The study assesses the performance of 24 model runs from five COordinated Regional climate Downscaling Experiment (CORDEX) regional climate models (RCMs) in simulating East Africa’s spatio-temporal precipitation characteristics using a set of eight descriptors: consecutive dry days (CDD), consecutive wet days (CWD), simple precipitation intensity index (SDII), mean daily annual (pr_ANN), seasonal (pr_MAM and pr_OND) precipitation, and representatives of heavy precipitation (90p) and very intense precipitation (99p) events. Relatively better performing RCM runs are then used to assess projected precipitation changes (for the period 2071–2099 relative to 1977–2005) over the study domain under the representative concentration pathway (RCP) 8.5 scenario. The performance of RCMs is found to be descriptor and scope specific. Overall, RCA4 (r1i1p1) forced by CNRM-CERFACS-CNRM-CM5 and MPI-M-MPI-ESM-LR, REMO2009 (r1i1p1) forced by MPI-M-MPI-ESM-LR, and RCA4 (r2i1p1) forced by MPI-M-MPI-ESM-LR emerge as the top four RCM runs. We show that an ensemble mean of the top four model runs outperforms an ensemble mean of 24 model simulations and ensemble means for all runs in an RCM. Our analysis of projections shows a reduction (increase) in mean daily precipitation for MAM(OND), an increase(decrease) in CDD(CWD) events, and a general increase in SDII and the width of the right tail of the precipitation distribution (99p–90p). An increase in SDII and 99p–90p implies a possibility of occurrence of heavy and extreme precipitation incidences by the end of the twenty-first century. Our findings provide important information to support the region’s climate change adaptation and mitigation efforts.

这项研究评估了来自五个协调区域气候降尺度实验（CORDEX）区域气候模型（RCM）的24个模型运行在模拟东非时空降水特征方面的性能，使用了八个描述符：连续干旱天（CDD），连续湿润天数（CWD），简单降水强度指数（SDII），年平均日降水量（pr_ANN），季节性（pr_MAM和pr_OND）降水，以及代表强降水（90p）和非常强降水（99p）的事件。然后，在代表性浓度路径（RCP）8.5情景下，相对较好的RCM运行用于评估研究范围内预计的降水变化（相对于1977-2005，为2071-2099年）。发现RCM的性能取决于描述符和范围。总体，由CNRM-CERFACS-CNRM-CM5和MPI-M-MPI-ESM-LR强制的RCA4（r1i1p1），由MPI-M-MPI-ESM-LR强制的REMO2009（r1i1p1）和由MPI-M强制的RCA4（r2i1p1） -MPI-ESM-LR出现在前四名RCM中。我们显示，在RCM中，前四个模型运行的整体均值优于24个模型仿真的整体均值和整体均值。我们对预测的分析表明，MAM（OND）的日平均降水量减少（增加），CDD（CWD）事件增加（减少），SDII和降水分布的右尾宽度普遍增加（ 99p–90p）。SDII和99p-90p的增加意味着到二十一世纪末可能出现强降雨和极端降雨。