Stationarity of atmospheric waves and blocking over Europe—based on a reanalysis dataset and two climate scenarios     

Frank Kreienkamp  Arne Spekat  Wolfgang Enke 《Theoretical and Applied Climatology》2010,102(1-2):205-212

In this investigation, a circulation index was used which is capable of tracing blocked states of the hemispheric circulation which has a relevance for a mid-latitude window between 40° and 60°N and between 30°W and 30°E. Results with respect to the seasonality of blocking situations are presented. Additionally, it is shown to which degree the circulation conditions, as they are simulated by the ECHAM5-MPI/OM1 climate model, have a tendency to exhibit blocking. Finally, results are presented which indicate the developments in blocking if the index is applied to scenario runs of the model.  相似文献   

Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments   总被引：1，自引：0，他引：1  

Gunvor M. Nystrm  Lisbeth M. Ottosen  Arne Villumsen 《Engineering Geology》2005,77(3-4):349-357

Electrodialytic removal of heavy metals from different harbour sediments was investigated. Electrodialytic remediation experiments in laboratory scale were made with calcareous and non-calcareous harbour sediments. Two different experimental set-ups were used for the study, one with stirring of the sediment slurry, the other without stirring. The removal of heavy metals was highest in the non-calcareous sediment, where 94% Cd, 91% Zn and 73% Cu were removed after 24 days. The highest removal obtained for the calcareous sediment was 81% Cd, 76% Zn, 75% Pb and 53% Cu after 21 days, with stirred sediment slurry. Electrodialytic experiments without stirring of calcareous sediment gave high removals (84% Zn, 58% Pb and 48% Cu), but there were problems with precipitations in the sediment, which limited the removal. The stirred experiments gave the highest removals of heavy metals and the voltage was the most stable in these experiments, and thus, the stirred set-up is the best choice for experimental set-up. The order in which the heavy metals were removed from the harbour sediments was Cd>Zn>Pb>Cu.  相似文献   

Method to Determine the Degree of Non-stoichiometry of Iron-Titanium Oxides     

Arne Gidskehaug 《Geophysical Journal International》1975,41(2):255-269

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Inherent gravitational instability of thickened continental crust with regionally developed low- to medium-pressure granulite facies metamorphism     

Taras V. Gerya  Walter V. Maresch  Arne P. Willner  Dirk D. Van Reenen  C.Andre Smit 《Earth and Planetary Science Letters》2001,190(3-4):221-235

Petrological arguments show that regionally developed low- to medium-pressure, high-temperature granulite facies metamorphism may critically enhance the lowering of crustal density with depth. This leads to gravitational instability of homogeneously thickened continental crust, mainly due to changes in mineral assemblages and the thermal expansion of minerals in conjunction with the exponential lowering of the effective viscosity of rocks with increasing temperature. It is argued that crustal processes of gravitational redistribution (crustal diapirism) contributing to the exhumation of granulite facies rocks may be activated in this way.  相似文献   

Population Belongs on the Johannesburg Agenda     

Wolfgang Lutz  Mahendra Shah  Richard E. Bilsborrow  John Bon-gaarts  Partha DasGupta  Barbara Entwisle  Günther Fischer  Brigida Garcia  Daniel J. Hogan  Arne Jernelöv  Zhenghua Jiang  Robert W. Kates  Sanjaya Lall  F. Landis MacKellar  P.K. Makinwa-Adebusoye  Anthony J. McMichael  Vinod Mishra  Norman Myers  Nebojsa Nakicenovic  Sten Nilsson  Brian C. O'Neill  Xizhe Peng  Harriet B. Presser  Nafis Sadik  Warren C. Sanderson  Gita Sen  Barbara Torrey  Dirk van de Kaa  Hans J.A. van Ginkel  Brenda Yeoh  Huda Zurayk 《Global Change & Human Health》2002,3(1):33-35

The forthcoming World Summit on Sustainable Development (WSSD) in Johannesburg (August 26-September 4, 2002) has been set by the United Nations to consider strategies toward sustainable development in all its dimensions. Hence, its mandate is broader than that of the Rio 1992 United Nations Conference on Environment and Development (UNCED). Population issues have so far been discussed in a separate series of World Population Conferences (Bucharest 1974, Mexico City 1984, Cairo 1994). With no new World Population Conference scheduled for 2004 and Johannesburg having a mandate that is stated to explicitly include social and economic aspects, population as a key component of sustainable development should figure prominently on the Johannesburg agenda. Yet, after the third of four preparatory meetings for Johannesburg (which ended in New York on April 5th), consideration of population is completely absent. The reasons for this are not entirely clear. We assume that they have to do with the fear of entering into political controversies over abortion. We are concerned that, despite its broader mandate, in most countries inputs to Johannesburg are being prepared mainly by environment ministries who have little experience in dealing with population questions. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Three-dimensional modelling of an isolated carbonate buildup (Triassic, Dolomites, Italy)   总被引：1，自引：0，他引：1  

Wolfgang Blendinger  Peter Brack†  Arne Kristoffer Norborg‡  Erik Wulff-Pedersen§ 《Sedimentology》2004,51(2):297-314

The Middle Triassic carbonate buildups of the Dolomites show facies similarities with mud mounds but display apparent architectural elements of flat‐topped carbonate platforms. In order to test whether the facies similarities to mounds are also reflected in the internal buildup architecture, a three‐dimensional modelling study of the Middle Triassic Monte Cernera buildup has been carried out. The Cernera buildup exhibits apparent geometries suggesting a mounded platform in the lower and uppermost part of the buildup, separated by an interval with apparent platform geometry and a retrogradational platform interior, which is difficult to explain with a flat top platform model. For this purpose, a number of three‐dimensional models were constructed using the three‐dimensional modelling programme petrel ^TM. Key geological horizons were constructed based on outcrop measurements, intermediate horizons were calculated in the modelling program, and the intersections of the modelled layers with a digital topography surface were displayed and compared with outcrop photographs. The models were refined stepwise until a best fit with the actual bedding architecture was achieved. The best fit model shows that the mounded geometries in the lower and uppermost part of the buildup are real architectural elements. The intermediate platform stage, about 1·5 km across, had probably retained a mounded top with a relief of up to 50 m, which is difficult to distinguish from an absolutely flat top, but necessary to explain the retrogradational platform interior. The present study shows that Monte Cernera was dominated by mounded geometries at all stages of platform development. The mounded geometry plus facies data suggest that the platform is a deep‐water accumulation, below the zone of intense wave energy, but within the photic zone. The Cernera represents a tropical buildup type, which did not have the capacity to grow into continuously wave‐swept environments because of the small size and the absence of a wave‐resistant energy barrier. Such buildup types are probably common after major crises in earth history, when reef organisms were virtually absent.  相似文献   

Elektrooptische entfernungsmessung     

Arne Bjerhammar 《Journal of Geodesy》1956,30(2):1-15

Ohne Zusammenfassung übersetzung von: Elektrooptisk avst?ndsm?tning,Svensk Lantm?teritidskr. 2 (1955).  相似文献   

Leaching of nitrate from arable land into groundwater in Sweden     

Arne Gustafson 《Environmental Geology》1983,5(2):65-71

The agricultural influence on the quality of the groundwater in Sweden is mostly associated with infiltration areas. The local conditions here determine the extent of the nitrate leakage. It is evident that certain combinations of factors in normal cropping can give unduly high nitrate concentrations in the groundwater.  相似文献   

Correlations between metamorphic events and Rb-Sr ages in metasediments and eclogite from Western Tasmania     

Arne Rheim  William Compston 《Lithos》1977,10(4):271-289

The Strathgordon area of low metamorphic grade (450±50°C, 4±1 Kb) and the eclogitebearing Lyell Highway-Collingwood River area, which is of higher grade (670±20°C, 11±1 Kb), have been studied by the Rb-Sr technique.

Three deformational events, D₁ to D₃ correlate in time with two important P,T events, here termed D₂₋₂ and D₃, D₁₋₂ reflects the continuous prograde P,T environment up to the metamorphic maximum of the two areas (D₂), while D₂ is a superimposed deformational event occuring at lower P,T conditions. According to stratigraphical constraints D₃ must have occured before or about 550 m.y. ago.

It is possible from rather complex Rb-Sr data to indicate ages for the D_1–2 and D₃ events. Two-point total rock+phengite (mica) ages together with total rock isochrons using closely spaced samples show that the main metamorphic event D_1–22 occurrred at about 800 m.y. in both areas. Similar data suggest that the superimposed event D₃ occurred between 550 and 630 m.y. ago, probably near the lower age limit. This deformation (crenulation cleavage) was responsible for the local resetting of total rock and mineral systems.

Consistent with later Palaeozoic events, the Cambrian-early Ordovician Jukesian Movement and the Devonian Tabberabberan Orogeny, which affected some Rb-Sr mineral systems (phengite, amphibole and chlorite), have ages of 500±20 m.y. and 385-350 m.y. respectively.

Due to dispersion of the eclogite total rock data points along secondary isochrons it is difficult to estimate an original age. The age of the original minerals must however have been set by the 800 m.y. D_1–2 event, as the P,T history of the eclogite is the same as that of the surrounding schists.  相似文献   

Secondary geologically meaningless Rb---Sr isochrons, low Sr/Sr initial ratios and crustal residence times of high-grade gneisses     

Dennis Field  Arne Rheim 《Lithos》1980,13(4):295-304

Dark green quartzo-feldspathic charnockitic ortho-gneisses from Arendal, southern Norway, have locally been decoloured in the vicinities of intrusive, undeformed granite sheets and pegmatite dikes. The result is a series of pink rocks which are macroscopically indistinguishable from primary augen granite gneisses. The main mineralogical changes associated with the secondary decolcuration occurred under relatively low-grade conditions, and mainly involved chlorite, serpentine ± actinolitic amphibole ± biotite growth. The alterations were initiated along narrow, irregularly spaced cracks. The primary ( 1540 m.y.) total rock Rb---Sr isotopic systems which relate to the charnockite mineralogy were disturbed, and sometimes reset, during the secondary event which occurred at 1060 m.y. Locality by locality, the decoloured samples yield linear arrays corresponding to 1457 ± 200 m.y., 1303 ± 50 m.y. and 1125 ± 185 m.y. The combined data (n = 19) give an apparent age of 1364 ± 43 m.y. with an ⁸⁷Sr/⁸⁶Sr initial ratio of 0.7011 ± 0.0018. This apparent age is unrelated to any geological event and there is no overlap at the 2δ level between the ⁸⁷Sr/⁸⁶Sr initial ratio and that defined by the primary event (0.70345 ± 0.00014). Any estimate of crustal residence time based on these decoloured samples would be in error. The weight of evidence is against significant involvement of Rb mobility in the isotopic resetting process which accompanied decolouration. A model involving modification of the ⁸⁷Sr/⁸⁶Sr ratios is preferred.  相似文献