Spatial-temporal characteristics and driving forces of drought in the Pearl River Basin

Drought is one of the most destructive natural disasters, which can seriously affect the safety of people's lives and property. Taking the Pearl River Basin as an example, this study uses the standardized precipitation index (SPI) and standardized runoff index (SRI) to characterize meteorological and hydrological droughts respectively, evaluates the change characteristics of meteorological and hydrological droughts in the Pearl River Basin. And uses cross wavelet transformation to explore the impact of teleconnection factors on drought in the Pearl River Basin. The results show that the meteorological drought in most areas of the Pearl River Basin is decreasing, and the decreasing trend is significant in the western part of the river basin. The hydrological drought in most areas showed a decreasing trend, and the decreasing trend was significant in the eastern and western parts of the Pearl River Basin. From 1981 to 2019, the frequency of meteorological drought was 22~46 times, and the frequency of hydrological drought was 16~43 times, but the duration and severity of hydrological droughts are greater than those of meteorological droughts. The influence of El Nino-Southern Oscillation (ENSO) and Pacific interdecadal Oscillation (PDO) on meteorological and hydrological droughts in each sub-regions were mainly concentrated in 8~48 months and 8~32 months, while Sunspots had relatively little influence on meteorological and hydrological droughts in the Pearl River Basin. ENSO and PDO are the main driving forces for meteorological and hydrological droughts in the Pearl River Basin.