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71.
Results of the DEKORP 1 (BELCORP-DEKORP) deep seismic reflection studies in the western part of the Rhenish Massif 总被引:1,自引:0,他引:1
DEKORP Research GroupH.-J. Anderle R. Bittner R. Bortfeld J. Bouckaert G. Büchel G. Dohr H.-J. Dürbaum H. Durst W. Fielitz E. Flüh T. Gundlach L. Hance A. Henk F. Jordan D. Kläschen M. Klöckner R. Meissner W. Meyer O. Oncken C. Reichert K.-H. Ribbert P. Sadowiak H.-U. Schmincke J. Schmoll R. Walter K. Weber U. Weihrauch Th. Wever 《Geophysical Journal International》1991,106(1):203-227
72.
73.
Florence Habets Julien Boé Michel Déqué Agnès Ducharne Simon Gascoin Ali Hachour Eric Martin Christian Pagé Eric Sauquet Laurent Terray Dominique Thiéry Ludovic Oudin Pascal Viennot 《Climatic change》2013,121(4):771-785
This study presents an analysis of climate-change impacts on the water resources of two basins located in northern France, by integrating four sources of uncertainty: climate modelling, hydrological modelling, downscaling methods, and emission scenarios. The analysis focused on the evolution of the water budget, the river discharges and piezometric heads. Seven hydrological models were used, from lumped rainfall-discharge to distributed hydrogeological models, and led to quite different estimates of the water-balance components. One of the hydrological models, CLSM, was found to be unable to simulate the increased water stress and was, thus, considered as an outlier even though it gave fair results for the present day compared to observations. Although there were large differences in the results between the models, there was a marked tendency towards a decrease of the water resource in the rivers and aquifers (on average in 2050 about ?14 % and ?2.5 m, respectively), associated with global warming and a reduction in annual precipitation (on average in 2050 +2.1 K and ?3 %, respectively). The uncertainty associated to climate models was shown to clearly dominate, while the three others were about the same order of magnitude and 3–4 times lower. In terms of impact, the results found in this work are rather different from those obtained in a previous study, even though two of the hydrological models and one of the climate models were used in both studies. This emphasizes the need for a survey of the climatic-change impact on the water resource. 相似文献
74.
K. G. Strassmeier M. Weber T. Granzer L. Schanne J. Bartus I. Ilyin 《Astronomische Nachrichten》2014,335(9):904-934
We present continuous and time‐resolved R = 55 000 optical échelle spectroscopy of ε Aurigae from 2006–2013. Data were taken with the STELLA Echelle Spectrograph of the robotic STELLA facility at the Observatorio del Teide in Tenerife. Contemporaneous photometry with the Automatic Photoelectric Telescopes at Fairborn Observatory in Arizona is presented for the years 1996–2013. Spectroscopic observations started three years prior to the photometric eclipse and are still ongoing. A total of 474 high‐resolution échelle spectra are analyzed and made available in this paper. We identify 368 absorption lines of which 161 lines show the characteristic sharp disk lines during eclipse. Another 207 spectral lines appeared nearly unaffected by the eclipse. From spectrum synthesis, we obtained the supergiant atmospheric parameters Teff = 7395 ± 70 K, log g ≈ 1, and [Fe/H] = +0.02 ± 0.2 with ξt = 9 km s–1, ζRT = 13 km s–1, and v sin i = 28 ± 3 km s–1. The residual average line broadening expressed in km s–1 varies with a period of 62.6 ± 0.7 d, in particular at egress and after the eclipse. Two‐dimensional line‐profile periodograms show several periods, the strongest with ≈110 d evident in optically thin lines as well as in the Balmer lines. Center‐of‐intensity weighted radial velocities of individual spectral lines also show the 110‐d period but, again, additional shorter and longer periods are evident and are different in the Balmer lines. The two main spectroscopic Hα periods, ≈ 116 d from the line core and ≈ 150 d from the center‐of‐intensity radial velocities, appear at 102 d and 139 d in the photometry. The Hβ and Johnson V I photometry on the other hand shows two well‐defined and phase‐coherent periods of 77 d and 132 d. We conclude that Hα is contaminated by changes in the circumstellar environment while the Hβ and V I photometry stems predominantly from the non radial pulsations of the F0 supergiant. We isolate the disk‐rotation profile from 61 absorption lines and found that low disk eccentricity generally relates to low disk rotational velocity (but not always) while high disk eccentricity always relates to high velocity. There is also the general trend that the disk‐absorption in spectral lines with higher excitation potential comes from disk regions with higher eccentricity and thus also with higher rotational velocity. The dependency on transition probability is more complex and shows a bi‐modal trend. The outskirts of the disk is distributed asymmetrically around the disk and appears to have been built up mostly in a tail along the orbit behind the secondary. Our data show that this tail continues to eclipse the F0 Iab primary star even two years after the end of the photometric eclipse. High‐resolution spectra were also taken of the other, bona‐fide, visual‐binary components of ε Aur (ADS 3605BCDE). Only the C‐component, a K3‐4‐giant, appears at the same distance than ε Aur but its radial velocity is in disagreement with a bound orbit. The other components are a nearby (≈ 7 pc) cool DA white dwarf, a G8 dwarf, and a B9 supergiant, and not related to ε Aur. The cool white dwarf shows strong DIB lines that suggest the existence of a debris disk around this star. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
75.
Zsolt Kővári Katalin Oláh János Bartus Klaus G. Strassmeier Michael Weber Albert Washuettl John B. Rice Szilárd Csizmadia 《Astrophysics and Space Science》2006,304(1-4):375-377
Doppler images are presented for the RS CVn-type binary ζ And. Our upgraded Doppler imaging code TempMapε takes into account the distorted geometry of the primary giant component. On the maps several low latitude spots are restored with a temperature contrast of about 1000 K. Some weak polar features are also found. Cross-correlation of the consecutive Doppler-maps suggests solar-like differential surface rotation. 相似文献
76.
77.
E. J. Weber 《Solar physics》1970,14(2):480-488
The solutions of a radially symmetrical solar wind model with thermal conductivity are discussed in the neighborhood of the loci of the critical points, called the critical line, and at infinity. It is shown that for constant mass and total energy flux the conditions at infinity are related uniquely to the conditions at the critical line. Furthermore the requirement that the solution is continuous and has the proper behavior at infinity will determine uniquely one specific point on the critical line through which the solution has to pass.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. 相似文献
78.
Richard R. Weber 《Solar physics》1978,59(2):377-385
Flux density spectra have been determined for ninety-one simple type III solar bursts observed by the Goddard Space Flight Center radio astronomy experiment on the IMP-6 spacecraft during 1971 and 1972. Spectral peaks were found to occur at frequencies ranging from 44 kHz up to 2500 kHz. Half of the bursts peaked between 250 kHz and 900 kHz, corresponding to emission at solar distances of about 0.3 to 0.1 AU. Maximum burst flux density sometimes exceeds 10–14 W m–2 Hz–1. The primary factor controlling the spectral peak frequency of these bursts appears to be variation in intrinsic power radiated by the source as the exciter moves outward from the Sun, rather than radio propagation effects between the source and IMP-6. Thus, a burst spectrum strongly reflects the evolution of the properties of the exciting electron beam, and according to current theory, beam deceleration could help account for the observations. 相似文献
79.
An analytical solution is presented for the stress and strain fields in a Mohr–Coulomb material in plane strain around a circular hole when it is compressed by an axisymmetric far-field pressure. It is shown that several solutions arise involving one to three plastic zones depending on the values of Poisson's ratio and the friction angle. The solution chosen for presentation was obtained and used to validate the functioning of the Mohr–Coulomb yield condition that was added to the NONSAP finite element code. Stress and strain field comparisons are made. 相似文献
80.