Updated predictive equations for broadband (0.01–10 s) horizontal response spectra and peak ground motions,based on a global dataset of digital acceleration records     

Carlo Cauzzi  Ezio Faccioli  Manuela Vanini  Aldo Bianchini 《Bulletin of Earthquake Engineering》2015,13(6):1587-1612

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Using sulfur and oxygen isotope data for sulfide oxidation assessment in the Freiberg polymetallic sulfide mine     

Manuela Junghans  Marion Tichomirowa   《Applied Geochemistry》2009,24(11):2034-2050

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Oxygen isotope evidence for sorption of molecular oxygen to pyrite surface sites and incorporation into sulfate in oxidation experiments     

Marion Tichomirowa  Manuela Junghans 《Applied Geochemistry》2009,24(11):2072-2092

Experiments were conducted to investigate (i) the rate of O-isotope exchange between SO₄ and water molecules at low pH and surface temperatures typical for conditions of acid mine drainage (AMD) and (ii) the O- and S-isotope composition of sulfates produced by pyrite oxidation under closed and open conditions (limited and free access of atmospheric O₂) to identify the O source/s in sulfide oxidation (water or atmospheric molecular O₂) and to better understand the pyrite oxidation pathway. An O-isotope exchange between SO₄ and water was observed over a pH range of 0–2 only at 50 °C, whereas no exchange occurred at lower temperatures over a period of 8 a. The calculated half-time of the exchange rate for 50 °C (pH = 0 and 1) is in good agreement with former experimental data for higher and lower temperatures and excludes the possibility of isotope exchange for typical AMD conditions (T  25 °C, pH  3) for decades.Pyrite oxidation experiments revealed two dependencies of the O-isotope composition of dissolved sulfates: O-isotope values decreased with longer duration of experiments and increasing grain size of pyrite. Both changes are interpreted as evidence for chemisorption of molecular O₂ to pyrite surface sites. The sorption of molecular O₂ is important at initial oxidation stages and more abundant in finer grained pyrite fractions and leads to its incorporation in the produced SO₄. The calculated bulk contribution of atmospheric O₂ in the dissolved SO₄ reached up to 50% during initial oxidation stages (first 5 days, pH 2, fine-grained pyrite fraction) and decreased to less than 20% after about 100 days. Based on the direct incorporation of molecular O₂ in the early-formed sulfates, chemisorption and electron transfer of molecular O₂ on S sites of the pyrite surface are proposed, in addition to chemisorption on Fe sites. After about 10 days, the O of all newly-formed sulfates originates only from water, indicating direct interaction of hydroxyls from water with S at the anodic S pyrite surface site. Then, the role of molecular O₂ is as proposed in previous studies: acting as electron acceptor only at the cathodic Fe pyrite surface site for oxidation of Fe(II) to Fe(III).  相似文献   

Geomorphological mapping for the valorization of the alpine environment. A methodological proposal tested in the Loana Valley (Sesia Val Grande Geopark,Western Italian Alps)   总被引：1，自引：1，他引：0  

Irene Bollati  Beatrice Crosa Lenz  Enrico Zanoletti  Manuela Pelfini 《山地科学学报》2017,14(6):1023-1038

Geomorphological mapping plays a key role in landscape representation: it is the starting point for many applications and for the realization of thematic maps, such as hazard and risk maps, geoheritage and geotourism maps. Traditional geomorphological maps are useful for scientific purposes but they need to be simplified for different aims as management and education. In tourism valorization, mapping of geomorphological resources (i.e., geosites, and geomorphosites), and of geomorphic evidences of past hazardous geomorphological events, is important for increasing knowledge about landscape evolution and active processes, potentially involving geomorphosites and hiking trails. Active geomorphosites, as those widespread in mountain regions, testify the high dynamicity of geomorphic processes and their link with climatic conditions. In the present paper, we propose a method to produce and to update cartographic supports (Geomorphological Boxes) realized starting from a traditional geomorphological survey and mapping. The Geomorphological Boxes are geomorphological representation of single, composed or complex landforms drawn on satellite images, using the official Italian geomorphological legend (ISPRA symbols). Such cartographic representation is also addressed to the analysis (identification, evaluation and selection) of Potential Geomorphosites and Geotrails. The method has been tested in the upper portion of the Loana Valley (Western Italian Alps), located within the borders of the Sesia Val Grande Geopark, recognized by UNESCO in 2013. The area has a good potential for geotourism and for educational purposes. We identified 15 Potential Geomorphosites located along 2 Geotrails; they were ranked according to specific attributes also in relation with a Reference Geomorphosite located in the Loana hydrographic basin and inserted in official national and regional databases of geosites (ISPRA; Regione Piemonte). Finally, the ranking of Potential Geomorphosites allowed to select the most valuable ones for valorization or geoconservation purposes. In this framework, examples of Geomorphological Boxes are proposed as supports to geo-risk education practices.  相似文献   

Elastic Ray-Born L₂-Migration/Inversion     

Wafik B. Beydoun  Manuela Mendes 《Geophysical Journal International》1989,97(1):151-160

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Climate change scenarios for surface temperature in Emilia-Romagna (Italy) obtained using statistical downscaling models     

R. Tomozeiu  C. Cacciamani  V. Pavan  A. Morgillo  A. Busuioc 《Theoretical and Applied Climatology》2007,90(1-2):25-47

Summary Possible changes of mean climate and the frequency of extreme temperature events in Emilia-Romagna, over the period 2070–2100 compared to 1960–1990, are assessed. A statistical downscaling technique, applied to HadAM3P experiments (control, A2 and B2 scenarios) performed at the Hadley Centre, is used to achieve this objective. The method applied consists of a multivariate regression based on Canonical Correlation Analysis (CCA), using as possible predictors mean sea level pressure (MSLP), geopotential height at 500 hPa (Z500) and temperature at 850 hPa (T850), and as predictands the seasonal mean values of minimum and maximum surface temperature (T_min and T_max), 90^th percentile of maximum temperature (T_max90), 10^th percentile of minimum temperature (T_min10), number of frost days (T_nfd) and heat wave duration (HWD) at the station level. First, the statistical model is optimised and calibrated using NCEP/NCAR reanalysis to evaluate the large-scale predictors. The observational data at 32 stations uniformly distributed over Emilia-Romagna are used to compute the local predictands. The results of the optimisation procedure reveal that T850 is the best predictor in most cases, and in combination with MSLP, is an optimum predictor for winter T_max90 and autumn T_min10. Finally, MSLP is the best predictor for spring T_min while Z500 is the best predictor for spring T_max90 and heat wave duration index, except during autumn. The ability of HadAM3P to simulate the present day spatial and temporal variability of the chosen predictors is tested using the control experiments. Finally, the downscaling model is applied to all model output experiments to obtain simulated present day and A2 and B2 scenario results at the local scale. Results show that significant increases can be expected to occur under scenario conditions in both maximum and minimum temperature, associated with a decrease in the number of frost days and with an increase in the heat wave duration index. The magnitude of the change is more significant for the A2 scenario than for the B2 scenario.  相似文献   

Tropospheric parameters: combination studies based on homogeneous VLBI and GPS data     

Manuela Krügel  Daniela Thaller  Volker Tesmer  Markus Rothacher  Detlef Angermann  Ralf Schmid 《Journal of Geodesy》2007,81(6-8):515-527

The combination of tropospheric parameters derived from different space-geodetic techniques has not been of large interest in geodesy so far. However, due to the high correlation between station coordinates and tropospheric parameters, the latter should not be neglected in combinations. This paper deals with the comparison and combination of tropospheric parameters derived from global positioning system (GPS) and very long baseline interferometry (VLBI) observations stemming from a 15-day campaign of continuous VLBI observations in 2002 (CONT02). The observation data of both techniques were processed homogeneously to avoid systematic differences between the solutions. We compared the tropospheric estimates of GPS and VLBI at eight co-location sites and found a very good agreement in the temporal behavior of the tropospheric zenith path delays (ZPD), reflected by correlation factors up to 0.98. Following this, a combination of the tropospheric parameters was performed. We demonstrate that the combination of tropospheric parameters leads to a stabilization of combined station networks. This becomes visible in the improvement of the repeatabilities of the station height components. Furthermore, the potential use of independent data from water vapor radiometers (WVRs) to validate space-technique-derived tropospheric parameters was investigated. Correlation coefficients of 0.95 or better were estimated between the tropospheric parameters of WVR and GPS or VLBI. Additionally, the utility of the tropospheric parameters for validation of local tie vectors was investigated. Both tropospheric zenith delays and tropospheric gradients were found to be very suitable to validate the height component and the horizontal components of the local tie, respectively.  相似文献   

Integrated modelling for water quality management in a eutrophic reservoir in south-eastern Portugal     

David Brito  Tiago B. Ramos  Maria C. Gonçalves  Manuela Morais  Ramiro Neves 《Environmental Earth Sciences》2018,77(2):40

The Enxoé Reservoir was built in 1998. Since 2000, it has exhibited frequent high chlorophyll-a concentrations, reaching a geometric mean three times higher than the national limit for eutrophication, presenting the reservoir with the highest eutrophic state in Portugal. Toxic algal blooms have also often been observed, which pose serious challenges to water managers, as the reservoir is used for potable water production (25,000 inhabitants). The objective of this study was to implement a reservoir model (CE-QUAL-W2), with inputs from a watershed model (SWAT), in order to represent the actual reservoir state and to test management measures to reduce its trophic level and algal bloom concentration peaks. The integrated model was used to depict the origin of its trophic status. Simulations were also compared to measured data at the reservoir surface (water level, nitrate, orthophosphate, suspended solids, and oxygen) and in water profiles (temperature, oxygen). The model was able to represent stratification and thermocline depths, as well as the actual chlorophyll-a and dissolved oxygen concentrations. The model results showed that internal phosphorus load from deposited sediments was an important factor in fuelling the algal blooms. This process occurs predominantly in summer, when stratification takes place and aeration is reduced, promoting anoxic conditions in the bottom waters. Since the reservoir is relatively shallow (average 5 m), released phosphorus is then easily able to reach the photic zone in most parts of the reservoir, where it is consumed. Different management scenarios were tested, suggesting that a mesotrophic level could barely be reached and maintained simply by reducing the nutrient loads (both external and internal). It is suggested that only an increase in the reservoir dam height could produce a mesotrophic level, averting anoxia by blocking the release of phosphorus from sediments to the photic zone. Future work should focus on a cost–benefit analysis to test the feasibility of each of the proposed scenarios, taking advantage of the integration strategy to assess where in the watershed load reductions would be most effective.  相似文献   

Assessing coastal landscape vulnerability using geospatial techniques along Vizianagaram–Srikakulam coast of Andhra Pradesh,India     

Meenu Rani  Sufia Rehman  Haroon Sajjad  B. S. Chaudhary  Jyoti Sharma  Sandeep Bhardwaj  Pavan Kumar 《Natural Hazards》2018,94(2):711-725

Vizianagaram–Srikakulam coastal shoreline consisting of beaches, mangrove swamps, tidal channel and mudflats is one of the vulnerable coasts in Andhra Pradesh, India. Five site-specific parameters, namely rate of geomorphology, coastal elevation, coastal slope, shoreline change and mean significant wave height, were chosen for constructing coastal vulnerability index and assessing coastal landscape vulnerability. The findings revealed a shift of 2.5 km in shoreline towards the land surface because of constant erosion and that of 1.82 km towards the sea due to accretion during 1997–2017. The rate of high erosion was found in zones IV and V, and high accretion was found in zones II and III. Coastal vulnerability index analysis revealed constant erosion along shoreline and sea level rise in the study area. Most of the coast in zone V has recorded very high vulnerability due to erosion, high slope, significant wave height and sea level rise. Erosion and accretion, significant wave height, sea level rise and slope are attributed to high vulnerability in zones III and IV. Zone II recorded moderate vulnerability. Relatively lower slope, mean sea wave height and sea level rise have made this zone moderately vulnerable. Very low vulnerability was found in zone I, and low vulnerability was recorded in zone II. Accretion, low slope and low sea level rise were found to be causative factors of lower vulnerability. Thus, zones III, IV and V should be accorded higher priorities for coastal management. The findings can be helpful in coastal land planning and management and preparing emergency plans of the coastal ecosystems.  相似文献   

High-silica zeolites in pyroclastic flows from Central Sardinia (Italy): clues on genetic processes and reserves from a mineralogical study     

Mormone  Angela  Ghiara  Maria Rosaria  Balassone  Giuseppina  Piochi  Monica  Lonis  Roberto  Rossi  Manuela 《Mineralogy and Petrology》2018,112(6):767-788

Mineralogy and Petrology - The island of Sardinia (Italy) presents some of the most interesting zeolite ores in Europe, most of which are associated with old pyroclastic deposits. In particular,...  相似文献