CAO Yongqiang, LU Jie, LI Linghui

In recent years, Liaoning Province has deeply been affected by drought and flood disasters. It is of great significance to make clear the spatiotemporal evolution characteristics for the disaster prevention and mitigation strategies. The evolution and persistence characteristics of drought and flood in Liaoning Province in recent 30 years were analyzed, and their influencing factors were explored by using Mann Kendall mutation test, linear tendency rate and path analysis based on the daily meteorological data of 23 meteorological stations in Liaoning Province from 1989 to 2018, in which the standardized precipitation evapotranspiration index (SPEI) of different time scales was calculated. The results show that: (1) Liaoning Province has experienced the evolution process of waterlogging, drought and waterlogging in recent 30 years. The drought in western Liaoning is significant, and the trend of waterlogging is the most significant in central and Northern Liaoning, followed by Eastern Liaoning where precipitation is the most abundant. (2) The period of 1999-2008 is the typical drought period, and 2009-2018 is the partial flood period from the frequency of moderate and above drought and flood disasters. The frequency of drought and flood events is spring > winter > autumn > summer. (3) The intensity of persistent drought events decreases,which mainly occurred in spring. The continuous flood events show an increasing trend, which mainly occurred in spring and summer. (4) Precipitation is the main factor affecting the change of drought and flood, followed by evapotranspiration. The temperature affects the change of drought and flood by affecting precipitation and evapotranspiration.

Keywords: SPEI index, drought and flood, persistence, Liaoning Province