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Improving daily CMIP6 precipitation in Southern Africa through bias Correction—Part 2: representation of extreme precipitation

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dc.contributor.author Addisuu, Amarech Alebie
dc.contributor.author Mengistu, Tsidu Gizaw
dc.contributor.author Basupi, Lenyeletse Vincent
dc.date.accessioned 2025-11-18T13:38:03Z
dc.date.available 2025-11-18T13:38:03Z
dc.date.issued 2025-05-04
dc.identifier.citation Addisuu, A. A., Mengistu Tsidu, G., & Basupi, L. V. (2025). Improving daily CMIP6 precipitation in Southern Africa through bias correction— Part 2: representation of extreme precipitation. Climate, 13(5), 93. https://doi.org/10.3390/cli13050093 en_US
dc.identifier.issn 2225-1154
dc.identifier.uri https://repository.biust.ac.bw/handle/123456789/699
dc.description.abstract Accurate simulation of extreme precipitation events is crucial for managing climate-vulnerable sectors in Southern Africa, as such events directly impact agriculture, water resources, and disaster preparedness. However, global climate models frequently struggle to capture these phenomena, which limits their practical applicability. This study investigates the effectiveness of three bias correction techniques—scaled distribution mapping (SDM), quantile distribution mapping (QDM), and QDM with a focus on precipitation above and below the 95th percentile (QDM95)—and the daily precipitation outputs from 11 Coupled Model Intercomparison Project Phase 6 (CMIP6) models. The Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) dataset was served as a reference. The bias-corrected and native models were evaluated against three observational datasets—the CHIRPS, Multi-Source Weighted Ensemble Precipitation (MSWEP), and Global Precipitation Climatology Center (GPCC) datasets—for the period of 1982–2014, focusing on the December-January-February season. The ability of the models to generate eight extreme precipitation indices developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) was evaluated. The results show that the native and bias-corrected models captured similar spatial patterns of extreme precipitation, but there were significant changes in the amount of extreme precipitation episodes. While bias correction generally improved the spatial representation of extreme precipitation, its effectiveness varied depending on the reference dataset used, particularly for the maximum one-day precipitation (Rx1day), consecutive wet days (CWD), consecutive dry days (CDD), extremely wet days (R95p), and simple daily intensity index (SDII). In contrast, the total rain days (RR1), heavy precipitation days (R10mm), and extremely heavy precipitation days (R20mm) showed consistent improvement across all observations. All three bias correction techniques enhanced the accuracy of the models across all extreme indices, as demonstrated by higher pattern correlation coefficients, improved Taylor skill scores (TSSs), reduced root mean square errors, and fewer biases. The ranking of models using the comprehensive rating index (CRI) indicates that no single model consistently outperformed the others across all bias-corrected techniques relative to the CHIRPS, GPCC, and MSWEP datasets. Among the three bias correction methods, SDM and QDM95 outperformed QDM for a variety of criteria. Among the bias-corrected strategies, the best-performing models were EC-Earth3-Veg, EC-Earth3, MRI-ESM2, and the multi-model ensemble (MME). These findings demonstrate the efficiency of bias correction in improving the modeling of precipitation extremes in Southern Africa, ultimately boosting climate impact assessments. en_US
dc.language.iso en en_US
dc.publisher MDPI en_US
dc.subject CHIRPS en_US
dc.subject CMIP6 models en_US
dc.subject GPCC en_US
dc.subject MSWEP en_US
dc.subject Southern Africa en_US
dc.subject Bias correction en_US
dc.subject Precipitation extremes en_US
dc.title Improving daily CMIP6 precipitation in Southern Africa through bias Correction—Part 2: representation of extreme precipitation en_US
dc.description.level phd en_US
dc.description.accessibility unrestricted en_US
dc.description.department ees en_US


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