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171.
Correlation between nitrate concentration in groundwater and parameters affecting aquifer intrinsic vulnerability 总被引:3,自引:0,他引:3
This paper is the result of a study which was carried out in order to verify if the traditional methods to evaluate the intrinsic
vulnerability or vulnerability related parameters, are able to clarify the problem of nitrate pollution in groundwater. In
particular, the aim was to evaluate limitations and problems connected to aquifer vulnerability methods applied to nitrate
contamination prevision in groundwater. The investigation was carried out by comparing NO3
− concentrations, measured in March and November 2004 in the shallow aquifer, and the vulnerability classes, obtained by using
GOD and TOT methods. Moreover, it deals with a comparison between NO3
− concentrations and single parameters (depth to water table, land use and nitrogen input). The study area is the plain sector
of Piemonte (Northern Italy), where an unconfined aquifer nitrate contamination exists. In this area the anthropogenic presence
is remarkable and the input of N-fertilizers and zootechnical effluents to the soil cause a growing amount of nitrates in
groundwater. This approach, used in a large area (about 10,000 km2) and in several monitoring wells (about 500), allowed to compare the efficiency of different vulnerability methods and to
verify the importance of every parameter on the nitrate concentrations in the aquifer. Furthermore it allowed to obtain interesting
correlations in different hydrogeological situations. Correlations between depth to water table, land use and nitrogen input
to the soil with nitrate concentrations in groundwater show unclear situations: in fact these comparisons describe the phenomenon
trend and highlight the maximum nitrate concentrations for each circumstance but often show wide ranges of possible nitrate
concentrations. The same situation could be observed by comparing vulnerability indexes and nitrate concentrations in groundwater.
These results suggest that neither single parameters nor vulnerability methods (GOD and TOT) are able to describe individually
the complex phenomena affecting nitrate concentrations in soil, subsoil and groundwater. In particular, the traditional methods
for vulnerability analysis do not analyze physical processes in aquifers, such as denitrification and nitrate dilution. According
to a recent study in the shallow unconfined aquifer of the Piemonte plain, dilution can be considered as the main cause for
nitrate attenuation in groundwater. 相似文献
172.
Gervasio Degrazia Domenico Anfossi Haroldo Fraga De Campos Velho Enrico Ferrero 《Boundary-Layer Meteorology》1998,86(3):525-534
A new method for deriving the Lagrangian decorrelation time scales for inhomogeneous turbulence is described. The expression for the time scales here derived for the convective boundary layer is compared to those estimated by Hanna during the Phoenix experiment. Then the values of C0, the Lagrangian velocity structure function constant, and of Bi, the Lagrangian velocity spectrum constant, were evaluated from the Eulerian velocity spectra and from the Lagrangian time scales derived, under unstable conditions, from Taylor's statistical diffusion theory. The numerical coefficient of the lateral and vertical Lagrangian spectra in the inertial subrange was found equal to 0.21, in good agreement with previous experimental estimates. 相似文献
173.
Unidata’s Common Data Model mapping to the ISO 19123 Data Model 总被引:1,自引:1,他引:0
Access to real-time distributed Earth and Space Science (ESS) information is essential for enabling critical Decision Support
Systems (DSS). Thus, data model interoperability between the ESS and DSS communities is a decisive achievement for enabling
cyber-infrastructure which aims to serve important societal benefit areas. The ESS community is characterized by a certain
heterogeneity, as far as data models are concerned. Recent spatial data infrastructures implement international standards
for the data model in order to achieve interoperability and extensibility. This paper presents well-accepted ESS data models,
introducing a unified data model called the Common Data Model (CDM). CDM mapping into the corresponding elements of the international
standard coverage data model of ISO 19123 is presented and discussed at the abstract level. The mapping of CDM scientific
data types to the ISO coverage model is a first step toward interoperability of data systems. This mapping will provide the
abstract framework that can be used to unify subsequent efforts to define appropriate conventions along with explicit agreed-upon
encoding forms for each data type. As a valuable case in point, the content mapping rules for CDM grid data are discussed
addressing a significant example.
相似文献
Lorenzo BigagliEmail: URL: www.imaa.cnr.it |
174.
D’Aniello Andrea Cozzolino Luca Cimorelli Luigi Della Morte Renata Pianese Domenico 《Natural Hazards》2015,75(2):1403-1433
Natural Hazards - In this paper, it is described the development and the assessment of a 1D numerical procedure for the simulation of debris flow phenomena. The procedure focuses on: (1) the... 相似文献
175.
176.
Domenico Montanari Chiara Del Ventisette Marco Bonini Federico Sani 《Geological Journal》2007,42(5):455-476
We present the results of a study of the Vena del Gesso Basin (Romagna Apennines, Italy) integrating field analyses and analogue modelling. This basin represents one of the best‐preserved top‐thrust basins in the Northern Apennines foreland and is one of the few examples where primary evaporites, related to the Messinian salinity crisis of the Mediterranean, widely crop out. The structural style affecting the Messinian gypsum is examined to get insights into the mechanism responsible for the overall deformation features recognizable in the area. The evaporites are completely detached at the base and widespread back‐thrusts, repeatedly doubling these deposits, strongly contrast with the regional forelandward vergence of structures in the Apennines. On the basis of the comparison between field data and experimental results, the features characterising this area can be described as the result of the deformation linked to the sequential activation of an obliquely propagating passive‐roof duplex. Analogue models evidenced the major role played (1) by syntectonic erosion that promoted the development of passive‐roof duplex style, as well as (2) the role of décollement level pinch‐out that determined an oblique progression of deformation. Finally our data lead to reconsider the palaeoenvironmental reconstruction concerning the onset of the Messinian salinity crisis in the Mediterranean. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
177.
178.
Andrea Marchi Domenico Gallese Davide Noè Gorini Paolo Franchin Luigi Callisto 《地震工程与结构动力学》2023,52(1):164-182
The seismic performance of integral abutment bridges (IABs) is affected by the interaction with the surrounding soil, and specifically by the development of interaction forces in the embankment-abutment and soil-piles systems. In principle, these effects could be evaluated by means of highly demanding numerical computations that, however, can be carried out only for detailed studies of specific cases. By contrast, a low-demanding analysis method is needed for a design-oriented assessment of the longitudinal seismic performance of IABs. To this purpose, the present paper describes a design technique in which the frequency- and amplitude-dependency of the soil-structure interaction is modelled in a simplified manner. Specifically, the method consists of a time-domain analysis of a simplified soil-bridge model, in which soil-structure interaction is simulated by means of distributed nonlinear springs connecting a free-field ground response analysis model to the structural system. The results of this simplified method are validated against the results of advanced numerical analyses, considering different seismic scenarios. In its present state of development, the proposed simplified nonlinear model can be used for an efficient evaluation of the longitudinal response of straight IABs and can constitute a starting point for a prospective generalisation to three-dimensional response. 相似文献
179.
Andrea D'Aniello Massimiliano Fabbricino Daniela Ducci Domenico Pianese 《Ground water》2020,58(4):598-610
The potential environmental impacts on subsurface water resources induced by unconventional gas production are still under debate. Solving the controversy regarding the potential adverse effects of gas leakages on groundwater resources is therefore crucial. In this work, an interesting real-world case is presented in order to give further insight into methane multiphase and transport behavior in the shallow subsurface, often disregarded compared to the behavior in the deep subsurface. Multiphase flow and solute transport simulations were performed to assess the vulnerability of an existing shallow unconfined aquifer with respect to a hypothetical methane leakage resulting from a well integrity failure of a former deep geothermal well. The analysis showed that migration of gaseous methane through the aquifer under examination can be extremely fast (of the order of a few minutes), occurring predominantly vertically upwards, close to the well. By contrast, dissolved methane migration is largely affected by the groundwater flow field and occurs over larger time scales (of the order of months/years), covering a greater distance from the well. Overall, the real concern for this site in case of gas leakages is the risk of explosion in the close vicinity of the well. Predicted maximum gaseous fluxes (0.89 to 22.60 m3/d) are comparable to those reported for leaking wells, and maximum dissolved methane concentrations may overcome risk mitigation thresholds (7 to 10 mg/L) in a few years. Therefore, surface and subsurface monitoring before decommissioning is strongly advised to ensure the safety of the site. 相似文献
180.
One of the main purposes of the International Seismological Centre (ISC) is to collect, integrate and reprocess seismic bulletins provided by agencies around the world in order to produce the ISC Bulletin. This is regarded as the most comprehensive bulletin of the Earth’s seismicity, and its production is based on a unique cooperation in the seismological community that allows the ISC to complement the work of seismological agencies operating at global and/or local-regional scale. In addition, by using the seismic wave measurements provided by reporting agencies, the ISC computes, where possible, its own event locations and magnitudes such as short-period body wave m b and surface wave M S . Therefore, the ISC Bulletin contains the results of the reporting agencies as well as the ISC own solutions. Among the most used seismic event parameters listed in seismological bulletins, the event magnitude is of particular importance for characterizing a seismic event. The selection of a magnitude value (or multiple ones) for various research purposes or practical applications is not always a straightforward task for users of the ISC Bulletin and related products since a multitude of magnitude types is currently computed by seismological agencies (sometimes using different standards for the same magnitude type). Here, we describe a scheme that we intend to implement in routine ISC operations to mark the preferred magnitudes in order to help ISC users in the selection of events with magnitudes of their interest. 相似文献