The Dynamics of Small Postglacial Lake Basins and the Nature of Their Archaeological Record: A Case Study of the Middle Palaeolithic Site Neumark‐Nord 2, Germany     

Eduard Pop  Corrie Bakels  Wim Kuijper  Herman Mücher  Madeleine van Dijk 《Geoarchaeology》2015,30(5):393-413

Due to favorable conditions of preservation, sedimentary basins provide rich records of human behavior and its environmental context. The conditions for the preservation of archaeological material however vary between basin types (large, river‐fed or small, closed basins), while conditions also differ within a particular basin environment. The goal of this paper is to understand how the dynamics of a small postglacial basin such as Neumark‐Nord 2, a context that dominates the Eemian archaeological record, affected the archaeology situated at its basin margin. The approach used here is to correlate the archaeological record with reconstructions of patterns of deposition and the water conditions within the basin, using lithology, micromorphology, pollen, and macroremains from a transect running from the basin center to the margin. The results show that (1) find levels were exposed to overland flow‐induced winnowing, which vertically concentrated finds but did not cause significant transport, (2) find levels correspond to phases of increased water presence in the basin, and (3) lateral shifts in hominin activity areas may reflect adjustments in the water level. The research shows the importance of large‐scale archaeological excavations and a multidisciplinary sampling strategy that covers both the basin center and the margins, when studying postglacial basin localities like Neumark‐Nord 2.  相似文献   

Mass upflows and magnetic-field dynamics in a forming sunspot penumbra     

V. M. Grigor’ev  L. V. Ermakova 《Astronomy Reports》2016,60(2):280-286

The formation of the penumbra of the leading spot of the active region NOAA 11117 has been studied using data fromthe Solar DynamicObservatory (SDO). HMI data on longitudinal magnetic fields, line-of-sight velocities, and continuum images were used. The appearance of localized upflows between the umbra and undisturbed photosphere precedes the penumbra formation. The sizes of them reach 1.5″–2″ and the velocity increases to 1 km/s over several minutes. These localized upflows change themselves to a region of material flowing horizontally from the penumbra (the Evershed effect). The formation of individual spine namely fine radial element of the penumbra magnetic field with higher strength and lower inclination than in the surrounding is traced for the first time. The formation of the spine manifests itself as appearance of region of 2″–3″ in size with enhanced upflow near the sunspot umbra, protrusion in longitudinal-field contours on one side of the upwelling center, and the subsequent appearance of magnetic pole of opposite polarity on the other side of the upwelling. This process is accompanied by a bending of the contour marking the boundary of the undisturbed photosphere, which puts the upwelling center in a zone of higher brightness. One possible explanation for this is the emergence of hot magnetic tube. The appearance and growth of the sunspot spines results in the formation of the penumbra.  相似文献   

Environmental protection in the Apuseni Mountains: The role of Environmental Non-Governmental Organisations (ENGOs)     

Mircea Buza  Levente Dimen  Grigor Pop  David Turnock 《GeoJournal》2001,55(2-4):631-653

The Apuseni Mountains constitute one of the most interesting parts of the Carpathians in terms of landscape, biodiversity and culture. Yet dislocations are now severe and there are development threats which also require a significant response. On the one hand there are some severe pollution problems associated with mining areas developed in the communist period which require remedial action and the cases of Roşia Montana and Zlatna are discussed. On the other hand, there are forest and pasture zones – especially the Padiş Plateau – which are coming under heavy pressure from farmers seeking to enhance their incomes following the decline of mining and manufacturing which has left many households without salaries. At the same time, tourist pressure is growing. Actions are already being taken to limit pollution damage and develop sustainable landuse practices. There is a national park project linked with nature reserves comprising picturesque landscapes, a rare flora and fauna and distinct geological and palaeotological formations (including fossil ice). There are major tourist attractions and with proper management they could become part of a development programme of the countryside. However it is essential that all stakeholders adopt sustainable practices and this means that official programmes – including the future national park authority administration's work in environment protection and tourism management – are backed up by Environmental Non-Governmental Organisations (ENGOs). The paper reviews their diverse activities and concludes that they are making a very substantial contribution in ensuring that the potentials of isolated regions can be utilised in a manner consistent with nature conservation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Dynamics of line-of-sight velocities and magnetic field in the solar photosphere during the formation of the large active region NOAA 10488     

V. M. Grigor’ev  L. V. Ermakova  A. I. Khlystova 《Astronomy Letters》2007,33(11):766-770

Analysis of SOHO longitudinal magnetograms and Dopplergrams has revealed the appearance of a region of enhanced upflow of matter in the photosphere when the top of a loop-shaped magnetic flux tube forming a large active region passed through it. The maximum upflow velocity reached 2 km s^?1, the maximum size exceeded 20 000 km, and the lifetime was about 2 h.  相似文献   

Impact of the past mining activity in Roşia Montană (Romania) on soil and vegetation     

Adina-Laura Lazăr  Călin Baciu  Carmen Roba  Tiberius Dicu  Cristian Pop  Călin Rogozan  Cristina Dobrotă 《Environmental Earth Sciences》2014,72(11):4653-4666

The paper presents the results of a combined soil and vegetation survey in Ro?ia Montan? mining area (western Romania), famous for its gold and silver deposits, extensively exploited over the last 2,000 years. As the ore extraction has ceased in 2006 and new operations could be initiated in the future, the study contributes to the definition of the environmental baseline. Samples of topsoil and leaves of the tree species Betula pendula and Carpinus betulus have been collected from the inside and outside of the mining area, on a total surface of more than 60 km². The pH and heavy metal concentrations (Cd, Cr, Cu, Ni, Pb, and Zn) have been measured on 262 soils/sediments samples, revealing the predominantly acidic character of soils and the generally low contents of heavy metals. Stronger acidity and higher contents of heavy metals have been noticed in the proximity of the mining site, on the tailings and waste rock dumps, and along the streams with acid water. More than 100 leaf samples have been analysed for the same heavy metals as soils and also for chlorophyll fluorescence and pigment concentrations. B. pendula has shown a particular ability to concentrate Zn in leaves, at levels that may greatly exceed the Zn content in the corresponding soil samples. The correlation between the heavy metal contents in leaves and in soils, in most of the cases, is not very strong, presumably in relation to the low concentrations in soils. The chlorophyll concentration in leaves of B. pendula slightly diminishes on soils with low pH.  相似文献   

Streamflow of Russian Rivers under Current and Forecasted Climate Changes: A Review of Publications. 1. Assessment of Changes in the Water Regime of Russian Rivers by Observation Data     

Frolova  N. L.  Magritskii  D. V.  Kireeva  M. B.  Grigor’ev  V. Yu.  Gelfan  A. N.  Sazonov  A. A.  Shevchenko  A. I. 《Water Resources》2022,49(3):333-350

Water Resources - Publications on changes in river water regime in Russia under the conditions of current climate changes are reviewed. Most recent generalizations of such publications are...  相似文献   

Statistical-dynamical downscaling of wind roses over the Czech Republic     

Jaroslav Svoboda  Zuzana Chladova  Lukas Pop  Jiri Hosek 《Theoretical and Applied Climatology》2013,112(3-4):713-722

The present study describes a new method for statistical-dynamical downscaling that combines two different approaches, namely, a set of patterns simulated with a numerical flow model and a transformation function used to process both calculated data and measurements at a reference station. The combined method produces wind roses and wind speed histograms at an arbitrary location in the model domain. The inflow wind direction represented the key parameter to define a set of wind field simulations. The other two inflow parameters, namely, thermal stratification and geostrophic wind speed, were derived from corresponding averaged soundings. The results showed that in the Czech Republic, there are areas where wind roses are deformed by the surrounding terrain. The deformations occur in relatively shallow and wide valleys, and they are more sensitive to the inflow wind direction. Calculated wind roses are compared to corresponding observations at 22 synoptic stations. The most frequent wind direction sector in simulations agreed with measurements at 17 stations. The resulting error in frequency in that sector was under 5 % at 10 stations. In general, the main features of the wind roses are modelled well, even at a relatively large distance from the reference station. However, better performance was achieved for smaller distances between reference station and the site. In further studies, a more extensive set of flow patterns with reduced intervals of thermal stratification and wind speed will likely improve calculated wind roses.  相似文献   

Stokes-meter observations of the solar mean magnetic field: Probable manifestations of strong small-scale magnetic fields     

M. L. Demidov  V. M. Grigor’ev  V. S. Peshcherov 《Astronomy Reports》2005,49(7):559-566

For many years, information on the solar mean magnetic field (SMMF) of the Sun—an important heliophysical and astrophysical parameter—was restricted to magnetographic measurements in only one spectral line, FeI λ525.02 nm. More informative observations of the Stokes-meter parameters of the SMMF were first initiated on a regular basis at the Sayan Solar Observatory. The availability of I and V data obtained simultaneously in several spectral lines has made it possible to study fundamentally new physical problems. In this paper, based on a comparison of SMMF observations in several spectral lines, we find high correlations in the data and important systematic differences in the magnetic-field strength B, which we interpret as a manifestation of kilogauss magnetic fields in fine-structure magnetic elements. Results of theoretical modeling of the SMMF strength ratios for the FeI λ525.02 nm-FeI λ524.70 nm and FeI λ630.15 nm-FeI λ630.25 nm lines are presented. The asymmetries of the V profiles of four lines near the FeI λ525.02 nm line are examined; these lines are important diagnostics for studies of small-scale dynamical processes. The Sayan Solar Observatory SMMF measurements are in good consistency with the Wilcox Solar Observatory data for 2003: for a comparison of N = 137 pairs of points in the two data sets, the correlation coefficient ρ is 0.92 for the linear regression between the datasets B_WSO = 0.03(±0.05) + 0.93(±0.03)B_SSO.  相似文献   

Studies of the Angular Structure of Scintillating Radio Sources at 111 MHz     

Tyul’bashev  S. A.  Chashei  I. V.  Grigor’eva  E. A. 《Astronomy Reports》2019,63(6):479-494

The angular sizes and compactnesses of 53 scintillating radio sources observed at 111 MHz on the Large Phased Array of the Lebedev Physical Institute are estimated. The parameters of the angular structures of the sources are estimated using a new method based on a joint analysis of the scintillation index and the asymmetry coefficient for the statistical distribution of the intensity fluctuations. The asymmetry coefficient for scintillations of a point source is estimated based on an analysis of observational data for turbulence in the solar wind. Different methods for estimating source angular sizes based on observations of interplanetary scintillations are compared. It is shown that the proposed new method is suitable for sources with angular sizes up to 1″. The accuracy of the estimated angular sizes and compactnesses of the sources is about 40%.

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Structural Properties of Pulsating Star Light Curves Through Fuzzy Divisive Hierarchical Clustering     

Adina Dumitrescu  Alexandru Pop  D. Dumitrescu 《Astrophysics and Space Science》1997,250(2):205-226

The aim of this paper is to explore the possibility of using a fuzzy divisive clustering technique to the classification of pulsating stars according to the shape of their light curves. The considered sample contains Cepheides, RR Lyrae stars, and high amplitude Scuti and SX Phoenicis stars. Our investigations proved the ability of this method to identify morphological groups in a given class of pulsating stars. The method is also useful for establishing the membership of an unknown variable star in a given class.  相似文献