Search results for " Rainfall"

Soil water erosion on Mediterranean vineyards: A review

2016

Soil water erosion on cultivated lands represents a severe threat to soil resources in the world, and especially in Mediterranean areas, due to their topographic, edaphic and climatic conditions. Among the cultivated lands, vineyards deserve a particular attention because, aside representing one of the most important crops in terms of income and employment, they also have proven to be the form of agricultural use that causes one of the highest soil losses. Although the topic of soil water erosion on vineyards has been studied, it still raises uncertainties, due to the high variability of procedures for data acquisition, which consists into different scales of analysis and measurement method…

Timing and patterns of the ENSO signal in Africa over the last 30 years: insights from normalized difference vegetation index data.

2014

Abstract A more complete picture of the timing and patterns of the ENSO signal during the seasonal cycle for the whole of Africa over the three last decades is provided using the normalized difference vegetation index (NDVI). Indeed, NDVI has a higher spatial resolution and is more frequently updated than in situ climate databases, and highlights the impact of ENSO on vegetation dynamics as a combined result of ENSO on rainfall, solar radiation, and temperature. The month-by-month NDVI–Niño-3.4 correlation patterns evolve as follows. From July to September, negative correlations are observed over the Sahel, the Gulf of Guinea coast, and regions from the northern Democratic Republic of Congo…

Investigating the changes in extreme rainfall series recorded in an urbanised area

2002

The aim of this study is to investigate and quantify changes in the rainfall regime of the metropolitan area of Palermo characterised by increasingly strong urbanisation. The rainfall data, considered in this study, were collected on a yearly basis from eight rain gauges within and outside the metropolitan area of Palermo, Sicily, Italy. A preliminary analysis made on the annual total rainfall depths showed a global reduction of total annual rainfall, with two different trends: more regular for the series observed in the rain gauges within the urbanised area and more variable for the series observed in the rain gauges outside the area. A further analysis has been performed using the series …

Time Series Analysis of Climatic Vegetation Data in the Oreto Watershed in Sicily

2008

Time series analysis of climate and vegetation variables in the Oreto watershed (Sicily, Italy)

2008

Verifica delle equazioni disponibili per la stima della potenza cinetica delle precipitazioni naturali

2016

Nella memoria sono riportati i risultati delle indagini condotte utilizzando le distribuzioni dimensionali delle gocce di pioggia (DSD) rilevate mediante un disdrometro ottico installato, nel periodo Giugno 2006 - Marzo 2014, presso il Dipartimento di Scienze Agrarie e Forestali dell’Università degli Studi di Palermo e nel periodo Luglio 2015-Gennaio 2016 presso la stazione sperimentale di El Teularet in Spagna. Dopo aver aggregato le DSD per classi di intensità differenti in ampiezza, è stata determinata la potenza cinetica associando a ciascun diametro della DSD aggregata la relativa velocità di caduta calcolata mediante una relazione reperita in letteratura. I valori di potenza cinetica …

Dispositivo e metodo di misura delle caratteristiche energetiche delle precipitazioni

2018

Trends of some high quantiles of average and extremes inter-arrival timesand rainfall depths at daily scale for an Italian Sub-Alpine area

2015

Modeling of rainfall statistical structure represents an important research area in hydrology, meteorology, atmospheric physics and climatology, because of the several theoretical and practical implications. The statistical inference of the alternation of wet periods (WP) and dry periods (DP) in daily rainfall records can be achieved through the modelling of inter-arrival time-series (IT), defined as the succession of times elapsed from a rainy day and the one immediately preceding it. It has been shown previously that the statistical structure of IT can be well described by the 3-parameter Lerch distribution (Lch). In this work, Lch was successfully applied to IT data belonging to a sub-al…

Uncertainty connected with design rainfall for urban flood risk evaluation

2010

Rainfall depth-duration-frequency curves for short-duration precipitation events in Sicily (Italy)

2019

The design criteria of the hydraulic infrastructures, including, for instance, those for flood defense, urban drainage systems, reservoirs spillways and bridges, are based on the coupled analysis of the magnitude of rainfall events for a fixed duration and their estimated annual exceedance probability. The well-known rainfall depth-duration-frequency (DDF) curves, typically derived from the analysis of long historical annual maxima data series, synthesize the relationships between rainfall depth, duration and exceedance probability which is usually expressed as a return period. The time-resolution of rainfall data typically available for the construction of DDF curves and provided by gauges…