2,187 research outputs found
Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)
Abstract. To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P â ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926â2012, the mean annual P â ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources at a regional scale, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterizations are also supposed to be useful for the assessment of mean annual runoff over carbonate mountains, which is another important topic concerning water management in the southern Apennines
Hydro-geomorphological modelling of ash-fall pyroclastic soils for debris flow initiation and groundwater recharge in Campania (southern Italy)
Carbonate mountain ranges surrounding volcanic centers in the Campania region of southern Italy are covered by discontinuous ash-fall pyroclastic deposits of variable thicknesses. The cover thickness and stratigraphy are relevant to hydrological controls on both rainfall-induced landslides and groundwater recharge. To improve understanding of the hydrologic regimes within the pyroclastic soil mantle, a hydrological monitoring station was installed upslope of a debris flow source area in the Sarno Mountains. Monitoring results demonstrate consistently unsaturated conditions, strong seasonal and inter-annual variations in pressure head, and delayed and damped dynamics at different depths related to rainfall and evapotranspiration patterns. Frequencies of recorded pressure head time series were analyzed to quantify the seasonal hydrological regime of the cover as a whole, as well as variations within individual soil horizons. For the whole ash-fall pyroclastic soil cover, variable seasonal frequencies of pressure head were recognized exceeding landslide alert and groundwater recharge threshold values. Analysis of frequencies for individual soil horizons showed a strongly delayed timing determining in winter and summer an opposite hydrological behavior between the shallowest and deepest soil horizons. A model that accounts for topographic variations in cover thickness and these hydrological regimes is proposed to quantify hydro-geomorphological controls on debris flows triggering and groundwater recharge. The model is based on the estimation of ash-fall pyroclastic soil thickness along slopes by the total thickness fallen in a given area and an inverse relationship with slope angle, allowing the assessment at the distributed scale over peri-volcanic mountainous areas. Moreover, it links the spatially variable thicknesses of ash-fall pyroclastic soils to the amount of soil water storage allowing the assessment of frequency of hydrological conditions leading to debris flow initiation and groundwater recharge
Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)
Abstract. Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation. In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO). The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period. Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis. The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index. Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results of this study allow for the establishment of a link between a large-scale atmospheric cycle and the groundwater recharge of carbonate karst aquifers. Consequently, the winter NAO index could also be considered as a proxy to forecast the decadal variability of groundwater flow in Mediterranean karst areas
Longitudinal relations between parentsâ math anxiety and childrenâs mathematical development from age 3 to 8
Effects of social media brand-related content on fashion products buying behaviour â a moderated mediation model
Purpose â This study examines in which circumstances consumerâs self-congruity moderates the indirect influence of consumer-based brand equity (mediating role) in the relationship between firm-created and user-generated social media content and intention to purchase fashion products.
Design/methodology/approach â In this study, we carried out an online survey with social media users of fashion brands and collected data from 622 participants across two samples to investigate whether consumersâ perceptions of equity of fashion brands mediate the relationship between social media brand-related communication created by both firms and users and the intention to buy the fashion brands. The indirect relationship is further moderated by self-congruity.
Findings â The results indicate that (i) brand equity mediates the relationship between social media communication and purchase intentions of fashion products, and (ii)
self-congruity moderates the relationship between social media communication types and purchase intentions, such that higher/lower levels of self-congruity strengthen/weaken the impact of social media communication on purchase intentions.
Originality/value â This study contributes to the business and marketing literature by exploring how social media communication, branding, and fashion align with the
individualâs self-concept and buying behaviour
Engineering geological 3D modeling and geotechnical characterization in the framework of technical rules for geotechnical design: the case study of the Nolaâs logistic plant (southern Italy)
model is an essential step to optimize costs of the construction and limit risks from failure or damage due to unforeseen ground conditions. The modeling of ground conditions is a challenging issue to be tackled especially in the case of geological units with complex geometries and spatially variable geotechnical properties. In such a direction, coupled geological and geotechnical criteria are usually adopted to define engineering geological units.
These concepts are considered by the current technical rules for geotechnical design such as the Eurocode 7 and in the national regulations which have followed it, known in Italy as âNorme Tecniche per le Costruzioni (NTC).â Notwithstanding this advanced regulatory framework, no comprehensive indications on methodological approaches were given for the 3D engineering geological modeling and geotechnical characterization of a design and construction site. In this paper, the case study of the highly heterogeneous and heteropic pyroclastic-alluvial stratigraphic setting of the Nola plain (Campania, southern Italy) characterizing the site of the Nolaâs logistic plant is dealt with. The approaches are based on the engineering geological modeling analysis of a high number of stratigraphic, laboratory and in situ geotechnical data, collected for the design of the plant, and the use of a specialized modeling software providing advanced capabilities in spatial modeling of geological and geotechnical information, as well as in their visual representation. The results obtained, including also the analysis of statistical variability of geotechnical properties and the identification of representative geotechnical values, can be potentially considered a methodological approach, consistent with the current technical rules for geotechnical design as
well as with fundamental concepts of engineering geological modeling and mapping
Statistical image processing for the detection of dermoscopic criteria
An image based system implementing a well-known diagnostic method is disclosed for the automatic detection of melanomas as support to clinicians. The software procedure is able to recognize automatically the skin lesion within the digital image, measure morphological and chromatic feature, carry out a suitable classification for the detection of structural dermoscopic criteria provided by the 7-Point Check List. Experimental results about the adoption of statistical techniques applied to the border detection, feature extraction and classification as well as the resulting diagnostic score are described with reference to a large image set. Copyright © 2011 by the International Measurement Confederation (IMEKO) All rights reserved
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