ABSTRACT

This study assesses bias error of rainfall from climate models and related error propagation effects to simulated streamflow in the Gidabo sub-basin, Ethiopia. Rainfall is obtained from a combination of four global and regional climate models (GCM-RCMs), and streamflow is simulated by means of the Hydrologiska Byråns Vattenbalansavdelning (HBV-96) rainfall-runoff model. Five bias correction methods were tested to reduce the rainfall bias. To assess the effects of rainfall bias error propagation, percent bias (PBIAS), difference in coefficient of variation (CV), and 10th and 90th percentile indicators were applied. Findings indicate that the bias of the uncorrected rainfall caused large errors in simulated streamflow. All five bias correction methods improved the HBV-96 model performance in terms of capturing the observed streamflow. Overall, the findings of this study indicate that the magnitude of the error propagation varies subject to the selected performance indicator, bias correction method and climate model.

摘要

本研究评估了来自气候模型的降雨偏差误差以及相关误差传播对埃塞俄比亚吉达博次流域模拟水流的影响。降雨是从四个全球和区域气候模型 (GCM-RCM) 的组合中获得的，而水流是通过 Hydrologiska Byråns Vattenbalansavdelning (HBV-96) 降雨径流模型模拟的。测试了五种偏差校正方法以减少降雨偏差。为了评估降雨偏差误差传播的影响，应用了百分比偏差 (PBIAS)、变异系数差异 (CV) 以及第 10 和第 90 个百分位数指标。研究结果表明，未校正降雨的偏差导致模拟水流出现较大误差。所有五种偏差校正方法在捕获观察到的流量方面都提高了 HBV-96 模型的性能。全面的，