Assessment of seasonal and annual rainfall trend in Calabria (southern Italy) with the ITA method

Abstract In this paper, an investigation on the temporal variability of seasonal and annual rainfall in the Calabria region (southern Italy) was carried out using a homogeneous and gap-filled monthly rainfall dataset of 129 rain gauges in the period 1951–2006. In particular, possible trends have been assessed by means of the Innovative Trend Analysis (ITA) technique, which allows the identification of a trend in the low, medium and high values of a series. Moreover, the results obtained with the ITA have been compared with the ones obtained with the Mann–Kendall test. These analyses have been performed in five rainfall zones (RZs) of the study area, characterized by different climatic conditions. As a result, both the methods evidenced a negative trend of the annual rainfall in the entire study area. On a seasonal scale, this negative tendency has been confirmed in autumn and winter although with some differences among the several RZs

Trend Analysis of Rainfall Using Gridded Data over a Region of Southern Italy

Climate change is affecting all regions worldwide. Globally, polar ice shields are melting and the sea is rising. Moreover, some regions are facing more common extreme weather events and rainfall, while others are experiencing more extreme heat waves and droughts, causing changes in mean renewable water supplies e.g., precipitation and runoff. In this work, in order to detect possible rainfall trends in the Calabria region (southern Italy), a gridded database has been obtained from a rainfall data set of 129 monthly series collected for the period 1951–2016. In particular, the Inverse Distance Weighed was applied to build 603 rainfall grid series with a spatial resolution of 5 km × 5 km and, for each grid point, the monthly, seasonal and annual rainfall series were analyzed with the Mann–Kendall non-parametric test and the Theil–Sen estimator. Results showed a decreasing trend for the annual and winter–autumn rainfall and an increasing trend for the summer one

A sub-regional approach to the influence analysis of teleconnection patterns on precipitation in Calabria (southern Italy)

AbstractIn this study, the problem of determining, with an adequate statistical significance, the relationship between teleconnection pattern indices and precipitation at climatological time scales has been addressed through a novel technique based on a rainfall zonation, by means of creating a regional precipitation database for a whole‐region correlation approach. Pearson correlation was performed to evaluate the mesoscale influence on precipitation in the Calabria region over the 1951–2010 time period, by means of a database of 79 rain gauges, divided in five Rainfall Zones (RZs) and seven teleconnection pattern indices relevant to the Mediterranean region, searching where results were significant (significance level < 0.05) and with an absolute correlation value higher than a prefixed threshold equal to 0.2. The Calabria region was chosen as it is located in the centre of the Mediterranean area, which constitutes a hot spot for climate change, and because it is equipped with a high‐density, long‐time series of precipitation gauge network, recently validated and homogenized. Correlation analysis between seasonal teleconnection indices and seasonal cumulated precipitation showed that the Western Mediterranean Oscillation and the East Atlantic/West Russian patterns were the most relevant teleconnections over all Calabria. Correlations of 3‐month averaged teleconnection indices versus monthly precipitation showed that the Mediterranean and Western Mediterranean Oscillations produce most significant results with correlation values higher than 0.2, with East Atlantic pattern a third close. Comparison between monthly teleconnection indices and monthly cumulated precipitation indicate that all modes of variability taken into account share a similarly weak correlation. Comparing the rainfall zone‐based study and the technique of averaging individual stations results post‐correlation, it was shown that on average only 43% of the stations would produce useful correlations, while the novel technique used all the valid and available station data, resulting in statistically more robust findings

TRMM-based rainfall temporal analysis over Italy

Rainfall is an irregular phenomenon showing large spatial variability. Unfortunately, spatially distributed data are not always available, because rain gauge networks are not continuously dense and adequately distributed, and they provide only point measurements. In this work, the temporal variability of rainfall in Italy has been investigated using the Tropical Rainfall Measuring Mission monthly product for the period 1998-2018. Within this aim, more than 650 grid points falling within the Italian territory have been selected. In order to evaluate the presence of trends and their significance, the monthly, seasonal and annual rainfall series were analysed at each grid point with the Mann-Kendall nonparametric test and the Theil-Sen estimator. The broad extension of the area under investigation allowed a better understanding of rainfall trend patterns over space. At annual scale, results evidenced few relevant trends, either positive or negative, involving central Italy (negative trend) and southern Italy (positive trend). A similar trend behaviour has been identified, at seasonal scale, in autumn, with a clear spatial difference between the north and the south of Italy, in winter for the negative trend and in spring for the positive one. In summer, only few grid points in central Italy showed a significant increasing trend

Trends in the Daily Precipitation Categories of Calabria (Southern Italy)

Abstract This study presents an analysis of daily rainfall categories over a region of southern Italy using a set of daily homogenous precipitation series for the period 1916–2006. Six daily rainfall categories have been considered: Light, 0–4 mm/day; Light-Moderate, 4–16 mm/day; Moderate-Heavy, 16–32 mm/day; Heavy, 32–64 mm/day; Heavy-Torrential, 64–128 mm/day; Torrential, 128-up mm/day. Results showed that Light-Moderate, Moderate-Heavy and Heavy rainfall are the main contributors to the total annual rainfall. Moreover, a trend analysis through the Mann-Kendall test showed a decreasing trend of the higher categories and an increasing trend of the weaker categories

Chapter Integrated Coastal Zone Management of Natura 2000 and cultural heritage sites in Calabrian coastal landscape (Southern Italy)

This study shows the link connecting natural and cultural goods in the coastal landscape of Calabria (Southern Italy), considering seaboard and human impact risk conditions. In fact, Calabria has 58 Natura 2000 sites located on seaboard areas within a length of 300 meters from coast and 63 cultural heritage sites of which 42.9% coincides with the Natura 2000 network. As a results of this paper, the increasing coastal erosion and a heavy human impact have been highlighted as the main hazards to which the natural and cultural goods are exposed, thus it’s necessary a broader approach for the integration of natural and cultural issues into an active Integrated Coastal Zone Management proces

The Role of Water-Rock Interaction Processes in Soil Formation: Geochemical, Mineralogical, Geomorphological, and Engineering-Geological Aspects

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Geochemical Characterization of Spring Waters in the Crati River Basin, Calabria (Southern Italy)

The characterization of the spatial variation of geochemical parameters in spring waters, especially the ones used for drinking purpose, is essential to identify potential risks to humans. In this work, results of a qualitative analysis on 190 samples of spring waters collected in the largest catchment of the Calabria region (southern Italy) are shown. Several physical and chemical parameters were analysed and the Langelier-Ludwig diagram was built to evaluate the hydrochemical facies of the sampled waters. Additionally, the relationships between water temperature and altitude and electric conductivity (EC) and altitude were assessed. Geostatistical methods were used to map the physical and chemical parameters. Results showed a good quality status of the spring waters in the Crati basin, with a predominant Ca-Mg-type hydrochemical facies. Then, a connection between EC and temperature with elevation has been detected in some area of the basin. Finally, the spatial analysis allowed identifying the distribution of the concentration of the several parameters

Environmental Estimation of Radiation Equivalent Dose Rates in Soils and Waters of Northern Calabria (Italy)

In this study, the equivalent dose rate of natural radionuclides ( H T ) in 99 spring water and surface soil samples was determined using an alpha, beta, and gamma high sensitivity detector up within a Geiger-Muller tube and with an external probe NaI (Tl). The samples were collected in the Crati basin (southern Italy), and during sample collection, water quality parameters were detected in situ and at the University of Calabria laboratories. A Pearson correlation coefficient analysis was applied to identify and clarify the relationships between water physical-chemical properties and soil and water radioactivity. Results show that the mean H T for spring waters is 97.07 μSv/h. Furthermore, the mean H T for surface soils is 97.92 μSv/h, thus evidencing higher mean H T values than worldwide ones reported in a previous literature. Low correlation coefficients were detected between water H T and conductivity and pH. On the contrary, a reasonable correlation was found between H T in spring water and in soil. This relationship is associated with some rocks of the Sila Massif and of Coastal Chain, i.e., plutonic and metamorphic crystalline rocks. Finally, the estimation of the health risk was calculated: results did not evidence serious dangers for people living in the studied environment. The results from this survey for the H T evaluation provide an extensive assessment of the background exposure levels in the investigated area