a comparison between conceptual and physically based models in predicting the hydrological behavior of green roofs

The evolving climate conditions contribute to increase flooding risk in urban areas. Green roofs are effective tools for controlling and managing stormwater runoff. With the aim to prevent these damaging events, an accurate modelling of the response of green roofs to storm events becomes essential. The goal of this research is to compare the accuracy of two hydrological models in predicting the behavior of two green roof test beds in terms of runoff production. The test beds are located in the campus of University of Salerno, in a typical Mediterranean climate and they differ in the composition of the drainage layer. The selected models are the Storm Water management model (SWMM) model and the Nash model. They have been calibrated against hourly data of 25 rainfall-runoff events observed at the experimental site and compared using a number of goodness of fit indexes. The Nash cascade model aims to be a very simple but effective approach. No substantial differences were observed in the behavior of the two green roof plots, though they differ in their design characteristics. Finally, the existence of a relationship between the errors and the rainfall characteristics has been found

Long-term regional changes in inter-annual precipitation variability in the Campania Region, Southern Italy

Precipitation variability in space and time has been a focus of research over the past decades. The largest body of literature was essentially focused on long-term changes in average climates and in climate extremes. Analyses of the changes in the inter-annual climate variability (the year-to-year variability), which represent an index of climatic risk, received instead very less attention, but it represents an important issue in order to quantitatively measure the socioeconomic impact of climate change impact over water resources. In order to depict a general characterization of the long-term climate variability for the Campania region, located in Southern Italy within the Mediterranean basin, an analysis of the precipitation coefficient of variation, assumed as an index of inter-annual climate variability, was performed over the period 1918-2015 and compared with the annual precipitation regime and the intra-annual precipitation variability of the same region. The Mann-Kendall and the modified Mann-Kendall tests were applied to detect the sign and significance of the temporal changes and Sen's test was applied to quantify the temporal changes in inter-annual variability. The results illustrated a generalized condition (73% of total stations) of statistically significant increase of inter-annual variability distributed almost over the whole analyzed area, even though the detected change appeared rather moderate in magnitude. The relationship between annual precipitation, intra-annual precipitation variability, and inter-annual precipitation variability was not clearly identified for the studied region, likely because of the characteristics of climatic homogeneity for the area under investigation. However, the comparative analyzes clearly showed how, if the variations in the annual precipitation regime and in the intra-annual precipitation variability are poorly significant (respectively for 9% and 11% of total station), changes in inter-annual precipitation variability are strongly marked over the studied region

Trend analysis of annual and seasonal rainfall time series in the Mediterranean area

ABSTRACT: Precipitation trend analysis, on different spatial and temporal scales, has been of great concern during the past century because of the attention given to global climate change by the scientific community. According to some recent studies, the Italian territory has been suffering a precipitation decrease, especially in the last 50 years, and the southern areas seem to be more affected. The aim of the present study is to analyse rainfall time series over a wide time interval and a wide area, detecting potential trends and assessing their significance. For this purpose, 211 gauged stations, mainly located within the Campania region, southern Italy, have been analysed for the period 1918–1999. An accurate database has been set up through a data quality and time series homogeneity process. Statistical analysis of the database highlight that (1) the trend appears predominantly negative, both at the annual and seasonal scale, except for the summer period when it appears to be positive; (2) over the whole reference period, positive and negative trends are significant respectively for 9 and 27% of total stations and (3) over the last 30 years, a negative trend is instead significant for 97% of the total stations. Copyright 2009 Royal Meteorological Societ

Results and findings from 15 years of sustainable urban storm water management

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An experimental plot for hydrological processes modeling

In this paper we describe the data and some preliminary analysis as the investigations of infiltration process, soil water content profiles dynamic and water movement systems, referring to an experimental plot. The broad aim of the work is to test the usefulness for hydrological modelling of a soil moisture monitoring methodology which is based on capacitance devices and has the benefit to be an easy and low cost system. Collected data are expected to be useful to improve the general understanding at the field scale

Topic Strategies and the Internal Structure of Nominal Arguments in Greek and Italian

In this article, we argue that a set of unexpected contrasts in the interpretation of clitic-left-dislocated indefinites in Greek and Italian derive from structural variation in the nominal syntax of the two languages. Greek resists nonreferential indefinites in clitic left-dislocation, resorting to the topicalization of an often bare noun for nonreferential topics. By contrast, clitic left-dislocation is employed in Italian for topics regardless of their definite/indefinite interpretation. We argue that this contrast is directly linked to the wide availability of bare nouns in Greek, which stems from a structural difference in the nominal syntax of the two languages. In particular, we hypothesize that Greek nominal arguments lack a D layer. Rather, they are Number Phrases. We situate this analysis in the context of Chierchia’s (1998) typology of nominals. We argue that, on a par with Italian nouns, Greek nouns are [−arg, +pred]. However, they do not employ a syntactic head (D) for type-shifting to e . Rather, they resort to covert type-shifting, a hypothesis that is necessary to account for the distribution and interpretations of bare nouns in Greek, vis-à-vis other [−arg, +pred] languages like Italian and French. </jats:p

Historical Storminess and Hydro-Geological Hazard Temporal Evolution in the Solofrana River Basin—Southern Italy

Precipitation extremes have always been part of the Earth’s climate system and associated multiple damaging hydrological events (MDHEs), the simultaneous triggering of different types of phenomena (landslides and floods), affect an always-increasing portion of human settlement areas. This paper aims to investigate the relationship between the temporal evolution of severe geomorphological events and combined precipitation indices as a tool to improve understanding the hydro-geological hazard at the catchment scale. The case study is the Solofrana river basin, Southern Italy, and the focus is on four of main municipalities severely affected by natural disasters. Data for about 45 MDH events, spanning 1951–2014, have been collected and analyzed for this purpose. A preliminary monthly scale analysis of event occurrences highlights a pronounced seasonal characterization of the phenomenon, as about 60% of the total number of reported events take place during the period from September to November. Following, a statistical analysis clearly indicates a significant increase in the frequency of occurrences of MDHEs during the last decades. Such an increase appears to be related to non-stationary features of an average catchment scale rainfall-runoff erosivity index, which combines maximum monthly, maximum daily, and a proxy of maximum hourly precipitation data

Predicting Stormwater Retention Capacity of Green Roofs: An Experimental Study of the Roles of Climate, Substrate Soil Moisture, and Drainage Layer Properties

Due to the ever-increasing degree of urbanization, blue and green infrastructures are becoming important tools for achieving stormwater management sustainability in urban areas. Concerning green roofs, although scientists have investigated their behaviors under different climates and building practices, their hydrological performance is still a thought-provoking field of research. An event scale analysis based on thirty-five rainfall&ndash;runoff events recorded at a new set of experimental green roofs located in Southern Italy has been performed with the aim of identifying the relative roles of climate, substrate moisture conditions, and building practices on retention properties. The retention coefficient showed a wide range of variability, which could not be captured by neither simple nor multiple linear regression analysis, relating the latter to rainfall characteristics and substrate soil water content. Significant improvements in the prediction of the retention coefficient were obtained by a preliminary identification of groups of rainfall&ndash;runoff events, based on substrate soil water content thresholds. Within each group, a primary role is played by rainfall. At the experimental site, building practices, particularly those concerning the drainage layer properties, appeared to affect the retention properties only for specific event types