Conditional distribution selection for SPEI-daily and its revealed meteorological drought characteristics in China from 1961 to 2017

摘要

Drought is one of the most complex natural disasters, while meteorological drought is the root cause of other types of drought. In this study, all meteorological drought events in China from 1961 to 2017 were calculated using the SPEI of the Julian calendar as a time step. The duration and intensity of meteorological drought events and the major meteorological factors that dominated their development were analyzed and discussed. Our study reveals that the normalized results of the log-logistic distribution almost subject to the standard normal dis- tribution; SPEI-daily can capture more detailed drought process than SPEI-month; The frequency of meteor- ological drought events in the eastern monsoon area of China is high, the duration is short, and the intensity of drought is weak, while the frequency of drought events the northwest arid region is low, the duration is long, and the intensity is strong; Trend of the drought events' frequency of China from 1961 to 2017 is consistent with the global trend; The dominant factors of drought events by Sobol's global sensitivity analysis revealed that the frequency of drought events dominated by PET in the northwest arid region and southern China decreased from 1961 to 1980, and began to increase after 1990; The characteristics of the changes in China's meteorological drought events that we reveal can not only provide reference for disaster prevention and mitigation, but also provide insights for China to adapt to global climate change.