Description

The program and tasks of the Palermo Research Unit are here described with reference to the same "Research Issues" used in the previous section ("Descrizione(Obiettivi e Metodi)).1) Research Issue “Water”: Costruction of quality assessment grids for the Sicilian coastal marine watersOver the two years of this research program, the activity will focus on the use of information on the level and mechanisms of growth of Posidonia oceanica meadows, along with information on the chemical-physical characteristics of the water column and on sediments, to build up quality assessment grids for the Sicilian coastal marine waters.The database used for this analysis, which will be carried out as a collaborative effort with the marine ecologists of the Department of Botanical Sciences at Palermo University, is being collected within the framework of an agrrement with the Sicily Environmental Protection Agency (ARPA Sicilia) and is one of the richest in the whole Mediterranean basin: at each of three stations of different depth (superficial, intermediate, deep) along 90 transects located at different sites of the Sicilian coast a sample of 30 P. oceanica shoots are extracted by a systematic random sampling scheme.By means of lepidochronology, in the laboratory several variables concerning the annual growth of each shoot are measured. At each transect, physical-chemical variables concerning the water column and variables concernig the sediments are also collected.The use of information on P. oceanica growth for the quality assessment of coastal marine waters requires, preliminarily, the ability to model the relationships between potentially explanatoryvariables and response variables measuring growth performance. As mentioned in the Scientific background, this will be done through Generalised Linear Mixed Models. This choice requires also the development of appropriate methods for inference and diagnostics, since many problems are still open in this area, concerning on one hand the definition of goodness-of-fit tests and on the other hand the definition of appropriate residuals and their use in graphical diagnostic tools (for some preliminary results, see Lovison, 2005 and Sciandra, Lovison, 2005). In a second stage, the research activity will address the methodological problems involved in the construction of synthetic indicators of water quality, with special attention to both their scientific rigour and their interpretability for decision makers.2) Scientific Issues Area “Air”: Analysis of the influence of meteorological variables on the concentrations of atmospheric pollutants in the Sicilian provincesThe research activity will aim at the extension to the Sicilian regional level of the study about the effect of meteorological variables on pollutant concentration already carried out in the city of Palermo (Bondì,Plaia, 2005). The available database contains the concentrations of the main pollutants and the measurements of some meteorological variables, recorded hourly/bihourly since 2001 by the monitoring networks of the Sicilian municipalities and/or provinces.Tha data therefore display a high time frequency and a variable space density, locally high within municipalities but globally low in the region; as a consequence, special attention will be devoted to modelling the spatial correlation.Two problems of special concern will be the acceptability of the assumption of separability of time and space components (see, for example, Shaddick, Wakefield, 2002), and the problem of "misalignement" between meteorological and pollution data, mentioned in t

Layman's description

The Palermo Research Unit will contribute to the activity of the National Research Project developing its effort along four lines,consistent with the Research Issues specified in the Modello A.1) Research Issue "Water": Costruction of quality assessment grids for the Sicilian coastal marine watersThe activity of this sub-group will focus on the analysis of the growth of Posidonia oceanica meadows, aimed at the construction ofquality assessment "grids" for the Sicilian coastal marine waters.P. oceanica is a marine plant which represents one of the best ecological markers of status of coastal marine waters (Cinelli et al.,1995). A joint research work, focussed on the growth of P. oceanica, has been carried out with the marine ecologists of theDepartment of Botanical Sciences of the University of Palermo for the past three years (see Tomasello et al., 2006, Tomasello et al2006).By means of a special technique called "lepidochronology" (Pergent, 1990), it is possible to reconstruct several variables concerning the growth performance for each plant, "backward" from the sampling year to the year of upright growth. Therefore, for each plant a longitudinal multivariate series of variable length (between 4 and 35 years) is available, along with some explanatory variables, among which the spatial localisation and calendar year.The methodological problems concern the use of models for the analysis of series of longitudinal data, relatively short in time and sparsely located in space. In particular, since the response variables are binary, discrete or continuous but markedly non-Normal, we have chosen to resort to the class of Generalised Linear Mixed Models (GLMM: Fahrmeir, Tutz, 1994; Molenberghs, Verbeke,2005).2) Research Issue "Air": Analysis of the influence of meteorological variables on the concentrations of atmospheric pollutants in the Sicilian provincesThe database usually available in studies concerning the effects of meteorological variables on pollutant concentration, consists on one hand of pollutants concentrations registered by a monitoring network (within a city or a larger district), and, on the other hand of meteorological variables, which are often measured only at a single monitoring site, sometimes even outside the investigated region. For example, Daniels et al. (2001) and Lee et al. (2003), in modelling the sources of variability of daily averages of ambient PM10 in Pittsburgh (USA), use meteorological data measured at the Pittsburgh international airport, which is outside the investigated area. In all these instances, the problem of the so-called spatial-temporal "misalignment" arises. This point has been already studied in Bondì and Plaia (2006), with reference to the data from the monitoring network of Palermo (Italy), and the results confirmed the importance of using aligned data, i.e. meteorological data recorded, or estimated, near the pollution monitoring stations.3) Research Issue "Soil": Seismic risk assessment in the South Thyrrenian Sea The activity of this sub-group will focus on the characterisation of stochastic point processes for modelling seismic events, with special reference to the South Thyrrenian Sea. Seismicity can be modelled through particular point processes (spatial or spatial-temporal), which describe the intensity of probability of occurrence of a seismic event at a given time in a given location, eventually depending on some covariates (Ogata, Zhuang, 2006, Adelfio et al. 2005).In the study of of seismicity, it is often relevant the distinction between components following a spatially non homog

Key findings

Ambiente e cambiamento climatico
StatoFinito
Data di inizio/fine effettiva2/9/072/9/09