On distinguishing snowfall from rainfall using near‐surface atmospheric information: C omparative analysis, uncertainties and hydrologic importance

作者：Ali Behrangi, Xungang Yin, S. Rajagopal, Dimitrios Stampoulis, Hengchun Ye · 发表于：Quarterly Journal of the Royal Meteorological Society · 年份：2018 · DOI：10.1002/qj.3240 · 被引用次数：67 · 研究领域：Precipitation Measurement and Analysis、Hydrology and Watershed Management Studies、Cryospheric studies and observations

The accurate estimation of precipitation phase has broad applications. In this study, we compared the skill of using various atmospheric variables and their combinations as predictors in accurately identifying surface precipitation phase, determined uncertainties associated with commonly used fixed temperature thresholds, and explored the sensitivity of hydrologic model output to uncertainty in precipitation phase using two case‐studies. The results suggest that among all single predictors, wet‐bulb temperature yields the highest skill score for determining precipitation phase and can reduce uncertainties due to regional differences, especially compared to the commonly used near‐surface air temperature. However, addition of good‐quality near‐surface wind speed measurement to dew‐point temperature and pressure showed slightly higher skill than wet‐bulb temperature. We showed that the scale mismatch between temperature from stations and gridded products can cause large uncertainties in determining precipitation phase, especially in regions with rugged topography. Such uncertainties need to be considered when the relationships developed based on station data are applied to remote‐sensing observations and model‐generated data to separate rain from snowfall. The sensitivity of hydrologic model outputs to uncertainty in precipitation phase delineation was also assessed over two major basins in California by modifying default near‐surface temperatures used in the Variable Infiltrati...