Interannual Variability and Trends of Extreme Rainfall Indices over Benin

Ezéchiel Obada,Eliezer Iboukoun Biao,Esdras B Josué Zandagba,Eric Adechina Alamou

doi:10.3390/cli9110160

Abstract

Observed rainfall data (1961–2016) were used to analyze variability, trends and changes of extreme precipitation indices over Benin. Nine indices out of the ones developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) were used. The results indicate a mix of downward and upward trends for maximum 1-day precipitation (RX1day) and maximum 5-days precipitation (RX5day). Decrease trends are observed for annual total precipitation of wet days (P), while significant increases are found for the simple daily intensity index (SDII). The number of wet days (RR1) and maximum consecutive dry days (CDD) show a mix of increase/decrease trends. However, the number of heavy (R10) and very heavy (R20) wet days and maximum consecutive wet days (CWD) show decreased trends. All wet indices increased over 1991–2010 in relation to 1971–1990. The increase in all wet indices over Benin could explain the intensification of hydrology, and the increase in the frequency and the intensity of floods. It caused damages such as soil erosion, crop destruction, livestock destruction, displacement of populations, proliferation of waterborne diseases and loss of human life. Some adaptive strategies are suggested to mitigate the impacts of changes in extreme rainfall.

Highlights

Accepted: 25 October 2021Extreme weather events are, by definition, events that occur only rarely, and very often with enormous consequences on the environment and human health
The spatio-temporal variability of rainfall is a challenge to food security and other socioeconomic activities over West Africa in general and over Benin in particular
Using observed rainfall data from 1961 to 2010, spatial variability, trends and changes of nine extreme rainfall indices have been analyzed over Benin

Summary

Introduction

Accepted: 25 October 2021Extreme weather events are, by definition, events that occur only rarely, and very often with enormous consequences on the environment and human health. In the context of climate change, extreme rainfall events are becoming more frequent and intense [1]. Extreme climate events frequently cause severe environmental, human and economic impacts such as soil erosion, crop damage, increase of drought and flood risk, decline in agricultural production which can lead to a situation of food insecurity and famine, etc., [5,6,7]. Many appreciated efforts have been made in the development of datasets of extreme indices over the word. This has led to great progress in climate extremes research over the last few decades.

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