Drought propagation in karst and non-karst regions in Southwest China compared on a daily scale

Abstract

Study region: Three subbasins with different karstification degrees in Southwest China. Study focus: To investigate the mechanism of karst influence on drought propagation, this paper used a daily-scale threshold level method to identify drought events and comparatively analyzed the differences in drought propagation characteristics among three subbasins. New hydrological insights for the region: (i) The karstification degree is appreciably correlated with the drought propagation from meteorological to hydrological droughts, and the stronger the karstification, the closer the relationship. (ii) Daily-scale drought events performed better in identifying drought characteristics; of all drought events, 55% were meteorological and 24% were hydrological and lasted < 31 d. (iii) 44.7–50% of meteorological droughts developed into hydrological droughts in karst basins, much more than 25% in the non-karst basin, and the proportion of hydrological droughts triggered by meteorological droughts is 63.6% and 68.2% in karst basins, much more than the 27.6% observed in the non-karst basin. This study will help to understand the influence of karst on drought propagation, provide effective information, and improve early warning and forecasting of hydrological drought in Southwest China.

Keywords

• Karst region
• Drought propagation
• Meteorological drought
• Hydrological drought
• Threshold level method
• Southwest China