A comment on the article “A collinearity diagnosis of the GNSS geocenter determination” by P. Rebischung,Z. Altamimi,and T. Springer     

Michael Meindl  Gerhard Beutler  Daniela Thaller  Rolf Dach  Stefan Schaer  Adrian Jäggi 《Journal of Geodesy》2015,89(2):189-194

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Highly gravity-driven flow of a NAPL in water-saturated porous media using the discontinuous Galerkin finite-element method with a generalised Godunov scheme     

Lauriane Schneider  Raphaël di Chiara Roupert  Gerhard Schäfer  Philippe Helluy 《Computational Geosciences》2015,19(4):855-876

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Winter-to-spring temperature dynamics in Turkey derived from tree rings since AD 1125   总被引：2，自引：1，他引：1  

Ingo Heinrich  Ramzi Touchan  Isabel Dorado Liñán  Heinz Vos  Gerhard Helle 《Climate Dynamics》2013,41(7-8):1685-1701

In the eastern Mediterranean in general and in Turkey in particular, temperature reconstructions based on tree rings have not been achieved so far. Furthermore, centennial-long chronologies of stable isotopes are generally also missing. Recent studies have identified the tree species Juniperus excelsa as one of the most promising tree species in Turkey for developing long climate sensitive stable carbon isotope chronologies because this species is long-living and thus has the ability to capture low-frequency climate signals. We were able to develop a statistically robust, precisely dated and annually resolved chronology back to AD 1125. We proved that variability of δ¹³C in tree rings of J. excelsa is mainly dependent on winter-to-spring temperatures (January–May). Low-frequency trends, which were associated with the medieval warm period and the little ice age, were identified in the winter-to-spring temperature reconstruction, however, the twentieth century warming trend found elsewhere could not be identified in our proxy record, nor was it found in the corresponding meteorological data used for our study. Comparisons with other northern-hemispherical proxy data showed that similar low-frequency signals are present until the beginning of the twentieth century when the other proxies derived from further north indicate a significant warming while the winter-to-spring temperature proxy from SW-Turkey does not. Correlation analyses including our temperature reconstruction and seven well-known climate indices suggest that various atmospheric oscillation patterns are capable of influencing the temperature variations in SW-Turkey.  相似文献   

An ESA NEOCC Effort to Eliminate High Palermo Scale Virtual Impactors     

Marco Micheli  Detlef Koschny  Gerhard Drolshagen  Olivier Hainaut  Fabrizio Bernardi 《Earth, Moon, and Planets》2014,113(1-4):1-13

In this work we summarize the initial results of a targeted effort of the ESA NEO Coordination Centre to obtain additional observational data in order to eliminate or reduce the impact probability estimate of a subset of the known near-Earth objects representing the highest fraction of the total known impact risk, as measured by the Palermo Scale.  相似文献   

Views and news     

L. C. Gerhard 《Environmental Geology》1995,26(2):136-137

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On the origin of the wide HI absorption line towards Sgr A*     

K. S. Dwarakanath  W. M. Goss  J. H. Zhao  C. C. Lang 《Journal of Astrophysics and Astronomy》2004,25(3-4):129-141

We have imaged a region of ∼ 5′ extent surrounding Sgr A* in the HI 21 cm-line absorption using the Very Large Array. A Gaussian decomposition of the optical depth spectra at positions within ∼ 2′ (∼ 5 pc at 8.5 kpc) of Sgr A* detects a wide line underlying the many narrow absorption lines. The wide line has a mean peak optical depth of 0.32 ± 0.12 centered at a mean velocity of V_1sr = −4 ± 15 km s{−1}. The mean full width at half maximum is 119 ± 42 km s⁻¹. Such a wide line is absent in the spectra at positions beyond ∼ 2′ from Sgr A*. The position-velocity diagrams in optical depth reveal that the wide line originates in various components of the circumnuclear disk (radius ∼ 1.3′ ) surrounding Sgr A*. These components contribute to the optical depth of the wide line in different velocity ranges. The position-velocity diagrams do not reveal any diffuse feature which could be attributed to a large number of HI clouds along the line of sight to Sgr A*. Consequently, the wide line has no implications either to a global population of shocked HI clouds in the Galaxy or to the energetics of the interstellar medium as was earlier thought.  相似文献   

Solar irradiance below 120 nm and its variations     

Gerhard Schmidtke 《Solar physics》1981,74(1):251-263

The solar irradiance below 120 nm was first predicted by astronomers. Since its accurate measurement required the solution of a variety of technological problems, little is known about the variability before 1972, though for more than two decades data have been collected. Therefore, on a quantitative basis only a very rough picture can be given for the solar cycle 19. Also, not enough data with sufficient absolute accuracy are available to describe the solar EUV flux variations of the solar cycle 20, especially during the period of solar maximum. However, due to technological improvements of space and laboratory instrumentations, an almost complete set of data has been obtained from 1972 to date. These observations exhibit strong differences of the flux variations from solar cycle 20 to 21. - For the theoretical and for semi-empirical treatments of many aeronomic processes controlled by the solar EUV radiation, its adequate representation e.g. as indices is required. The problems involved and possible solutions are discussed. Results from some relevant aeronomically oriented computations based on variable solar EUV fluxes are presented.Proceedings of the 14th ESLAB Symposium on Physics of Solar Variations, 16–19 September 1980, Scheveningen, The Netherlands.  相似文献   

The ‘land-locked’ viewpoint     

Gerhard Hafner 《Marine Policy》1981,5(3):281-282

While the Draft Convention still leaves the land-locked states with very considerable disadvantages, it can be said to represent a success for such states in so far as the notion of land-locked states forms a definite part of the proposed law of the sea and therefore provided them with the power to influence further developments.  相似文献   

Changes in dimensions, stresses and gravitational energy of the Earth due to crystallization at the inner-core boundary under isochemical conditions     

Heinz Häge  Gerhard Müller 《Geophysical Journal International》1979,58(2):495-508

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The gaseous Halo of the Virgo Cluster Galaxy 45     

Gerhard Hensler  Daniel Tschöke  Dominik Bomans  Alessandro Boselli 《Astrophysics and Space Science》2003,284(2):467-470

Observations of the Virgo Cluster galaxy NGC 4569 in soft X-rays and in Hα reveal both an asymmetrically distributed hot gaseous halo and a giant filament of diffuse emission, respectively, extending from the same side of the disk, the latter one to at least 8.8 kpc. A deep longslit spectrum along the filament shows velocities systematically different from the systemic velocity of NGC 4569. With the inclination of the disk one can determine the Hα spur as a giant outflow in NGC 4569. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献