Despite its importance for hydrology and water resources, accurate estimation of snowfall rate over snow-covered regions has remained a major observational challenge from both in-situ and remote sensing instruments. Snowfall accumulation can be measured by either accumulating snowfall estimates or measuring snowpack properties such as Snow Water Equivalent (SWE) and mass. By focusing on snowfall over snow accumulation period and using case studies and long-term average (2003 to 2015) over CONUS, this study compares snowfall accumulation from gauge stations (using GPCC and PRISM products), satellite products (GPCP and the suite of IMERG products), and reanalysis (ERA-interim, ERA5, and MERRA-2). Changes in SWE based on the recent UA-SWE product together with mass change observation from GRACE were used for assessment of precipitation products. We also investigated two popular gauge undercatch correction factors (CFs) used to mitigate precipitation undercatch in GPCC and GPCP. The results show that snow accumulation from most of the products is bounded by GPCC with and without correction, highlighting the critical importance of selecting proper CFs for gauge-undercatch correction. The CF based on Legates and Willmott method was found to be more consistent with the SWE-based analysis than CF based on the Fuchs method. Reanalysis show very similar spatial pattern among themselves, but represent large variation in simulating snow accumulation, with ERA-interim showing the least accumulation and MERRA-2 showing the highest accumulation and closest to the snow accumulation suggested by SWE.

中文翻译：

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来自不同数据集的降雪累积和量规不足校正因子的比较分析：原位，卫星和再分析

尽管它对水文学和水资源具有重要意义，但对冰雪覆盖地区的降雪率进行准确估算仍然是现场和遥感仪器面临的主要观测挑战。可以通过累积降雪估计值或测量积雪的属性（例如雪水当量（SWE）和质量）来测量降雪累积。通过集中研究积雪时期的降雪，并使用案例研究和CONUS的长期平均值（2003年至2015年），本研究比较了标准站（使用GPCC和PRISM产品），卫星产品（GPCP和IMERG套件）的降雪量产品）和重新分析（ERA-临时，ERA5和MERRA-2）。基于最近的UA-SWE产品的SWE变化以及GRACE的质量变化观测值被用于评估降水产品。我们还研究了两种常用的量规下雨量校正因子（CF），它们可用于缓解GPCC和GPCP中的降水量不足。结果表明，大多数产品的积雪受GPCC约束（有和没有进行校正），这突出显示了选择适当的CFs进行量表欠捕校正的至关重要。发现基于Legates和Willmott方法的CF与基于SWE的分析比基于Fuchs方法的CF更一致。重新分析显示出彼此之间非常相似的空间格局，但是在模拟积雪方面表现出很大的差异，其中ERA中期显示的积雪最少，而MERRA-2显示的积雪最高，最接近SWE建议的积雪。