Seminar by Prof. Hyungjun Kim from KAIST
24 October 2024
KST 10:30 – 11:30
The Seminar is being held in Room 1010 (Jasmin) – Integrated mechanical engineering building. Click here for the campus map.
Compound extreme events refer to the simultaneous occurrence of two or more extreme weather phenomena, such as superimposed drought, heatwave, and fire. These events often cause more significant impacts on human society and natural ecosystems than individual extremes. However, consecutive type of compound extreme events occurring in succession have received comparatively less attention.
In this study, we provide a global perspective on the changes in consecutive wet and dry spells to indicate hydroclimatic intensity. Using large ensemble climate simulations, we find that the intensification of consecutive extreme events is projected to increase significantly worldwide in warmer futures. Notably, extreme intensification could be up to 10 times stronger than average intensification, indicating the potential for dramatic shifts between flood and drought conditions. Additionally, the response to varying levels of warming is non-linear, and the acceleration of intensification differ markedly across regions.
In particular, we observe a rapid shift in East Asia (EA) over recent decades, closely tied to the intensification of the region’s summer monsoon system. This shift is linked to the strengthening of the western North Pacific subtropical high (WNPSH) and increased water vapor convergence, which leads to stationary frontal rainfall over coastal EA during the wet season (mid-June to mid-July). In contrast, during the subsequent season, the development of the WNPSH increases the frequency of hot extremes. This suggests that consecutive wet and hot extreme events are closely connected, driven by a shared regional climate mechanism.
Furthermore, our findings demonstrate that these observed changes in compound extremes are attributable to anthropogenic global warming. As a result, the amplification of wet-hot swings in the coming decades appears to be an unavoidable consequence, particularly in coastal EA regions.