Analyzing the impact of different forms of precipitation (rain and snow) on drought

ABSTRACT Precipitation is a key driving factor of drought. This study used the gridded dataset of different forms of precipitation (snow, sleet, and rain) and terrestrial hydrological dataset, with the study period from 1961 to 2015. The standardized precipitation index (SPI) and the standardized runoff index (SRI) were employed to monitor meteorological drought and hydrological drought, respectively. The SPI calculated based on rainfall, precipitation, and snowfall was defined as SPIr, SPIp, and SPIs, respectively. Run theory was used to identify drought events. The drought propagation time and degree were estimated based on the maximum Pearson correlation coefficient method. The results showed that (1) the annual snowfall amounts were higher in the Qinghai–Tibetan Plateau (QTP) and the temperate humid and sub-humid northeast China (THSN). The Southeast Basin and Pearl River Basin showed a higher runoff amount and an increasing trend. (2) The meteorological drought events of rainfall presented obviously higher severity and duration than the precipitation in northern China and QTP. The hydrological drought event exhibited relatively high severity and duration in THSN and QTP. (3) The propagation degree and time of SPIr–SRI were higher than those of SPIp–SRI in northeastern China and QTP.