Abstract. Precipitation is a crucial driver of hydrological processes. Ironically, reliable characterization of its spatiotemporal variability is challenging. Ground-based rainfall measurements using rain gauges can be more accurate. However, installing a dense gauging network to capture rainfall variability can be impractical. Satellite-based rainfall estimates (SREs) can be good alternatives, especially for data-scarce basins like in Ethiopia. However, SREs rainfall is plagued with uncertainties arising from many sources. The objective of this study was to evaluate the performance of the latest versions of several SREs products (i.e., CHIRPS2, IMERG6, TAMSAT3, and 3B42/3) for the Dhidhessa River Basin (DRB). Both statistical and hydrologic modelling approaches were used for performance evaluation. The Soil and Water Analysis Tool (SWAT) was used for hydrological simulations. The results showed that whereas all four SREs products are promising to estimate and detect rainfall for the DRB, the CHIRPS2 dataset performed the best at annual, seasonal, and monthly timescales. The hydrologic simulation-based evaluation showed that SWAT's calibration results are sensitive to the rainfall dataset. The hydrologic response of the basin is found to be dominated by the subsurface processes, primarily by the groundwater flux. Overall, the study showed that both CHIRPS2 and IMERG6 products can be reliable rainfall data sources for hydrologic analysis of the Dhidhessa River Basin.

中文翻译：

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埃塞俄比亚Dhidhessa流域（DRB）的多种卫星降雨产品的性能评估

摘要。降水是水文过程的关键驱动力。具有讽刺意味的是，其时空变异性的可靠表征具有挑战性。使用雨量计的基于地面的降雨量测量可以更加准确。但是，安装密集的测量网络以捕获降雨的变化可能是不切实际的。基于卫星的降雨量估算（SRE）可能是不错的选择，尤其是对于埃塞俄比亚等数据匮乏的盆地。但是，SRE的降雨受许多来源带来的不确定性困扰。这项研究的目的是评估Dhidhessa流域（DRB）的几种SRE产品（即CHIRPS2，IMERG6，TAMSAT3和3B42 / 3）的最新性能。统计和水文建模方法都用于绩效评估。土壤和水分析工具（SWAT）用于水文模拟。结果表明，尽管所有四种SRE产品都有望评估和检测DRB的降雨，但CHIRPS2数据集在年度，季节性和每月时间尺度上表现最佳。基于水文模拟的评估表明，SWAT的校准结果对降雨数据集很敏感。发现盆地的水文响应主要由地下过程决定，主要由地下水流量决定。总体而言，研究表明，CHIRPS2和IMERG6产品均可作为可靠的降雨数据来源，用于对Dhidhessa流域进行水文分析。CHIRPS2数据集在年度，季节和月度时间尺度上表现最佳。基于水文模拟的评估表明，SWAT的校准结果对降雨数据集很敏感。发现盆地的水文响应主要由地下过程决定，主要由地下水流量决定。总体而言，研究表明，CHIRPS2和IMERG6产品均可作为可靠的降雨数据来源，用于对Dhidhessa流域进行水文分析。CHIRPS2数据集在年度，季节和月度时间尺度上表现最佳。基于水文模拟的评估表明，SWAT的校准结果对降雨数据集很敏感。发现盆地的水文响应主要由地下过程决定，主要由地下水流量决定。总体而言，研究表明，CHIRPS2和IMERG6产品均可作为可靠的降雨数据来源，用于对Dhidhessa流域进行水文分析。