Evolution characteristics and relationship of meteorological and hydrological droughts from 1961 to 2018 in Hanjiang River Basin, China

Abstract

In the context of global warming and increasing human activities, the acceleration of the water cycle will increase the risk of basin drought. In this study, to analyze the spatial and temporal evolution characteristics of hydrological and meteorological droughts over the Hanjiang River Basin (HRB); the Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI) were selected and applied for the period 1961–2018. In addition, the cross-wavelet method was used to discuss the relationship between hydrological drought and meteorological droughts. The results and analysis indicated that: (1) the meteorological drought in the HRB showed a complex cyclical change trend of flood-drought-flood from 1961 to 2018. The basin drought began to intensify from 1990s and eased in 2010s. The characteristics of drought evolution in various regions are different based on scale. (2) During the past 58 years, the hydrological drought in the HRB has shown a significant trend of intensification, particularly in autumn season. Also, the hydrological droughts had occurred frequently since the 1990s, and there were also regional differences in the evolution characteristics of drought in various regions. (3) Reservoir operation reduces the frequency of extreme hydrological drought events. The effect of reducing the duration and intensity of hydrological drought events by releasing water from the reservoir is most obvious at Huangjiagang Station, which is the nearest to Danjiangkou Reservoir. (4) The hydrological drought and meteorological drought in the HRB have the strongest correlation on the yearly scale. After 1990, severe human activities and climate change are not only reduced the correlation between hydrological drought and meteorological drought in the middle and lower reaches of the basin, but also reduced the lag time between them. Among them, the hydrological drought in the upper reaches of the basin lags behind the meteorological drought by 1 month, and the hydrological drought in the middle and lower reaches of the basin has changed from 2 months before 1990 to 1 month lagging after 1990.

Possible Future Climate Change Impacts on the Meteorological and Hydrological Drought Characteristics in the Jinghe River Basin, China

“…The primary cause of meteorological drought is a lack of precipitation. When meteorological drought lasts for a certain time and reaches a certain severity where the precipitation is insufficient to allow the soil water content to reach saturation and produce surface runoff, this is defined as hydrological drought [10][11][12]. The standardized precipitation index (SPI) is recommended by the World Meteorological Organization (WMO).…”

Extreme historical droughts and floods in the Hanjiang River Basin, China, since 1426

“…On the other hand, drought and flood control as well as water supply in the basin are of great importance in national socioeconomic development and ecological restoration. As the water source area of the South-North Water Diversion Middle Line Project and a key river basin for flood control in the middle reaches of the Yangtze River, the Hanjiang River has a wide range of socioeconomic impacts in terms of precipitation as well as drought and flood variability Wang et al, 2021). Therefore, there is an urgent need for research on precipitation as well as drought and flood variability at multi-decadal to centennial scales in the HRB.…”