4 research outputs found
Validazione a scala nazionale della ricostruzione con il modello WRF dei profili verticali dei parametri meteorologici
No full textLAUREA MAGISTRALELa modellistica della qualità dell’aria utilizza come fondamentale dato in ingresso informazioni sulle caratteristiche meteorologiche dell’area di studio. Tali informazioni, che assumono la connotazione di campi bi-tridimensionali dei parametri meteorologici vengono predisposte tramite specifiche ricostruzioni modellistiche a partire da dati osservati. Ad esempio, il modello WRF (Weather Research and Forecasting) è tra i più utilizzati per la ricostruzione dei profili verticali, ovvero dell’andamento dei parametri di interesse con la quota. È del tutto evidente che, tanto più accurata è la ricostruzione dei campi meteorologici,
tanto migliore sarà la ricostruzione della distribuzione spaziale delle concentrazioni di inquinanti atmosferici. Infatti, discrepanze tra i valori osservati di concentrazione e risultati modellistici possono talora derivare da non corrette ricostruzioni della forzante meteorologica. È pertanto necessario validare, almeno in forma puntuale, limitatamente ad alcuni punti del dominio della simulazione modellistica, i risultati del modello meteorologico che costituisco poi l’ingresso al modello di qualità dell’aria.
Nel seguente elaborato si è svolta la validazione dei profili verticali di temperatura, umidità relativa, velocità e direzione del vento prodotti dal modello WRF per i punti corrispondenti alle stazioni meteorologiche del territorio nazionale in cui vengono effettuate osservazioni sperimentali tramite radiosondaggi atmosferici. Le stazioni meteorologiche considerate coprono l’intero territorio nazionale e sono localizzate a Milano-Linate, Rivolto (UD), Cuneo, Pratica di Mare (RM), San Pietro Capofiume (BO), Brindisi, Trapani e Decimomannu (CA). La validazione dei risultati modellistici è stata sviluppata su base annuale per gli anni 2010 e 2017. Disponendo delle ricostruzioni modellistiche dei profili verticali delle variabili meteorologiche da simulazioni WRF effettuate a diversa risoluzione spaziale orizzontale, la validazione ha potuto anche analizzare l’effetto di tale parametro sulla prestazione del modello stesso.
Dai risultati ottenuti si può concludere che il modello in questione è in grado di descrivere in maniera soddisfacente l’andamento dei principali parametri meteorologici in funzione della quota.Air quality modelling uses as input data information about weather related info of the observed area. Such information, considered bi-three dimensional fields of meteorological parameters, are set up by means of specific modelling retrieving from observed data. The WRF model (Weather Research and Forecasting), for example, is one of the most used models to recreate vertical profiles, which means altitude parameter trend. It is obvious that the more accurate is the retrieving of meteorological fields the better recreation of space distribution of atmospheric pollutants. Discrepancies between observed concentration values and modelling results might in fact derive from not correct remake of meteorological forcing. It is therefore necessary to validate, at least in punctual way and for given points of the domain of modelling simulation, results of meteorological model which then represent the entry of air quality model. This study validates vertical profiles of temperature, related humidity, wind speed and direction from WRF model for points corresponding to meteorological stations of national territory, where are made experimental observations through atmospheric radiosoundings. The meteorological stations considered cover the whole national territory and are located at Milano-Linate, Rivolto (UD), Cuneo, Pratica di Mare (RM), San Pietro Capofiume (BO), Brindisi, Trapani and Decimomannu (CA). Modelling results validation has been developed on yearly basis for 2010 and 2017. The availability of modelling retrieving of vertical profiles of meteorological variables from WRF simulations, realized at different horizontal space resolution, has allowed validation of the effect of such parameter on model performance itself. From obtained results it is possible to determine that the model considered is able to describe appropriately the trend with the altitude of main meteorological parameters
Tra storia e natura: un'ipotesi di percorso a misura d’uomo ed ecosostenibile tra i Parchi dell’Appia Antica e dei Castelli Romani.
No full textModeling the Effect of COVID-19 Lockdown on Mobility and NO2 Concentration in the Lombardy Region
No full textRecent observation and modeling-based studies have shown how air quality has been positively affected by the containment measures enforced due to the COVID-19 outbreak. This work aims to analyze Lombardy’s NO2 atmospheric concentration during the spring lockdown. The region of Lombardy is known for having the largest number of residents in Italy and high levels of pollution. It is also the region where the first European confinement measures were imposed by the Italian government. The modeling suite composed of CAMx (Comprehensive Air Quality Model with Extensions) and WRF (Weather Research and Forecasting model) provides the setting to compare the atmospheric NO2 concentration from mid-February to the end of March with a business as usual situation. The main interest in this work is to investigate the response of NO2 atmospheric concentration to increasingly reduced road traffic. We can simulate, for the first time, a real circumstance of progressively reduced mobility, as well as validating it with measured air quality data. Focusing on the city of Milan, we found that the decrease in NO2 concentration reflects progressively reduced traffic contraction. In the case of a large traffic abatement (71%), the concentration level is reduced by one third. We also find that industrial activities have a relevant impact on NO2 atmospheric concentration, especially in the provinces of Brescia and Bergamo. This study provides an overview of how incisive policies must be implemented to achieve the set environmental targets and protect human health
On the Chemical Composition and Hygroscopicity of Aerosols Deposited on the Insulators of Italian Power Lines
No full textThe reliability of the national power grid is a key issue in modern society. Atmospheric aerosols are the main cause of the reduction in the performance of insulators and the increase in the possibility of flashovers, resulting in power line failures. Under high ambient humidity, the water-soluble compounds of atmospheric aerosols collected on the insulators’ surface can dissociate in ions and form a conductive layer, which may lead to flashover events. With a view to investigating the processes that drive these phenomena, the chemical composition of aerosol deposits on insulators in Italy was determined by ion chromatography analysis and thermos-optical and X-ray techniques. In addition, a synthetic aerosol with the same analyzed chemical composition was generated in a laboratory and deposited on PTFE filters and glass specimens allowing us to determine the deliquescence and crystallization relative humidity and the conductive effect in an aerosol exposure chamber. The results evidenced the presence of a hazardous inorganic ion layer, which generates a sharp phase transition of the aerosol deposit as a function of the ambient relative humidity; this layer poses a dangerous threat to the reliability of the power grid, increasing the probability of flashover events where the conductive layer facilitates the flow of electrical current across the insulator surface, potentially causing power outages or damage to the power lines
