boundary element method for the elastic medium. By using the WDBEM model for the pile row, the transfer matrices for the beams and piers, the joint conditions at the beam–beam–pier (BBP) junction as well as the periodicity condition for the viaduct, the wavenumber domain response of the periodic viaduct to spatially harmonic waves is determined. Based on the wavenumber domain response of the viaduct, the space-domain response of the viaduct to an arbitrary seismic wave can be obtained by invoking the inverse sequence Fourier transform method. Numerical results show that when the periodic viaduct is exposed to the spatially harmonic wave, resonances may occur at the bounding frequencies of the passbands of the characteristic waves of the viaduct. Also, it is found that the coincidence between the traveling seismic wave and characteristic waves of the viaduct will generate additional resonant frequencies located in passbands of the characteristic waves. 相似文献
10.
O’Leary F. González José Leonardo Alvarez Bladimir Moreno Giuliano F. Panza 《Pure and Applied Geophysics》2012,169(1-2):101-122
An overview of the S-wave velocity (V s) structural model of the Caribbean with a resolution of 2°?×?2° is presented. New tomographic maps of Rayleigh wave group velocity dispersion at periods ranging from 10 to 40?s were obtained as a result of the frequency time analysis of seismic signals of more than 400 ray-paths in the region. For each cell of 2°?×?2°, group velocity dispersion curves were determined and extended to 150?s by adding data from a larger scale tomographic study (Vdovin et al., Geophys. J. Int 136:324–340, 1999). Using, as independent a priori information, the available geological and geophysical data of the region, each dispersion curve has been inverted by the “hedgehog” non-linear procedure (Valyus, Determining seismic profiles from a set of observations (in Russian), Vychislitielnaya Seismologiya 4, 3–14. English translation: Computational Seismology (V.I. Keylis-Borok, ed.) 4:114–118, 1968), in order to compute a set of V s versus depth models up to 300?km of depth. Because of the non-uniqueness of the solutions for each cell, a local smoothness optimization has been applied to the whole region in order to choose a three-dimensional model of V s, satisfying this way the Occam's razor concept. Several known and some new main features of the Caribbean lithosphere and asthenosphere are shown on these models such as: the west directed subduction zone of the eastern Caribbean region with a clear mantle wedge between the Caribbean lithosphere and the subducted slab; the complex and asymmetric behavior of the crustal and lithospheric thickness in the Cayman ridge; the predominant oceanic crust in the region; the presence of continental type crust in Central America, and the South and North America plates; as well as the fact that the bottom of the upper asthenosphere gets shallower going from west to east. 相似文献
11.
Magnetosphere-associated storms and the autonomous storms in the ionosphere–plasmasphere environment
Global GPS-derived ionosphere maps (GIM) of total electron content (TEC) were transformed into magnetic latitude (MLAT) versus magnetic local time (MLT) frame. TEC enhancement or depletion marked by W index show dominant electron content depressions and the ionosphere–plasmasphere storms increasing by nighttime, at high magnetic latitudes and over the crests of equatorial anomaly. Based on W maps, the planetary Wp index was produced and used for derivation of a catalogue of more than 140 TEC storms during 1999–2009. In total 33 space weather intense storms and 35 moderate storms are revealed with four series of indices (AE, Ap, Dst and Wp) but more than half Wp storms were either partially overlapping in time with magnetic storm or observed autonomously under non-storm magnetosphere conditions. Relation between an annual number of intense Dst storms and Wp storms has been used for their prediction towards the peak of the forthcoming 24th solar cycle. 相似文献
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ABSTRACTWe thank the authors, Varis and Keskinen, and Nauditt, for their constructive contributions. We endorse their key comments, further referring to recent literature and events, including the UN 2018 High Level Political Forum on sustainable development. Here, we elaborate on the epistemological perspective of the water–energy–food nexus conceptualization, assessment, discourse and operationalization. 相似文献
13.
Meir Abelson Amotz Agnon Ahuva Almogi-Labin 《Earth and Planetary Science Letters》2008,265(1-2):33-48
The Eocene/Oligocene boundary, at about 33.5 Myr ago, marks the transition from ‘greenhouse-’ to ‘icehouse-world’, accompanied by a sudden cooling of ocean bottom-water. We show that this global event is simultaneous with a deep rooted mantle process: an abrupt suppression of the Iceland plume triggered rapid deepening of the Greenland–Scotland Ridge (GSR) — the sill moderating deep circulation between the Nordic seas and North Atlantic. Striking coincidence of several sets of events reflects the abrupt suppression of the Iceland plume and a rapid removal of its influence on the nearby Reykjanes Ridge (RR): 1) A sudden segmentation of the paleo-RR seen on seafloor magnetic anomalies, 2) a drop in spreading rate of the North Atlantic, 3) a transition from thick to normal oceanic crust, and 4) a rapid deepening and accelerated subsidence of the GSR, inferred from the sedimentary record of DSDP site 336. The plume suppression and the concomitant GSR deepening coincide with the initiation of North Atlantic Deep Water (NADW) at the Eocene/Oligocene (E/O) transition, attested by onset of drift sedimentation in the Faroe–Shetland Channel (FSC), the deepest spill-point on the GSR, and in the North Atlantic, the Feni Drift. These processes have influenced global deepwater composition and temperature as indicated by the striking correlation with the jump in global δ18O (> 1‰) measured on benthic foraminifers that reflects the E/O global cooling, and with enrichment of unradiogenic Nd isotopes in the southeastern Atlantic and Southern Ocean. The initiation of Atlantic thermohaline circulation at that time is inferred from the abrupt split between planktonic and benthic δ18O, indicating the building of ocean-water stratification. This scenario is further corroborated by a reversal in benthic δ18O at the late Oligocene, coincident with the renewal of vigorous Iceland plume some 25 Myr ago, causing a considerable retardation in NADW fluxes. The plume renewal is inferred from the emergence of the Iceland plateau, the transition to oblique-unsegmented RR axis, the cessation in deepening of the GSR, and rapid increase in spreading rate of the North Atlantic. These events coincide with decreasing difference in planktonic–benthic in global δ18O by the late Oligocene. All these inferences suggest the role of the NADW sourced at the Nordic seas to form background cooler conditions in the long time scale since the early Oligocene, or to form permanent conditions of invigorated thermohaline circulation that forces CO2 trap in the oceans. 相似文献
14.
Piotr A. Przybylski James G. Ogg Andrzej Wierzbowski Angela L. Coe Mark W. Hounslow John K. Wright François Atrops Erik Settles 《Earth and Planetary Science Letters》2010,289(1-2):256-272
A magnetic polarity pattern for Boreal and Sub-Boreal ammonite zones of the Upper Oxfordian to Lower Kimmeridgian was established and confirmed in four British sections, including the proposed Global Boundary Stratotype Section and Point (GSSP) on the Isle of Skye (Scotland) to define the base of the international Kimmeridgian Stage. A coeval pattern for Sub-Mediterranean ammonite zones was compiled from seven sections in Poland, one German section and multi-section composites from France and Spain. The mean paleopole for the European Craton (excluding Spain) at the Oxfordian–Kimmeridgian boundary is 74.2°N, 181.3°E (Α95 = 3.8°). The common magnetic polarity scale enables inter-correlation of ammonite subzones among these three faunal provinces and to the marine magnetic-anomaly M-Sequence. The proposed GSSP at the base of the Pictonia baylei Zone is near the base of an extended interval dominated by reversed polarity, which is interpreted to be Chron M26r. This GSSP level projects to the lower to middle part of the Epipeltoceras bimammatum Subzone, which is the middle subzone of this E. bimammatum Zone in the Sub-Mediterranean standard zonation. In contrast, the traditional placement of the Oxfordian–Kimmeridgian boundary in that Sub-Mediterranean standard zonation (base of Sutneria platynota Zone) is at the base of Chron M25r, or nearly 1 million years younger. 相似文献
15.
A statistical study of magnetosphere–ionosphere coupling in the Lyon–Fedder–Mobarry global MHD model
B. Zhang W. Lotko M.J. Wiltberger O.J. Brambles P.A. Damiano 《Journal of Atmospheric and Solar》2011,73(5-6):686-702
The statistics of magnetosphere–ionosphere (MI) coupling derived from a two-month long run of the Lyon–Fedder–Mobarry (LFM) global simulation model are investigated. MI coupling characteristics such as polar cap potential and field-aligned current (FAC), downward Poynting flux and vorticity of ionospheric convection are compared with observed statistical averages and with results from the Weimer 05 empirical model. The comparisons for eight different IMF clock-angle orientations show that the LFM model produces reasonably accurate average distributions of the Region I and Region II currents. Both current systems have average amplitudes similar to those observed by the Iridium satellite constellation; however, the average LFM amplitudes are smaller by a factor of two compared with the values from the Weimer 05 model. The comparisons of polar cap potential show that the LFM model produces reasonable patterns of ionospheric convection, but the average cross polar cap potential (CPCP) is greater than the observed results by a factor of approximately 2 and greater than Weimer 05 by a factor of 1.5. The differences in convection in LFM results relative to the Weimer 05 model accounts for much of the difference in the Poynting flux patterns and integrated power produced by the two models. The comparisons of average ionospheric field-aligned vorticity show good agreement on the dayside; however, the LFM model gives higher nightside vorticity which may imply that the ionospheric conductance on the nightside is too small in the simulation. 相似文献
16.
We recall how the Sun is introduced in the present climatic models and discuss why the solar standard model (SSM) framework is insufficient to describe the Sun–Earth medium term relationship. We then report on the different sources of variability. The SoHO mission allows a comparison between two successive solar minima and puts new constraints on the internal rotation profile. The coming space missions SDO and PICARD will add crucial information on internal circulations and on the superficial asphericity. The interplay between the solar dynamics and terrestrial atmospheric models is in its infancy, it calls for medium term uninterrupted solar observations which will take benefit of a formation flying concept. 相似文献
17.
Slinchuk G. E. Yakovlev D. V. Yakovlev A. G. Shirokova E. P. 《Izvestiya Physics of the Solid Earth》2022,58(5):655-669
Izvestiya, Physics of the Solid Earth - Abstract—The deep structure of the northern framing of the Siberian Platform is studied based on three-dimensional (3D) inversion of regional... 相似文献
18.
While it is well known that high fluxes of relativistic electrons in the Earth's radiation belts are associated with high-speed solar wind and its heightened geoeffectiveness, less known is the fact that the Russell–McPherron (R–M) effect strongly controls whether or not a given high-speed stream is geoffective. To test whether it then follows that the R–M effect also strongly controls fluxes of relativistic electrons, we perform a superposed epoch analysis across corotating interaction regions (CIR) keyed on the interfaces between slow and fast wind. A total of 394 stream interfaces were identified in the years 1994–2006. Equinoctial interfaces were separated into four classes based on the R–M effect, that is, whether the solar wind on either side of the interface was either (geo)effective (E) or ineffective (I) depending on season and the polarity of the interplanetary magnetic field (IMF). Four classes of interface identified as II, IE, EI, and EE are possible. The classes IE and EI correspond to CIRs with polarity changes indicating passage through the heliospheric current sheet. To characterize the behavior of solar wind and magnetospheric variables, we produced maps of dynamic cumulative probability distribution functions (cdfs) as a function of time over 10-day intervals centered on the interfaces. These reveal that effective high-speed streams have geomagnetic activity nearly twice as strong as ineffective streams and electron fluxes a factor of 12 higher. In addition they show that an effective low-speed stream increases the flux of relativistic electrons before the interface so that an effective to ineffective transition results in lower fluxes after the interface. We conclude that the R–M effect plays a major role in organizing and sustaining a sequence of physical processes responsible for the acceleration of relativistic electrons. 相似文献
19.
Ascertaining the emplacement mechanism of oceanic basaltic lavas is important in understanding how ocean floor topography is produced and oceanic plates evolve, particularly during the early stages of crustal development of a supra-subduction zone. A detailed study of the volcanic stratigraphy at International Ocean Discovery Program (IODP) Site U1438 in the Amami Sankaku Basin, west of the Kyushu–Palau Ridge, has revealed the development of lava accretion and ridge topography on the Philippine Sea plate at about 49 Ma. Igneous basement rocks penetrated at Site U1438 are the uppermost 150 m of ~6 km-thick oceanic crust, and comprise, in a downhole direction, sheet flows (12.6 m), lobate sheet flows (61.3 m), pillow lavas (50.7 m), and thin sheet flows (25.3 m). The lowermost sheet flows are intercalated with layers of limestone and epiclastic tuff. Lithofacies analysis reveals that the lowermost sheet flows, limestone, and tuff formed on an axial rise, the pillow lavas were emplaced on a ridge slope, and the lobate sheet flows formed off ridge on an abyssal plain. The lithofacies of the basement basalt corresponds to the upper portions of fast-spreading oceanic crust, suggesting that subduction initiation was associated with intermediate to fast rates of seafloor spreading. The surface sheet flows are olivine–clinopyroxene-phyric basalt and differ from the lower basalt flows that contain phenocrysts of olivine and plagioclase, with or without clinopyroxene. The depleted chrome-spinel composition and olivine–clinopyroxene phenocryst assemblage in the surface sheet flows suggests a slight contribution of water for magma generation not present for the lower basalt flows. Considering the lithological difference between the backarc and forearc oceanic crust in the Izu–Bonin–Mariana arc, with sheet flow dominant in the former, seafloor spreading occurred faster in the later stage of subduction initiation. 相似文献