Dynamics and potential synchronization of regional precipitation concentration and drought-flood abrupt alternation under the influence of reservoir climate

Abstract

Study region: Three Gorges Reservoir area, the largest reservoir area in China Study focus: The frequency and intensity of extreme weather events increase with climate warming, and the local climate effects in the large reservoir area may also change the local precipitation structure. Therefore, based on the precipitation sequence data in the Three Gorges Reservoir (TGR) area from 1959 to 2019, the proposed multi-time-scale mutual information entropy (MTSMIE) method was used to reveal the cyclic synchronous changes of drought-flood abrupt alternation and precipitation concentration. New hydrological insights: The results demonstrate that (1) the spatial distribution of the precipitation concentration index in the TGR area has obvious regional variability. On the temporal scale, the precipitation concentration increased by 5.5% and decreased by 8.2% after impoundment at the head and tail of the TGR, respectively. (2) The frequency of drought-to-flood (DTF) events from the head of the reservoir area to the tail of the reservoir area presents a ''more-less'' feature. The frequency of DTF events after impoundment was less than that before the impoundment of the reservoir. However, the flood-to-drought (FTD) events are the opposite. (3) The period of reliable research and monitoring of DFAA and precipitation concentration in the Three Gorges region is about 15–17 years through the MTSMIE method.

Keywords

• Precipitation concentration
• Spatiotemporal distribution
• Drought-flood abrupt alternation
• MTSMIE
• Three Gorges Reservoir