The hourly precipitation intensity and frequency in the Yarlung Zangbo river basin in China during last decade

Abstract

The analysis of precipitation intensity and frequency should be conducted on data with high temporal resolution, such as hourly precipitation data. This study focuses on the spatial distribution and temporal variation of precipitation intensity and frequency in the Yarlung Zangbo River basin during 2008–2017, based on a merged hourly precipitation dataset with 0.1° of latitude/longitude spatial resolution. The hourly precipitation intensity is represented as the mean accumulated amount in each observation hour and the precipitation frequency is the proportion of precipitation hours in this study. The multi-year mean values and temporal changes of precipitation intensity and frequency are compared at annual time scale, during the warm season (from May to October) and cold season (from November to the next April), as well as among the upper, middle and lower basins. For the whole stream region, the mean hourly precipitation intensity is 0.92 mm/h during the warm season, larger than 0.69 mm/h during the cold season. The mean precipitation frequency is about 7.79% during the warm season, larger than 4.40% during the cold season. For the sub-region, the mean hourly precipitation intensity and frequency are largest for the lower basin during the warm season (1.10 mm/h and 10.62%), whereas largest for the upper basin during the cold season (0.86 mm/h and 4.26%). The hourly precipitation intensity increases during the warm season but decreases during the cold season. The precipitation frequency continuously decreases with larger tendency during the warm season than that during the cold season.