1,720,985 research outputs found
High water in Venice ( flood forecasting)
No full textStatistical and deterministic models capable of forecasting high and low water in Venice, Italy are discussed. Using data on atmospheric pressure, wind fields and sea levels, measured up to 30 hours before, as input to the model, a short term flood warning (about 6 hours in advance) is possible. The city authority is currently using the model to warn the population.-from Author
PMSS and gral inter-comparison: Strengths and weaknesses of the two models in reproducing Urban NOx levels in a real case application
Full text linkAir dispersion models are useful tools for quantifying pollutant concentrations in urban environment however many issues related to the dispersion estimation within urban canopy still persist. Most of them concern the emissions estimation, the flow field reconstruction between obstacles (buildings, bridges, tunnels, etc.) and the pollutant dispersion driven by the estimated flow field. This study presents results of a model inter-comparison conducted in a real case study, focusing on a 6 km x 6 km square domain covering the city of Modena (Italy), between two Lagrangian dispersion models set-up with the aim of estimating the NOx concentrations produced by traffic flow within the urban area of the city. Comparisons are made between the Graz Lagrangian Model (a.k.a. GRAL) and the Parallel Micro SWIFT and SPRAY (a.k.a. PMSS) modelling suite, in terms of dispersion concentrations and computing cost. The horizontal resolution for both the models is set to 4 meters and the traffic emissions estimation is based on a bottom-up approach: the PTV VISUM traffic model is used to estimate traffic flows on the Modena urban road network and the EMEP/EEA cold and hot emission factors are employed to estimate related emissions. All the other urban emission sources were considered to contribute to the regional background concentrations and estimated with the WRF-Chem model, which estimates also initial and boundary meteorological conditions (multi-scale approach). The general objective of the inter-comparison is to use equivalent input data for both the models keeping the emissions and the meteorological initial and boundary/condition consistent so that any discrepancies in output would be the results of differences in the micro-scale dispersion models. Since different turbulence parametrisation and dispersion scheme are implemented in the two models, the goal of this study is to identify the strengths and the weaknesses of both the models in reproducing urban NOx concentrations, in a real case application, at urban traffic and urban background sites
Forecast of the impact by local emissions at an urban micro scale by the combination of Lagrangian modelling and low cost sensing technology: The TRAFAIR project
No full textThe use of a physiologically based pharmacokinetic modelling in a “full-chain” exposure assessment framework: A case study on urban and industrial pollution in northern italy
Full text linkBackground and goals: The estimate of the internal dose provided by physiologically based pharmacokinetic (PBPK) modelling is a big step forward in the frame of human health risk assessment (HRA) from contaminating sources. The PBPK model included in the MERLIN-Expo platform was here tested with data collected in a human biomonitoring (HBM) pilot study to check model efficacy in predicting concentrations in human blood and urine of people exposed to a modern solid waste incinerator (SWI). The aim of the study was to investigate if the use of a PBPK model integrated in a computational platform could replace more expensive and invasive pilot studies. Twenty eight subjects living and working within 4 km of the incinerator (exposed) and 21 subjects living and working outside this area (unexposed) were selected among the population recruited in the HBM study. The group of exposed (E) subjects and the group of non-exposed (NE) subjects were comparable for all relevant anthropometric characteristics and exposure parameters except for the exposure to SWI emissions. Three different scenarios were created: an “only diet-scenario” (DS), a “worst case scenario” (WCS) and a “most likely scenario” (MLS). The platform was tested for blood-lead (B-Pb), urinary-lead (U-Pb), urinary-anthracene (U-Ant) and urinary-fluoranthene (U-Flt). Average estimated U-Pb was statistically equal to the measured one (est. 0.411~0.278; meas. 0.398~0.455 μg/L) and estimated vs. measured U-Ant differ by one order of magnitude only (est. 0.018~0.010; meas. 0.537~0.444 ng/L) while for U-Flt and B-Pb, the error was respectively of two and four orders of magnitude. It is likely that the extremely high accuracy in the Pb concentration input values referring to diet led to the very accurate estimate for this chemical in urine, but the higher error in the B-Pb computed value suggests that PBPK model equations cannot entirely capture the dynamics for blood compartments. MERLIN-Expo seems a very promising tool in saving time, energy and money in the screening step of the HRA framework; however, many software validations are still required
Impact of vehicular emissions in an urban area of the Po valley by microscale simulation with the GRAL dispersion model
Full text linkThis work sets out the test of the GRAL model (Graz Lagrangian Model, vs.18.1) in the urban area of Modena (Po valley, Northern Italy). The simulation domain sizes 2 000 x 3 000 m2 and it features 'microscale' cells of 4 x 4 m2. The simulation focuses on an intersection featured by large traffic flows next to a school and a regulatory air quality monitoring station classified as an urban traffic site. The model is a lagrangian particle dispersion model and it takes into account the presence of buildings as obstacles and generating microscale wind fields accordingly, making this class of model suitable for investigating spatial pattern of atmospheric pollution in urban areas where local accumulation might occur. The simulation investigates traffic emissions of nitrogen oxides (NOx) over the period October 29 to November 10, 2016, when direct measurements of traffic flow were collected by four one-channel doppler radar traffic counters. These counters provided continuous estimate of vehicle length, speed and number. These latter data were combined with available traffic flows at rush hour by PTV VISUM mobility software and the fleet composition of the municipality to estimate the total NOx emissions by vehicular traffic over the roads included in the simulation domain. NOx simulated concentrations showed a moderate correlation with the NOx observations at the nearby monitoring site. To have a better insight on the potential and the limitations of the GRAL model, its results will be compared with the output of the lagrangian particle dispersion model PMSS over the same area
Urban micro-scale investigation of nox and co emissions from vehicular traffic and comParison with air quality data
No full textMicroscale simulation of road traffic emissions from vehicular flow automatic surveys and comparison with measured concentration data
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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