Climatology of seasonal snowfall accumulation across the Sierra Nevada (USA): Accumulation rates, distributions, and variability
Climatology of seasonal snowfall accumulation across the Sierra Nevada (USA): Accumulation rates, distributions, and variability
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DOI：
10.1002/2017wr020915
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发表时间：
2017-07-01
影响因子：
5.4
通讯作者：
Margulis, Steven A.
中科院分区：
文献类型：
--
作者：
Huning, Laurie S.;Margulis, Steven A.
关于高海拔山脉降雪量在空间和时间上如何变化的详细情况，仍然是理解山地水文循环的知识空白。以往的研究一般使用点尺度的积雪测量，试图代表整个范围内的降雪量的空间变异性，然而，这些传统的方法提供了不完整的洞察到累积降雪量（CS）分布从流域尺度到山脉尺度。在这项研究中，高分辨率，空间分布的雪再分析被用来表征31个冬天（水年1985-2015）的降雪分布，降雪累积率，和雪暴在整个内华达州（美国）。CS数据集（雪水当量单位量化）进行了验证，对超过2600站年的原位观测。季节性CS被发现有24和12厘米，分别为平均值和均方根差，和0.96与雪枕观测的相关性。使用这种新的CS信息，结果表明，CS积累迅速，在所有20个流域检查，平均至少有50%的综合CS积累在小于或等于6天或3个雪暴在每个盆地。每个季节最大的（或主要的）暴风雪平均产生近似于CS的27%，最常见的是持续4天。在整个范围内，超过40%的主要暴风雪发生在2月。这项研究表明，内华达州的水文气候学是由水文极端表现在其季节性综合CS的高年际变化，4.4-41.3 km（3），在31年。
A detailed picture of how snowfall varies across high-elevation mountain ranges in both space and time remains a knowledge gap in understanding the montane hydrologic cycle. Previous studies generally used point-scale snow measurements in an attempt to represent the spatial variability of snowfall across a range; however, these traditional approaches provide incomplete insight into the cumulative snowfall (CS) distribution from the basin-scale to the mountain range-scale. In this study, a high-resolution, spatially distributed snow reanalysis was utilized to characterize 31 winters (water years 1985-2015) of snowfall distributions, snowfall accumulation rates, and snowstorms across the Sierra Nevada (USA). The CS data set (quantified in units of snow water equivalent) was verified against over 2600 station years of in situ observations. The seasonal CS was found to have mean and root-mean-squared differences of 24 and 12 cm, respectively, and a correlation of 0.96 with snow pillow observations. Using this novel CS information, results indicated that the CS accumulates rapidly across all 20 basins examined with, on average, at least 50% of the integrated CS accumulating in less than or equal to 6 days or three snowstorms over each basin. The largest (or leading) snowstorms each season yield similar to 27% of the CS, on average, and most frequently last 4 days. Across the range, over 40% of the leading snowstorms occur in February. This study showed that the hydroclimatology of the Sierra Nevada is driven by hydrological extremes as manifested in the high interannual variability of its seasonally integrated CS, 4.4-41.3 km(3), during the 31 years.