Ice-sheet growth and high-latitudes sea-surface temperature     

A. Berger  H. Gallée  X. S. Li  A. Dutrieux  M. F. Loutre 《Climate Dynamics》1996,12(7):441-448

The response of the LLN 2-D climate model to the insolation and CO₂ forcings during the Eemian interglacial is compared to reconstructions obtained from deep-sea cores drilled in the Norwegian Sea and in the North Atlantic. Both reconstructions and modeling results show a decrease of sea-surface temperature (SST) in the higher latitudes (70–75 °N zonal belt for the model and the Norwegian Sea for the proxy records), associated with a more moderate cooling at lower latitudes (50–55 °N and North Atlantic), at the middle of isotopic substage 5e, several millenia before the beginning of continental ice-sheet growth. Such a comparison between the simulated SST and ice volume of the Northern Hemisphere has been extended to the whole last glacial-interglacial cycle. The influence of the insolation forcing on SST and the shortcomings of the model due to its zonal character are discussed. Received: 6 July 1995/Accepted: 19 December 1995  相似文献   

Extreme value analysis of the sea state at the “nordsee” research platform and off Hörnum/Sylt     

Ralf Berger 《Ocean Dynamics》1993,45(2):107-113

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Application de méthodes d’analyse biochimique à un problème taxonomique: les Corégones du lac de Neuchâtel1, 2, 4     

Jean-Pierre Par Bargetzi 《Aquatic Sciences - Research Across Boundaries》1960,22(2):641-758

Sans résumé Travail réalisé avec l’appui du Fonds national suisse de la Recherche. La rédaction du présent travail est antérieure au mémoire deDottrens [254]³). La parution du texte de cet auteur a très exactement co?ncidé avec la présentation de notre thèse. Ces deux recherches ont été accomplies indépendamment. D’après les conclusions deDottrens, les Corégones du lac de Neuchatel doivent désormais être désignés par Le mot ?ichtyologie? et les termes de la même famille sont orthographiés avec un seul ?h? en accord avec une décision récente de l’Académie.  相似文献   

Differences in grain growth of calcite: a field-based modeling approach     

Marco?HerweghEmail author  Alfons?Berger 《Contributions to Mineralogy and Petrology》2003,145(5):600-611

Normal grain growth of calcite was investigated by combining grain size analysis of calcite across the contact aureole of the Adamello pluton, and grain growth modeling based on a thermal model of the surroundings of the pluton. In an unbiased model system, i.e., location dependent variations in temperature-time path, 2/3 and 1/3 of grain growth occurs during pro- and retrograde metamorphism at all locations, respectively. In contrast to this idealized situation, in the field example three groups can be distinguished, which are characterized by variations in their grain size versus temperature relationships: Group I occurs at low temperatures and the grain size remains constant because nano-scale second phase particles of organic origin inhibit grain growth in the calcite aggregates under these conditions. In the presence of an aqueous fluid, these second phases decay at a temperature of about 350 °C enabling the onset of grain growth in calcite. In the following growth period, fluid-enhanced group II and slower group III growth occurs. For group II a continuous and intense grain size increase with T is typical while the grain growth decreases with T for group III. None of the observed trends correlate with experimentally based grain growth kinetics, probably due to differences between nature and experiment which have not yet been investigated (e.g., porosity, second phases). Therefore, grain growth modeling was used to iteratively improve the correlation between measured and modeled grain sizes by optimizing activation energy (Q), pre-exponential factor (k₀) and grain size exponent (n). For n=2, Q of 350 kJ/mol, k₀ of 1.7×10²¹ mⁿs^–1 and Q of 35 kJ/mol, k₀ of 2.5×10^-5 mⁿs^–1 were obtained for group II and III, respectively. With respect to future work, field-data based grain growth modeling might be a promising tool for investigating the influences of secondary effects like porosity and second phases on grain growth in nature, and to unravel differences between nature and experiment.Editorial responsibility: J. Hoefs  相似文献   

Regional land surface energy fluxes by satellite remote sensing in the Upper Xilin River Watershed (Inner Mongolia, China)   总被引：1，自引：0，他引：1  

L. Fan  Sh. Liu  Ch. Bernhofer  H. Liu  F. H. Berger 《Theoretical and Applied Climatology》2007,88(3-4):231-245

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Synthesis of deep-sea drilling results in the Indian ocean. Elsevier oceanography series, 21 | C.C. van der Borch (editor), 1978. Elsevier,Amsterdam, 175 pp., Dfl. 90.00, U.S. $ 37.50     

W.H. Berger 《Earth》1979,14(3):306-307

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Deformation pattern in a heterogeneous material: Folded and cleaved sedimentary cover immediately overlying a crystalline basement (Oisans, French Alps)     

Jean-Pierre Gratier  Pierre Vialon 《Tectonophysics》1980,65(1-2)

Particularly well exposed structures in folded and cleaved sedimentary cover immediately overlying a crystalline basement have been studied. Chemical analysis (X.R.F. and microprobe) reveal pressure solution process and give the possibilities of measurement of mass transfer. Study of fluid inclusion veins has determined the temperature pressure conditions: thermal effect of the basement and decrease of temperature and pressure with the age of various synkinematic veins.Characteristic examples of the behaviour of a heterogeneous material during coaxial and non-coaxial deformation are shown:

1. (1) Successive different asymmetrical folds, various cleavages and fractures appear in a shear zone parallel to the main fabric with variations of thickness and rock behaviour.

2. (2) Evolution of cleavage in such a shear zone (with or without slipping) is linked to the relations between the rotation of contraction direction and the rate of the cleavage process.

3. (3) Fold axes changed from the horizontal y direction to the vertical (or E—W transversal to the crystalline massif) X direction, with increase of the (X/Z) and (X/Y) ratios (obtained by fossils and reconstructed fold shape). This strain is always heterogeneous and the most deformed zone frequently evolves to discontinuities with slip.

4. (4) Indentation exists on all scale: from hard object (100 μ, with parenthesis form of pressure solution cleavage apparent on map distribution of various element) to basement block (with variation of strain value in the indented cover).

A model of the evolution of the deformation of sedimentary cover immediately overlying a crystalline basement is given in conclusion.  相似文献   

Les tremblements de terre en France: J. Vogt (Editeur), Bureau de Recherches Géologiques et Miniéres, Mémoire 96, 1979, 80.00 FF, US $ 20.00     

Jean-Pierre Roth 《Tectonophysics》1980,70(1-2)

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First-order analysis of deformation of a thrust sheet moving over a ramp     

Philip Berger  Arvid M. Johnson   《Tectonophysics》1980,70(3-4):T9-T24

John L. Rich introduced the revolutionary concept that many folds in the Appalachian Mountains can be explained as superficial structures formed by passive translation of thrust blocks over ramps in detachment surfaces. The amount of layer-parallel shortening can be negligible in the formation of these folds. Rich primarily was concerned with an explanation for the Powell Valley anticline, in the southern Appalachians, but the essential kinematic features of his model of folding have been verified in other folds in the Appalachians, in the Canadian Rockies, in the Idaho-Wyoming thrust belt, and in the Pyrenees. In this paper we solve the boundary-value problem for an idealized thrust block moving over a detachment surface and ramp with zero drag, and produce theoretical fold forms in the thrust block that closely resemble those in Rich's idealized model. The anticline is narrow and rounded if the translation is small, and broad and flat-topped if the translation is large. The limbs of the anticline are symmetric. We also incorporate drag along the ramp part of the detachment surface in order to derive a possible explanation for the asymmetry of dips of the two limbs of the Powell Valley anticline. We show that drag can explain the asymmetry, particularly if drag between relatively competent rocks in opposition at the ramp caused an initial anticline to form as the thrust block began to move, and then drag reduced markedly as relatively soft shales at the base of the block were thrust over competent rocks in the ramp. The existence of the initial anticline should be reflected in asymmetry of the two limbs and in a bulge at the distal edge of the broad anticline.  相似文献   

Upper Limit of Iodine Oxide in the Lower Stratosphere     

Irene Pundt  Jean-Pierre Pommereau  Celine Phillips  Eric Lateltin 《Journal of Atmospheric Chemistry》1998,30(1):173-185

It has been suggested that iodine oxides, IOx, could play a significant role in the ozone destruction in the lower stratosphere. To investigate this suggestion, spectra from nine SAOZ uv-visible spectrometer balloon flights were examined for the IO absorption signature between 405 and 450 nm. IO was not detected, either at mid- or high latitude, in the morning or the evening, in summer or winter. An upper limit of 0.2 parts per trillion by volume (pptv) at 20 km and 0.1 pptv at 15 km at the 95% confidence level (2), was derived from the best measurements at 90° SZA at sunset and sunrise. Since a photochemical model shows that 70% of inorganic iodine should be in the form IO at that time, it is concluded that unless iodine chemistry is different from that assumed at the moment, the role of iodine in stratospheric ozone depletion is small.  相似文献