Characterisation of heatwaves over Burkina Faso using multi-model climate simulations.

Abstract

This study characterises heatwave patterns in Burkina Faso using observed data and climate model simulations. Key metrics used include Heat Wave Amplitude (HWA), Heat Wave Frequency (HWF), Heat Wave Duration (HWD), Heat Wave Magnitude (HWM), and Heat Wave Number (HWN). The Bias-Correction Spatial Disaggregation (BCSD) method generated the NEX-GDDP-CMIP6 dataset. The models were subjected to statistical tests using Taylor's diagram. The Taylor diagram showed that IPSL-CM6A-LR, with the least Root Mean Square Error (RMSE) and Standard Deviation (S.D.) values, and also had the highest R² values for both temperature readings, is the best-substituted model for the observed data. Most models overestimated for minimum temperature with an RMSE of approximately 1, a S.D. of 2.6 and a correlation coefficient of 0.7; maximum temperature was overestimated by about 2.1 RMSE, with a standard deviation close to 3.0 and a correlation ranging between 0.7 and 0.87. MRI-ESM2-0 had the lowest correlation (0.69) for minimum temperature, while EC-Earth3 recorded the lowest correlation for maximum temperature. The observed data reveal a north-south gradient, with higher intensities in the north. Climate models show varying accuracy in replicating this gradient, with models like CMCC-ESM2 and IPSL-CM6A-LR closely mirroring observed patterns. However, models like KIOST-ESM and MRI-ESM2-0 exhibit significant discrepancies. Nighttime and daytime heat wave numbers ranged between 6^oC (24-30 °C) and 11^oC (32-43 °C). The recorded heat wave duration over the northern part of Burkina Faso was about five (5) days, with most models aligning except KIOST-ESM, which recorded over seven (7) days. The study highlights the importance of employing reliable climate models for future heat wave predictions and underscores the increasing threat of heat waves due to climate change. These findings are crucial for informing adaptation and mitigation strategies in Burkina Faso concerning heat stress.