Drought-flood abrupt alteration events over China

Area of Science:

• Climatology
• Environmental Science
• Meteorology

Background:

• Drought-flood abrupt alternation (DFAA) poses significant risks to ecosystems and socioeconomic stability.
• Existing research on DFAA primarily uses monthly and regional scales, limiting detailed analysis.
• Understanding DFAA dynamics is crucial for developing effective climate adaptation strategies.

Purpose of the Study:

• To develop and apply a novel multi-indicator, daily-scale method for identifying DFAA events.
• To investigate the spatiotemporal characteristics and trends of DFAA events in China from 1961 to 2018.
• To explore potential driving mechanisms behind DFAA events.

Main Methods:

• Development of a multi-indicator approach for daily DFAA event identification.
• Analysis of DFAA occurrence and spatial coverage across China using historical data (1961-2018).
• Statistical trend analysis to assess changes in DFAA spatial coverage over time.

Main Results:

• DFAA events predominantly occurred in central and southeastern China, including major river basins.
• A statistically significant increasing trend in DFAA spatial coverage was observed across China (0.355%/decade).
• DFAA occurrence and spatial extent have increased decade by decade, with a strong seasonal concentration in summer (approx. 85%).

Conclusions:

• The new daily-scale method provides a more precise tool for DFAA event identification.
• Observed increases in DFAA events and spatial coverage highlight a growing climate risk in China.
• Global warming, atmospheric circulation anomalies, and soil properties are likely contributors to DFAA events.