{"title":"Exploring the influence of anthropogenic forcing on meteorological drought pattern in East Africa: An analysis using CMIP6 models","authors":"Tamirat Yohannes , Jinhua Yu , Mulualem Abera , Philemon King’uza , Jonah Kazora , Xuyu Zhang","doi":"10.1016/j.jastp.2025.106569","DOIUrl":null,"url":null,"abstract":"<div><div>This study evaluated the performance of twelve Global Climate Models (GCMs) from CMIP6 in simulation of precipitation and drought over East Africa (EA) from 1981 to 2014. We employed different statistical and drought indices methods to identify systematic bias and to select the best ranking of models to reduce uncertainties. The evaluation was preformed against with Observed data from Climate Hazard Group InfraRed precipitation with stations (CHIRPS) and Climate Research Unit (CRU). Based on the mean MAM seasonal models and observed CHIRPS data, evaluated through statistical metrics, the results show that the top preforming models: CMCC-CM2-HR4, CanESM5, GFDL-ESM4, and TaiESM1 better captured precipitation over EA precipitation, with bias ranging from 12 to 39 % during the historical period. The study highlights the importance of understanding the influences of human-induced climate change on MAM droughts. The study uses two drought indices, its aims to detect changes in drought patterns and attribute these changes to anthropogenic climate forcing. Historical simulations, including all types of forcing, successfully replicate observed spatial trends. The Standardized Precipitation Evapotranspiration Index (SPEI) shows a drying trend in most parts, except the south and southeast of Tanzania and Kenya. The drying trend is more pronounced in the simulations that include all types of forcing, highlighting the significant impact of human-induced climate change on drought patterns in EA. This outcome strongly suggests that human-induced climate change significantly contributes to the intensification of MAM seasonal drought in EA. More comprehensive detection work is carried out using the signal's fingerprint of both ALL and NAT, which are projected onto the observation and evaluated against the background noise from control simulations without external forcing. The trend pattern signal of ALL is observed SPEI and shows a stronger signal. However, the NAT signal is not detected in SPEI. The findings reveal that changes in precipitation due to human activity are predominant in the south and southeast, while changes in temperature due to human activity are more evident in northern East Africa.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"274 ","pages":"Article 106569"},"PeriodicalIF":1.9000,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Atmospheric and Solar-Terrestrial Physics","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1364682625001531","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
This study evaluated the performance of twelve Global Climate Models (GCMs) from CMIP6 in simulation of precipitation and drought over East Africa (EA) from 1981 to 2014. We employed different statistical and drought indices methods to identify systematic bias and to select the best ranking of models to reduce uncertainties. The evaluation was preformed against with Observed data from Climate Hazard Group InfraRed precipitation with stations (CHIRPS) and Climate Research Unit (CRU). Based on the mean MAM seasonal models and observed CHIRPS data, evaluated through statistical metrics, the results show that the top preforming models: CMCC-CM2-HR4, CanESM5, GFDL-ESM4, and TaiESM1 better captured precipitation over EA precipitation, with bias ranging from 12 to 39 % during the historical period. The study highlights the importance of understanding the influences of human-induced climate change on MAM droughts. The study uses two drought indices, its aims to detect changes in drought patterns and attribute these changes to anthropogenic climate forcing. Historical simulations, including all types of forcing, successfully replicate observed spatial trends. The Standardized Precipitation Evapotranspiration Index (SPEI) shows a drying trend in most parts, except the south and southeast of Tanzania and Kenya. The drying trend is more pronounced in the simulations that include all types of forcing, highlighting the significant impact of human-induced climate change on drought patterns in EA. This outcome strongly suggests that human-induced climate change significantly contributes to the intensification of MAM seasonal drought in EA. More comprehensive detection work is carried out using the signal's fingerprint of both ALL and NAT, which are projected onto the observation and evaluated against the background noise from control simulations without external forcing. The trend pattern signal of ALL is observed SPEI and shows a stronger signal. However, the NAT signal is not detected in SPEI. The findings reveal that changes in precipitation due to human activity are predominant in the south and southeast, while changes in temperature due to human activity are more evident in northern East Africa.
期刊介绍:
The Journal of Atmospheric and Solar-Terrestrial Physics (JASTP) is an international journal concerned with the inter-disciplinary science of the Earth''s atmospheric and space environment, especially the highly varied and highly variable physical phenomena that occur in this natural laboratory and the processes that couple them.
The journal covers the physical processes operating in the troposphere, stratosphere, mesosphere, thermosphere, ionosphere, magnetosphere, the Sun, interplanetary medium, and heliosphere. Phenomena occurring in other "spheres", solar influences on climate, and supporting laboratory measurements are also considered. The journal deals especially with the coupling between the different regions.
Solar flares, coronal mass ejections, and other energetic events on the Sun create interesting and important perturbations in the near-Earth space environment. The physics of such "space weather" is central to the Journal of Atmospheric and Solar-Terrestrial Physics and the journal welcomes papers that lead in the direction of a predictive understanding of the coupled system. Regarding the upper atmosphere, the subjects of aeronomy, geomagnetism and geoelectricity, auroral phenomena, radio wave propagation, and plasma instabilities, are examples within the broad field of solar-terrestrial physics which emphasise the energy exchange between the solar wind, the magnetospheric and ionospheric plasmas, and the neutral gas. In the lower atmosphere, topics covered range from mesoscale to global scale dynamics, to atmospheric electricity, lightning and its effects, and to anthropogenic changes.