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141.
Andreas J. Scheib Manfred Birke Enrico Dinelli GEMAS Project Team 《Boreas: An International Journal of Quaternary Research》2014,43(1):175-192
Hafnium (Hf) and zirconium (Zr) concentrations measured in over 4100 agricultural soil samples from Europe were assessed with the focus on their relationship to the distribution of aeolian deposits, such as loess and coversands. Comparison of extractable (aqua regia; ICP‐MS) and total (XRFS) concentrations shows that only 1.0 to 1.7% of the total Hf and Zr is chemically extractable because of the resistant nature of their host minerals. Resistate minerals, such as zircon, are commonly found in the predominantly silty fraction of loess deposits. In this study a statistical analysis of total Hf and Zr soil data from areas with and without loess was carried out to derive threshold values of 10 mg kg?1 (Hf) and 318 mg kg?1 (Zr). These values were subsequently applied across the project area in an attempt to indicate the presence of aeolian deposits. The spatial distribution of above‐threshold concentrations suggests a more extensive and coherent loess belt across central and eastern Europe, providing additional evidence of loess across Brittany, Aquitaine and near the Vosges mountains in France as well as in the basins of central and northern Spain. Above‐threshold concentrations were also detected in loess regardless of its thickness, emphasising the importance of the abundance of zircon in the upper part of the soil profile rather than the actual thickness of the deposit. Soil data however, failed to indicate various loess facies within most of the Pannonian Basin, suggesting that this approach only works where deposits contain a sufficient amount of zircon. This may also explain why the extensive coversands across northern Germany and Poland were largely undetected. This study demonstrates that continental‐scale soil geochemical data can help identify and map the distribution of zircon‐rich loess and coversand, and subsequently enhance and improve current knowledge of the extent of these deposits. 相似文献
142.
Andreas Pilger 《International Journal of Earth Sciences》1950,38(2):139-144
Zusammenfassung In der vorliegenden Arbeit werden Aufwölbungen im Eis der Wattenküste vor Büsum mit den von H. Cloos beschriebenen Beulen in der Erdoberfläche verglichen. Beide entstehen durch vertikalen Druck von unten ohne Sehnenverkürzung, in deren Folge sich Spalten im Scheitel der Gewölbe bilden. Die völlige übereinstimmung in Form und Entstehung beider Erscheinungen lä\t die Watteisbeulen als geeignetes Beispiel erscheinen, um den Werdegang der Gro\formen zu verfolgen. Die kurze Notiz von H. Cloos über einen Scheitelgraben im Eise (1948) erschien erst nach Abschlu\ dieses Aufsatzes. 相似文献
143.
José?Rodríguez-AlgecirasEmail authorView authors OrcID profile Abel?Tablada Andreas?Matzarakis 《Theoretical and Applied Climatology》2018,133(3-4):663-679
Walkability and livability in cities can be enhanced by creating comfortable environments in the streets. The profile of an urban street canyon has a substantial impact on outdoor thermal conditions at pedestrian level. This paper deals with the effect of asymmetrical street canyon profiles, common in the historical centre of Camagüey, Cuba, on outdoor thermal comfort. Temporal-spatial analyses are conducted using the Heliodon2 and the RayMan model, which enable the generation of accurate predictions about solar radiation and thermal conditions of urban spaces, respectively. On these models, urban settings are represented by asymmetrical street canyons with five different height-to-width ratios and four street axis orientations (N-S, NE-SW, E-W, SE-NW). Results are evaluated for daytime hours across the street canyon, by means of the physiologically equivalent temperature (PET index) which allows the evaluation of the bioclimatic conditions of outdoor environments. Our findings revealed that high profiles (façades) located on the east-facing side of N-S streets, on the southeast-facing side of NE-SW streets, on the south-facing side of E-W street, and on the southwest-facing side of SE-NW streets, are recommended to reduce the total number of hours under thermal stress. E-W street canyons are the most thermally stressed ones, with extreme PET values around 36 °C. Deviating from this orientation ameliorates the heat stress with reductions of up to 4 h in summer. For all analysed E-W orientations, only about one fifth of the street can be comfortable, especially for high aspect ratios (H/W > 3). Optimal subzones in the street are next to the north side of the E-W street, northwest side of the NE-SW street, and southwest side of the SE-NW street. Besides, when the highest profile is located on the east side of N-S streets, then the subzone next to the east-facing façade is recommendable for pedestrians. The proposed urban guidelines enable urban planners to create and renovate urban spaces which are more efficient in diminishing pedestrian thermal stress. 相似文献
144.
A geography of insurance exclusion: perceptions of unemployment risk and actuarial risk assessment 总被引:4,自引:0,他引:4
Andreas Cebulla 《Area》1999,31(2):111-121
Summary Proposed welfare reform in Great Britain advocates joint public and private provision of insurance. Using omnibus survey data, this paper projects the availability and geographical coverage of private unemployment insurance in Britain among currently employed persons, on the basis of actuarial risk assessment criteria. It compares actuarial risk assessments with the respondents' subjective job risk assessments and their declared intention to take out private unemployment insurance. The paper identifies the extent and geography of structural/self-exclusion from insurance. 相似文献
145.
Andreas Herschel 《Limnologica》1999,29(2):195
A series of 7 growth experiments with Metallogenium sp. was conducted in a flow-through reactor (chemostat). The results demonstrate that Metallogenium sp. grows under simulated lake water conditions in the laboratory. Metallogenium reacted in the chemostat in the same way as a microorganism. The growth rates of the microorganism Metallogenium were determined. It can be concluded therefore that the maximal growth rate at a temperature of 15 °C was 0.7 d−1. 相似文献
146.
Variabilität der Primärproduktion aus dreidimensionalen Modellrechnungen für die Nordsee mit ECOHAM1
Ocean Dynamics - Mit dem dreidimensionalen Modell ECOHAM1 (Ecological North Sea Model, Hamburg, Version 1) wurde die jährliche Primärproduktion für die Jahre 1985 bis 1994 regional... 相似文献
147.
Jeffrey B. Ross Greg A. Ludvigson Andreas Möller Luis A. Gonzalez J. D. Walker 《中国科学:地球科学(英文版)》2017,60(1):44-57
Understanding of the role of atmospheric moisture and heat transport in the climate system of the Cretaceous greenhouse world represents a major challenge in Earth system science.Stable isotopic paleohydrologic data from mid-Cretaceous paleosols in North America,from paleoequatorial to paleoArctic latitudes,have been used to constrain the oxygen isotope mass balance of the Albian hydrologic cycle.Over the range from 40°-50°N paleolatitude,sideritic paleosols predominate,indicating paleoenvironments with positive precipitation-evaporation(P-E)balances.Local exceptions occur on leeward side of the Sevier Orogen,where calcic paleosols in the wedge-top depozone record paleoenvironments with negative P-E balances in the orographic rain shadow.Stratigraphic sections in the Wayan Formation of Idaho(WF)were sampled from the wedge-top depozone.The units consist of stacked m-scale mudstone paleosols separated by m-scale sandstone-siltstone beds.Sections were sampled for organic carbon isotope profiles,and B-horizons from 6 well-developed paleosols were sampled for detrital zircons to determine maximum depositional ages.The first of these from the WF has produced a U-Pb concordia age of 101.0±1.1 Ma.This same WF section has produced a stratigraphic trend of upwardly decreasingδ~(13)C values ranging from-24‰upwards to-27‰VPDB,suggesting correlation to the late Albian C15 C-isotope segment.Pedogenic carbonates from the WF principally consist of micritic calcite,with carbon-oxygen isotope values that array along meteoric calcite lines(MCLs)withδ~(18)O values that range from-9.47‰up to-8.39‰VPDB.At approximately 42°N paleolatitude,these MCL values produce calculated paleoprecipitation values of-8.12‰to-7.04‰VSMOW,a range that is consistent with the estimates produced from other proxies at the same paleolatitudes across North America.These results indicate that despite the orographic rain shadow effect,the processes of meridional atmospheric moisture transport in this locale were similar to those in more humid mid-latitude paleoenvironments elsewhere in the continent. 相似文献
148.
Naki Akçar Susan Ivy‐Ochs Vasily Alfimov Fritz Schlunegger Anne Claude Regina Reber Marcus Christl Christof Vockenhuber Andreas Dehnert Meinert Rahn Christian Schlüchter 《地球表面变化过程与地形》2017,42(14):2414-2425
In this study, we use isochron‐burial dating to date the Swiss Deckenschotter, the oldest Quaternary deposits of the northern Alpine Foreland. Concentrations of cosmogenic 10Be and 26Al in individual clasts from a single stratigraphic horizon can be used to calculate an isochron‐burial age based on an assumed initial ratio and the measured 26Al/10Be ratio. We suggest that, owing to deep and repeated glacial erosion, the initial isochron ratio of glacial landscapes at the time of burial varies between 6.75 and 8.4. Analysis of 22 clasts of different lithology, shape, and size from one 0.5 m thick gravel bed at Siglistorf (Canton Aargau) indicates low nuclide concentrations: <20 000 10Be atoms/g and <150 000 26Al atoms/g. Using an 26Al/10Be ratio of 7.6 (arithmetical mean of 6.75 and 8.4), we calculate a mean isochron‐burial age of 1.5 ± 0.2 Ma. This age points to an average bedrock incision rate between 0.13 and 0.17 mm/a. Age data from the Irchel, Stadlerberg, and Siglistorf sites show that the Higher Swiss Deckenschotter was deposited between 2.5 and 1.3 Ma. Our results indicate that isochron‐burial dating can be successfully applied to glaciofluvial sediments despite very low cosmogenic nuclide concentrations. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
149.
Rainfall–runoff models with different conceptual structures for the hydrological processes can be calibrated to effectively reproduce the hydrographs of the total runoff, while resulting in water budget components that are essentially different. This finding poses an open question on the reliability of rainfall–runoff models in reproducing hydrological components other than those used for calibration. In an effort to address this question, we use data from the Glafkos catchment in western Greece to calibrate and compare the ENNS model, a research-oriented lumped model developed for the river Enns in Austria developed for the river Enns in Austria, with the operational MIKE SHE model. Model performance is assessed in the light of the conceptual/structural differences of the modelled hydrological processes, using indices calculated independently for each year, rather than for the whole calibration period, since the former are stricter. We show that even small differences in the representation of hydrological processes may impact considerably on the water budget components that are not measured (i.e. not used for model calibration). From all water budget components, direct runoff exhibits the highest sensitivity to structural differences and related model parameters.
EDITOR M.C. AcremanASSOCIATE EDITOR S. Huang 相似文献
150.
Ngin Chanrith Grayman Jesse Hession Neef Andreas Sanunsilp Nichapat 《Natural Hazards》2020,103(1):299-316
Natural Hazards - Drawing on interviews with Cambodian and Thai communities in Auckland, New Zealand, this paper examines the role of Buddhist temples in disaster preparedness, response and... 相似文献