Work

Multiscale drivers of catastrophic heavy rainfall event in early August 2022 in South Korea

Year: 2024

Type: article

Abstract: On 8–11 August 2022, South Korea experienced a catastrophic heavy rainfall event (HRE) with 14 fatalities. To elucidate its driving mechanisms, the present study performs a multiscale analysis by hierarchically delineating the synoptic and large-scale characteristics of the HRE. Its synoptic condition was featured by the confrontation of the western North Pacific subtropical high and the continental cyclone in the north of the Korean Peninsula. At their interface, a tremendous amount of moisture was transported in an elongated shape (i.e., atmospheric river) along with strong frontogenetic activity. This provided a favorable environment for local convective instability. The continental cyclone maintained throughout the HRE period although a transient cyclone was also superposed in the early stage of the HRE. A persistent cyclonic circulation in the north of the Korean Peninsula was originated from a far-upstream-originated cutoff low that became a part of the quasi-stationary wave train along the Asian subtropical jet. The stagnation of the cutoff low sustained the low-level continental cyclone via non-local potential vorticity forcing, facilitating its prolonged confrontation with the western North Pacific subtropical high. A linear model experiment confirms that the quasi-stationary Rossby wave was excited by the enhanced tropical convection associated with the boreal summer intraseasonal oscillation. The anomalously strong subtropical jet is also found to have acted as an effective waveguide. It is suggested that the integration of multiscale processes is essential to understand this unprecedented HRE.

Source: Weather and Climate Extremes

DOI: 10.1016/j.wace.2024.100681

Authors: Chanil Park, Min-Jee Kang, Jaeyoung Hwang, Hyeong-Oh Cho, Sujin Kim, Seok-Woo Son

Institutions: Boston College, Seoul National University

Language: English

Topic: Meteorological Phenomena and Simulations

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,030