Patterns in Climate-Related Parameters as Proxy for Rainfall Deficiency and Aridity: Application to Burkina Faso

Abstract

This work is aimed to propose a methodology for the identification of areas for which extreme climatological conditions may intensify aridity processes and rainfall deficiency. The proposed procedure, which is based on the analysis of climate projections derived from high-resolution regional simulations, is composed of three main elements. First, extreme temperature, extreme precipitation, and extreme dry periods (in terms of consecutive dry days) are modeled using extreme value theory. Second, an aridity index is used as a proxy of long-term processes leading to aridity. Third, clustering techniques are used to group zones with similar climatic parameters. In this way, areas with the more extreme climate conditions are identified. Possible effects due to selected climate-change scenarios are considered by analyzing possible nonstationary conditions in extreme events and by performing calculations in both a historical period and a projection period (where different scenarios are considered). An application of the proposed procedure is implemented in an area around Ouagadougou, Burkina Faso. From the analyses, it emerged that the eastern part of the case study area will experience both large rainfall deficit and the highest extreme temperatures. Those two aspects, combined with a potential water demand increase (due to the increasing of number of inhabitants), may favor the intensification of the aridity processes.