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1.
Eugen Vujić Giuliana Verbanac Stanislav Francisković-Bilinski Vladis Vujnović Antun Marki 《Studia Geophysica et Geodaetica》2011,55(1):175-190
Based on the ground survey of total-field magnetic data at 53 sites, which recorded a time-series over the interval 2003–2005,
the core field + long wavelength lithospheric field over the middle-northern Croatia region was calculated. The area of the
survey was 18900 km2, an average distance between the neighbouring sites being 12 km. The results were reduced to 2004.5 epoch. This “normal”
total-field was estimated using the firstorder Taylor polynomial as a function of geographic coordinates, and the polynomial
coefficients were calculated with three methods of adjustment: simple and weighted least squares fits and adjustment according
to the most frequent value. The stability of the normal field was tested using the Monte Carlo-type test, by decreasing the
input data set in each adjustment (up to 90%). All obtained field residuals (measured-“normal”) were mutually compared, as
well as fit coefficients of the Taylor polynomials. The residual values indicate the presence of shorter-wavelength anomalies,
specifically three major residual anomalies were found (−106 nT, 74 nT and 57 nT). The geostatistical analysis of the ground
survey data and the normal field residuals (respectively), using the median absolute deviation method, was further conducted
in order to evaluate the calculated anomalies. The geological situation around the anomalies derived by the median absolute
deviation method, and around the normal field residual anomalies, is given. The correlation was found between higher value
anomalies of the normal field residuals, and shallow volcanic rocks and oil field, respectively. 相似文献
2.
Bojan Vršnak Mateja Dumbović Jaša Čalogović Giuliana Verbanac Ivana Poljanǐć–Beljan 《Solar physics》2017,292(9):140
We present an analysis of the geoeffectiveness of corotating interaction regions (CIRs), employing the data recorded from 25 January to 5 May 2005 and throughout 2008. These two intervals in the declining phase of Solar Cycle 23 are characterised by a particularly low number of interplanetary coronal mass ejections (ICMEs). We study in detail how four geomagnetic-activity parameters (the Dst, Ap, and AE indices, as well as the Dst time derivative, \(\mathrm{dDst}/\mathrm{d}t\)) are related to three CIR-related solar wind parameters (flow speed, \(V\), magnetic field, \(B\), and the convective electric field based on the southward Geocentric solar magnetospheric (GSM) magnetic field component, \(\mathit{VB}_{s}\)) on a three-hour time resolution. In addition, we quantify statistical relationships between the mentioned geomagnetic indices. It is found that Dst is correlated best to \(V\), with a correlation coefficient of \(\mathrm{cc}\approx0.6\), whereas there is no correlation between \(\mathrm{dDst}/\mathrm{d}t\) and \(V\). The Ap and AE indices attain peaks about half a day before the maximum of \(V\), with correlation coefficients ranging from \(\mathrm{cc}\approx0.6\) to \(\mathrm{cc}\approx0.7\), depending on the sample used. The best correlations of Ap and AE are found with \(\mathit{VB}_{s}\) with a delay of 3 h, being characterised by \(\mathrm{cc}\gtrsim 0.6\). The Dst derivative \(\mathrm{dDst}/\mathrm{d}t\) is also correlated with \(\mathit{VB}_{s}\), but the correlation is significantly weaker \(\mathrm{cc}\approx 0.4\)?–?0.5, with a delay of 0?–?3 h, depending on the employed sample. Such low values of correlation coefficients indicate that there are other significant effects that influence the relationship between the considered parameters. The correlation of all studied geomagnetic parameters with \(B\) are characterised by considerably lower correlation coefficients, ranging from \(\mathrm{cc}=0.3\) in the case of \(\mathrm{dDst}/\mathrm{d}t\) up to \(\mathrm{cc}=0.56\) in the case of Ap. It is also shown that peak values of geomagnetic indices depend on the duration of the CIR-related structures. The Dst is closely correlated with Ap and AE (\(\mathrm{cc}=0.7\)), Dst being delayed for about 3 h. On the other hand, \(\mathrm{dDst}/\mathrm{d}t\) peaks simultaneously with Ap and AE, with correlation coefficients of 0.48 and 0.56, respectively. The highest correlation (\(\mathrm{cc}=0.81\)) is found for the relationship between Ap and AE. 相似文献
3.
Adrianna Ianora Raffaella Casotti Mauro Bastianini Christophe Brunet Giuliana D’Ippolito Francesco Acri Angelo Fontana Adele Cutignano Jefferson T. Turner Antonio Miralto 《Marine Ecology》2008,29(3):399-410
Egg production rates and/or hatching success in the copepods Acartia clausi, Calanus helgolandicus and Temora longicornis were negatively affected by a late spring (May–June 2003) phytoplankton bloom in the North Adriatic Sea, dominated mainly by the large diatom Cerataulina pelagica. Highest total concentrations of 3.3·104 cells·ml?1 were located in the vicinity of the Po River, which also corresponded to the area where the highest numbers of phaeophorbides were measured (0.779, 0.528 and 0.419 μg·l?1, respectively, compared to an average of the remaining stations of 0.183 ± 0.049 SD), suggesting some grazing on the bloom. Phytoplankton biomass in terms of carbon was dominated by diatoms, representing on average 42% of total phytoplankton carbon and more than 80% at several stations. Cerataulina pelagica, Cyclotella spp., Chaetoceros spp. and small unidentified centric diatoms dominated the diatom community numerically but C. pelagica was by far the dominant diatom in terms of carbon due to its large cell size. This species represented more than 60% of the diatom biomass at nine of the 14 stations sampled, and was absent only at one station, which was the most offshore station sampled during the cruise. Although polyunsaturated aldehydes (PUAs) were not detected, other oxylipins which are hydroxy and keto derivatives of eicosapentaenoic and docosahexaenoic acids that affect copepod reproduction were found in these samples. Hence, we can attribute the negative impact of diatoms not only to PUAs, as previously believed, but also to these compounds. This is the first direct evidence of the presence of oxylipins other than PUAs in marine blooms dominated by diatoms. 相似文献
4.
Rosa Nappi Giuliana Alessio Giovanni Bronzino Carlo Terranova Giuseppe Vilardo 《Natural Hazards》2008,45(1):73-85
In this article the implementation and potential of the Seismotectonic Information System of the Campania Region (SISCam)
are described, in particular an application of this Web-based GIS system to the seismotectonic analysis of the Sannio area
(Southern Apennines) is performed. WEB-GIS technologies greatly contribute to both the environmental monitoring and the disaster
management of areas affected by high natural risks. Specifically the SISCam system has been developed with the aim of providing
easy access and fast diffusion, through Internet technology, of the most significant geological, geophysical, and territorial
data relative to the Campania Region. The Sannio area has been selected as our application example because it is among the
most active seismic regions in Italy. This portion of the Southern Apennines which was hit by the June 5, 1688 strong earthquake
(M
W = 6.7, CPTI 1999) and by some low- and moderate-energy seismic sequences (1990–1992, 1997), is characterized by a complex
inherited tectonic setting and low-tectonic deformation rates that hide the seismogenic sources position. Since this case
study turned out to be complicated, the use of the SIScam WEB-GIS has become indispensable because it allowed us to visualize,
integrate and analyze all the data available, in order to obtain an accurate and direct picture of the seismotectonic setting
of the area. Moreover, a different approach of data analysis was necessary, due to the lack of up-to-date neotectonic and
structural data; therefore, the operation of this GIS system enabled us to process and generate some original informative
layers, through image analysis, such as new structural lineaments represented on a map of the potential active faults of the
area, which has been the final result of our application, as a contribution to new knowledge about the local seismic risk
parameters. 相似文献
5.
Hydrogeochemical investigations and groundwater provinces of the Friuli Venezia Giulia Plain aquifers,northeastern Italy 总被引：2，自引：0，他引：2
Water resources are a key factor, particularly for the planning of the sustainable regional development of agriculture, as
well as for socio-economic development in general. A hydrochemical investigation was conducted in the Friuli Venezia Giulia
aquifer systems to identify groundwater evolution, recharge and extent of pollution. Temperature, pH, electric conductivity,
total dissolved solids, alkalinity, total hardness, SAR, Ca2+, Na+, K+, Mg2+, Cl−, SO4
2−, NO3
−, HCO3
−
, water quality and type, saturation indexes and the environmental stable isotope δ18O were determined in 149 sampling stations. The pattern of geochemical and oxygen stable isotope variations suggests that
the sub-surface groundwater (from phreatic and shallow confined aquifers) is being recharged by modern precipitations and
local river infiltrations. Four hydrogeological provinces have been recognised and mapped in the Friuli Venezia Giulia Plain
having similar geochemical signatures. These provinces have different degrees of vulnerability to contamination. The deep
confined groundwater samples are significantly less impacted by surface activities; and it appears that these important water
resources have very low recharge rates and would, therefore, be severely impacted by overabstraction. 相似文献
6.
Holocene climate variability in Sicily from a discontinuous stalagmite record and the Mesolithic to Neolithic transition 总被引：2，自引：0，他引：2
Silvia Frisia Andrea Borsato Augusto Mangini Christoph Sptl Giuliana Madonia Ugo Sauro 《Quaternary Research》2006,66(3):388-400
Fabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ13C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ13C and δ18O values. A high variability of δ13C values is recorded from ca. 7500 to ca. 6500 yr ago and indicates that the transition from a pluvial early Holocene to the present-day climate conditions was punctuated by decadal-scale periods of relatively dry winters. In northern Sicily, the traditional elements of the Neolithic appear at ca. 7700 yr ago. It is possible that changes in rainfall influenced the passage from hunter-gathering to farming and sheep-herding economies. 相似文献
7.
8.
José M. Carcione Davide Gei Giuliana Rossi Gianni Madrussani 《Geophysical Prospecting》2005,53(6):803-810
We estimate the concentration of gas hydrate and free gas at an area located to the north of the Knipovich Ridge (western Svalbard margin). The method is based on P-wave velocities computed by reflection tomography applied to multicomponent ocean-bottom seismometer data. The tomographic velocity field is fitted to theoretical velocities obtained from a poro-elastic model based on a Biot-type approach (the interaction between the rock frame, gas hydrate and fluid is modelled from first physical principles). We obtain average hydrate concentrations of 7% and maximum free-gas saturations of 0.4% and 9%, depending on the saturation model. 相似文献
9.
Barbara J. Thompson Sarah E. Gibson Peter C. Schroeder David F. Webb Charles N. Arge Mario M. Bisi Giuliana de Toma Barbara A. Emery Antoinette B. Galvin Deborah A. Haber Bernard V. Jackson Elizabeth A. Jensen Robert J. Leamon Jiuhou Lei Periasamy K. Manoharan M. Leila Mays Patrick S. McIntosh Gordon J. D. Petrie Simon P. Plunkett Liying Qian Peter Riley Steven T. Suess Munetoshi Tokumaru Brian T. Welsch Thomas N. Woods 《Solar physics》2011,274(1-2):29-56
We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar?Cheliospheric?Cplanetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March??C?16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth??s mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum. 相似文献
10.
Georges Ona-Nguema Guillaume Morin Yuheng Wang Farid Juillot Giuliana Aquilanti Christian Ruby François Guyot Gordon E. Brown Jr. 《Geochimica et cosmochimica acta》2009,73(5):1359-1446
X-ray Absorption Fine Structure (XAFS) spectroscopy was used in combination with high resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), X-ray energy dispersive spectroscopy (XEDS), X-ray powder diffraction, and Mössbauer spectroscopy to obtain detailed information on arsenic and iron speciation in the products of anaerobic reduction of pure and As(V)- or As(III)-adsorbed lepidocrocite (γ-FeOOH) by Shewanella putrefaciens ATCC 12099. We found that this strain of S. putrefaciens is capable of using Fe(III) in lepidocrocite and As(V) in solution or adsorbed on lepidocrocite surfaces as electron acceptors. Bioreduction of lepidocrocite in the absence of arsenic resulted in the formation of hydroxycarbonate green rust 1 [FeII4FeIII2(OH)12CO3: GR1(CO3)], which completely converted into ferrous-carbonate hydroxide (FeII2(OH)2CO3: FCH) over nine months. This study thus provides the first evidence of bacterial reduction of stoichiometric GR1(CO3) into FCH. Bioreduction of As(III)-adsorbed lepidocrocite also led to the formation of GR1(CO3) prior to formation of FCH, but the presence of As(III) slows down this transformation, leading to the co-occurrence of both phases after 22-month of aging. At the end of this experiment, As(III) was found to be adsorbed on the surfaces of GR1(CO3) and FCH. After five months, bioreduction of As(V)-bearing lepidocrocite led directly to the formation of FCH in association with nanometer-sized particles of a minor As-rich Fe(OH)2 phase, with no evidence for green rust formation. In this five-month experiment, As(V) was fully converted to As(III), which was dominantly sorbed at the surface of the Fe(OH)2 nanoparticles as oligomers binding to the edges of Fe(OH)6 octahedra at the edges of the octahedral layers of Fe(OH)2. These multinuclear As(III) surface complexes are characterized by As-As pairs at a distance of 3.32 ± 0.02 Å and by As-Fe pairs at a distance of 3.50 ± 0.02 Å and represent a new type of As(III) surface complex. Chemical analyses show that the majority of As(III) produced in the experiments with As present is associated with iron-bearing hydroxycarbonate or hydroxide solids, reinforcing the idea that, at least under some circumstances, bacterial reduction can promote As(III) sequestration instead of mobilizing it into solution. 相似文献