Using the CHIRPS Dataset to Investigate Historical Changes in Precipitation Extremes in West Africa

Didi Sacré Regis M,Kouadio Koffi Claude A,Savané Issiaka,Coulibaly Houebagnon Saint J,Ly Mouhamed,Coulibaly Talnan Jean H,Obahoundje Salomon,Bichet Adeline,Diedhiou Arona,Kouadio Kouakou

doi:10.3390/cli8070084

Abstract

This study aims to provide improved knowledge and evidence on current (1986–2015) climate variation based on six rainfall indices over five West African countries (Senegal, Niger, Burkina Faso, Ivory Coast, and Benin) using the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) dataset. On average, precipitation has increased over the central Sahel and the western Sahel. This increase is associated with increase in the number of rainy days, longer wet spells and shorter dry spells. Over the Guinea Coast, the slight increase in precipitation is associated with an increase in the intensity of rainfall with a shorter duration of wet spells. However, these mean changes in precipitation are not all statistically significant and uniform within a country. While previous studies are focused on regional and sub-regional scales, this study contributes to deliver a climate information at a country level that is more relevant for decision making and for policy makers, and to document climate-related risks within a country to feed impact studies in key sectors of the development, such as agriculture and water resources.

Highlights

Since the 1990s, the frequency of hydro-climatic hazards has increased in West Africa [1,2]
In Côte d’Ivoire and Benin (Guinea Coast), the results show that the increase in annual rainfall over 1981–2015 results from a slight increase in precipitation frequency, shorter dry spells and a slight increase in precipitation intensity that does not occur in the form of very wet days
Over the Sahel area, we find that the reported ‘Sahel rainfall recovery’ results from an increase in precipitation frequency, which suggests a clear decrease in drought incidences

Summary

Introduction

Since the 1990s, the frequency of hydro-climatic hazards (floods, drought, coastal erosion, storms, and strong winds) has increased in West Africa [1,2]. Along the coastline of the Gulf of Guinea (mainly from Dakar to Cotonou via Abidjan, Accra, and Lomé), one of the three most vulnerable coastal zones in the world [4], some districts are flooded almost every year, with a recent increase in frequency [5]. The occurrence of these extreme events are usually associated with strong rainfall [6] and may be due to a change in the stationarity of precipitation at the local or large scale. West Africa is considered as one of the most vulnerable regions to climate change and is affected by changes in extreme events [7,10,11,12]

Objectives

Methods

Findings

Discussion

Conclusion