Analysis of Climate Trends from 1981 to 2050 for Precipitation and Temperatures in the Mouhoun Watershed (Samandeni, Burkina Faso) Based on CMIP6 Simulations Corrected Using NEX-GDDP

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Résumé

In the Sahelian context, characterized by high climate variability, this study aims to produce reliable, high-resolution climate information that can be directly used by climate services to support decision-making in agriculture, water management and climate risk reduction in Burkina Faso. Changes in precipitation and temperatures are analyzed over the period 1981-2050 using local observation data and CMIP6 projections from NEX-GDDP, corrected for bias using Quantile Mapping. Trends are assessed using the Mann-Kendall test, their amplitude estimated using the Theil-Sen estimator, and breaks detected using the Pettitt test. The analysis is based on future climate normals (2001-2030, 2011-2040 and 2021-2050) and includes extreme indices relevant to sectoral uses, such as the duration of consecutive dry and wet sequences (CDD and CWD), average daily rainfall intensity (SDII) and maximum daily precipitation (RX1day). The results show a gradual increase in annual precipitation: +2.86 mm/year over the historical period, +4.53 mm/year under SSP2-4.5 and +5.56 mm/year under SSP5-8.5, accompanied by a continuous rise in average temperatures (0.024˚C/year over 1981-2014, then 0.02˚C/year and 0.046˚C/year according to future scenarios), all of which are significant trends (p < 0.05). Major disruptions appear around 1995 for the for historical data and 2031-2032 for projections. The intensification of daily rainfall and the reduction in dry and wet sequences reflect increased intra-seasonal variability. These results provide a solid scientific basis for agricultural planning, optimization of water infrastructure and anticipation of hydrometeorological risks, reinforcing adaptation strategies in response to rapid climate change in the Sahel, particularly in the Mouhoun basin in Samandeni.

Mots-clés

climate trends, precipitation change, temperature change, Sahel, CMIP6 projections, NEX-GDDP, bias correction, quantile mapping, climate normals, extreme precipitation indices, consecutive dry days, daily rainfall intensity, climate change adaptation, climate services