Radon variations in a Hungarian village     

E. Tóth  F. Deak  C. S. Gyurkócza  Z. S. Kasztovszky  R. Kuczi  G. Marx  B. Nagy  S. Oberstedt  L. Sajó-Bohus  C. S. Sükösd  G. Toth  N. Vajda 《Environmental Geology》1997,31(1-2):123-127

 A steady radon exhalation is assumed in most publications. In a village of North-East Hungary, however, high radon concentrations have been measured, differing strongly in neighbouring houses and varying in time, due to the interplay of geochemical phenomena. Received: 20 November 1995 · Accepted: 18 June 1996  相似文献   

Quantitative basin characterisation to refine debris-flow triggering criteria and processes: an example from the Italian Western Alps   总被引：1，自引：1，他引：0  

Davide Tiranti  Sabrina Bonetto  Giuseppe Mandrone 《Landslides》2008,5(1):45-57

This paper investigates rapid channelized debris flow related to rainfalls in small alpine basins. Its goal is to evaluate and correlate different geological and technical aspects with predisposing and triggering factors that can control these phenomena. The study area is the upper part of the Susa Valley where 12 small basins were selected. For each of them, lithological, geomorphological, climatic and technical information were mapped and analysed. Debris-flow triggering conditions, flow and depositional processes were related to physical characteristics of the basin that can be easily measured and quantified. At least three different groups of basins were found: G1) basins with one event each 4–6 years, characterised by massive or blocky calcareous rocks, G2) basins with more than one event per year that show an abundance of layered or sheared fine-grained rocks and G3) basins with recurrence levels exceeding 10 years, activated only by heavy and prolonged rainfalls, marked by massive or blocky coarse-grained igneous rocks. Furthermore, important morphometric differences were found. These considerations are useful in terms of hazard zonation and risk mitigation.  相似文献   

Linking foraging behavior and diet in a diving seabird          下载免费PDF全文

Sabrina Harris  Flavio Quintana  Javier Ciancio  Luciana Riccialdelli  Andrea Raya Rey 《Marine Ecology》2016,37(2):419-432

Foraging behavior and diet of breeding seabirds may be analysed simultaneously with the combined use of remote sensing devices and stable isotope analysis. Imperial shag, Phalacrocorax atriceps, breeding at Punta León colony, Argentina, were equipped with global positioning system (GPS) loggers to record foraging trips and blood samples were taken after removal of the devices in order to analyse their nitrogen and carbon stable isotope composition in whole blood and plasma. Whole blood was correlated to plasma isotopic composition for each individual (n = 35), linking diet in the short and medium term. Sexes did not differ in isotopic signatures. The maximum distance reached and the total number of dives that individuals made on two consecutive foraging trips were correlated to their plasma nitrogen isotopic signature. Individuals that went further from the colony and dived fewer times presented more positive signatures, indicative of benthic prey consumption (e.g. Raneya brasiliensis). Diet was predominantly benthic with some individuals incorporating pelagic prey (Engraulis anchoita) and even cephalopods (Octopus tehuelchus). Within breeding pairs (n = 9), different combinations of foraging and prey preferences were observed. Estimated trophic levels of these individuals were similar to those of the same species in other colonies further south along the Patagonian coast.  相似文献   

Geomagnetic field residuals from CHAMP satellite: <Emphasis Type="Italic">essential for revealing unmodelled sources</Emphasis>     

Sabrina Tair  Yasmina Yahiat  Mohamed Hamoudi  Vincent Lesur  Mioara Mandea  Ioan Rus 《Arabian Journal of Geosciences》2018,11(1):1

  相似文献   

Comparison of Agricultural Impacts of Climate Change Calculated from High and Low Resolution Climate Change Scenarios: Part I. The Uncertainty Due to Spatial Scale   总被引：1，自引：1，他引：1  

L. O. Mearns  W. Easterling  C. Hays  D. Marx 《Climatic change》2001,51(2):131-172

We investigated the effect of two different spatial scales of climate change scenarios on crop yields simulated by the EPIC crop model for corn, soybean, and wheat, in the central Great Plains of the United States. The effect of climate change alone was investigated in Part I. In Part II (Easterling et al., 2001) we considered the effects ofCO₂ fertilization effects and adaptation in addition to climate change. The scenarios were formed from five years of control and 2 ×CO₂ runs of a high resolution regional climate model (RegCM) and the same from an Australian coarse resolution general circulation model (GCM), which provided the initial and lateral boundary conditions for the regional model runs. We also investigated the effect of two different spatial resolutions of soil input parameters to the crop models. We found that for corn and soybean in the eastern part of the study area, significantly different mean yield changes were calculated depending on the scenario used. Changes in simulated dryland wheat yields in the western areas were very similar, regardless of the scale of the scenario. The spatial scale of soils had a strong effect on the spatial variance and pattern of yields across the study area, but less effect on the mean aggregated yields. We investigated what aspects of the differences in the scenarios were most important for explaining the different simulated yield responses. For instance, precipitation changes in June were most important for corn and soybean in the eastern CSIRO grid boxes. We establish the spatial scale of climate changescenarios as an important uncertainty for climate change impacts analysis.  相似文献   

Search for strange attractors in magnetic field data: An example from a tertiary volcanic area near Bonn, Germany     

Sabrina Leonardi  Hans-Joachim Kümpel 《Journal of Geodynamics》1996,21(4):329-338

Spatial variations of the magnetic field, measured at the Earth's surface, are mainly due to geological inhomogeneities within the crust. The present state of the crust, in turn, reflects its past dynamical processes and evolution. We analyzed the magnetic field intensity along a few but densely sampled profiles in a Tertiary volcanic province near Bonn, Germany. The aim was to find out whether the variation of the magnetic intensity can be related to a deterministic, although chaotic, generating system or to a stochastic one. In the former case, the geodynamical history would depend on a few degrees of freedom, whereas in the latter case, the parameters to take into account were so many that a statistic approach appears to be more suitable. Since strange attractors do not emerge from the analyzed data, we exclude the presence of a chaos generating system. Autocorrelation functions and a rescaled-range analysis, on the other hand, reveal and quantify a certain degree of correlation among successive data points and allow calculation of a range of spectral exponents in log-log diagrams, which are clearly distinct from those of white noise and Brownian motion. Only one of the profiles exhibits similarity to uncorrelated or white noise. In this case, the signal variations do not result from the local geology but from a buried gas pipe-line, aligned subparallel to that profile. If self-organized crustal evolution generally produces signatures that can be described as correlated noise, within a limited bandwidth of spectral exponents, erraneous or disturbed data could eventually be discriminated from records containing purely natural data by applying analysis tools of the dynamic system theory together with autocorrelation tests.  相似文献   

Clinopyroxenes from mantle-related xenocrysts in alkaline basalts from Hannuoba (China): augite–pigeonite exsolutions and their thermal significance     

Elisabetta?Brizi  Sabrina?NazzareniEmail author  Francesco?Princivalle  Pier?Francesco?Zanazzi 《Contributions to Mineralogy and Petrology》2003,145(5):578-584

Optically homogeneous augite xenocrysts, closely associated with spinel–peridotite nodules, occur in alkali basalts from Hannuoba (Hebei province, China). They were studied by electron and X-ray diffraction to define the occurrence and significance of pigeonite exsolution microtextures. Sub-calcic augite (Wo₃₄) exsolved into En_62–62Fs_25–21Wo_13–17 pigeonite and En_46–45Fs_14–14Wo_40–42 augite, as revealed by TEM through diffuse coarser (001) lamellae (100–300 Å) and only incipient (100) thinner ones (<70 Å). C2/c augite and P2₁/c pigeonite lattices, measured by CCD-XRD, relate through a(Aug)?a(Pgt), b(Aug)?b(Pgt), c(Aug)≠c(Pgt) [5.278(1) vs 5.189(1)Å] and β(Aug)≠β(Pgt) [106.55(1) vs 108.55(2)°]. Cell and site volumes strongly support the hypothesis that the augite xenocrysts crystallised at mantle depth from alkaline melts. After the augite xenocrysts entered the magma, (001) lamellae first formed by spinodal decomposition at a T_min of about 1,100 °C, and coarsened during very rapid transport to the surface; in a later phase, possibly on cooling, incipient (100) lamellae then formed.  相似文献   

Observing Entrainment Processes Using a Small Unmanned Aerial Vehicle: A Feasibility Study   总被引：1，自引：0，他引：1  

Sabrina Martin  Frank Beyrich  Jens Bange 《Boundary-Layer Meteorology》2014,150(3):449-467

Measurement flights with the meteorological mini aerial vehicle (M $^2$ AV) were performed in spring 2011 to assess the capability of an unmanned aerial vehicle (UAV) to measure the structure of the transition zone between the convective boundary layer and the stably stratified free atmosphere. The campaign took place at the Meteorological Observatory Lindenberg/Richard-Aßmann-Observatory of the German Meteorological Service. Besides the M $^2$ AV flights, observations were made from a 12-m and a 99-m tower, a sodar, two ceilometers, radiosondes, and a tethered balloon with sensor packages at six different levels. M $^2$ AV measurements were intentionally combined with remote sensing systems. The height range of the entrainment zone as well as its diurnal cycle were provided by the remote sensing instruments. The UAV provided the high-resolution in situ data of temperature and wind for the study of turbulent processes. It is shown that the M $^2$ AV is able to maintain constant altitude with very small deviations—a pre-requisite to study processes inside the often quite thin entrainment zone and that M $^2$ AV high-resolution wind and temperature measurements allow for very detailed studies of the fine structure of the atmosphere and thus for the identification of quite local and/or short-duration processes such as overshooting thermals or downward intrusions of warm air. Spatial series measured by the M $^2$ AV during horizontal flights show turbulent exchange of heat in short turbulent bursts at heights close to and within the entrainment zone. Scaled vertical profiles of vertical velocity, potential temperature variance, and sensible heat flux confirm the general shape found by previous measurements and numerical studies.  相似文献   

The effect of cation ordering and temperature on the high-pressure behaviour of dolomite     

Azzurra Zucchini  Paola Comodi  Sabrina Nazzareni  Michael Hanfland 《Physics and Chemistry of Minerals》2014,41(10):783-793

Synchrotron single-crystal X-ray diffraction experiments at high-pressure and high-temperature conditions were performed up to 20 GPa and 573.0(2) K on a fully ordered stoichiometric dolomite and a partially disordered stoichiometric dolomite [order parameter, s = 0.26(6)]. The ordered dolomite was found to be stable up to approximately 14 GPa at ambient temperature and up to approximately 17 GPa at T = 573.0(2) K. The P–V data from the ambient temperature experiments were analysed by a second-order Birch–Murnaghan equation-of-state giving K ₀ = 92.7(9) GPa for the ordered dolomite and K ₀ = 92.5(8) GPa for the disordered dolomite. The high-temperature data, collected for the ordered sample, were fitted by a third-order Birch–Murnaghan equation-of-state resulting in K ₀ = 95(6) GPa and K′ = 2.6(7). In order to compare the three experiments results, a third-order Birch–Murnaghan equation-of-state was also calculated for the ambient temperature experiments giving K ₀ = 93(3) GPa, K′ = 3.9(6) for the ordered dolomite and K ₀ = 92(3) GPa, K′ = 4.0(4) for the disordered dolomite. The derived axial moduli show that dolomite compresses very anisotropically, being the c-axis approximately three times more compressible than the a-axis. The axial compressibility increases as T increases, and the a-axis is the most temperature-influenced axis. On the contrary, axial compressibility is not influenced by disordering. Structural refinements at different pressures show that Ca and Mg octahedra are almost equally compressible in the ordered dolomite with K(CaO₆) = 109(4) GPa and K(MgO₆) = 103(3) GPa. On the contrary, CaO₆ compressibility is reduced and MgO₆ compressibility is increased in the disordered crystal structure where K(CaO₆) = 139(4) GPa and K(MgO₆) = 89(4) GPa. Disordering is found to increase CaO₆ and to decrease MgO₆ bond strengths, thus making stiffer the Ca octahedron and softer the Mg octahedron. Cation polyhedra are distorted in both ordered and disordered dolomites and they increase in regularity as P increases. Ordered dolomite approaches regularity at approximately 14 GPa. The increase in regularity of octahedra in the disordered dolomite is strongly affected by the very slow regularization of MgO₆ with respect to CaO₆. The phase transition to the high-pressure polymorph of dolomite (dolomite-II), which is driven by a significant increase in the regularity of both cations polyhedra and mineral crystal structure, occurs in the ordered dolomite at ambient temperature at approximately 14 GPa; whereas no clear evidences of phase transition were observed as regards the disordered crystal structure.  相似文献   

Improved reliability of ENSO hindcasts with multi-ocean analyses ensemble initialization     

Jieshun Zhu  Bohua Huang  Magdalena A. Balmaseda  James L. Kinter III  Peitao Peng  Zeng-Zhen Hu  Lawrence Marx 《Climate Dynamics》2013,41(9-10):2785-2795

Currently, ensemble seasonal forecasts using a single model with multiple perturbed initial conditions generally suffer from an “overconfidence” problem, i.e., the ensemble evolves such that the spread among members is small, compared to the magnitude of the mean error. This has motivated the use of a multi-model ensemble (MME), a technique that aims at sampling the structural uncertainty in the forecasting system. Here we investigate how the structural uncertainty in the ocean initial conditions impacts the reliability in seasonal forecasts, by using a new ensemble generation method to be referred to as the multiple-ocean analysis ensemble (MAE) initialization. In the MAE method, multiple ocean analyses are used to build an ensemble of ocean initial states, thus sampling structural uncertainties in oceanic initial conditions (OIC) originating from errors in the ocean model, the forcing flux, and the measurements, especially in areas and times of insufficient observations, as well as from the dependence on data assimilation methods. The merit of MAE initialization is demonstrated by the improved El Niño and the Southern Oscillation (ENSO) forecasting reliability. In particular, compared with the atmospheric perturbation or lagged ensemble approaches, the MAE initialization more effectively enhances ensemble dispersion in ENSO forecasting. A quantitative probabilistic measure of reliability also indicates that the MAE method performs better in forecasting all three (warm, neutral and cold) categories of ENSO events. In addition to improving seasonal forecasts, the MAE strategy may be used to identify the characteristics of the current structural uncertainty and as guidance for improving the observational network and assimilation strategy. Moreover, although the MAE method is not expected to totally correct the overconfidence of seasonal forecasts, our results demonstrate that OIC uncertainty is one of the major sources of forecast overconfidence, and suggest that the MAE is an essential component of an MME system.  相似文献