Assessment of Extremes in Global Precipitation Products: How Reliable Are They?
Assessment of Extremes in Global Precipitation Products: How Reliable Are They?
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DOI：
10.1175/jhm-d-20-0040.1
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发表时间：
2020-10
影响因子：
3.8
通讯作者：
C. R. Rajulapati;S. Papalexiou;M. Clark;S. Razavi;G. Tang;J. Pomeroy
中科院分区：
文献类型：
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作者：
C. R. Rajulapati;S. Papalexiou;M. Clark;S. Razavi;G. Tang;J. Pomeroy
事实证明，全球网格降水产品对于从水文建模和气候模型验证到自然灾害风险评估等许多应用至关重要。它们提供了降水量如何随时间和空间变化的全球图景，特别是在地面观测稀缺的地区。虽然全球降水产品的应用已经广泛，但人们对这些产品如何准确地反映极端降水的强度和频率（引发洪水灾害的关键特征）的了解有限。此处，对五个全球降水数据集（MSWEP、CFSR、CPC、PERSIANN-CDR 和 WFDEI）进行相互比较以及与地面观测结果的比较。对 1979-2017 年期间相对较高的降水事件（尾重）的空间变异性以及由此产生的预测降水回归水平数据集之间的差异进行了评估。分析表明：1) 这些产品不能一致地表示通过尾部重量量化的极端行为，2) 尾部指数存在很强的空间变异性，3) 尾部重量的空间模式通常与柯本-盖革气候分类相匹配，4) 网格产品之间 100 年和 1000 年的预测回报水平存在显着差异。更一般地说，我们的研究结果揭示了全球降水产品在代表极端情况方面的缺点，并强调没有单一的全球产品能够在所有地区和气候下表现最佳。
Global gridded precipitation products have proven essential for many applications ranging from hydrological modeling and climate model validation to natural hazard risk assessment. They provide a global picture of how precipitation varies across time and space, specifically in regions where ground-based observations are scarce. While the application of global precipitation products has become widespread, there is limited knowledge on how well these products represent the magnitude and frequency of extreme precipitation—the key features in triggering flood hazards. Here, five global precipitation datasets (MSWEP, CFSR, CPC, PERSIANN-CDR, and WFDEI) are compared to each other and to surface observations. The spatial variability of relatively high precipitation events (tail heaviness) and the resulting discrepancy among datasets in the predicted precipitation return levels were evaluated for the time period 1979–2017. The analysis shows that 1) these products do not provide a consistent representation of the behavior of extremes as quantified by the tail heaviness, 2) there is strong spatial variability in the tail index, 3) the spatial patterns of the tail heaviness generally match the Köppen–Geiger climate classification, and 4) the predicted return levels for 100 and 1000 years differ significantly among the gridded products. More generally, our findings reveal shortcomings of global precipitation products in representing extremes and highlight that there is no single global product that performs best for all regions and climates.