Search results for "Extreme events"

Establishing a soil loss threshold for limiting rilling

2015

In this paper a frequency analysis of event soil loss measurements collected in the period 1999–2012 at the microplots and plots of the Sparacia Experimental Area in Sicily, southern Italy, was developed. The analysis was carried out using the annual maximum soil loss measurements normalized by the mean soil loss measured at a given temporal and spatial scale. The empirical frequency distribution of the normalized variable was well fitted by two Gumbel’s theoretical probability distributions discriminated by a value of the normalized variable equal to 2. This last value discriminates between the relatively low and frequent values of the normalized variable and the high and rare ones. The an…

The geo-hydrologic event in the Peloritan – Ionian area of 2009: debris-flow susceptibility assessment by means of forward logistic regression

2012

On the 1st of October 2009, the area centred on the village of Giampilieri (Messina), on the Ionian side of the Peloritan belt, suffered thousands of landslides activated in the time lapse of about five hours, which caused 36 victims, more than 100 injured and more than 0.5M€ of damage to structures. This unprecedented phenomenon was triggered by an exceptional meteorological event, recorded at the foothills with 250mm of rain in just 8 hours; this amount of rainfall was cumulated to two previous events (16/IX: 75mm; 23/IX: 190mm) for a total amount of more than 500mm in less than two weeks. Due to the peculiar triggering conditions a huge number of debris flows involved the shallow weather…

Statistical distribution of soil loss and sediment yield at Sparacia experimental area, Sicily

2010

Abstract An analysis of the statistical distribution of event soil loss was carried out using the data collected in the period 1999–2008 at the microplots and plots of the Sparacia experimental area (Sicily, Italy). For a given microplot size, the analysis allowed to establish that the soil loss frequency distribution was skewed. Using the soil loss normalized by the event mean value, the analysis also showed that the frequency distributions corresponding to different microplot and plot sizes were overlapping, i.e. all distributions were extracted by the same statistical population. The developed analysis allowed to suggest that the soil loss of a given return period can be estimated using …

Roadmap on optical rogue waves and extreme events

2016

Nail Akhmediev et al. ; 38 págs.; 28 figs.

Current and emerging developments in subseasonal to decadal prediction

2020

Weather and climate variations on subseasonal to decadal time scales can have enormous social, economic, and environmental impacts, making skillful predictions on these time scales a valuable tool for decision-makers. As such, there is a growing interest in the scientific, operational, and applications communities in developing forecasts to improve our foreknowledge of extreme events. On subseasonal to seasonal (S2S) time scales, these include high-impact meteorological events such as tropical cyclones, extratropical storms, floods, droughts, and heat and cold waves. On seasonal to decadal (S2D) time scales, while the focus broadly remains similar (e.g., on precipitation, surface and upper-…

The relationship between precipitation depth and weather circulation patterns over Sicily

2019

Some weather circulation patterns (WPs) derived by the UK Met Office and defining a certain type of atmospheric circulation over Europe have been recently used to analyze the relationship of the regional UK precipitation and drought with respect to the atmospheric circulation over Europe (Richardson et al. 2018). In this study, we attempt to find out one or more relationships between precipitation depth and weather patterns over a non UK-centred domain, such as Sicily (Italy), which is characterized by a totally different climate as compared to the climate of UK. Since the island has been affected by many floods in the last years, occurred as a consequence of extreme rainfall events, it wou…

What Do We Know About the Second Moment of Financial Markets?

2021

Recent research shows that the vast majority of scientific studies published in leading finance journals fails scientific replication (Hou, Xue, and Zhang, 2020; Harvey, Liu, and Zhu; 2016). This study argues that p-hacking, publication pressure and the selection bias from leading finance journals are perhaps not the underlying root cause for this issue. We show that standard methodologies often used in finance research are inevitably sample-specific due to the very nature of financial markets. While the consensus of earlier research postulates a rejection of the time-honored Levy hypothesis, our results strongly indicate that the variance of variance does not exist in any of the financial …

Study of the effects of climate extremes on functioning of intertidal assemblages to design an early warning sensor network

2020

Extreme events in fiber based amplifiers

2009

International audience; We present experimental and theoretical results showing the emergence of rogue wave-like extreme intensity spikes during fiber-based amplification processes such as Raman effect or induced-modulational instability that rely on quasi-instantaneous gain. We outline that under certain circumstances, a partially incoherent pumping can induce large fluctuations of the amplified signal, and we propose various means to spectrally select the most extreme structures.

Rainfall and water yield in Macizo del Caroig, Eastern Iberian Peninsula. Event runoff at plot scale during a rare flash flood at the Barranco de Ben…

2021

[EN] Floods are a consequence of extreme rainfall events. Although surface runoff generation is the origin of discharge, flood research usually focuses on lowlands where the impact is higher. Runoff and sediment delivery at slope and pedon scale receiving much less attention in the effort to understand flood behaviour in time and space. This is especially relevant in areas where, due to climatic and hydrogeological conditions, streams are ephemeral, so-called dry rivers (¿wadis¿, "ramblas" or ¿barrancos¿) that are widespread throughout the Mediterranean. This paper researches the relationship between water delivery at pedon and slope scale with dry river floods in Macizo del Caroig, Eastern…