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661.
Catchments as reactors: a comprehensive approach for water fluxes and solute turnover 总被引:1,自引:1,他引:0
Peter Grathwohl Hermann Rügner Thomas Wöhling Karsten Osenbrück Marc Schwientek Sebastian Gayler Ute Wollschläger Benny Selle Marion Pause Jens-Olaf Delfs Matthias Grzeschik Ulrich Weller Martin Ivanov Olaf A. Cirpka Ulrich Maier Bertram Kuch Wolfgang Nowak Volker Wulfmeyer Kirsten Warrach-Sagi Thilo Streck Sabine Attinger Lars Bilke Peter Dietrich Jan H. Fleckenstein Thomas Kalbacher Olaf Kolditz Karsten Rink Luis Samaniego Hans-Jörg Vogel Ulrike Werban Georg Teutsch 《Environmental Earth Sciences》2013,69(2):317-333
Sustainable water quality management requires a profound understanding of water fluxes (precipitation, run-off, recharge, etc.) and solute turnover such as retention, reaction, transformation, etc. at the catchment or landscape scale. The Water and Earth System Science competence cluster (WESS, http://www.wess.info/) aims at a holistic analysis of the water cycle coupled to reactive solute transport, including soil–plant–atmosphere and groundwater–surface water interactions. To facilitate exploring the impact of land-use and climate changes on water cycling and water quality, special emphasis is placed on feedbacks between the atmosphere, the land surface, and the subsurface. A major challenge lies in bridging the scales in monitoring and modeling of surface/subsurface versus atmospheric processes. The field work follows the approach of contrasting catchments, i.e. neighboring watersheds with different land use or similar watersheds with different climate. This paper introduces the featured catchments and explains methodologies of WESS by selected examples. 相似文献
662.
The authors attempt to identify and standardize the cartographic symbols (“images”) used to represent a variety of specific geomorphological features. A large number of cartographic representations of landform features found on geological-geomorphological maps are classified in terms of their basic pattern/configuration and the level of complexity within each major pattern type. It is argued that the pattern or configuration of a cartographic symbol used to represent a geomorphological feature should represent the spatial structure of that feature with sufficient reliability to serve as a key to an understanding of its genesis. Translated from: Geomorfologiya, 1987, No. 2, pp. 62-66. 相似文献
663.
Using proxy series that includes ancient observations of sunspots and auroras, concentrations of cosmogenic isotopes 14C and 10Be, we reconstruct sunspot activity level since 850 AD to the present. As a main reference index of solar activity we use
the Wolf sunspot numbers, which, as we demonstrate, reflect true levels of the activity in the 18th and 19th centuries better
than the Group sunspot numbers. We construct a set of linear and nonlinear inductive models, which are in a good agreement
with each other and reproduce the known global solar activity extrema. According to our results, amplitudes of the global
maxima are in intermediate positions in respect to estimations of other authors. It follows from our reconstructions that
the global maximum of the 20th century is not much higher, if at all, than others. 相似文献
664.
665.
Launch of martian meteorites in oblique impacts 总被引:1,自引:0,他引:1
A high-velocity oblique impact into the martian surface accelerates solid target material to escape velocity. A fraction of that material eventually falls as meteorites on Earth. For a long time they were called the SNC meteorites (Shergotty, Nakhla, and Chassigny). We study production of potential martian meteorites numerically within the frame of 3D hydrodynamic modeling. The ratio of the volume of escaping solid ejecta to projectile volume depends on the impact angle, impact velocity and the volatile content in the projectile and in the target. The size distribution of ejected fragments appears to be of crucial importance for the atmosphere-ejecta interaction in the case of a relatively small impact (with final crater size <3 km): 10-cm-sized particles are decelerated efficiently, while 30-50% of larger fragments could escape Mars. The results of numerical modeling are compared with shock metamorphic features in martian meteorites, their burial depth, and preatmospheric mass. Although it is impossible to accelerate ejected fragments to escape velocity without substantial compression (above 10 GPa), the maximum temperature increase in dunite (Chassigny) or ortopyroxenite (ALH84001) may be lower than 200 degree. This result is consistent with the observed chaotic magnetization of ALH84001. The probability of microbes' survival may be rather high even for the extreme conditions during the ejection process. 相似文献
666.
A. T. Basilevsky G. Neukum B. A. Ivanov S. K. Werner S. van Gesselt J. W. Head T. Denk R. Jaumann H. Hoffmann E. Hauber T. McCord 《Solar System Research》2005,39(2):85-101
The images of the western part of Olympus Mons and adjacent plains acquired by the HRSC camera onboard the Mars Express spacecraft were studied. The morphology, topography, and color of the surface were investigated. The surface age was determined by the frequencies of impact craters. The examination of the HRSC images combined with an analysis of the MOC imagery and MOLA altitude profiles have shown that the Olympus Mons edifice, at least in its western part, is composed of not only lavas but also of sedimentary and volcanic-sedimentary rocks consisting of dust, volcanic ash, and, probably, H2O ice that precipitated from the atmosphere. These data also indicate that glaciations, traces of which are known on the western foot of Olympus Mons (Lucchitta, 1981; Milkovich and Head, 2003), probably also covered the gentle upper slopes of the mountain. It is probable that the ice is still there, protected from sublimation by a dust blanket. Confirming (or rejecting) its presence is a challenge for the scheduled radar sounding with the MARSIS instrument mounted on the Mars Express spacecraft as well.__________Translated from Astronomicheskii Vestnik, Vol. 39, No. 2, 2005, pp. 99–116.Original Russian Text Copyright © 2005 by Basilevsky, Neukum, Ivanov, Werner, S. van Gesselt, Head, Denk, Jaumann, Hoffmann, Hauber, McCord, the HRSC Co-Investigator Team. 相似文献
667.
668.
669.
Some results derived in the course of exploration of seawater dynamics over the Mediterranean and Black Seas shelf, conducted in the framework of the Black Sea and Internal Waves projects during the summer of 1991, are described.Translated by V. Puchkin. 相似文献
670.
U–Pb (SIMS) dating of zircons from granite of the Petrokamensk gabbro–granitoid complex, marking termination of the Devonian island–arc magmatism in the Verkhisetsk–Tura Zone of the Middle Urals, gave an age of 386 ± 3 Ma. Zircons from the West Verkhisetsk granitoids, the formation of which corresponds to the beginning stage of magmatism of the continental margin in the region, yielded ages of 386.6 ± 4.1 and 381.8 ± 6.0 Ma. This suggests that the change in the regime of the island–arc geodynamic mode to an active continental margin took place at the boundary of the Middle and Late Devonian. The upper boundary of existence of the continental margin subduction zone is determined by the closure of the Ural paleo-ocean and the beginning of continental collision processes, which resulted in accumulation of flysch in the Ural foreland trough from the second half of the Bashkirian Stage. 相似文献