Uncertainty in climate change impacts on river discharge in the Upper Awash Basin, Ethiopia, is assessed using five MIKE SHE hydrological models, six CMIP5 general circulation models (GCMs) and two representative concentration pathways (RCP) scenarios for the period 2071–2100. Hydrological models vary in their spatial distribution and process representations of unsaturated and saturated zones. Very good performance is achieved for 1975–1999 (NSE: 0.65–0.8; r: 0.79–0.93). GCM-related uncertainty dominates variability in projections of high and mean discharges (mean: –34% to +55% for RCP4.5, –42% to +195% for RCP8.5). Although GCMs dominate uncertainty in projected low flows, inter-hydrological model uncertainty is considerable (RCP4.5: –60% to +228%, RCP8.5: –86% to +337%). Analysis of variance uncertainty attribution reveals that GCM-related uncertainty occupies, on average, 68% of total uncertainty for median and high flows and hydrological models no more than 1%. For low flows, hydrological model uncertainty occupies, on average, 18% of total uncertainty; GCM-related uncertainty remains substantial (average: 28%).

在2071–2100年期间，使用五个MIKE SHE水文模型，六个CMIP5普通环流模型（GCM）和两个代表性的集中路径（RCP）情景，评估了埃塞俄比亚上阿瓦斯盆地的气候变化影响的不确定性。水文模型的空间分布和非饱和区和饱和区的过程表示各不相同。在1975-1999年期间取得了非常好的表现（NSE：0.65-0.8；r：0.79–0.93）。GCM相关的不确定性在高流量和平均流量的预测中占主导地位（平均值：RCP4.5为–34％至+ 55％，RCP8.5为–42％至+ 195％）。尽管在预估的低流量中，GCM占主导地位，但水文模型间的不确定性相当可观（RCP4.5：–60％至+ 228％，RCP8.5：–86％至+ 337％）。方差不确定性归因分析表明，与GCM相关的不确定性平均占中，高流量的总不确定性的68％，而水文模型的不超过1％。对于低流量，水文模型的不确定性平均占总不确定性的18％。与GCM相关的不确定性仍然很大（平均：28％）。