Analysis of Rainfall Time Series with Application to Calculation of Return Periods

Ramón Egea Egea Pérez,Francisco J Navarro-González,Mónica Cortés-Molina

doi:10.3390/su13148051

Ramón Egea Egea Pérez, Francisco J Navarro-González + Show 1 more

Open Access

https://doi.org/10.3390/su13148051

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Journal: Sustainability	Publication Date: Jul 19, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Alicante

Abstract

This paper presents a study of the characteristics of rainfall in a typical Mediterranean climate, characterized by infrequent and irregular rain in the territorial area and its intensity. One of the main components of this type of climate is short-duration and high-intensity rain events that cause a large amount of damage to property and human lives, seriously affecting the operation of infrastructure and the activity of society in general. The objective of this study was to design a methodology based on peak over threshold (POT) analysis. This methodology allows us to establish reference precipitation values and more approximate return periods in the absence of sufficiently extensive historical precipitation series. In addition, the frequency of these extreme events or return periods is established. The characteristics of the precipitation regime make direct analysis difficult. Thus, the functions of the probability distributions underlying the described phenomena are improved.

Highlights

Estimating such events can be done by analyzing precipitation time series associated with generally asymmetric or skewed distribution functions: Gumbel, generalized distribution of extreme values (GEV), SQRT-ETmax, log-normal, Weibull, Fréchet, generalized Pareto distribution (GPD), and others [2]
The analysis developed in this research allows return period adjustments to be used in hydrological planning, related to the frequency of extreme episodes of precipitation used in the definition of intensities, and the frequency of extreme rain events, which are increasingly common and intense due to climate change
It is based on the general theory of extreme values and assumes that the observed values represent an underlying process that manifests itself only on occasions when precipitation occurs

Summary

Introduction

Episodes of isolated atmospheric depression at high levels (in Spanish, depresion aislada en niveles altos (DANA)), generated by the collision of a cold air mass at altitude with warm surface air, produce extreme precipitation events. These events have a return period, T, or estimated number of years that, on average, will equal or exceed a given value. In the case of the Mediterranean coast, there is a greater influence of the upper-level atmospheric circulation, which generates extreme episodes of precipitation This phenomenon has been studied in [3,4], an approximation of which is made by means of decomposing singular values. This method isolates linear combinations of variables within two fields that tend to be linearly related to each other

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