Investigating the Characteristics of Drought-Flood Abrupt Alternation Events Based on SWAP Index in South Korea

Abstract

In recent years, as the frequency of droughts and floods and extreme precipitation has increased, the alternation of droughts and floods in a short period of time has become more frequent. Drought-to-flood transition is a typical alternating phenomenon of drought and flood caused by abnormal seasonal rainfall. Due to the coexistence of drought and flood and rapid transition, drought-to-flood transition is often more harmful than a single drought or flood event. Based on the daily precipitation data of 228 meteorological stations in South Korea from 1973 to 2014, this study uses the standardized weighted average precipitation index (SWAP), combined with the travel theory, to propose a new method to identify sudden drought and flood events. The method is applied to investigate the occurrence and characteristics of the sudden turn of drought and flood in South Korea. From the perspectives of the change trend of the rapid turn of drought and flood and the analysis of the temporal and spatial distribution of the rapid turn of drought and flood in South Korea, the rapid turn of drought and flood in South Korea from 1973 to 2014 Event characteristics. The conclusions show that: (1) Principal component analysis and K-means cluster analysis can perfectly divide Korea into four major regions according to meteorological characteristics SWAP index has a good ability to identify drought and flood events. (2) The drought-flood abrupt alternation events in South Korea show obvious regional patterns: high-intensity drought and flood events are mainly concentrated in low-incidence areas, low-intensity drought and flood rapid events are mainly concentrated in high-incidence areas, and high-intensity events are mainly concentrated In the northern part of South Korea. (3) The frequency of drought-flood abrupt alternation events in Region A will increase in the future. The research results show that the method based on SWAP index combined with the run theory can more accurately identify the drought-flood abrupt alternation events, and can be further applied to the prediction and evaluation of drought-flood abrupt alternation events.