An intercomparison of empirical schemes for partitioning precipitation phase

Abstract

Study regionPrecipitation phase in China has changed with global warming, and accurate partitioning of the precipitation phase is crucial for understanding the hydrological processes and energy balance. Study focusBased on a 36-year daily meteorological dataset from the China Meteorological Administration, this study conducted a comprehensive evaluation of six empirical methods in estimating the precipitation phase nationwide and explored the applicability and distinction across different meteorological, topographic and geographic categories. These methods utilized inputs of air temperature, with two variants incorporating relative humidity, and encompassed a range of combined non-linear air temperature and hydrometeor temperature methods to more simple air temperature threshold methods. New hydrological insights for the regionMethods implementing non-linear functions without air temperature thresholds performed better than those relying solely on air temperature thresholds. The exponential functions with air temperature and relative humidity exhibited the best performance, while those relying only on air temperature thresholds exhibited the worst overall performance. Optimal methods were identified and recommended under different scenarios (i.e., multivariate meteorological and geographic parameters, different geographic regions). The rain–precipitation ratio exhibited a significant increasing trend, and the meteorological stations showing an increase were primarily concentrated in the three major snow-covered areas, the west and vicinity of the “Hu Huanyong Line”. This study can be applied to other regions and offers valuable insights for analyzing precipitation data and developing hydrological models.