Abstract The present study assessed the accuracy of twenty-three available globally and regionally gridded precipitation products over Iran. The datasets were classified into five different categories based on the data sources used: gauge-only, gauge-satellite, gauge-reanalysis, reanalysis-only, and gauge-satellite-reanalysis. By considering monthly rain gauge observation data as reference, the above precipitation products were assessed based on a variety of metrics over the period 1979 to 2013. The results indicated that the time-series of the spatial averaged precipitation of all the products do reasonably well in tracking the month-to-month variations with the majority of the products underestimating precipitation amounts with respect to the reference rain gauge observations. Overall, the best performances were demonstrated by Asfazari and APHRODITE followed by CHIRPS and GPCC. WFDEI-CRU was the worst performer among the twenty-three gridded products in revealing precipitation tempo-spatial patterns. The results demonstrate the high performance for all products in the west of the country (the Zagros Range) and in all seasons except the summer. The results also indicate that there is a better agreement between rain gauge observations and the gridded products during the rainy seasons (winter, spring and autumn) compared to the dry season (summer). This study improved our knowledge of the suitability of different precipitation gridded product estimates to capture the temporal and spatial variability of precipitation. Furthermore, it is applicable for developing precipitation products and provides valuable guidance for selecting alternative precipitation products to in situ observations.

中文翻译：

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使用伊朗雨量计观测的网格降水数据集的统计评估

摘要 本研究评估了伊朗上空 23 种可用的全球和区域网格降水产品的准确性。根据所使用的数据源，将数据集分为五个不同的类别：仅轨距、轨距卫星、轨距再分析、仅再分析和轨距卫星再分析。以月雨量计观测数据为参考，对上述降水产品进行了1979-2013年的多种指标评估。结果表明，所有产品的空间平均降水时间序列表现较好。跟踪月度变化，大多数产品相对于参考雨量计观测值低估了降水量。全面的，表现最好的是 Asfazari 和 APHRODITE，其次是 CHIRPS 和 GPCC。WFDEI-CRU 在揭示降水时空模式的 23 个网格产品中表现最差。结果表明，该国西部（扎格罗斯山脉）和除夏季外的所有季节的所有产品都具有高性能。结果还表明，与旱季（夏季）相比，雨季（冬季、春季和秋季）的雨量计观测值与网格产品之间存在更好的一致性。这项研究提高了我们对不同降水网格产品估计值在捕捉降水时空变异性方面的适用性的认识。此外，