Author(s): Lilingjun Liu; Xiaosheng Qin

Linked Author(s): Xiaosheng Qin

Keywords: Compound hot droughts (CHD); Compound drought and hot extremes (CDHE); Copula analysis

Abstract: This study comprehensively investigates the extreme conditions of compound drought and hot extremes (CDHE, or CHD) that occurred in the summer of 2022 over Sichuan province with the utilization of copula analysis. The concurrence of compound events is analyzed over the last 60 years (1963-2022), with surface runoff and daily maximum temperature used as indicators to measure drought and hot extremes, respectively. The JRP (joint return period) and LMF (likelihood multiplication factor) are computed to measure the extreme conditions and correlation strength of CDHE, followed by the assessment of CDHE occurred in 2022 summer. The results show that the year 2022 is marked by its exceptionally high return period of hot extremes as well as the third largest return period of drought. The concurrence of these two extreme events collectively contribute to the unprecedented JRP of CDHE up to 538 years in 2022, which is significantly larger than the 86 years in 2006, which is the 2nd severe CDHE in the past 60 years. The increase of LMF of compound events in year 2022 over 5 different LULC types are analyzed. It is shown that compared with non-urban area, where the LMF increase by 1.4 times in 2022, the LMF over urban area experience a surge to 13.63, with a drastic increase of 10.3 times. This research provides a quantitative analysis of the severity and dynamics of compound climate extremes in Sichuan, highlighting the increasing risk, particularly in urban regions. It offers valuable insights for future risk assessment and planning to mitigate the impact of such climate events.

DOI: https://doi.org/10.3850/iahr-hic2483430201-119

Year: 2024