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161.
Bas J. van Ruijven Marc A. Levy Arun Agrawal Frank Biermann Joern Birkmann Timothy R. Carter Kristie L. Ebi Matthias Garschagen Bryan Jones Roger Jones Eric Kemp-Benedict Marcel Kok Kasper Kok Maria Carmen Lemos Paul L. Lucas Ben Orlove Shonali Pachauri Tom M. Parris Anand Patwardhan Arthur Petersen Benjamin L. Preston Jesse Ribot Dale S. Rothman Vanessa J. Schweizer 《Climatic change》2014,122(3):481-494
This paper discusses the role and relevance of the shared socioeconomic pathways (SSPs) and the new scenarios that combine SSPs with representative concentration pathways (RCPs) for climate change impacts, adaptation, and vulnerability (IAV) research. It first provides an overview of uses of social–environmental scenarios in IAV studies and identifies the main shortcomings of earlier such scenarios. Second, the paper elaborates on two aspects of the SSPs and new scenarios that would improve their usefulness for IAV studies compared to earlier scenario sets: (i) enhancing their applicability while retaining coherence across spatial scales, and (ii) adding indicators of importance for projecting vulnerability. The paper therefore presents an agenda for future research, recommending that SSPs incorporate not only the standard variables of population and gross domestic product, but also indicators such as income distribution, spatial population, human health and governance. 相似文献
162.
Dario Del Moro Luca Giovannelli Ermanno Pietropaolo Francesco Berrilli 《Experimental Astronomy》2017,43(1):23-37
Hyperspectral imaging is an ubiquitous technique in solar physics observations and the recent advances in solar instrumentation enabled us to acquire and record data at an unprecedented rate. The huge amount of data which will be archived in the upcoming solar observatories press us to compress the data in order to reduce the storage space and transfer times. The correlation present over all dimensions, spatial, temporal and spectral, of solar data-sets suggests the use of a 3D base wavelet decomposition, to achieve higher compression rates. In this work, we evaluate the performance of the recent JPEG2000 Part 10 standard, known as JP3D, for the lossless compression of several types of solar data-cubes. We explore the differences in: a) The compressibility of broad-band or narrow-band time-sequence; I or V Stokes profiles in spectropolarimetric data-sets; b) Compressing data in [x,y, λ] packages at different times or data in [x,y,t] packages of different wavelength; c) Compressing a single large data-cube or several smaller data-cubes; d) Compressing data which is under-sampled or super-sampled with respect to the diffraction cut-off. 相似文献
163.
Khaled Al-Kahtany Abdelbaset El-Sorogy Fahd Al-Kahtany Mohamed Youssef 《Arabian Journal of Geosciences》2018,11(7):155
To assess heavy metals in mangrove swamps of Sehat and Tarut coastal areas along the Arabian Gulf, 18 sediment samples were collected for Al, V, Cr, Mn, Cu, Zn, Cd, Pb, Hg, Sr, As, Fe, Co, and Ni analysis. The results indicated that the distribution of some metals was largely controlled by anthropogenic inputs, while others were of terrigenous origin and most strongly associated with distribution of aluminum and total organic carbon in sediments. Mangrove sediments were extremely severe enriched with Sr (EF?=?67.59) and very severe enriched with V, Hg, Cd, Cu, As (EF?=?44.28, 37.45, 35.77, 25.97, and 11.53, respectively). Average values of Sr, V, Hg, Cd, Cu, Ni, As, and Cr were mostly higher than the ones recorded from the Mediterranean Sea, the Red Sea, the Gulf of Aqaba, the Caspian Sea, the Arabian and Oman gulfs, coast of Tanzania, sediment quality guidelines, and the background shale and the earth crust. Landfilling due to coastal infrastructure development around mangrove forests, oil spills and petrochemical and desalination effluents from Al-Jubail industrial city to the north were the anthropogenic activities that further enhanced heavy metals in the studied mangrove sediments. 相似文献
164.
James P. Adams Robert Kirst Lance E. Kearns Mark P. S. Krekeler 《Environmental Geology》2009,58(6):1269-1280
The Chesapeake Bay is greatly impacted by numerous pollutants including heavy metals and understanding the controls on the
distribution of heavy metals in the watershed is critical to mitigation and remediation efforts in controlling this type of
pollution. Clasts from a stormwater catchment basin draining a subdivision near George Mason University, Fairfax VA (38°50.090°N
78°19.204°W) were investigated using X-ray diffraction (XRD), Scanning electron microcopy (SEM) and energy dispersive spectroscopy
(EDS) to determine the nature of Mn-oxide coatings and relationship to bound heavy metals. Mn-oxides are poorly crystalline
and occur as subhedral to anhedral platy particles and more rarely as euhedral plates. Micronodules are a commonly observed
texture. Chemical compositions of coatings are variable with average major constituent concentrations being Mn (33.38 wt%),
Fe (11.88 wt%), Si (7.33 wt%), Al (5.03 wt%), and Ba (0.90 wt%). Heavy metals are found in the coatings with Zn being most
prevalent, occurring in approximately 58% of analyses with an average concentration of (0.66 wt%). Minor amounts of Co, Ni,
Pb, and Cl are observed. Heavy metals and Cl are interpreted as being derived from road pollution. Mn-oxides can serve as
a sequestration mechanism for pollution but may also release heavy metals. Field and laboratory observations indicate Mn-oxides
occurring on the surface of the clasts can be mechanically mobilized. This is a mechanism for transporting heavy metals into
the Chesapeake Bay watershed. Deicing agents may serve as a mechanism to release heavy metals through cation exchange and
increased ionic strength. This is the first detailed mineralogical investigation of Mn-oxides and the roles they may play
in pollution in the Chesapeake Bay. 相似文献
165.
Position and velocity perturbations for the determination of geopotential from space geodetic measurements 总被引:10,自引:0,他引:10
Peiliang Xu 《Celestial Mechanics and Dynamical Astronomy》2008,100(3):231-249
Although space geodetic observing systems have been advanced recently to such a revolutionary level that low Earth Orbiting
(LEO) satellites can now be tracked almost continuously and at the unprecedented high accuracy, none of the three basic methods
for mapping the Earth’s gravity field, namely, Kaula linear perturbation, the numerical integration method and the orbit energy-based
method, could meet the demand of these challenging data. Some theoretical effort has been made in order to establish comparable
mathematical modellings for these measurements, notably by Mayer-Gürr et al. (J Geod 78:462–480, 2005). Although the numerical
integration method has been routinely used to produce models of the Earth’s gravity field, for example, from recent satellite
gravity missions CHAMP and GRACE, the modelling error of the method increases with the increase of the length of an arc. In
order to best exploit the almost continuity and unprecedented high accuracy provided by modern space observing technology
for the determination of the Earth’s gravity field, we propose using measured orbits as approximate values and derive the
corresponding coordinate and velocity perturbations. The perturbations derived are quasi-linear, linear and of second-order
approximation. Unlike conventional perturbation techniques which are only valid in the vicinity of reference mean values,
our coordinate and velocity perturbations are mathematically valid uniformly through a whole orbital arc of any length. In
particular, the derived coordinate and velocity perturbations are free of singularity due to the critical inclination and
resonance inherent in the solution of artificial satellite motion by using various types of orbital elements. We then transform
the coordinate and velocity perturbations into those of the six Keplerian orbital elements. For completeness, we also briefly
outline how to use the derived coordinate and velocity perturbations to establish observation equations of space geodetic
measurements for the determination of geopotential. 相似文献
166.
167.
Hemant Kumar Singh Aswathi Thankappan Poonam Mohite Satish Kumar Sinha Dornadula Chandrasekharam Trupti Chandrasekhar 《Arabian Journal of Geosciences》2018,11(6):137
Tulsishyam thermal springs are located in the Saurashtra region of Gujarat, India with discharge temperatures varying from 39 to 42 °C. The pH of these thermal springs varies from 7.1 to 7.4, indicating neutral character. Though these thermal springs propagate through the near surface layer of Deccan basalt, detailed geochemical analysis of the thermal waters using Piper diagram suggests that the water is interacting with the granitic basement rock. Silica and cation geothermometry estimates have reservoir temperature in the range of 138 to 207 °C categorizing it into a low to moderate enthalpy geothermal system. Furthermore, the area has high heat flow values of 53–90 mW/m2 because of shallow Moho depth. The prevailing conditions suggest that the geothermal energy can potentially be exploited through an enhanced geothermal system (EGS). The study also indicates different mineral phases that may precipitate out of water during exploitation of geothermal energy and it should be taken into account while designing an EGS for the area. 相似文献
168.
Analysis of noble gases in water using a quadrupole mass spectrometer in static mode 总被引:1,自引:0,他引:1
Jason C. Poole Gavin W. McNeill Stephen R. Langman Frank Dennis 《Applied Geochemistry》1997,12(6):707-714
A quadrupole-based mass spectrometer used in static mode has been employed to determine noble gas concentrations of water samples by isotope dilution. Water samples are degassed and spiked with minor isotopes of each noble gas. After separation of the various gas components, the isotopic ratios are measured in the mass spectrometer. Because a spike is added to each sample, the recovery of each gas component does not have to be quantitative. Equilibration temperatures are calculated from the gas concentrations, based on noble gas solubility data. An accuracy of ±1°C, from the air equilibration temperature, is attainable for air-saturated water samples prepared under controlled conditions in the laboratory. The method has been applied to groundwaters from the London Basin Chalk aquifer. The noble-gas-derived temperatures are consistent with climatic conditions prevailing at the periods of recharge. 相似文献
169.
The presence of a gassy ground condition is an important problem in tunneling. In this study, the effects of groundwater H2S and CH4 emissions are investigated and characterized together with the factors that created these conditions in Nosoud tunnel in Iran. Through the geological investigations, the presence of these gasses was not detected prior to the construction of the tunnel. Groundwater sampling indicated that about 1 L of H2S is released per 100 L of the water inflow into the Nosoud tunnel under normal conditions. However, the volume of the released gas was varying with the changes in the groundwater discharge rate. Thus, estimation of groundwater inflow into the tunnel is necessary for predicting the volume of gas emission. Based on the experience of the Nosoud tunnel excavations, there are several geological and hydrogeological factors that must be considered as the indicators of gas emissions during tunneling. Considering the importance of ground water gas emission into the tunnels located in gassy conditions, the present work was conducted to predict the H2S seepage before the excavation using geological and hydrogeological indicators. 相似文献
170.
Javad Ashjari Mojtaba Noori Reza Azimi Mohammad Nakhaei 《Arabian Journal of Geosciences》2016,9(3):227
Hydrogeologically, faults may impede, conduit, exert no influence, or may play a combination of these roles on groundwater flow. The object of this paper is to study the hydrogeological role of the Tabarteh fault, which is located on the border of Zagros and Central Iran tectonic zones in an alluvial aquifer. The recorded data of water table levels, chemical parameters, and discharge rate of wells, in addition to geological maps and geophysical results, were collected and evaluated. The outcrop of travertine in limited areas and the emergence of a few small springs within the alluvium show a barrier role of the fault in the groundwater flow. The spatial analysis of chemical components, head time series, and groundwater flow direction assessment demonstrated that the fault acts as both a barrier and a non-barrier in different sections. The multivariate statistical methods of cluster and discriminant analyses also confirm the dual role of the fault. 相似文献