Stable isotopes of water as a tool to study groundwater–seawater interactions in coastal south-eastern Sicily     

M.A. Schiavo  S. Hauser  P.P. Povinec 《Journal of Hydrology》2009,364(1-2):40-49

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Investigating dynamic coupling in geospace through the combined use of modeling,simulations and data analysis     

Ioannis A. Daglis  Georgios Balasis  Natalia Ganushkina  Fiori-Anastasia Metallinou  Minna Palmroth  Risto Pirjola  Ioanna Tsagouri 《Acta Geophysica》2009,57(1):141-157

Comprehensive understanding of the dynamics of the coupled solar wind-magnetosphere-ionosphere system is of utmost interest, both from the perspective of solar system astrophysics and geophysics research and from the perspective of space applications. The physical processes involved in the dynamical evolution of this complex coupled system are pertinent not only for the Sun-Earth connection, but also for major phenomena in other astrophysical systems. Furthermore, the conditions in geospace collectively termed space weather affect the ever increasing technological assets of mankind in space and therefore need to be understood, quantified and efficiently forecasted. The present collaborative paper communicates recent advances in geospace dynamic coupling research through modeling, simulations and data analysis and discusses future directions.  相似文献   

VARNET-96: influence of the Variscan and Caledonian orogenies on crustal structure in SW Ireland   总被引：1，自引：0，他引：1  

Michael Landes  C. Prodehl  F. Hauser  A. W. B. Jacob  & N. J. Vermeulen 《Geophysical Journal International》2000,140(3):660-676

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Shock deformation confirms the impact origin for the Cerro do Jarau,Rio Grande do Sul,Brazil, structure     

Wolf Uwe Reimold  Alvaro Penteado Crsta  Maximilian Hasch  Astrid Kowitz  Natalia Hauser  Joana Paula Sanchez  Luiz Sergio Amarante Simes  Grace Juliana de Oliveira  Patrice T. Zaag 《Meteoritics & planetary science》2019,54(10):2384-2397

Cerro do Jarau is a conspicuous, circular morpho‐structural feature in Rio Grande do Sul State (Brazil), with a central elevated core in the otherwise flat “Pampas” terrain typical for the border regions between Brazil and Uruguay. The structure has a diameter of approximately 13.5 km. It is centered at 30^o12′S and 56^o32′W and was formed on basaltic flows of the Cretaceous Serra Geral Formation, which is part of the Paraná‐Etendeka Large Igneous Province (LIP), and in sandstones of the Botucatu and Guará formations. The structure was first spotted on aerial photographs in the 1960s. Ever since, its origin has been debated, sometimes in terms of an endogenous (igneous) origin, sometimes as the result of an exogenous (meteorite impact) event. In recent years, a number of studies have been conducted in order to investigate its nature and origin. Although the results have indicated a possible impact origin, no conclusive evidence could be produced. The interpretation of an impact origin was mostly based on the morphological characteristics of the structure; geophysical data; as well as the occurrence of different breccia types; extensive deformation/silicification of the rocks within the structure, in particular the sandstones; and also on the widespread occurrence of low‐pressure deformation features, including some planar fractures (PFs). A detailed optical microscopic analysis of samples collected during a number of field campaigns since 2007 resulted in the disclosure of a large number of quartz grains from sandstone and monomict arenite breccia from the central part of the structure with PFs and feather features (FFs), as well as a number of quartz grains exhibiting planar deformation features (PDFs). While most of these latter grains only carry a single set of PDFs, we have observed several with two sets, and one grain with three sets of PDFs. Consequently, we here propose Cerro do Jarau as the seventh confirmed impact structure in Brazil. Cerro do Jarau, together with Vargeão Dome (Santa Catalina state) and Vista Alegre (Paraná State), is one of very few impact structures on Earth formed in basaltic rocks.  相似文献   

Estimating masses of selected stars in the Pulkovo program by means of astrometry methods     

Natalia A.Shakht  Denis L.Gorshanov  Olga O.Vasilkova 《天文和天体物理学研究(英文版)》2018,(8)

Stars in the Pulkovo Observatory program are observed with a 65-cm refractor during many years to study their positions and movements. We present examples of two visual binary stars, for which orbits and masses of components were determined, and two astrometric stars, for which masses of their unseen companions were estimated. The first two stars are ADS 14636(61 Cygni) and ADS 7251,and the others are Gliese 623 and ADS 8035(Alpha UMa). Direct astrometric methods are used for estimation of mass-ratio and masses.  相似文献   

The characteristic pattern of multiple colored layers in coastal stratified lakes in the process of separation from the White Sea   总被引：1，自引：1，他引：0  

Krasnova  Elena D.  Matorin  Dmitry N.  Belevich  Tatiana A.  Efimova  Ludmila E.  Kharcheva  Anastasiia V.  Kokryatskaya  Natalia M.  Losyuk  Galina N.  Todorenko  Daria A.  Voronov  Dmitry A.  Patsaeva  Svetlana V. 《中国海洋湖沼学报》2018,36(6):1962-1977

An unusual feature of the saline stratified lakes that were formed due to ongoing postglacial uplift on the White Sea coast is the presence of several differently colored thin layers in the zone with sharp gradients. Colored layers in five lakes at various stages of separation from the sea were investigated using optical microscopy, spectrophotometry, spectrofluorimetry, and photobiology. The upper greenish colored layer located in the aerobic strata of all lakes near the compensation depth of 1% light penetration contains green algae. In the chemocline, another layer, brightly green, red or pink, is dominated by mixotrophic flagellates. Despite the very low light intensities and the presence of H 2 S, active photosynthesis by these algae appears to be occurring, as indicated by high values of the maximum quantum yield of primary photochemistry, electron transport activity, photosynthetic activity of photosystem II, the fraction of active centers, and low values of heat dissipation. In the reduced zone of the chemocline, a dense green or brown suspension of anoxygenic phototrophs(green sulfur bacteria) is located.  相似文献   

Snow carrots after the Chelyabinsk event and model implications for highly porous solar system objects          下载免费PDF全文

Robert Luther  Natalia Artemieva  Marina Ivanova  Cyril Lorenz  Kai Wünnemann 《Meteoritics & planetary science》2017,52(5):979-999

After the catastrophic disruption of the Chelyabinsk meteoroid, small fragments formed funnels in the snow layer covering the ground. We constrain the pre‐impact characteristics of the fragments by simulating their atmospheric descent with the atmospheric entry model. Fragments resulting from catastrophic breakup may lose about 90% of their initial mass due to ablation and reach the snow vertically with a free‐fall velocity in the range of 30–90 m s^?1. The fall time of the fragments is much longer than their cooling time, and, as a consequence, fragments have the same temperature as the lower atmosphere, i.e., of about ?20 °C. Then, we use the shock physics code iSALE to model the penetration of fragments into fluffy snow, the formation of a funnel and a zone of denser snow lining its walls. We examine the influence of several material parameters of snow and present our best‐fit model by comparing funnel depth and funnel wall characteristics with observations. In addition, we suggest a viscous flow approximation to estimate funnel depth dependence on the meteorite mass. We discuss temperature gradient metamorphism as a possible mechanism which allows to fill the funnels with denser snow and to form the observed “snow carrots.” This natural experiment also helps us to calibrate the iSALE code for simulating impacts into highly porous matter in the solar system including tracks in the aerogel catchers of the Stardust mission and possible impact craters on the 67P/Churyumov‐Gerasimenko comet observed recently by the Rosetta mission.  相似文献   

Influence of the atmospheric conditions on PM<Subscript>10</Subscript> concentrations in Poznań, Poland     

Bartosz Czernecki  Marek Półrolniczak  Leszek Kolendowicz  Michał Marosz  Sebastian Kendzierski  Natalia Pilguj 《Journal of Atmospheric Chemistry》2017,74(1):115-139

This study investigates atmospheric conditions’ influence on the mean and extreme characteristics of PM₁₀ concentrations in Poznań during the period 2006–2013. A correlation analysis was carried out to identify the most important meteorological variables influencing the seasonal dynamics of PM₁₀ concentrations. The highest absolute correlation values were obtained for planetary boundary layer height (r = ?0.57), thermal (daily minimum air temperature: r = ?0.51), anemological (average daily wind speed: r = ?0.37), and pluvial (precipitation occurrence: r = ?0.36) conditions, however the highest correlations were observed for temporal autocorrelations (1 day lag: r = 0.70). As regulated by law, extreme events were identified on the basis of daily threshold value i.e. 50 μg m^?3. On average, annually there are approximately 71.3 days anywhere in the city when the threshold value is exceeded, 46.6 % of those occur in winter. Additionally, 83.7 % of these cases have been found to be continuous episodes of a few days, with the longest one persisting for 22 days. The analysis of the macro-scale circulation patterns led to the identification of an easy-to-perceive seasonal relations between atmospheric fields that favour the occurrence of high PM₁₀ concentration, as well as synoptic situations contributing to the rapid air quality improvement. The highest PM₁₀ concentrations are a clear reaction to a decrease in air temperature by over 3 °C, with simultaneous lowering of PBL height, mean wind speed (by around 1 m s^?1) and changing dominant wind directions from western to eastern sectors. In most cases, such a situation is related to the expansion of a high pressure system over eastern Europe and weakening of the Icelandic Low. Usually, air quality conditions improve along with an intensification of westerlies associated with the occurrence of low pressure systems over western and central Europe. Opposite relations are distinguishable in summer, when air quality deterioration is related to the inflow of tropical air masses originating over the Sahara desert.  相似文献   

Information infrastructure for Australia’s Integrated Marine Observing System     

Marton G. Hidas  Roger Proctor  Natalia Atkins  Julian Atkinson  Laurent Besnard  Peter Blain  Philip Bohm  Jon Burgess  Kim Finney  Dan Fruehauf  Guillaume Galibert  Xavier Hoenner  Jacqui Hope  Craig Jones  Sebastien Mancini  Benedicte Pasquer  David Nahodil  Kate Reid  Katherine Tattersall 《Earth Science Informatics》2016,9(4):525-534

Australia’s Integrated Marine Observing System (IMOS, imos.org.au) is research infrastructure to establish an enduring observing program for Australian oceanic waters and shelf seas. The observations cover physical, biological, and chemical variables to address themes of multi-decadal ocean change, climate variability and weather extremes, boundary currents and inter-basin flows, continental shelf processes and ecosystem responses.IMOS observations are collected by national facilities based on various platform types and operated by partner institutions around the country. In this paper we describe the infrastructure and workflows developed to manage and distribute the data to the public. We highlight the existing standards and open-source software we have adopted, and the contributions we have made. To demonstrate the value of this infrastructure we provide some illustrations of use and uptake.All IMOS data are freely and openly available to the public via the Ocean Portal (https://imos.aodn.org.au). All IMOS-developed software is open-source and accessible at https://github.com/aodn.  相似文献   

Evolution of the groundwater chemical composition in the Poyang Lake catchment,China     

Stepan Shvartsev  Zhaoli Shen  Zhanxue Sun  Guangcai Wang  Evgeniya Soldatova  Natalia Guseva 《Environmental Earth Sciences》2016,75(18):1239

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